A variety of perfluorocycloalkenyl (PFCA) arylether monomers and polymers with enchained triarylamineunits were successfully synthesized, characterized andreported here. These polymers are highly thermally stableand show variable thermal properties. Successful conver-sion of the newly synthesized TAA enchained perfluoro-cyclopentenyl (PFCP) aryl ether polymers via formylationand EAS demonstrates the synthetic versatility of TAAmoiety and provides an excellent option for applicationspecific post polymerization reactions. The cross-linkingbehavior of PFCP aryl ether polymers was studied underdifferent reaction conditions. The combination of pro-cessability, thermal stabilities, and tailorability makes thesepolymers suitable for a wide variety of applicationsincluding electro-optics, proton exchange membranes andsuper-hydrophobic applications.
A variety of perfluorocycloalkenyl (PFCA) aryl ether monomers and polymers with enchained triarylamine units were successfully synthesized, characterized and reported here. These polymers are highly thermally stable and show variable thermal properties. Successful conver- sion of the newly synthesized TAA enchained perfluoro- cyclopentenyl (PFCP) aryl ether polymers via formylation and EAS demonstrates the synthetic versatility of TAA moiety and provides an excellent option for application specific post polymerization reactions. The cross-linking behavior of PFCP aryl ether polymers was studied under different reaction conditions. The combination of pro- cessability, thermal stabilities, and tailorability makes these polymers suitable for a wide variety of applications including electro-optics, proton exchange membranes and super-hydrophobic applications.
Investigation of spatial configuration of Polypropylene and the influence of ...IOSR Journals
Abstract: Polypropylene is considered as one of the most important plastic types because of its substantial
supreme properties such as high melting temperature, good chemical resistance and desirable mechanical
properties, and achieving desired properties of Polypropylene is a significant activity, besides, gaining this
properties is the most important economical factor in reactor polymerization which gives a considerable curve
for performance cost polypropylene. In this paper, polypropylene properties, finding physical factor_ the form,
and other factors such as molecular weight _ the type of used catalyst and molecular mass which would be
expanded to properties of final polypropylene application, are all described. The state of mechanical changes
_thermal and photic changes of polymer which are closely dependant to foresaid factors_ is also discussed in
present paper, and this indicates the path toward achieving desired quality. Keyword: Polypropylene ¸ Stereo specificity Stereochemistry ،Ziegler-Natta catalysts، Atacticity
synthesis and spectral studies on cardanol based polyurethanesINFOGAIN PUBLICATION
Cardanol is a renewable organic resource obtained as a byproduct from the cashew industry. The present study has been carried out with an aim to manufacture rigid polyurethanes from natural and eco – friendly sources due to the rising prices of petrochemicals and also as an environmental concern. Vegetable oil based polyurethanes promising a new generation polymers which are low cost materials in the family of polyurethanes. Cardanol based phenolic resin has been synthesized by condensing cardanol with furfural in a particular mole ratio using phthalic acid as catalyst. The progress of the reaction was monitored by determining the free furfural and free phenol content. The resin was cured by using the curing agent 4, 41 - methylene bis(cyclohexyl isocyanate) and the catalyst dibutyltin dilaurate to produce polyurethane. Polyurethanes are an important class of polymers that have found place in many applications. The physico chemical and spectral properties of resin and polyurethane have also been studied.
This study aimed to investigate the polymerisation process of Merbau extractives (ME) and the characteristics of the phenolic resin polymers made from ME. These polymerised ME (PME) can potentially be utilised as an impregnating material to enhance the wood properties of young plantation timber. Selected PME were characterised via Fourier transform
infrared (FTIR) spectroscopy, differential scanning calorimetry, thermogravimetric analysis, Xray diffraction analysis, and ultraviolet-visible analysis. The prediction of the enhancement to
the wood properties when treated with the obtained PME was discussed in relation to the physico-chemical and thermal characteristics of the polymeric materials. The results showed that the ME can be polymerised in its base condition with formaldehyde and resorcinol as the copolymer to produce the PME. The resin was classified as a resole and polymerisation can be done at room temperature. The physico-chemical tests and analyses, via boiling tests and FTIR spectra confirmed that the polymeric compound is a promising impregnating material that can enhance wood properties. This polymeric material is also eco-friendly as the low level of free formaldehyde.
1. POLYMER by RAVI GOYANI. M.S(pharma) pharmaceutics, NIPER. Raebareli(U.P)
2. Contents of the presentation: Introduction, Classification, Properties of polymer,Characteristics of ideal polymer,Advantages of polymer,Applications of polymer.
3. Introduction of general terminology about the polymer like homopolymer, copolymer and monomer.
4. Figure representation of different monomer which combine to form polymer.
5. Introduction about the copolymer and how its form by one or more monomer.
6. Classification of the polymer on the bases of source, degradability, structure, properties, nature of the polymer and polymerization process.
7.8.9.10.11.12 Example of the polymer according to the class of that polymer.
13. Characteristics of ideal polymer like Should be inert and compatible with environments, Should be nontoxic, Should be easily administered, Should have good mechanical strength, Should be biodegradable, Should have biocompatible.
14. Properties of polymer.
15. Advantages of polymer in to the different area of pharmaceutics.
16. Application of the polymer like as binding agents, coating agents, thickening agents, disintegrants, and also in the formulation of hard and soft gelatin capsules.
17.18. Tables for the examples of different polymer and its specific application.
19. Application of the polymer in to the various drug delivery system in which extended, pulsatiles, controlled release drug delivery systems.
20.21 Other application of polymers in different formulation such as nanocrystals, gels, micro- spheres and also useful for the cancer study or complexation study.
22. List of references.
A variety of perfluorocycloalkenyl (PFCA) aryl ether monomers and polymers with enchained triarylamine units were successfully synthesized, characterized and reported here. These polymers are highly thermally stable and show variable thermal properties. Successful conver- sion of the newly synthesized TAA enchained perfluoro- cyclopentenyl (PFCP) aryl ether polymers via formylation and EAS demonstrates the synthetic versatility of TAA moiety and provides an excellent option for application specific post polymerization reactions. The cross-linking behavior of PFCP aryl ether polymers was studied under different reaction conditions. The combination of pro- cessability, thermal stabilities, and tailorability makes these polymers suitable for a wide variety of applications including electro-optics, proton exchange membranes and super-hydrophobic applications.
