Polymers

Poly (vinyl acetate) or PVA or PVAc. Poly(vinyl acetate) is a synthetic polymer. It is also known as poly(ethenyl ethanoate), wood glue, white glue, carpenter's glue, school glue, PVA glue, Elmer's glue . It is prepared by the free radical polymerisation of vinyl acetate in the presence of free radical initiator like benzoyl peroxide . Poly(vinyl acetate). Poly(vinyl acetate) is an amorphous polymer . It is a colourless, transparent, soft and sticky material. It is soluble in organic solvents. It is resistant to heat but turns slightly yellow on prolonged storage above 120°C. It is used in adhesives , lacquers. It is used for making chewing gums, surgical dressings etc. It is used for the manufacture of poly(vinyl alcohol) etc. It is used in water based emulsion paints . Uses of poly(vinyl acetate). Questions on Poly(vinyl acetate); Q1) What is Poly(vinyl acetate)? Ans) Poly(vinyl acetate) is a synthetic polymer.  Q2) What is the monomer of Pol...

Poly (vinyl chloride) or PVC. PVC is a very important thermoplastic and is known as koroseal. It is prepared by the free radical polymerisation of vinyl chloride in the presence of small amount of free radical initiator like benzoyl peroxide. Poly (vinyl chloride). It is colourless, odourless, non- inflammable and a chemically inert plastic. Due to strong intermolecular attractions in polymeric chains, it is a hard polymer. It is soluble in cyclohexanone and Tetrahydrofuran (THF) . It has high resistance to chemicals, oils and weathering. PVC is used for making plastic bags. PVC is used for making sewage pipe. PVC is used for making insulating wires. PVC is used for making window frames. PVC is used for making bottles for storing mineral water, vinegar, cosmetics, detergents etc. Next Uses of PVC. Questions on polyvinyl chloride Q1) What is polyvinyl chloride? Ans) Polyvinyl chloride is a very important thermoplastic and is also known as koroseal. Q2...

Buna N or Nitrile rubber; Bu stands for butadiene, Na stands for sodium and N stands for ethylene nitrile. Nitrile rubber, also known as NBR, Buna-N, GR-N and acrylonitrile butadiene rubber, is a synthetic rubber. It is prepared by the copolymerisation of 1,3-butadiene and acrylonitrile. Buna N. It is a copolymer of butadiene and acrylonitrile . It possesses extraordinary resistance to oils, acids, salts, heat, abrasion and sunlight. It is less resistant to alkalies. It swells in organic solvents to a certain limit. It is used for making fuel tanks, gasoline hoses, conveyor belts. It is used as adhesives . It is also used to make automobile parts, high altitude air craft components. Uses of Buna N. Questions on Buna N Q1) What is Buna N? Ans) Buna N is a synthetic rubber. It is a copolymer of butadiene and acrylonitrile. Q2) What are the monomers of Buna N? Ans) 1,3-Butadiene and acrylonitrile are the monomers of Buna N. Q3) How is Buna N prepared? ...

Buna S or styrene butadiene rubber (SBR). In Buna S, Bu stands for butadiene and, Na stands for sodium and S stands for styrene. Styrene and butadiene are the monomers of Buna-S rubber. It is a co-polymer formed by the emulsion polymerisation of a mixture of butadiene and styrene in the presence of peroxide catalyst. Buna S. The rubber obtained is also called styrene butadiene rubber (SBR) or GR-S rubber. It is a type of synthetic rubber. It has good abrasion resistance. It is very tough and a good substitute for natural rubber.  It swells in organic solvents upto limited extend. It gets oxidised in the presence of traces of ozone. It is widely used in shoe soles and even in chewing gums. It is used to make car tyres, floor tiles. It is also used as adhesives . Uses of Buna S. Questions on Buna S Q1) What is Buna S? Ans) Buna S is a synthetic rubber. Styrene and butadiene are the monomers of Buna-S rubber. Q2) What are the monomers of Buna-S? ...

