This document provides an introduction to polymers. It discusses that polymers are formed through polymerization reactions where small monomer units join together to create large polymer molecules. There are two main types of polymerization - addition and condensation polymerization. Polymers can be classified as homopolymers, formed from one monomer, or copolymers, formed from multiple monomers. The document also discusses important polymer properties like glass transition temperature, molecular weight, types of polymers including thermoplastics and thermosets, and basic mechanical properties.
The presentation gives a brief idea about polymers,its definition,types of polymers,common examples of polymers,polymerization and its types,polymer processing and applications of polymers.
The presentation gives a brief idea about polymers,its definition,types of polymers,common examples of polymers,polymerization and its types,polymer processing and applications of polymers.
Brief intro about crystalline and amorphous structures,
glass transition temperature,
free volume theory of glass transition temperature,
factors effecting glass transition temperature etc.
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...Jaynish Amipara
additives of plastic.
uses of filler in plastic.
types of a heat stabilizer.
types of lubricant.
types of plasticizer in plastic.
plastic in antioxidant.
Brief intro about crystalline and amorphous structures,
glass transition temperature,
free volume theory of glass transition temperature,
factors effecting glass transition temperature etc.
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...Jaynish Amipara
additives of plastic.
uses of filler in plastic.
types of a heat stabilizer.
types of lubricant.
types of plasticizer in plastic.
plastic in antioxidant.
Polymer science revolves around the study of macromolecules known as polymers, which are formed by linking together repeating units called monomers. Understanding the relationship between polymers and monomers is fundamental to grasping the diverse properties and applications of these materials.
Additionally, we'll delve into the nomenclature of polymers, which involves the systematic naming conventions used to describe their structure and composition. Clear and standardized nomenclature ensures effective communication within the scientific community and facilitates the classification of polymers based on their chemical structure, properties, and applications.
Basic Terms : Macromolecule, Monomer , Repeat Unit, Classification of polymers based on Origin, thermal response Polymerisation , Addition and condensation , Degree of Polymerisation, Polymer Structures - Linear , Branched and Cross-linked. Molecular weight of Polymers: Definition and Formulae of Number Average Molecular Weight , Weight Average Molecular weight, Viscosity Average Molecular Weight , Z-average Molecular Weight. Polydispersity Index
Types of fibres,their classification,applications,properties, and structures
Further more polymers,their types and different type chemical bonds present in fibres,
Polymers play a very important role in human life. Our body is made of lot of polymers, e.g. Proteins, enzymes, etc. Other naturally occurring polymers like wood, rubber, leather and silk are have wide application. Now a day synthetic polymer like useful plastics, rubbers and fiber materials are synthesized. presentation includes introduction classification and preparation methods. Polymers play a very important role in human life. Our body is made of lot of polymers, e.g. Proteins, enzymes, etc. Other naturally occurring polymers like wood, rubber, leather and silk are have wide application. Now a day synthetic polymer like useful plastics, rubbers and fiber materials are synthesized. Leo Baekeland patented the first totally synthetic polymer called Bakelite (1910). Bakelite is a versatile, durable material prepared from low-cost materials phenol and formaldehyde and was the most important synthetic polymer material. In the 1920s Hermann Staudinger showed that polymers were high-molecular-weight compounds held together by normal covalent bonds.
The suffix in polymer ‘mer’ is originated from Greek word meros – which means part. The word polymer is thus coined to mean material consisting of many parts or mers. A macromolecule having high molecular mass (103-107u) and generally not a well-defined structure or molecular weight. The macromolecules formed by joining of repeating structural units on a large scale. The repeating structural units are simple and reactive molecules linked to each other by covalent bonds. This process of formation of polymers from respective monomers is called polymerization. Most of the polymers are basically organic compounds, however they can be inorganic (e.g. silicones based on Si-O network).
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
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.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
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.
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.
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 .
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
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.
2. Introduction to Polymers
– Polymers are extremely important materials. we have been
using polymeric materials in our daily life.
– Have known since ancient times – cellulose, wood, rubber,
etc…
– Biopolymers – proteins, enzymes, DNA , etc…
– Last ~50 years – tremendous advances in synthetic polymers.
3. Polymers
e.g. polyethylene is built from ethylene units.
Polymers are compounds which consist of very large molecules
formed by repeated joining of many small molecules.
n Ethylene units
polymerization
Polyethylene
4. It is the process of joining together many small molecules
repeatedly to form very large molecules.
These are compounds that join together repeatedly to
form polymer in polymerization.
Polymerization
Monomers
n monomer units
polymerization
polymer
5. Homopolymer and Copolymer
Homopolymer
If formed from one type of monomers (all the repeat units
are the same type) – this is called homopolymer.
Copolymer
If formed from multiple types of monomers (all the repeat
units are not the same type) – this is called copolymer.
e.g. -A-A-A-A-A-A-A-A-A-A-A-
e.g. -A-B-A-B-A-B-A-B-A-B-
6. Copolymer types
Two different monomers polymerized together to give
different types of copolymers.
Random Copolymers:
A and B randomly positioned along chain.
-A-B-B-A-A-B-A-B-B-
Alternating Copolymers:
A and B alternate in polymer chain.
-A-B-A-B-A-B-A-B-
7. Block Copolymers:
Large blocks of A units alternate with large blocks of B
units.