Investigation of spatial configuration of Polypropylene and the influence of ...IOSR Journals
Abstract: Polypropylene is considered as one of the most important plastic types because of its substantial
supreme properties such as high melting temperature, good chemical resistance and desirable mechanical
properties, and achieving desired properties of Polypropylene is a significant activity, besides, gaining this
properties is the most important economical factor in reactor polymerization which gives a considerable curve
for performance cost polypropylene. In this paper, polypropylene properties, finding physical factor_ the form,
and other factors such as molecular weight _ the type of used catalyst and molecular mass which would be
expanded to properties of final polypropylene application, are all described. The state of mechanical changes
_thermal and photic changes of polymer which are closely dependant to foresaid factors_ is also discussed in
present paper, and this indicates the path toward achieving desired quality. Keyword: Polypropylene ¸ Stereo specificity Stereochemistry ،Ziegler-Natta catalysts، Atacticity
synthesis and spectral studies on cardanol based polyurethanesINFOGAIN PUBLICATION
Cardanol is a renewable organic resource obtained as a byproduct from the cashew industry. The present study has been carried out with an aim to manufacture rigid polyurethanes from natural and eco – friendly sources due to the rising prices of petrochemicals and also as an environmental concern. Vegetable oil based polyurethanes promising a new generation polymers which are low cost materials in the family of polyurethanes. Cardanol based phenolic resin has been synthesized by condensing cardanol with furfural in a particular mole ratio using phthalic acid as catalyst. The progress of the reaction was monitored by determining the free furfural and free phenol content. The resin was cured by using the curing agent 4, 41 - methylene bis(cyclohexyl isocyanate) and the catalyst dibutyltin dilaurate to produce polyurethane. Polyurethanes are an important class of polymers that have found place in many applications. The physico chemical and spectral properties of resin and polyurethane have also been studied.
This study aimed to investigate the polymerisation process of Merbau extractives (ME) and the characteristics of the phenolic resin polymers made from ME. These polymerised ME (PME) can potentially be utilised as an impregnating material to enhance the wood properties of young plantation timber. Selected PME were characterised via Fourier transform
infrared (FTIR) spectroscopy, differential scanning calorimetry, thermogravimetric analysis, Xray diffraction analysis, and ultraviolet-visible analysis. The prediction of the enhancement to
the wood properties when treated with the obtained PME was discussed in relation to the physico-chemical and thermal characteristics of the polymeric materials. The results showed that the ME can be polymerised in its base condition with formaldehyde and resorcinol as the copolymer to produce the PME. The resin was classified as a resole and polymerisation can be done at room temperature. The physico-chemical tests and analyses, via boiling tests and FTIR spectra confirmed that the polymeric compound is a promising impregnating material that can enhance wood properties. This polymeric material is also eco-friendly as the low level of free formaldehyde.
1. POLYMER by RAVI GOYANI. M.S(pharma) pharmaceutics, NIPER. Raebareli(U.P)
2. Contents of the presentation: Introduction, Classification, Properties of polymer,Characteristics of ideal polymer,Advantages of polymer,Applications of polymer.
3. Introduction of general terminology about the polymer like homopolymer, copolymer and monomer.
4. Figure representation of different monomer which combine to form polymer.
5. Introduction about the copolymer and how its form by one or more monomer.
6. Classification of the polymer on the bases of source, degradability, structure, properties, nature of the polymer and polymerization process.
7.8.9.10.11.12 Example of the polymer according to the class of that polymer.
13. Characteristics of ideal polymer like Should be inert and compatible with environments, Should be nontoxic, Should be easily administered, Should have good mechanical strength, Should be biodegradable, Should have biocompatible.
14. Properties of polymer.
15. Advantages of polymer in to the different area of pharmaceutics.
16. Application of the polymer like as binding agents, coating agents, thickening agents, disintegrants, and also in the formulation of hard and soft gelatin capsules.
17.18. Tables for the examples of different polymer and its specific application.
19. Application of the polymer in to the various drug delivery system in which extended, pulsatiles, controlled release drug delivery systems.
20.21 Other application of polymers in different formulation such as nanocrystals, gels, micro- spheres and also useful for the cancer study or complexation study.
22. List of references.
In this work a new prodrug polymer was
prepared with two attachment groups (amid-ester), using di
functional spacer such as ethanol amine, which could react with
polyacrylic acid producing amide group, with remain ethanol
terminal group which could react with captopril acyl chloride,
producing ester group with extended the arm substituted drug to
improve the hydrolysis and to prevent the steric effect of polymer
chains. Many advantages enhanced the prodrug of polymer. The
prepared polymers were characterized by FTIR, 1H –NMR
spectroscopies. Controlled drug release was studied in different
pH values at 37℃, using UV. Spectra with comparing with
calibration curve. The modification percentage test was studied,and swelling percentage was calculated and all physical properties were observed.
Gelatin-grafted N- proflavine acryl amide was synthesized through two steps; firstly the Gelatin was grafted with
acrylic acid free radically using Ammonium per-sulfate at 60℃, Then it was modified to its corresponding acyl
chloride derivation, second step included the substitution with amino group of proflavine, in this research Gelatin
was used as a natural nontoxic, water soluble polymer as a drug carrier.
The prepared pro drug polymer was characterized by FTIR and 1H-NMR spectroscopies, Controlled drug release
was studied in different pH values at 37℃. Many advantages were obtained comparing with other known
methods.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Rheological and optical characterization of Polyvinylpyrrolidone (PVP) - Poly...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Oct...Babloo Sharma, Ph.D.
A unique class of aromatic ether polymers
containing perfluorocyclopentenyl (PFCP) enchainment was
prepared from the simple step growth polycondensation of
commercial bisphenols and octafluorocyclopentene (OFCP)
in the presence of triethylamine. Model studies indicate that
the second addition/elimination on OFCP is fast and poly-
condensation results in linear homopolymers and copolymers
without side products. The synthesis of bis(heptafluoro-
cyclopentenyl) aryl ether monomers and their condensation
with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.