Neoprene rubber. Neoprene is also known as polychloroprene or pc rubber. Neoprene is a synthetic rubber. It is prepared by free radical polymerisation of chloroprene (2-chlorobuta-1,3-diene). Neoprene. It has strong resistance to oils, chemicals, UV light, ozone. It has good chemical stability. It is flexible over a wide temperature range. Neoprene is waterproof. Neoprene is used to make laptop sleeves. Neoprene is used to make wetsuits,drysuits and waders. Neoprene is widely used in the manufacture of safety gloves and other safety equipment. Neoprene is also used in some sports shoes to provide extra padding for insoles. Neoprene is also used to make orthopaedic braces (wrist,knee,etc). Uses of neoprene. Questions on Neoprene Q1) What is neoprene ? Ans) Neoprene is a synthetic rubber. Neoprene is also known as polychloroprene or pc rubber. Q2) What is the monomer of neoprene? Ans) Chloroprene is the monomer of neoprene. Q3) How is neoprene pre...

Natural rubber (Polyisoprene) Polyisoprene (polymer of isoprene) is the primary chemical constituent of natural rubber. Thus isoprene is a monomer of natural rubber. Polyisoprene. Natural rubber is soft and sticky. It has elasticity. It can be used over a narrow range of temperature (from 10°C to 60°C). Natural rubbers are sensitive to heat. Natural rubbers are easily oxidised by air. It is insoluble in water. It is soluble in solvents like ether, carbon tetrachloride, petrol etc. Natural rubbers are used to make rubber bands. They are also used to make shoe soles and rubber tubes. They are used to make gloves, erasers, mats etc. Next Uses of natural rubber. Questions on polyisoprene; Q1) What is polyisoprene? Ans) Polyisoprene (polymer of isoprene) is the primary chemical constituent of natural rubber. Q2) What is the monomer of polyisoprene? Ans) Isoprene is the monomer of polyisoprene. Q3) Write some properties of polyisoprene? Ans) Some properti...

Glyptal Glyptal is a polymer. Glyptal is also known as alkyd resins. Glyptal is formed by condensation polymerisation of ethylene glycol and phthalic acid. Glyptal. Glyptal is a synthetic polymer. It is basically a Polyester. Polyester is a category of polymers that contain the ester functional group in their main chain. Glyptal is non biodegradable i.e it cannot be broken down by natural organisms and acts as a source of pollution. Glyptal is a thermosetting plastic i.e it is a polymer that irreversibly becomes rigid when heated. When its solution in a suitable solvent is evaporated, it leaves a tough but non flexible film. It is therefore used in the manufacture of paints and lacquers. Uses of glyptal. Glyptal is formed by condensation polymerisation of ethylene glycol and phthalic acid, but terylene is formed by condensation polymerisation of ethylene glycol and terepthalic acid. Next

Terylene Terylene is a synthetic polyester fibre. Terylene is formed by condensation polymerisation of ethylene glycol and terepthalic acid. Formation of Terylene. It is also known as Polyethylene terepthalate (PET) or Dacron. Terylene is a very strong fibre and will suffer very little loss in strength when wet. It is elastic in nature and it resist creasing. Terylene dries quickly. It is light weight. It can be used in bottle making. It is used to make ropes. It is also used to make sails for boats. Terylene is extensively used in textile industry to make sarees, dress material etc. Next Uses of Terylene.

Difference between low density polyethylene (LDPE) and high density polyethylene (HDPE). Density Low density polyethylene has low density than high density polyethylene. High density polyethylene has high density than low density polyethylene. Synthesis Low density polyethylene is prepared by heating pure ethylene to 350-570K under high pressure (1000-2000 atm) in the presence of traces of oxygen or peroxide initiator (catalyst) which initiates polymerisation. High density polyethylene is prepared by heating ethene in a hydrocarbon solvent at about 333-343K under pressure of 6-7 atm in the presence of a catalyst such as triethylaluminium and titanium tetrachloride (known as Zeiglar Natta catalyst). Low density polyethylene and High density polyethylene. Structure Low density polyethylene has lots of branching. High density polyethylene has less branch. Strength HDPE is stronger than LDPE. Low density polyethylene vs high density polyethylene. Flexib...

Polyacrylonitrile (PAN) or Orlon. Orlon is a polymer of vinyl cyanide (acrylonitrile). It is obtained by addition polymerisation of acrylonitrile in the presence of a peroxide catalyst. Polyacrylonitrile It appears as a white solid. Polyacrylonitrile is insoluble in water. It is very inert and resistant to most organic solvents and acids. It is UV resistant. Its fibers are resistant to breaking, are soft, comfortable and thermal insulation. It is used as fibres to make knitted clothes like socks, sweaters etc. It is also used as fibre reinforced concrete, sails for yachts etc. Polyacrylonitrile is usually used to make other polymers like carbon fibres. It is also used as fibres for outdoor awnings. Next Uses of polyacrylonitrile.

