Poly(phenylethene), also known as polystyrene, is the third most produced polymer from ethylene. It has a wide range of uses from packaging to appliances due to its physical properties being adjustable. Production techniques have increased its strength, impact resistance, and insulating abilities. It is made through radical polymerization of its monomer styrene, which is produced from benzene in multi-step processes. Common applications include food packaging, appliances, and insulation.
poly styrene is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed. General purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled .
Polyethylene is the most common plastic. Its global production is ca. 80 million tones.
Chemical Formula: (C2H4)nH2
http://apps.kemi.se/flodessok/floden/kemamne_eng/polyeten_eng.htm
http://en.wikipedia.org/wiki/Polyethylene
http://www.answers.com/Q/What_are_advantages_and_disadvantages_of_polythene
poly styrene is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed. General purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled .
Polyethylene is the most common plastic. Its global production is ca. 80 million tones.
Chemical Formula: (C2H4)nH2
http://apps.kemi.se/flodessok/floden/kemamne_eng/polyeten_eng.htm
http://en.wikipedia.org/wiki/Polyethylene
http://www.answers.com/Q/What_are_advantages_and_disadvantages_of_polythene
Miscibility and Thermodynamics of Polymer BlendsAbhinand Krishna
Presentation includes classification of polymer blends based on miscibility, phase diagram of polymer blends and thermodynamics polymer blends which includes Gibbs energy theory and Flory-Huggins Theory
Polyvinyl Alcohol
Polyvinyl alcohol (PVA) is one hydrophilic water-soluble synthetic polymer for electrospinning due to the presence of a hydroxyl group in its repeating unit, which makes it cross-linkable by means of its interconnected hydrogen bonding.
It low molecular wt. raw polymeric materials
It is used for binders, curable molding compositions adhesives and coatings.
They normally have a melting or softening range, are brittle in the solid state.
Resins : natural resins and synthetic resins.
Synthetic resins:
phenol-formaldehyde resins*, urea-formaldehyde,
melamine-formaldehyde resins, polyesters resins,
silicone resins, epoxy resins, acrylic resins and alkyd resins.
LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at a temperature range of175-250oC in presence of some oxygen, peroxide, or azocompounds as initiators.
LDPE has nearly 20–50 branches (both long and short branches) per 1000 linear carbon atoms in the chain molecules.
The loss of molecular symmetry due to the high degree of branching results in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting temperature.
LDPE dissolves in toluene at or above 60°C.HDPE is usually more resistant to chemicals than LDPE.
HDPE is soluble in toluene at 900C.
2–5 short branches or side chains per 1000 carbon atoms in the main chain, thus having a higher density range (0.945–0.96) and high melting temperature (125–130°C) compared to LDPE. HDPE-The polymerization at a low temperature and pressure in presence of metal oxide catalyst
Poly ethylenes are very good insulating materials and are adequately flexible hence used as an insulator in wires and cables.
They find extensive uses and applications as molded or formed objects, films, sheets, bottles and containers, pipes, and tubes.
Polythene finds application in packaging, waterproofing, irrigation, and water management including canal lining and mulching, and in coating and lamination.
Polypropylene - Addition polymer
Thermoplastic
Monomer propylene
USES
For making household appliances
In package industry
For making plastic parts of machinery
For making plastic furniture
For making syringes, medical vials, Petri dishes, pill containers, specimen bottles. Polystyrene is synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide initiator. It is used as an electrical insulator.
Expanded polystyrene finds extensive use in packaging and shock absorbing applications, in thermal insulation, and as acoustic improvers in halls and auditoria.
High impact grades are suitable for use as toys, games and sports articles, casings and cabinets for electrical/ electronic gadgets and equipment, and inner liners of refrigerators.
Another major use of polystyrene is in the making of ion-exchange resins. Kevlar is an aromatic polyamide
Five times more tensile strength than steel.