Improved Stability of Formate Dehydrogenase by Coating with Didodecyldimethyl...researchinventy
Hydrophilic formate dehydrogenase (FDH) from candida boidinii was chemically modified by coating it with didodecyldimethylammonium bromide (DDAB). This coating changed the phase behavior of the enzyme, making it highly soluble in hydrophobic solvents and thereby offering the chance for biphasic enzyme recycling from hydrophilic substrates and products. Different coating procedures of FDH with DDAB were investigated and all proved suitable for efficient coating of the enzyme’s outer surface. A 50 mM Tris- (hydroxymethyl)-amminomethan (tris) buffer at pH 8 was chosen to make DDAB soluble and avoid aggregation. The reaction of NAD+ with uncoated and coated FDH to NADH and CO2 was monitored by UV-vis spectroscopy and kinetic parameters (rmax, Km, KI , EA) for the the FDH were determined. The coated enzyme resulted in a lower relative initial activity between 40-60% compared to the uncoated one. The stability of the coated enzyme (FDH*) was improved significantly and remained stable in long-term experiments, resulting in a deactivation rate kD smaller than 3% per day and a half-life time t1/2largerthan 23 days, while the deactivation rate of the uncoated enzyme was 260% per daywitha t1/2of 0.3 days. Both activation energies were similar, with 42 kJ mol-1 for the coated and 48 kJ mol-1 for the uncoated enzyme.This result suggests that there is not significant transport resistance originating from the DDAB coating layer. The reason for the significantly lower activity of the coated FDH probably stems from accumulation of formed CO2 in the coating layer, thereby preventing high equilibrium conversions
C–H bond hydroxylation at non heme carboxylate-bridged diiron centersDaniel Morton
This unit provides an overview of how Nature has inspired the development of novel diiron bridged complexes for use in C–H Hydroxylation.
Contributed by Omar Villanueva and Cora MacBeth, Emory University, 2014
In this work a new prodrug polymer was
prepared with two attachment groups (amid-ester), using di
functional spacer such as ethanol amine, which could react with
polyacrylic acid producing amide group, with remain ethanol
terminal group which could react with captopril acyl chloride,
producing ester group with extended the arm substituted drug to
improve the hydrolysis and to prevent the steric effect of polymer
chains. Many advantages enhanced the prodrug of polymer. The
prepared polymers were characterized by FTIR, 1H –NMR
spectroscopies. Controlled drug release was studied in different
pH values at 37℃, using UV. Spectra with comparing with
calibration curve. The modification percentage test was studied,and swelling percentage was calculated and all physical properties were observed.
Gelatin-grafted N- proflavine acryl amide was synthesized through two steps; firstly the Gelatin was grafted with
acrylic acid free radically using Ammonium per-sulfate at 60℃, Then it was modified to its corresponding acyl
chloride derivation, second step included the substitution with amino group of proflavine, in this research Gelatin
was used as a natural nontoxic, water soluble polymer as a drug carrier.
The prepared pro drug polymer was characterized by FTIR and 1H-NMR spectroscopies, Controlled drug release
was studied in different pH values at 37℃. Many advantages were obtained comparing with other known
methods.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Rheological and optical characterization of Polyvinylpyrrolidone (PVP) - Poly...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Oct...Babloo Sharma, Ph.D.
A unique class of aromatic ether polymers
containing perfluorocyclopentenyl (PFCP) enchainment was
prepared from the simple step growth polycondensation of
commercial bisphenols and octafluorocyclopentene (OFCP)
in the presence of triethylamine. Model studies indicate that
the second addition/elimination on OFCP is fast and poly-
condensation results in linear homopolymers and copolymers
without side products. The synthesis of bis(heptafluoro-
cyclopentenyl) aryl ether monomers and their condensation
with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.
Improved Stability of Formate Dehydrogenase by Coating with Didodecyldimethyl...researchinventy
Hydrophilic formate dehydrogenase (FDH) from candida boidinii was chemically modified by coating it with didodecyldimethylammonium bromide (DDAB). This coating changed the phase behavior of the enzyme, making it highly soluble in hydrophobic solvents and thereby offering the chance for biphasic enzyme recycling from hydrophilic substrates and products. Different coating procedures of FDH with DDAB were investigated and all proved suitable for efficient coating of the enzyme’s outer surface. A 50 mM Tris- (hydroxymethyl)-amminomethan (tris) buffer at pH 8 was chosen to make DDAB soluble and avoid aggregation. The reaction of NAD+ with uncoated and coated FDH to NADH and CO2 was monitored by UV-vis spectroscopy and kinetic parameters (rmax, Km, KI , EA) for the the FDH were determined. The coated enzyme resulted in a lower relative initial activity between 40-60% compared to the uncoated one. The stability of the coated enzyme (FDH*) was improved significantly and remained stable in long-term experiments, resulting in a deactivation rate kD smaller than 3% per day and a half-life time t1/2largerthan 23 days, while the deactivation rate of the uncoated enzyme was 260% per daywitha t1/2of 0.3 days. Both activation energies were similar, with 42 kJ mol-1 for the coated and 48 kJ mol-1 for the uncoated enzyme.This result suggests that there is not significant transport resistance originating from the DDAB coating layer. The reason for the significantly lower activity of the coated FDH probably stems from accumulation of formed CO2 in the coating layer, thereby preventing high equilibrium conversions
C–H bond hydroxylation at non heme carboxylate-bridged diiron centersDaniel Morton
This unit provides an overview of how Nature has inspired the development of novel diiron bridged complexes for use in C–H Hydroxylation.
