Polymer Technology

241. Viscose rayon is

1. Cellulose nitrate
2. Regenerated cellulose nitrate
3. Regenerated cellulose acetate
4. None of these

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242. Viscosity of a polymer solution or melt

1. Decreases with increase in molecular weight
2. Decreases with increase in temperature
3. Increases with increase in temperature
4. Does not vary with temperature rise

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243. Vulcanisation of raw rubber makes it

1. Soft
2. Less elastic
3. Plastic
4. Tacky

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244. Vulcanisation of rubber

1. Decreases its tensile strength
2. Increases its ozone & oxygen reactivity
3. Increases its oil & solvent resistance
4. Converts its plasticity into elasticity

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245. Vulcanisation of rubber decreases its

1. Tensile strength
2. Resistance to organic solvents
3. Tackiness
4. Working temperature range

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246. Vulcanisation of rubber does not increase its

1. Elasticity
2. Plasticity
3. Ductility
4. None of these

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247. Which of the following additives are added to plastics to make it impervious to X-rays?

1. Asbestos
2. Barium salt
3. Carborundum
4. Phthalic acid

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248. Which of the following has the weakest intermolecular forces?

1. Polyisoprene
2. Nylon-66
3. Polystyrene
4. Bakelite

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249. Which of the following is a copolymer?

1. PVC
2. Bakelite
3. Polythene
4. Teflon

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250. Which of the following is a natural polyamide fibre?

1. Wool
2. Silk
3. Cotton
4. None of these

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