POLYVINYL PYROLIDONE(PVP)(POVIDONE),ETHYLENE VINYL ACETATE (EVA), SARAN , TEFLON (polytetrafluoroethylene) – A fluoro polymer, POLYACRYLONITRILE (PAN),Poly(Methyl Methacrylate) (PMMA), Poly(Hexamethylene Adipamide): Nylon 66, Nylon 6, KEVLAR, Terylene, GLYPTAL, Lexan, POLYURETHANES, UF( Urea –Formaldehyde)
MF (Melamine- formaldehyde)
PF (Phenol-Formaldehyde),MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF), NATURAL RUBBER, VULCANISATION, SYNTHETIC RUBBER, Butadiene rubber(BR), polybutadiene, Buna-S, BUNA- N, EPDM ( ethylene, propylene, diene monomer) , Neoprene, silicone rubber, Pollution due to plastics , and recycling of plastics are the other topics discussed here.
Miscibility and Thermodynamics of Polymer BlendsAbhinand Krishna
Presentation includes classification of polymer blends based on miscibility, phase diagram of polymer blends and thermodynamics polymer blends which includes Gibbs energy theory and Flory-Huggins Theory
Polyvinyl Alcohol
Polyvinyl alcohol (PVA) is one hydrophilic water-soluble synthetic polymer for electrospinning due to the presence of a hydroxyl group in its repeating unit, which makes it cross-linkable by means of its interconnected hydrogen bonding.
It low molecular wt. raw polymeric materials
It is used for binders, curable molding compositions adhesives and coatings.
They normally have a melting or softening range, are brittle in the solid state.
Resins : natural resins and synthetic resins.
Synthetic resins:
phenol-formaldehyde resins*, urea-formaldehyde,
melamine-formaldehyde resins, polyesters resins,
silicone resins, epoxy resins, acrylic resins and alkyd resins.
LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at a temperature range of175-250oC in presence of some oxygen, peroxide, or azocompounds as initiators.
LDPE has nearly 20–50 branches (both long and short branches) per 1000 linear carbon atoms in the chain molecules.
The loss of molecular symmetry due to the high degree of branching results in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting temperature.
LDPE dissolves in toluene at or above 60°C.HDPE is usually more resistant to chemicals than LDPE.
HDPE is soluble in toluene at 900C.
2–5 short branches or side chains per 1000 carbon atoms in the main chain, thus having a higher density range (0.945–0.96) and high melting temperature (125–130°C) compared to LDPE. HDPE-The polymerization at a low temperature and pressure in presence of metal oxide catalyst
Poly ethylenes are very good insulating materials and are adequately flexible hence used as an insulator in wires and cables.
They find extensive uses and applications as molded or formed objects, films, sheets, bottles and containers, pipes, and tubes.
Polythene finds application in packaging, waterproofing, irrigation, and water management including canal lining and mulching, and in coating and lamination.
Polypropylene - Addition polymer
Thermoplastic
Monomer propylene
USES
For making household appliances
In package industry
For making plastic parts of machinery
For making plastic furniture
For making syringes, medical vials, Petri dishes, pill containers, specimen bottles. Polystyrene is synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide initiator. It is used as an electrical insulator.
Expanded polystyrene finds extensive use in packaging and shock absorbing applications, in thermal insulation, and as acoustic improvers in halls and auditoria.
High impact grades are suitable for use as toys, games and sports articles, casings and cabinets for electrical/ electronic gadgets and equipment, and inner liners of refrigerators.
Another major use of polystyrene is in the making of ion-exchange resins. Kevlar is an aromatic polyamide
Five times more tensile strength than steel.