Polytetrafluoroethylene (PTFE) Polytetrafluoroethylene (trade name- Teflon), was accidentally discovered by Roy Plunkett (a Dupont chemist). This is a polymer which has repeating chains of -(-CF₂-CF₂-)- in it. It is an addition polymer of tetrafluoroethylene (CF₂= CF₂). It is obtained by heating tetrafloroethylene in a presence of catalyst at high pressure. Polytetrafluoroethylene. Polytetrafluoroethylene is produced by the free radical mechanism. It is resistant to many chemicals. It is weather and UV resistant. It is non sticky. It appears to be quite slippery. It has outstanding performance at extreme temperatures. It is used as a non-stick coating for cooking pans and utensils. Teflon is also used in curling irons and straighteners. Teflon is also coated on the iron to quicken the heating up process. Teflon is also used as artificial limb and body parts. Teflon tape or plumber's tape is a polytetrafluoroethylene film tape commonly used in plumbing. Teflon...

Difference between nylon 6 and nylon 6,6 Definition Nylon 6, also known as polycaprolactam, is a polyamide formed via ring opening polymerisation. Nylon 6,6 is a polyamide made via condensation polymerisation. Monomer Nylon 6 requires only one type of monomer for its production. Nylon 6,6 requires two types of monomers for its production. Produced from Nylon 6 is produced from caprolactam. Nylon 6,6 is produced from hexamethylene diamine and adipic acid. Polymerisation Nylon 6 is produced via ring opening polymerisation. Nylon 6,6 is produced via condensation polymerisation. Melting point Nylon 6 has lower melting point. Nylon 6,6 has higher melting point. Crystalline Nylon 6 is less crystalline. Nylon 6,6 is more crystalline. Next

Nylon 6,6 Nylon 6,6 is a type of polyamide or nylon. Nylon 6,6 is produced via condensation polymerisation. Nylon 6,6 is made of two monomers each containing 6 carbon atoms, hexamethylene diamine and adipic acid, which give nylon 6,6 its name. Nylon 6,6 Nylon 6,6 has a high melting point which makes it more resistant to heat and friction. Its chemical stability enables it not to be affected by solvents such as water, alcohol, alkali etc. Its amorphous structure accounts for its elastic property. Nylon 6,6 is used to make airbags, tires, ropes etc. It is a light material, so it is suitable to be used for parachutes. It is waterproof, so it is used to make swimwear. It is also used to make machine parts. Next Uses of nylon 6,6

Nylon 6 There are many types of nylon available. The most common type of nylon are nylon 6 and nylon 6,6. Nylon 6 or polycaprolactam is a polymer. It is a semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring opening polymerisation. Nylon 6 is synthesized by ring opening polymerisation of caprolactam. Caprolactam. Nylon 6 is made from a caprolactam monomer having 6 carbon atoms. Hence the name nylon 6. When caprolactam is heated at about 533K in an inert atmosphere of nitrogen for about 4-5 hours, the ring breaks and undergoes polymerisation. Then the molten mass is passed through spinneret to form fibres of nylon 6. Polycaprolactam. Nylon 6 fibres are tough, possessing high tensile strength, as well as elasticity and lusture. They are wrinkleproof and highly resistant to abrasion and chemicals such as acid and alkalies. It is used to make toothbrush bristles, and strings for acoustic and class...

Nylon Wallace Carothers was an American chemist, inventor and the leader of organic chemistry at DuPont, credited with the invention of nylon (nylon 6,6). This fiber was first introduced in the 1930s as an early substitute for silk. The nylons are polyamides with recurring amide groups. They contain carbon, oxygen, nitrogen and hydrogen elements. Amide group. Nylon is a synthetic fibre that is strong and very light in weight. Nylon is also easy to wash. Nylon fibre is highly resistant to heat, UV rays and chemicals. Nylon is a lustrous fibre. Nylon fabrics retain their shape and appearance after washing. It has good stability and does not shrink. Nylon can be easily dyed with a wider range of dyes. The dyed fabrics retain their colour and have good resistance to fading. Nylon is used to make ropes for different purposes, curtains, socks, toothbrush bristles, sleeping bags, tents, fishing nets, parachutes, sportswear, strings of badminton and tennis racquets and car s...