Contributed by Omar Villanueva and Cora MacBeth, Emory University, 2014
Building a Graph of Names and Contextual Patterns for Named Entity Classifica...Grupo HULAT
Authors: César de Pablo Sánchez and Paloma Martínez
31st European Conference on Information Retrieval, Tolouse, France (April 6-9, 2009)
Building a Graph of Names and Contextual Patterns for Named Entity Classification
DINTO An Ontology for Drug-Drug InteractionsGrupo HULAT
Authors: María Herrero Zazo, Janna Hastings, Isabel Segura-Bedmar, Samuel Croset, Paloma Martínez and Christoph Steinbeck
SWAT4LS, International Workshop Semantic Web Applications and tools for life sciences, Edinburgh, UK (December 10, 2013)
DINTO, An Ontology for Drug-Drug Interactions
A successful car accident claim should result in compensation for pain and suffering, general damages, and loss of quality of life. The severity of your injury will greatly influence the size of your settlement.
Detecting Drugs and Adverse Events from Spanish Health Social Media StreamsGrupo HULAT
Authors: Isabel Segura-Bedmar, Ricardo Revert, Paloma Martínez
Louhi 2014 (The Fifth International Workshop on Health Text Mining and Information Analysis). Gothenburg, Sweden (April 27, 2014) (http://dsv.su.se/en/research/research-areas/language/description/louhi-2014-1.154970)
Abstract: To the best of our knowledge, this is the first work that does drug and adverse event detection from Spanish posts collected from a health social media. First, we created a gold-standard corpus annotated with drugs and adverse events from social media. Then, Textalytics, a multilingual text analysis engine, was applied to identify drugs and possible adverse events. Overall recall and precision were 0.80 and 0.87 for drugs, and 0.56 and 0.85 for adverse events.
Bis-perfluorocycloalkenyl (PFCA) aryl ether monomers towards a versatile clas...Babloo Sharma, Ph.D.
A unique class of perfluorocycloalkenyl (PFCA) aryl ether monomers was synthesized from commercially available perfluorocycloalkenes (PFCAs) and bisphenols in good yields. This facile one pot reaction of perfluorocycloalkenes, namely, octafluorocyclopentene (OFCP), and decafluorocyclohexene (DFCH), with bisphenols occurs at room temperature via an addition–elimination reaction in the presence of a base. The synthesis of PFCA monomers and their condensation with bisphenols lead to perfluorocycloalkenyl (PFCA) aryl ether homopolymers and copolymers with random and/or alternating polymer architectures.
Perfluorocyclohexenyl Aryl Ether Polymers via Polycondensation of Decafluoroc...aaaa zzzz
ABSTRACT: A novel class of semifluorinated perfluorocyclohex- enyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step-growth polymer- ization of commercially available bisphenols and decafluorocy- clohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis-perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal
stabilities with a 5% decomposition temperature ranging from 359 to 444 ﰀC in air and nitrogen atmosphere. These semifluori- nated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as cross- linking and application specific functionalization possible. VC 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 232–238
Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Oct...aaaa zzzz
ABSTRACT: A unique class of aromatic ether polymers
containing perfluorocyclopentenyl (PFCP) enchainment was
prepared from the simple step growth polycondensation of
commercial bisphenols and octafluorocyclopentene (OFCP)
in the presence of triethylamine. Model studies indicate that
the second addition/elimination on OFCP is fast and poly-
condensation results in linear homopolymers and copolymers
without side products. The synthesis of bis(heptafluoro-
cyclopentenyl) aryl ether monomers and their condensation
with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
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yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Bis-perfluorocycloalkenyl (PFCA) aryl ether monomers towards a versatile clas...aaaa zzzz
A unique class of perfluorocycloalkenyl (PFCA) aryl ether monomers was synthesized from commercially available perfluorocycloalkenes (PFCAs) and bisphenols in good yields. This facile one pot reaction of per- fluorocycloalkenes, namely, octafluorocyclopentene (OFCP), and decafluorocyclohexene (DFCH), with bisphenols occurs at room temperature via an addition–elimination reaction in the presence of a base. The synthesis of PFCA monomers and their condensation with bisphenols lead to perfluorocycloalkenyl (PFCA) aryl ether homopolymers and copolymers with random and/or alternating polymer architectures.
Published by Elsevier Ltd.
Spatial charge separation on the (110)/(102) facets of cocatalyst-free ZnIn2S...Pawan Kumar
Photorefining of biomass and its derivatives to value-added chemicals is an alternative solution to address the global energy shortage and environmental issues. Herein, efficient and selective oxidation of 5-hydroxymethylfurfural (HMF, 91.1% conversion) to 2,5-diformylfuran (DFF, 99.4% selectivity) is demonstrated by visible light-driven photocatalysis over cocatalyst-free ZnIn2S4 nanosheets with crystal facet engineering. The spatial accumulation of photogenerated electrons and holes on the (110) and (102) crystal facets triggers a two-electron oxygen reduction reaction (2e-ORR) for H2O2 generation and HMF oxidation into DFF, respectively. The severe attenuation of photostability is caused by the irreversible photocorrosion of Zn–S with the formation of Zn–O chemical bonds by the formation of ˙OH from the in situ decomposition of H2O2. Spontaneous substitution of oxygen with sulfur has been proven to efficiently improve the photostability of ZnIn2S4. This present work provides insights into improving the durability of ZnIn2S4 and sheds new light on biomass valorization via photorefinery.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
2. ORIGINAL ARTICLE
Triarylamine-enchained semifluorinated perfluorocycloalkenyl
(PFCA) aryl ether polymers
Babloo Sharma • Mohammad Faisal •
Shawna M. Liff • Dennis W. Smith Jr.
Received: 6 May 2014 / Accepted: 12 May 2014
Ó The Author(s) 2014. This article is published with open access at Springerlink.com
Abstract A variety of perfluorocycloalkenyl (PFCA) aryl
ether monomers and polymers with enchained triarylamine
units were successfully synthesized, characterized and
reported here. These polymers are highly thermally stable
and show variable thermal properties. Successful conver-
sion of the newly synthesized TAA enchained perfluoro-
cyclopentenyl (PFCP) aryl ether polymers via formylation
and EAS demonstrates the synthetic versatility of TAA
moiety and provides an excellent option for application
specific post polymerization reactions. The cross-linking
behavior of PFCP aryl ether polymers was studied under
different reaction conditions. The combination of pro-
cessability, thermal stabilities, and tailorability makes these
polymers suitable for a wide variety of applications
including electro-optics, proton exchange membranes and
super-hydrophobic applications.