POLYVINYL PYROLIDONE(PVP)(POVIDONE),ETHYLENE VINYL ACETATE (EVA), SARAN , TEFLON (polytetrafluoroethylene) – A fluoro polymer, POLYACRYLONITRILE (PAN),Poly(Methyl Methacrylate) (PMMA), Poly(Hexamethylene Adipamide): Nylon 66, Nylon 6, KEVLAR, Terylene, GLYPTAL, Lexan, POLYURETHANES, UF( Urea –Formaldehyde)
MF (Melamine- formaldehyde)
PF (Phenol-Formaldehyde),MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF), NATURAL RUBBER, VULCANISATION, SYNTHETIC RUBBER, Butadiene rubber(BR), polybutadiene, Buna-S, BUNA- N, EPDM ( ethylene, propylene, diene monomer) , Neoprene, silicone rubber, Pollution due to plastics , and recycling of plastics are the other topics discussed here.
Today the world is facing problem related to spread of plastic all around us which cause infection and pollution. PET {poly(ethylene terephthalate)} is extensively used throughout the world. PET is made from petroleum and is widely used in textile industries and plastic bottles. Most of the PET product simply end up by land filling and never enter the recycling process. About 56 million ton of PET was produce worldwide in 2013 alone. Currently the only PET products being recycled are bottles, but the amount of recycled account are just 37% of the total production volume of PET bottle i.e. 6.13 million tons. Currently the chemical method is being used to recycle PET waste, which is quite energy consuming process and shows only assimilation of PET waste. Various microorganisms have also been reported to assimilate PET waste. However, assimilation is not the final solution of this problem as it is only a partial degradation. Recently, a novel microorganism Ideonella sakaiensis strain 201-F6 has been identified which uses PET as an energy resource and is able to produce environment friendly bi products such as ethylene glycol and terephthalic acid. Scientists also discovered two enzymes (PETase and MHETase) produced by the strain 201-F6 which hydrolyze PET. Based on the property of PETase and MHETase it is now understood that the strain 201-F6 is capable to use PET as its major energy source and convert it into easily degradable components.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
1. Poly(phenylethene), commonly known as polystyrene, is the third most important
polymer, in terms of amount made from ethene. Its physical properties can be
adjusted to suit a range of everyday uses. Techniques have been developed which
increase its mechanical strength, its ability to absorb shock and its thermal
insulating properties.
Polymers Poly(phenylethene) (Polystyrene)
Poly(phenylethene) (Polystyrene)
Uses of poly(phenylethene) (polystyrene)
The largest use for poly(phenylethene) is for packaging, particularly for foods such as poultry and eggs, for cold
drinks and take-away meals.
Figure 1 Uses of poly(phenylethene).
It is also used in making appliances, including refrigerators, microwaves and blenders. It is the leading choice for
jewel boxes (cases for CDs and DVDs) and is also widely used for its insulating properties.
Annual production of poly(phenylethene) (polystyrene)
World 14.6 million tonnes
Europe 3.4 million tonnes
US 4.0 million tonnes1
Russia 0.27 million tonnes2
Data from:
1. American Chemistry Council 2013 Statistics
2. Federal State Statistics: Russian Federation 2011
Manufacture of poly(phenylethene) (polystyrene)
Poly(phenylethene) is manufactured from its monomer, phenylethene. Phenylethene, in turn, is produced from
benzene and ethene via ethylbenzene. There are thus three stages:
a) the manufacture of ethylbenzene from benzene
b) the manufacture of phenylethene (styrene)
c) the polymerization of phenylethene (styrene)
(a) The manufacture of ethylbenzene from benzene
Benzene vapour and ethene are mixed and passed over an acid catalyst, at 650 K and 20 atm pressure:
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(Polyvinyl chloride)
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Poly(ethene) (Polyethylene)
Poly(methyl 2-
methylpropenoate)
(Polymethyl methacrylate)
Poly(phenylethene)
(Polystyrene)
Poly(propene)
(Polypropylene)
Poly(propenoic acid)
(Polyacrylic acid)
Poly(propenonitrile)
(Polyacrylonitrile)
Poly(tetrafluoroethene)
(Polytetrafluoroethylene)
Polyurethanes
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2. Figure 2 This
Triumph motorcycle
has a fairing (the
structure around the
bike that reduces
drag by streamlining)
made of a blend of
ABS and a polyamide.
