What is the structural difference between HDP and LDP? How does the structure account for different behaviour and nature, hence the use of a polymer?
LDP consists of highly branched chain molecules. Due to branching, the molecules do not pack well and therefore, it has low density (0.92 g cm 3) and low melting point. LDP is transparent of moderate tensile strength and high toughness. It is chemically inert.
HDP consists of linear chains and therefore, the molecules can closely pack in space. Therefore, it has high density (0.97 g cm 3) and high melting point. It is quite hard, tougher and has greater tensile strength than LDP.
Name the polymers used in laminated sheets and give the name of monomeric units involved in its formation.
Write the monomers used for gettingThe following polymers:
(i) Polyvinylchloride
(ii) Teflon (iii) Bakelite
Out of chain growth polymerisation and step growth polymerisation, in which type will you place the following.
Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the polymers with this property collectively called? What are the structural similarities between such polymers? Bakelite, urea-formaldehyde resin, polythene, polyvinyl, polystyrene.
Which of the following polymers are used as fibre?
(a) Polytetrafluoroethane (b) Poly chloroprene
(c) Nylon (d) Terylene
Which of the following are characteristics of thermosetting polymers?
(a) Heavily branched cross linked polymers.
(b) Linear slightly branched long chain molecules.
(c) Become infusible on moulding so cannot be reused.
(d) Soften on heating and harden on cooling, can be reused.
Assertion (A): Olefinic monomers undergo addition polymerization.
Reason (R): Polymerisation of vinyl chloride is initiated by peroxides/ persulphates.
What is the role of benzoyl peroxide in addition polymerization of alkenes? Explain its mode of action with the help of an example.
Assertion (A): Polyamides are best used as fibres because of high tensile strength.
Reason (R): Strong intermolecular forces (like hydrogen bonding within polyamides) lead to close packing of chains and increase the crystalline character, hence, provide high tensile strength to polymers.
Which of the following polymers are condensation polymers?
(a) Bakelite (b) Teflon
(c) Butyl rubber (d) Melamine formaldehyde resin
Which of the following polymers are thermoplastic?
(a) Teflon (b) Natural rubber (c) Neoprene (d) Polystyrene
Which of the following monomers form biodegradable polymers?
(a) 3-hydroxybutanoic acid +3-hydroxypentanoic acid
(b) Glycine + aminocaproic acid
(c) Ethylene glycol + phthalic acid
(d) Caprolactam
What is a biodegradable polymer ? Give an example of a biodegradable aliphatic polyester.
Assertion (A): For making rubber synthetically, isoprene molecules are polymerised.
i Reason (R): Neoprene (a polymer of chloroprene) is a synthetic rubber.
Write the names and structures of the monomers of the following polymers:
(i) Buna-S (ii) Buna-N (iii) Dacron (iv) Neoprene
What is the structural difference between HDP and LDP? How does the structure account for different behaviour and nature, hence the use of a polymer?
Which of the following are examples of synthetic rubber?
(a) Polychloroprene (b) Polyacrylonitrile
(c) Buna-N (d) cis-polyisoprene
Why should the monomers used in addition polymerisation through free radical pathway be very pure?
A natural linear polymer of 2-methyl-l,3-butadiene becomes hard on treatment with sulphur between 373 to 415 K and -S – S – bonds are formed between chains. Write the structure of the product of this treatment?
What is the structural difference between HDP and LDP? How does the structure account for different behaviour and nature, hence the use of a polymer?
How is the following resin intermediate prepared and which polymer is formed by this monomer unit?
Assertion (A): Olefinic monomers undergo addition polymerization.
Reason (R): Polymerisation of vinyl chloride is initiated by peroxides/ persulphates.
Why should the monomers used in addition polymerisation through free radical pathway be very pure?
Match the polymers given in Column I with the type of linkage present in them given in Column II.
Assertion (A): Network polymers are thermosetting.
Reason (R): Network polymers have high molecular mass.
Low density polythene and high density polythene, both are polymers of ethane but there is marked difference in their properties. Explain.
Classify the following as addition and condensation polymers:
Terylene, Bakelite, Polyvinyl chloride,Polythene
Arrange the following polymers in increasing order of their intermolecuiar forces.
(i) Nylon 6,6, Buna-S, Polythene
(ii) Nylon 6, Neoprene, Polyvinyl chloride
Vulcanisation makes rubber .
(a) more-elastic (b) soluble in inorganic solvent
(c) crystalline (d) more stiff
Which type of biomolecules have some structural similarity with synthetic polyamides? What is this similarity?
Phenol and formaldehyde undergo condensation to give a polymer (A) which on heating with formaldehyde gives a thermosetting polymer (B). Name the polymers. Write the reactions involved in the formation of (A). What is the structural difference between two polymers?