Keywords Semi-fluorinated polymers Á Step-growth
polycondensation Á Addition–elimination reaction Á
Perfluorocycloalkenes
Introduction
The serendipitous discovery of poly(tetrafluoroethylene)
by Roy Plunkett caught the global attention and led to
tremendous improvement in fluoropolymer field [1, 2].
Due to their high thermal and chemical stabilities, fluo-
ropolymers are regarded for adverse applications. Fluo-
ropolymers also exhibit low refractive index and fraction
coefficient, low optical loss at telecom wavelength, good
hydrophobicity and oleophobicity, low intermolecular
and intramolecular interactions, which result in low
surface energy and low relative permittivity [3, 4].
Crediting to these properties, fluoropolymers have shown
their use in a variety of applications including paints
and coatings, optical fibers, antifouling coatings, materi-
als for photoresist and micro-lithography, conducting
polymers, aerospace, and wire and cable industry mate-
rials [5–19].
Due to their high crystalline nature, high melting point
and the low solubility problem, the processability of these
fluoropolymers is difficult. The modification of these
fluoropolymers to high performance materials without melt
and solution processing limitations demands high cost.
There is always a constant demand for fluoropolymers with
cheaper feed stocks, variable thermal properties and
excellent properties. Although, majority volume of fluo-
ropolymers is derived via chain growth polymerization of
fluorinated olefin monomers, step growth polymerization
methodology also has been used. Perfluorocyclobutyl
(PFCB) aryl ether polymers and fluorinated arylene
vinylene ether (FAVE) polymers are two such classes,
synthesized via step growth polymerization of aromatic
trifluorovinyl ether (TFVE) monomers (Scheme 1). [20–
24] The aromatic backbones in these semifluorinated
polymers not only address the performance issue, but also
Electronic supplementary material The online version of this
article (doi:10.1007/s13203-014-0063-0) contains supplementary
material, which is available to authorized users.
B. Sharma Á M. Faisal Á D. W. Smith Jr. (&)
Department of Chemistry, The Alan G. MacDiarmid NanoTech
Institute, The University of Texas at Dallas, Richardson,
TX 75080, USA
e-mail: dwsmith@utdallas.edu
S. M. Liff
Intel Corporation, Chandler, Arizona 85226, USA
123
Appl Petrochem Res
DOI 10.1007/s13203-014-0063-0
3. provide a means for facile modification to achieve modular
utility.
PFCB aryl ether polymers are first synthesized and
investigated by The Dow Chemical Company in the early
1990s as potential dielectric materials for integrated cir-
cuits applications [20]. PFCB aryl ether polymers are
prepared via [2 ? 2] thermo-cyclodimerization reaction
of TFVE monomers at reaction temperature of
150–200 °C (Scheme 1a). The cycloaddition results in
stereo-random PFCB rings in primarily 1,2 fashion (i.e.,
head-to-head). These uniquely amorphous polymers
demonstrate excellent solution processability, modular
utility, comparable properties with the highly-market
fluoropolymers and high performance in a variety of
applications including electro-optics, fuel cell mem-
branes, etc. [21, 25].
In 2006, our research group extended TFVE monomer
chemistry and introduced a new class of fluoropolymers,
namely, fluorinated arylene vinylene ether (FAVE) poly-
mers, derived from the step-growth polycondensation of
TFVE monomers with bisphenols (Scheme 1b) [22, 23].
FAVE polymers are telechelic in nature and possess dual
functionalities, which facilitate chain extension (via ther-
mal [2 ? 2] cyclodimerization of end groups) and tandem
cross-linking (due to internal olefins) to polymeric network
without the use of any cross-linker additives [23]. The
content of internal fluoro-olefin moieties depends on the
reaction conditions and can be manipulated on the
requirement [22, 26].
More recently, we have extended our high performance
fluoropolymer materials research and developed perflu-
orocyclopentenyl (PFCP) aryl ether polymers and perflu-
orocyclohexenyl (PFCH) aryl ether polymers, collectively
categorized as perfluorocycloalkenyl (PFCA) aryl ether
polymers via polycondensation of commercially available
perfluorocycloalkenes (PFCAs) and bisphenols (Scheme 2)
[27, 28]. In this manuscript, we are presenting new per-
Scheme 1 a Synthesis of PFCB
aryl ether polymers via thermal
mediated [2 ? 2]
cyclodimerization reaction.
b Synthesis of FAVE polymers
via step-growth polymerization
Scheme 2 Synthesis of perfluorocycloalkenyl (PFCA) aryl ether
polymers [28]
Appl Petrochem Res
123
4. fluorocycloalkenyl (PFCA) aryl ether polymers with tria-
rylamine moieties, and cross-linking behavior of PFCA
aryl ether polymers. TAA moieties provide an excellent
reaction site for post polymerization modification to make
these fluoropolymers application specific [26, 29].
Results and discussion
Step-growth polymers: methodology
PFCP aryl ether polymers and PFCH aryl ether polymers
are synthesized via step-growth polymerization of com-
mercially available bisphenols with octafluorocyclopentene
(OFCP) and decafluorocyclohexene (DFCH), respectively
(Scheme 2) [27, 28]. In optimized reaction condition, the
bisphenols are mixed with perfluorocycloalkene (PFCA)
monomers in a stoichiometric ratio of 1:1 and heated at
80 °C in the presence of a base, triethylamine. This method
produces PFCA aryl ether polymers with enchained per-
fluoro-olefin moieties intact, in good yield.
Nucleophilic attack on a perfluoro-olefin is a well
studied and documented organofluorine transformation and
continues to attract attention periodically [30]. Here, attack
on PFCA ring by phenoxide ion, resulted in situ due to
action of base on bisphenol, generates a carbanion on
perfluorocycloalkene ring which, theoretically, can elimi-
nate fluoride ion resulting in allyl and vinyl substituted
products (Scheme 3). However, as the literature demon-
strates, the ratio of vinyl to allyl substituted products varies
and depends on the PFCA ring size, nucleophilicity of
attacking anion, and reaction conditions. [28, 31, 32].