-A-A-A-A-B-B-B-B-
Graft Copolymers:
Chains of B units grafted onto A backbone.
-A-A-A-A-A-A-A-A-
B-B-B-B-B-
8. Types of polymerization
There are two types of polymerization
• Addition polymerization
• Condensation polymerization
Addition polymerization:
When molecules just add on to form the polymer, the
process is called addition polymerization.
e.g. polyethylene
9. Condensation polymerization
When molecules do not just add on but also undergo
some reaction in forming the polymer, the process is called
Condensation polymerization.
Degree of Polymerization:
The size of the polymer molecule is decided by the
number of repeat units present in it. this number denotes the
degree of polymerization.
10. Classification of polymers
Polymers can be classified in different ways.
Natural polymers:
those isolated from natural materials are called natural
polymers.
e.g. cotton , silk, wool and rubber.
Synthetic polymers:
polymers synthesized from low molecular weight
compounds are called synthetic polymers.
e.g. Polyethylene, Nylon , PVC and Terylene.
11. Organic polymers:
A polymer whose backbone chain is essentially
made up of carbon atoms is termed an organic polymer.
The majority of synthetic polymers is organic
polymers.
Inorganic polymers:
The molecules of inorganic polymers generally
contain no carbon atom in their backbone chain.
e.g. Glass , Silicone and Rubber.
12. Thermoplastics
• Those which soften on heating and then harden again on cooling.
these are called thermoplastics.
• These polymer molecules consist of long chains which have only
weak bonds between the chains.
• The bonds between the chains are so weak that they can be
broken when the plastic is heated.
• The chains can then move around to form a different shape.
• The weak bonds reform when it is cooled.
• Thermoplastic material keeps its new shape.
13. Thermosetting
• Those which never soften once they have been moulded.
These are called thermosetting polymers because once set into
a shape, that shape cannot be altered .
• These polymer molecules consist of long chains which have
many strong chemical bonds between the chains.
• The bonds between the chains are so strong that they cannot be
broken when the plastic is heated.
• This means that the thermosetting material always keeps its
shape.
14. MOLECULAR WEIGHT
High MW
• Polymers can have various lengths depending on the number of
repeat units.
• During the polymerization process, not all chains in a polymer
grow to the same length, so there is a distribution of molecular
weights. There are several ways of defining an average molecular
weight.
15. Average molecular weight
• Each molecule has the same molecular weight for all the low
molecular weight compounds.
• In polymer, it comprises molecules of different molecular
weights and, hence, its molecular weight is expressed in terms
of an ‘average’ value.
16. Molecular weight: a few definitions
i
i
i
ii
n
N
NM
M
__
Mn -Number average molecular weight
i
ii
i
ii
w
MN
MN
M
2
__
Mw -Weight average molecular weight
Mi –Molecular weight of the ith polymer chain
Ni -Number of polymer chains with molecular weight Mi
17. 17
Molecular weight
Molecular weight is expressed as follows,
m- Molecular weight of the monomer or the
repeating unit.
Dp- The degree of polymerisation.
M=Dp.m
18. The ratio of the weight to number average molecular
weights is called Polydispersity Index.
Polydispersity Index(PDI)
PDI ˭
Weight average molecular weight
Number average molecular weight
19. Glass transition temperature
• The transition from glassy solid state to molten liquid
state occurs at a temperature. This is known as the
glass transition temperature (Tg).
• The temperature at which the change of state occurs
( from solid state to liquid state ) is called the melting
temperature (Tm).
20. With the low molecular weight substances in the condensed state,
we can have two states of affairs.
• The first without Brownian movement, but with long range
order when stress transfer phenomenon is possible. This state
is called solid.
• The second with Brownian movement, but without long range
order and with energy dissipation. This state is called liquid.
21. The two types of motions exhibited within a polymeric material,
namely,
• The localised mobility of the segments, this is called
segmental motion. its another name is called as the internal or
micro Brownian movement.
• The total mobility of the molecule as a whole, this is called
molecular motion. its another name is called as the external or
macro Brownian movement.
22. There are three major observations in states of phase.
• Both crystalline and amorphous solids are in the solid state of
aggregation, whereas only crystalline solid exist in the
crystalline state phase.
• Although amorphous solids are in a solid physical state, they
really exist in a liquid phase state.
• Both amorphous and crystalline substances can exist in a
molten liquid state.
23. Glass transition temperature
Low molecular weight substance
Crystalline Amorphous
BM : -
LRO : +
ST : +
Crystalline solid
BM : -
LRO : -
ST : +
Glassy solid
BM : +
LRO : -
ST : -
Liquid
T
e
m
pe
ra
tu
re
Tm
Tg
24. Polymeric materials
Crystalline Amorphous
IBM : -
EBM : -
LRO : +
ST : +
Crystalline solid
IBM : +
EBM : -
LRO : -
ST : +/-
Rubber
IBM : -
EBM : -
LRO : -
ST : +/-
Glassy solid
IBM : +
EBM : +
LRO : -
ST : - polymer melt
Tm
Tg
Tf
T
e
m
pe
ra
tu
re
25. Here,
BM-Brownian Movement
IBM-Internal Brownian Movement
EBM-External Brownian Movement
LRO- Long Range Order
ST- Stress Transfer property
- Frozen
+ Activated
- does not exist
+ exists
- Lost
+/- partially retained
+ Fully retained
