Differentiate between rubbers and plastics on the basis of intermolecular forces.
Rubber is a natural polymer which is capable of returning to its original length, shape or size after being stretched or deformed. It is a common example of an elastomer. The m-polyisoprene molecule (natural rubber) consists of various chains held together by weak van der Waals interactions and has a coiled structure.
Thermoplastics are the polymers in which intermolecular forces of attraction are in between those of elastomers and fibres. They are neither very strong nor very weak and have no cross links between the chains molecules capable of repeatedly softening on heating and hardening on cooling.
Which of the following polymers are used as fibre?
(a) Polytetrafluoroethane (b) Poly chloroprene
(c) Nylon (d) Terylene
Write the monomers used for gettingThe following polymers:
(i) Polyvinylchloride
(ii) Teflon (iii) Bakelite
Which of the following polymers are condensation polymers?
(a) Bakelite (b) Teflon
(c) Butyl rubber (d) Melamine formaldehyde resin
Name the polymers used in laminated sheets and give the name of monomeric units involved in its formation.
Assertion (A): Olefinic monomers undergo addition polymerization.
Reason (R): Polymerisation of vinyl chloride is initiated by peroxides/ persulphates.
What is a biodegradable polymer ? Give an example of a biodegradable aliphatic polyester.
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.
Out of chain growth polymerisation and step growth polymerisation, in which type will you place the following.
Which of the following polymers are thermoplastic?
(a) Teflon (b) Natural rubber (c) Neoprene (d) Polystyrene
What is the role of benzoyl peroxide in addition polymerization of alkenes? Explain its mode of action with the help of an example.
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.
Write the names and structures of the monomers of the following polymers:
(i) Buna-S (ii) Buna-N (iii) Dacron (iv) Neoprene
Which of the following are examples of synthetic rubber?
(a) Polychloroprene (b) Polyacrylonitrile
(c) Buna-N (d) cis-polyisoprene
How is the following resin intermediate prepared and which polymer is formed by this monomer unit?
Assertion (A): For making rubber synthetically, isoprene molecules are polymerised.
i Reason (R): Neoprene (a polymer of chloroprene) is a synthetic rubber.
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?
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.
Assertion (A): For making rubber synthetically, isoprene molecules are polymerised.
i Reason (R): Neoprene (a polymer of chloroprene) is a synthetic rubber.
Which of the following are addition polymers?
(a) Nylon (b) Melamine formaldehyde resin
(c) Orion (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
Which type of biomolecules have some structural similarity with synthetic polyamides? What is this similarity?
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 does the presence of double bonds in rubber molecules influence their structure and reactivity?
Which of the following polymers can have strong intermolecular forces?
(a) Nylon (b) Polystyrene (c) Rubber (d) Polyester
Assertion (A): Polytetrafluoroethene is used in making non-stick cookware. Reason (R): Fluorine has highest electronegativity.
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?