Synthesis and characterization
PFCP aryl ether polymers derived from the OFCP gave
exclusively vinyl fluoro-olefin enchainments, no trace of
allyl product was noticed [27]. However, the PFCH aryl
ether polymers prepared from DFCH gave both, vinyl fluoro-
olefins as major and allyl fluoro-olefins as minor enchain-
ments via a double addition–elimination mechanism [28].
Gel permeation chromatography (GPC) showed num-
ber-average molecular weights (Mn) from 9,100 to 15,400
for PFCP aryl ether polymers derived from different bi-
sphenols [27]. In case of PFCH aryl ether polymers, Mn
ranged from 9,400 to 15,600 [28]. Thermogravimetric
analysis (TGA) showed excellent thermal stability of these
polymers. The degradation temperature at 5 % weight loss
(Td 5 %) varied from 432 to 483 °C and 383 to 444 °C for
PFCP aryl ether polymers and PFCH aryl ether polymers,
respectively. Thermal analysis via differential scanning
calorimetry (DSC) showed variable glass transition tem-
perature (Tg) ranging from 432 to 483 °C and 90 to 132 °C
for PFCP aryl ether polymers and PFCH aryl ether poly-
mers, respectively. Interestingly, both PFCA aryl ether
polymers synthesized from Bisphenol-AF also showed
melting peaks in their respective DSC thermogram. This
anomalous crystalline nature was attributed to a higher
fluorine content, as found with -C(CF3)2 moiety of the
bisphenol-AF group [33].
In this manuscript, PFCP aryl ether monomer and
polymers with enchained triarylamine (TAA) units were
synthesized and studied (Scheme 4, 5). The latent reac-
tivity of TAA unit provides the post polymerization mod-
ification opportunities to achieve application specific
properties Scheme 6.
Bis(4-methoxyphenyl)phenylamine (A) and its depro-
tected analogous (B) were prepared by following the
standard literature procedure via Ullman coupling (i) and
BBr3 methoxy deprotection (ii), respectively [26, 34, 35].
The bis(perfluorocyclopentenyloxy)triarylamine monomer
(M) was synthesized by treating B with OFCP in a stoi-
chiometric ratio of 1:3 in the presence of a base, triethyl-
amine at room temperature (Scheme 4). 19
F NMR shows
only three distinct resonances (8:4:2) corresponding to
three different fluorine atoms (Fig. 1). As expected, PFCA
Scheme 3 Nucleophilic attack
on PFCA rings leads to vinyl
and allyl products [28]
Appl Petrochem Res
123
5. aryl ether monomers derived from OFCP, there was no
product with allyl substituted enchainments [31].
The polymerization of M with different bisphenols, in the
presence of base, triethylamine, and reaction temperature of
80 °C, yields a variety of copolymers with alternating
architectures (Scheme 5). Polymers P1–P3 were obtained in
good yield ([70 %) and characterized via, 1
H NMR, 19
F
NMR, GPC, TGA and DSC techniques (Table 1). 19
F NMR
spectra show the uniform vinyl linkage along the polymer
chain and supports the concept of double addition–elimina-
tion reaction on OFCP rings which leave the double bond
intact. A small 19
F NMR signal around -150 ppm was
observed for polymer P3 indicating the presence of a trace
amount of allyl substitution along the polymer chain (Figs. 2,
3s, 5s). Thermal stabilities for these polymers studied via
TGA analysis. The decomposition temperature (Td at 5 %
weight loss, in nitrogen atmosphere) ranges from 370 to
456 °C (Fig. 3). The impressive degradation temperatures
(Td 5 %) up to 450 °C are typicalforPFCP aryl ether polymer
systems [27]. Thermal analysis via differential scanning
calorimetry (DSC) shows the polymers show variable glass
transition temperature (Tg) depending on the bisphenol used.
The Tg for these polymers ranges from 87 to 106 °C (Fig. 4).
There was no sign of melting peak, as expected.
Post-polymerization functionalization [e.g. chromoph-
orization- synthesizing an electro-optic (EO) chromophore
NH2
+
I
O
N
O
2
N
OHO HO
i ii
N
OO
FF
F
F
F
F F
F
F
F
F
F
F
F
F
F
F
F F
F
F
F
Monomer (M)
(A) (B)
Scheme 4 Synthesis of
monomer/precursor (M)
Scheme 5 Synthesis of PFCP-
TAA ether polymers
Appl Petrochem Res
123
6. on an inert polymer backbone] is an excellent tool to make
a polymer system application specific. Here, we have post-
functionalized PFCP aryl ether polymer with enchained
TAA moieties via formylation and electrophilic aromatic
substitution (EAS) (Scheme 6). Successful conversion of
the TAA enchained PFCP polymers via formylation and
EAS demonstrated the synthetic versatility of TAA moiety.
All these reported reactions resulted in high yields. The
Scheme 6 Post polymerization
modification (i.e.
chromophorization) of PFCP-
TAA ether polymer
Fig. 1 19
F NMR for monomer
M
Appl Petrochem Res
123
7. incorporated aldehyde (P4) can be further modified into a
range of application-specific molecules, including exten-
sion into an EO chromophore, hole-transport and photo-
voltaic materials [29, 34, 36, 37]. EAS reaction on these
PFCP aryl ether polymers demonstrates the accessibility of
these TAA moieties for further post polymerization mod-
ifications, which extends the overall versatility of this
polymeric system.
Network polymers: cross-linking behavior of PFCA
polymers
(a) Thermal mediated cross-linking
FAVE polymers with enchained fluoro-olefins show
induced thermal cross-linking of internal fluoro-olefins on
heating to [325 °C [23]. Being similar in backbone
structure, PFCP polymers were also tested for thermal
cross-linking. The heating of PFCP aryl ether polymer with
biphenyl enchainments to temperature [240 °C gives
cross-linked product. Possible cross-linking mechanisms
might involve [2 ? 2] cyclodimerization between two
PFCP-olefin moieties, [2 ? 2] cyclodimerization between
PFCP-olefin and the benzene ring, or [4 ? 2] cycloaddition
reaction between PFCP-olefin (dienophile) and the biphe-
nyl (diene). As experimental results show, the successful
thermal cross-linking was obtained only with PFCP aryl
ether polymer with biphenyl enchainment, whereas with
PFCP polymers with bisphenol A and Bisphenol-6F
enchainments do not show any gel formation (Fig. 5).
