1. Which polyamide can be used as substitute of steel in belted radial tires?
a) kevlar
b) nomex
c) nylon 12
d) nylon 11
Explanation:Kevlar provides a fibre material, than has strength equal to steel at one-fifth of its weight. So it is used as a substitute for the steel in belted radial tires and also in manufacturing of protective clothing.
2. Which of the following nylons has a lower specific gravity than the others?
a) nylon 6
b) nylon 66
c) both have nearly same
d) none of the mentioned
Explanation:Nylon 6 and Nylon 66 have nearly same specific gravities which are close to 1.13 and 1.14, respectively.
3. How the viscosity of aromatic polyamide solutions does vary with the increase in volume fraction of polymer formed?
a) Increases always
b) first increases then decreases
c) first decreases then increases
d) decreases always
Explanation:The aromatic polyamide solutions show an initial increase in the viscosity with increase in volume fraction of polymer followed by a reversal in the trend and an abrupt decrease in viscosity when a critical volume fraction of polymer is exceeded.
4. Which of the following area of application restricts the use of cellulose nitrate?
a) photographic films
b) lacquor coatings
c) tool handles
d) printing inks
Explanation: Due to high inflammability and poor chemical and solvent resistance of cellulose nitrate, the use of cellulose nitrate in many areas of application has been considered no suitable. Those areas include photographic films, machine guards, toys, etc. Presently, it finds use in lacquor coatings and printing inks, tool handles, etc.
5. What is the role of H2SO4 in the preparation of cellulose nitrate?
a) catalyst
b) condensing agent
c) plasticizer
d) swelling agent
Explanation: H2SO4 is used as a condensing agent. A very low content of water tends to produce high degree of nitration and H2SO4 provides that service.
6. What should be the content of N2 in commercial cellulose nitrate used for plastic and coating purposes?
a) 10.9-12.2%
b) 13.5-14%
c) 8.9-9.2%
d) 16-18%
Explanation: Commercial cellulose nitrate used for plastic and coating applications have N2 content in the range of 10.9-12.2% whereas nitrates with N2 content greater than 12.5 are used for explosives.
7. Which of the following acts as a swelling agent for the cellulose in preparation of cellulose acetate?
a) acetic anhydride
b) acetic acid
c) sulphuric acid
d) alkyl chloride
Explanation: Acetic acid acts as a swelling agent for the cellulose and the pretreatment by it, makes cellulose swell whereby it makes accessible to acetic anhydride for acetylation.
8. Which of the following type of cellulose acetate is soluble in chloroform?
a) primary cellulose acetate
b) secondary cellulose acetate
c) all of the mentioned
d) none of the mentioned
Explanation:The primary acetate is soluble in the chlorinated hydrocarbons like chloroform and trichloro ethane while secondary acetate is insoluble in chloroform.
9.Which of the following cellulose ethers is used as viscosity modifiers in aqueous suspensions and emulsions?
a) ethyl cellulose
b) methyl cellulose
c) sodium carboxymethyl cellulose
d) propyl cellulose
Explanation:Sodium carboxymethyl cellulose of DS in the range of 0.5-1.0 is water soluble and is used in synthetic detergents and as stabilizers and viscosity modifiers in aqueous suspensions and emulsions. Ethyl cellulose is used in hot melt strippable coating formulations and surface coating formulations while methyl cellulose is used as a thickening agent and an emulsifying agent.
10. Which solvent is used for reaction with soda cellulose in the production of regenerated cellulose?
a) carbon disulphide
b) carbon tetrachloride
c) toluene
d) none of the mentioned
Explanation: Soda cellulose is transformed into sodium cellulose xanthate by reacting it with CS2 i.e. carbon disulphide. The xanthate formed is soluble in dilute aqueous alkali, which on acidification decomposes; the xanthate structure is broken and cellulose is regenerated.