It is light, very strong
and has a high
chemical and heat
This is an example of a Friedel-Crafts reaction. The acid catalyst now used is a zeolite, ZSM-5, an
aluminosilicate.
(b) The manufacture of phenylethene (styrene)
Ethylbenzene vapour is mixed with excess steam and passed over heated iron(lll) oxide. Other metal oxides used
as the catalyst including those of magnesium, chromium(III) and zinc, usually coated on carbon or alumina. It is
dehydrogenated:
A small amount of potassium oxide is mixed with the iron(lll) oxide (which keeps the catalyst in the iron(lll) state).
The steam reduces 'coking' (the formation of soot on the catalyst from the decomposition of ethylbenzene at the
high temperatures used).
(c) The polymerization of phenylethene (styrene)
Radical polymerization is used to produce the polymer. The process is an example of addition polymerization
The predominant polymerization technique is continual thermal mass polymerization which is initiated by heat
alone. Suspension polymerization is also used. This technique requires the use of an initiator such as dibenzoyl
peroxide.
Poly(phenylethene) is a clear thermoplastic, with good moisture resistance, but is rather brittle. A tougher
product is also manufactured by polymerizing phenylethene containing 5-10% dissolved poly(buta-1,3-diene)
rubber. This tougher product - generally knownas High Impact Polystyrene (HIPS) - is made exclusively by
continuous thermal mass polymerization, in which heat is required to initiate the polymerization reaction. This
toughened polymer is translucent.
The structure of poly(phenylethene) made by these technologies is completely random in structure and is known
as an atactic structure. By modification of the polymerization technique - principally by the use of metallocene
catalysts - stereoregular (syndiotactic) structures can be obtained. This syndiotactic polymer (sPS) has
improved properties - particularly thermal and mechanical.
Another co-polymer is formed on polymerizing a mixture of phenylethene (styrene) and propenonitrile
(acrylonitrile). It is known as SAN (styrene-acrylonitrile). It is less flexible, more transparent and has more
resistance to heat and chemicals than poly(phenylethene). It is used in car headlamps, cassette covers, syringes
and high quality kitchen appliances.
A further modification involves the co-polymerization of phenylethene (styrene) with propenonitrile (acrylonitrile)
in the presence of poly(buta-1,3-diene) to make ABS plastics. A, B, S represent acrylonitrile, butadiene and
styrene, which give strength (A), flexibility (B), and hardness (S). Typically this plastic has a composition: 60%
(w/w) phenylethene (styrene), 25% propenonitrile (acrylonitrile), 15% buta-1,3-diene. The initiator used is often
potassium peroxydisulfate, K2S2O8.
3. resistance, which
means the fairing can
be installed near the
engine and the
exhaust pipe.
By kind permission of
BASF.
Figure 3 These
poly(phenylethene)
beads are shown prior to
and after expansion.
They were impregnated
during manufacture with
very fine particles of
graphite to improve
further their ability to
absorb heat.
By kind permission of
BASF.
ABS is tougher, scratch proof and more chemically resistant than rubber-modified poly(phenylethene) and is
used, for example, in casings for computers, cycle helmets, calculators, telephones, vacuum cleaners and toys.
Often ABS is blended with SAN to make it even more rigid.
Another variation is the co-polymer formed between ABS and methyl 2-methylpropenoate, which has a high
resistance to chemical attack, high transparency and is very tough.
Expanded poly(phenylethene) (polystyrene)
Expanded poly(phenylethene) is manufactured as beads containing pentane (a liquid at room temperature).
When they are heated in steam, the hydrocarbon volatilises and the beads expand (Figure 3). These are
subsequently blown into moulds and fused by further steaming and then cooling. The expanded
poly(phenylethene) has good thermal insulation and shock absorbing properties.