This observation suggests the cross-linking might follow
[4 ? 2] cycloaddition reaction between diene of biphenyl
moiety and dienophile of PFCP ring, and thus the presence
of biphenyl (diene) moiety is necessary for network
formation. Further studies on the cross-linking mechanism,
Fig. 2 19
F NMR of polymer P1
Fig. 3 TGA thermograms for polymers P1–P5
Table 1 PFCP aryl ether polymers with enchained triarylamine
unites
Entry Mn Mw PDI Td 5 % (°C) Tg (°C)
Polymer P1 23,600 36,800 1.4 456 99
Polymer P2 11,100 18,500 1.6 420 87
Polymer P3 22,100 36,000 1.6 370 106
Polymer P4 14,100 26,500 1.8 337 101
Polymer P5 17,200 32,100 1.8 416 100
Appl Petrochem Res
123
8. extent of cross-linking and reaction conditions are
warranted.
(b) Free radical cross-linking
Cross-linking efforts using free radical initiators including
AIBN and lauroyl peroxide did not work. As the literature
suggests, perfluorocyclic-olefins do not homopolymerize
under radical conditions [38]. Therefore, electron deficiency
factor combined with steric hindrance factor inhibits the cross-
linking of these PFCP polymers via free radical mechanism.
(c) Ionic cross-linking
The PFCP polymers keep the cyclic olefin intact. The lit-
erature suggests, in suitable conditions, multiple nucleophilic
substitutions on PFCP ring are possible [39]. Model reactions
also support the multiple substitutions on PFCP rings
(Scheme 7). Model compound 1,2-diphenyl
perfluorocyclopentenyl ether (1) shows two clean signals,
corresponding to two kinds of fluorine atoms in a symmetric
environment, as expected (Fig. 6a). When the sodium phen-
oxide reacts with (1), 19
F NMR shows vinyl fluorine signal at
158.6 ppm confirming the third substitution (Fig. 6b). This
vinyl fluorine signal goes away with further reaction of (2)
with the phenoxide ion.
Initial studies show PFCP aryl ether polymers react with
dinucleophiles, undergo cross-linking in different reaction
conditions and give insoluble products (Scheme 8). Vari-
ous parameters, including different reaction conditions and
different dinucleophiles are under study.
Experimental details
Materials and instrumentation
Octafluorocyclopentene and decafluorocyclohexene were
purchased from SynQuest Laboratories, while all other
chemicals were purchased from Alfa Aesar. Commercially
purchased chemicals were used as purchased unless otherwise
stated. All synthesized polymers P1–P5 were characterized by
1
H and 19
F NMR Spectroscopy, Gel permeation chromatog-
raphy (GPC), Thermogravimetric analysis (TGA) and Dif-
ferential scanning calorimetry (DSC) techniques. NMR
Spectroscopy was performed on Bruker advanced IIITM
500 MHz spectrometer. Chemical shifts were reported in ppm
(d) with reference to deuterated acetone (2.09 ppm) and tri-
chlorofluoromethane (0 ppm) for 1
H and 19
F NMR, respec-
tively. GC–MS was obtained on Shimadzu GCMS solution.
Analytical thin layer chromatography was performed on EM
reagents 0.25 mm silica gel 60-F plates. Molecular weight
Fig. 5 Thermal cross-linking
behavior for PFCA aryl ether
polymers
Fig. 4 DSC thermograms for polymers P1–P5
Appl Petrochem Res
123
9. measurements were performed on gel permeation chroma-
tography (Viscotek GPCmax, VE2001) system equipped with
a ViscotekTDA 302Triple ArrayDetector andtwo ViscoGEL
I-Series (I-MBHMW 3078, Viscotek) columns in series. THF
was used as eluent and polystyrene standards were used for
calibration. Attenuated total reflectance—Fourier transform
infrared (ATR-FTIR) spectroscopy was done on a Thermo-
Nicolet Magna 550 FIR spectrophotometer with a high
endurance diamond ATR attachment. DSC analysis was per-
formed on a Mettler Toledo DSC 1 system in the nitrogen
atmosphere with heating and cooling rate of 10 C/min. The Tg
of polymers were measured from the third heating cycle using
Star-E version 10.0 software suite. The thermal stability
measurementswere performedon a Mettler Toledo TGA/DSC
1 LF instrument, in the nitrogen atmosphere with a heatingrate
of 10 C/min.
Synthesis of monomer (M)
In a flame dried 50 ml single necked round bottom flask,
equipped with a magnetic stirrer, 3.84 mmol of bis(4-
hydroxyphenyl)phenylamine (B), 9.60 mmol of triethyl-
amine and 6 ml of anhydrous DMF were introduced. The
solution was purged with nitrogen for 10 min. The solution
was heated at 65 °C for 2 h. Let the reaction mixture cooled
down to room temperature. This reaction mixture was added
to a 6 ml DMF solution containing 9.60 mmol of octaflu-
orocyclopentene, in a 100 ml single necked flask equipped
with stirrer, dropwise with a syringe. The solution was stirred
at room temperature for next 12 h. Further, the reaction was
heated at 65 °C for the next 2 h to ensure the completion of
the reaction. The solution was then cooled down, and the pure
product was isolated by column chromatography with pure
hexane, as eluent, to give white product (yield = 71 %). 1
H
NMR (500 MHz, acetone-d6, d): 7.18–7.08 (m, 2H),
6.94–6.86 (m, 4H), 6.74–6.65 (m, 7H), 3.37 (brs, 2H). 19
F
NMR (470 MHz, acetone-d6, d): -115.64 (m, 8F), -129.72
(brs, 4F), -150.95 (brs, 2F). FTIR (m, cm-1
): 825, 973, 1003,
1,128, 1,195, 1,291, 1,335, 1,364, 1,487, 1,601, 1,727.
