Polymers

 Number average, Weight average and viscosity average molecular weight (Comparison): • We know that the number average molecular weight, Weight average molecular weight and viscosity average molecular weight are given by Number average, Weight average and viscosity average molecular weight. • For monodisperse sample Number average molecular weight = Weight average molecular weight. Number average molecular weight = Weight average molecular weight. • When a is unity Weight average molecular weight = viscosity average molecular weight. Weight average molecular weight = viscosity average molecular weight. • For a polydispersed polymer  Relation between number average,weight average and viscosity average molecular weight. as shown in fig below Distribution of molecular weights in a typical polymer sample. • Let us compare the number average molecular weight and weight average molecular weight.  The number average molecular weight and weight average molecular weight. 

Fibre Reinforced Polymer; Fibre reinforced polymer are also called fibre reinforced plastic. A composite is a combination of two or more materials which differ in form or composition on a macroscale . Fibre reinforced polymer (FRP) is a composite that consist of high performance fibres embedded in a polymer matrix. Fibres utilized in FRP are carbon, glass and aramid. Polymers utilized in FRP are epoxy, vinyl ester, polyester and phenol formaldehyde resins. Fibre reinforced composites can have different arrangement of fibres within the polymer. (a) One dimensional arrangement;  Here the fibres are only aligned in X-direction. (b) Two dimensional arrangement, random; Here the fibres are randomly aligned in X-direction and Y-direction. (c) Two dimensional arrangement, oriented; Here the fibres are aligned in X-direction and Y-direction in a particular manner. (d) Three dimensional arrangement, random; Here the fibres are randomly aligned in X-direction, Y-dire

Polyester, Polycarbonate, Polyamide and Polyurethane; Polyester Ester linkage; In ester linkage an oxygen atom (irrespective of position) is bonded to carbonyl group. The polymer containing ester linkage is called Polyester. For example; glyptal, terylene,PHBV and Polyglycolic acid. Polycarbonate Carbonate linkage; In carbonate linkage two oxygen atoms are bonded to carbonyl group. The polymer containing many carbonate linkage is called Polycarbonate. Polyamide Amide linkage; In amide linkage -NH-group (irrespective of position) is bonded to carbonyl group. The polymer containing many amide linkage is called Polyamide. For example; Nylon6, Nylon6,6, Kevlar, Nylon-2-Nylon-6. Polyurethane Urethane linkage; In urethane linkage an -NH-group and an oxygen atom is bonded to carbonyl group. The polymer containing many urethane linkage is called Polyurethane. Questions on Polyester, Polycarbonate, Polyamide and Polyurethane; Q1) What is Polyester? Ans)A pol

Polymerisation; Polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymers. For example; Nylon 6,6 is obtained by polymerisation of hexamethylene diamine and adipic acid . Polytetrafluoroethylene/Teflon is obtained by polymerisation of tetrafluoroethylene . Polyacrylonitrile is obtained by polymerisation of acrylonitrile . Glyptal is produced by polymerisation of ethylene glycol and phthalic acid . Polyisoprene is produced by polymerisation of isoprene . Polychloroprene/Neoprene is produced by polymerisation of chloroprene . Buna S is produced by polymerisation of butadiene and styrene . Buna N is produced by polymerisation of butadiene and acrylonitrile. Polyvinyl chloride is produced by polymerisation of vinyl chloride . Polyvinyl acetate is produced by polymerisation of vinyl acetate . Polystyrene is produced by polymerisation of styrene. Polypropylene is made from the polymerisation

Monomers. A monomer is a molecule that can be reacted together with other monomer molecules to form a larger polymer chain. Some monomers are given below with their polymers . Tetrafluoroethene ; Tetrafluoroethene is the monomer of Teflon . Teflon and its monomer. Acrylonitrile (vinyl cyanide); Acrylonitrile is the monomer of Polyacrylonitrile . Polyacrylonitrile and its monomer. Isoprene; Isoprene is the monomer of Polyisoprene (natural rubber). Polyisoprene and its monomer. Chloroprene; Chloroprene is the monomer of Neoprene . Neoprene and its monomer. Vinyl chloride; Vinyl chloride is the monomer of Poly(vinyl chloride) . Polyvinyl chloride and its monomer. Vinyl acetate; Vinyl acetate is the monomer of Poly(vinyl acetate). Poly(vinyl acetate) and its monomer. Propylene; Propylene is the monomer of Polypropylene . Polypropylene and its monomer. Styrene; Styrene is the monomer of Polystyrene . Polystyrene and i

Polylactic acid/PLA. Polylactic acid is a biodegradable thermoplastic polymer . Polylactic acid is obtained from lactic acid monomer. Polylactic acid. Polylactic acid is stable to UV radiation. Polylactic acid has good resistance to moisture. Polylactic acid has good elasticity. Polylactic acid is an aliphatic polyester . It can be used as a food packaging polymer. Polylactic acid is suitable for textile fibre applications such as shirts, carpets, sportswear etc. Polylactic acid is used in implants and medical devices (screws, sutures etc). Polylactic acid is suitable for use in floor mats. Uses of Polylactic acid. Questions on Polylactic acid/PLA; Q1) What is Polylactic acid? Ans) Polylactic acid is a biodegradable thermoplastic polymer. Q2) What is the monomer of Polylactic acid? Ans) Polylactic acid is obtained from lactic acid monomer. Q3) Write some properties of Polylactic acid? Ans) Some properties of Polylactic acid are given below;