Polyethylene. Polyethylene(or polythene) is made from the polymerisation of ethylene (or ethene) monomer in the presence of catalyst. Polyethylene. It is a polymer of ethylene. Polyethylene is resistant to water,acids, alkalies and most solvents. Polyethylene contains the chemical elements carbon and hydrogen. Polyethylene (PE) is a plastic. Polyethylene belongs to the family of plastics called thermoplastics. Types of polyethylene. Based on density, polyethylene is classified into two types. Low density polyethylene. High density polyethylene. Low density polyethylene. Low density polyethylene (LDPE) has a density range of 0.910 - 0.940 g/cm³ and is prepared by the free radical polymerisation of ethene. It is a poor conductor of electricity and is chemically inert. The LDPE is used for making plastic bags and film wrap. High density polyethylene. High density polyethylene (HDPE) has a density range of 0.93 - 0.97 g/cm³. It is obtained when add...

Difference between rubber and plastic. Difference between rubber and plastic. Definition Rubber is an elastic material that is either obtained from rubber plants or synthesized using petroleum oil. Plastic is a polymer material that has the ability to be molded and shaped by application of heat and pressure. Property Rubber has elasticity (resume its normal shape after being stretched). Plastic has plasticity (easily shaped or molded). Obtained from Rubber is obtained from both industrial methods and natural methods. Plastics are obtained from industrial methods. Made of Rubber is made from the sap of tree, synthetic rubber is created from chemicals found in petroleum. Plastics are made from crude oil. Benefits Rubber is flexible and can be turned into any shape. Plastic is cheap to produce and is unbreakable. Disadvantages Rubber becomes soft and sticky when it is heated. Plastics may cause cancer and when it burns it produces poisonous gases...

Difference between thermoplastic and thermosetting resins. Action of Heat. Thermoplastic polymers or resins soften on heating. Thermosetting polymers or resins do not soften on heating. At higher temperature they burn or char. Difference between thermosets and thermoplastics. Polymerisation Thermoplastic polymers are formed by addition polymerisation. Thermosetting polymers are formed by condensation polymerisation. Nature Thermoplastics are moldable. Thermosetting resins are brittle. Molecular weight Thermoplastic polymers have low molecular weight. Thermosetting polymers have high molecular weight. Solubility Thermoplastics are soluble in organic solvents. Thermosetting polymers are insoluble in organic solvents. Reshaping  Thermoplastic polymers can be softened and reshaped. Thermosetting polymers cannot be softened and reshaped again. Example Polyethylene, polystyrene, PVC etc are thermoplastic polymers. Phenol formaldehyde, ure...

Difference between organic and inorganic polymers. Definition Organic polymers are the polymers that essentially contain carbon atom in the backbone. Inorganic polymers are the polymers that have no carbon atom in the backbone. Structure Most organic polymers have simple structures. Almost all inorganic polymers are highly branched and have complex structures. Electrical Conductivity In most of the aqueous solutions, organic polymers are typically poor conductors of electricity and heat. Inorganic polymers in aqueous solutions are good conductors of electricity, this is because they have high ability to ionise and this makes them better conductors. Flammability Organic polymers are flammable whereas inorganic polymers are nonflammable. Effect on nature Organic polymers are environmental friendly as these are biodegradable. Inorganic polymers are not environmental friendly as these are non biodegradable. Examples Organic polymers include polysaccharide...

Polymer Degradation. Polymer degradation is a change in the properties (color, shape, etc) of a polymer or polymer- based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalies and some salts. These changes are usually undesirable. Types of degradation in polymer 1)Photoinduced degradation. 2)Thermal degradation. 3)Chemical degradation. 4)Biological degradation. Photoinduced degradation Most polymers can be degraded by photolysis to give lower molecular weight molecules. Electromagnetic waves with energy of visible light or higher, such as ultraviolet light rays and gamma rays are usually involved in such reaction. Thermal degradation Chain growth polymers like poly(methyl methacrylate) can be degraded by thermolysis at high temperature to give monomers, oils, gases and water. Chemical degradation It is a type of polymer degradation that involves a change of the polymer properties due to a...