Synthesis of polymer P1
To a heat dried 100 ml single necked round bottom flask,
equipped with a magnetic stirrer, 0.980 g (1.48 mmol) of
monomer(M),0.276 g (1.48 mmol) ofbiphenol,and0.679 g
(6.67 mmol) of triethylamine was added and then dissolved
in 1 ml of anhydrous DMF. The solution was degassed with
nitrogen for 10 min and the flask was heated slowly to 80 °C
for 36 h under stirring. The dissolved polymer was then
precipitated in 100 ml of methanol and washed again with the
same, giving a white powder after drying (yield = 81 %). 1
H
NMR (500 MHz, acetone-d6, d): 6.61–7.70 (m). 19
F NMR
(470 MHz, acetone-d6, d): -113.59 (4F), -114.38 (4F),
-129.74 (4F). FTIR (d m, cm-1
): 823 (aromatic C–H),
1,080–1,285 (C–F and C–O–C), 1,497 and 1,599 (aromatic
C=C), and 1,686 (C=C).
Synthesis of polymer P2
Polymer P2 was synthesized using the same method as P1,
giving a white powder after drying (yield = 85 %). 1
H
NMR (500 MHz, acetone-d6, d): 1.58 (brs, 6H), 6.63–7.39
(m). 19
F NMR (470 MHz, acetone-d6, d): -114.20 (8F),
-129.73 (4F). FTIR (m, cm-1
): 831 (aromatic C–H),
Scheme 7 Model study for
multiple substitutions on PFCA
ring
Appl Petrochem Res
123
10. 1,080–1,285 (C–F and C–O–C), 1,497 and 1,595 (aromatic
C=C), and 1,686 (C=C).
Synthesis of polymer P3
Polymer P3 was synthesized using the same method as P1,
giving a white powder after drying (yield = 80 %). 1
H
NMR (500 MHz, acetone-d6, d): 6.70–7.40 (m). 19
F NMR
(470 MHz, acetone-d6, d): -63.35 (6F), -113.88 (4F),
-114.74 (4F), -129.69 (4F). FTIR (m, cm-1
): 827 (aromatic
C–H), 1,080–1,285 (C–F and C–O–C), 1,498 and 1,603
(aromatic C=C), and 1,688 (C=C).
Synthesis of polymer P4
A mixture of phosphorous oxychloride (0.3 ml) and 0.45
gram of polymer P1 were dissolved in 15 ml anhydrous
DMF under the nitrogen atmosphere. The reaction mixture
was heated for next 5 h at 90 °C. The reaction mixture was
cooled down and poured in H2O to complete the reaction
and precipitate the polymer. Polymer was filtered after 1 h
of stirring and dried under vacuum (yield = 75 %). 1
H
NMR (500 MHz, acetone-d6, d): 6.59–7.59 (m), 9.78 (s).
19
F NMR (470 MHz, acetone-d6, d): -113.61 (4F),
-114.40 (4F), -129.76 (4F). FTIR (m, cm-1
): 825 (aromatic
C–H), 1,080–1,285 (C–F and C–O–C), 1,498 and 1,596
(aromatic C=C), 1,691 (C=C) and 1,706 (C=O).
Synthesis of polymer P5
Polymer P1 (0.49 gram) and tetracyanoethylene (0.23
gram) were dissolved in 15 ml anhydrous DMF under
nitrogen atmosphere. The reaction mixture was stirred for
next 12 h. The product was then precipitated in H2O and
washed with methanol. The purple colored polymer was
filtered and dried under vacuum (yield = 79 %). 1
H NMR
(500 MHz, acetone-d6, d): 6.52–7.59 (m). 19
F NMR
(470 MHz, acetone-d6, d): -113.66 (4F), -114.36 (4F),
-129.80 (4F). FTIR (m, cm-1
): 825 (aromatic C–H),
1,080–1,285 (C–F and C–O–C), 1,496 and 1,597 (aromatic
C=C), and 1,689 (C=C).
Conclusion
We have developed a step-growth polymerization of bi-
sphenols with PFCA towards synthesis of a new class of
PFCA aryl ether polymers from commercial feedstock.
PFCA aryl ether polymers can be easily modified and
functionalized using bisphenols with different spacer
functional groups. PFCA aryl ether polymers exhibited
very interesting thermal properties with variable Tg
depending upon the chosen bisphenol. These polymers
were obtained in good yields and show high thermal sta-
bilities under nitrogen atmosphere. Successful conversion
of the newly synthesized TAA enchained PFCP aryl ether
polymers via formylation and EAS demonstrated the syn-
thetic versatility of TAA moiety and provides an excellent
option for application specific post polymerization
reactions.
PFCP aryl ether polymers with biphenyl units also
demonstrate cross-linking behavior upon thermal activa-
tion. Exact mechanistic details for this thermal cross-link-
ing are still unknown and further investigations are
warranted. Also, PFCP aryl ether polymers undergo ionic
cross-linking upon treatment with strong dinucleophiles.
Future studies include the mechanistic studies on the
cross-linking behavior of PFCA aryl ether polymers, full
chromophorization on TAA units of these successfully
Fig. 6 a 19
F NMR for 1,2-diphenyl perfluoropentenyl ether (1); and
b 19
F NMR of the crude reaction mixture showing third substitution
Appl Petrochem Res
123
11. synthesized PFCP aryl ether polymers, and their incorpo-
ration in electro-optics and photonic devices.
Acknowledgments The authors want to express their gratitude
towards Intel Corporation (Grant # 4606175) CHEMS (Grant# IIP-
1035024), Welch Foundation (Grant # AT-0041) and University of
Texas at Dallas for providing the financial supports. The authors
also acknowledge the NSF-MRI grant (CHE-1126177) used to pur-
chase the Bruker Advance III 500 NMR spectrometer.
Open Access This article is distributed under the terms of the
Creative Commons Attribution License which permits any use, dis-
tribution, and reproduction in any medium, provided the original
author(s) and the source are credited.
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