Zeolites Zeolites are crystalline solid structures made of silicon, aluminium and oxygen that form a framework with cavities and channel inside where cations, water or small molecules may reside. Examples of zeolites. They are often also reffered to as molecular sieves. Sieve and molecular sieve. Many of them occur naturally as minerals and are extensively mined in many parts of the world finding application in industry and medicine. However, most of zeolites have been made synthetically. Zeolites are of two types    1) Natural zeolite.    2) Synthetic zeolite. Natural zeolite: There are about 40 naturally occurring zeolites. Natural zeolite are non porous. For example; Natrolite. Synthetic zeolite: Synthetic (artificial) zeolites (around 150) have been designed for specific purposes. Synthetic zeolite are porous. Mordenite is a synthetic zeolite. Natural zeolites are used as animal feed, odour control, water purification and water treatme...

Polyester resins Polyester resins are unsaturated synthetic resins. These unsaturated polyester resins are condensation polymer formed on reacting polyols i.e the compound containing multiple 'hydroxy' functional group, with a saturated or unsaturated dibasic acid. Typically, the Polyols used are glycols for example ethylene glycol and the dibasic acid used are phthalic acid, isophthalic acid and maleic acid. The biproduct water formed during esterification is continuously removed and driving the reaction to completion. An example of polyester resin is polyethylene terepthalate (PET). Polyester resins have adequate resistance to water and other chemicals, low shrinkage, styrene odour and are difficult to mix than other resins. Polyester resins have adequate resistance to weathering and ageing. Polyester resins can withstand a temperature upto 80°C. The wall panel fabricated from polyester reinforce with fibreglass called fibreglass reinforced plastic (FRP) are use...

Ion exchange resins. Ion exchange resins or polymers are the resins or polymer which act as a medium for ion exchange. For example Sodium polystyrene sulfonate. Ion exchange is a reversible chemical reaction where the ions dissolve in a solution are removed and replaced by other ion of same electrical charge. Ion exchange resins are normally in the form of small microbeads, usually white or yellowish in colour. Image license: CC-BY-SA The beads are typically porous. Most of these resins are made of polystyrene sulfonate. Polystyrene sulfonate. Ion exchange resins consist of two main types namely cation exchange resins and anion exchange resins. Cation exchange resins exchange positively charged ions. Anion exchange resins exchange negatively charged ions. Ion exchange resins are used for removal of calcium, magnesium, iron and manganese salts from water (water softening). They are also used as an alternative to zeolites. These resins are also used in biodi...

Epoxy resins Epoxy resins are also known as polyepoxides. They belong to the category of reactive prepolymers and polymers that contain the epoxide group. The epoxide group is also called oxirane group, is shown below. Epoxide group. Most common epoxy resins are produced from a reaction between epichlorohydrin (ECH) and bisphenol-A (BPA), though the latter may be replaced by other raw materials. Diglycidyl ether of bisphenol-A (DGEBA) and novolac epoxy resins are most commonly used epoxies. Diglycidyl ether of bisphenol-A (DGEBA) is a typical commercial epoxy resins and are synthesized by reacting bisphenol-A with epichlorohydrin in presence of a basic catalyst. Diglycidyl ether of bisphenol-A. There are two main categories of epoxy resins, namely the glycidyl epoxy resins and non glycidyl epoxy resins. The glycidyl epoxies are further classified as glycidyl ether, glycidyl ester and glycidyl amine. The non glycidyl epoxies are either aliphatic or cycloaliphatic ep...

Amino resins Amino resins are condensation products obtained by reaction of formaldehyde with nitrogen bearing compounds such as aniline, amides. For example urea formaldehyde, melamine formaldehyde. Urea formaldehyde is prepared by condensation reaction between urea and formaldehyde in acidic or alkaline medium. The first product formed during the formation of resin is monomethylol and dimethylol ureas. Synthesis of amino resins step 1. Polymerisation can take place from mono or di methylol urea or possibly through both with the formation of long chain. Synthesis of amino resins step 2 The formation of melamine formaldehyde resin is similar to formation of urea formaldehyde. Amino resins are clear and colourless. They are harder and have high strength but lower heat and moisture resistance than phenolics. The melamine formaldehyde resins have high moisture, heat and ageing resistance than urea formaldehyde resins but are usually costly. Both urea formaldehyde and...