Tag: plastic
Questions Related to plastic
Which of the following is not a characteristic of thermosetting polymers?
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Linear or slightly branched long chain polymers.
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Heavily branched and cross-linked polymers.
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Become infusible on moulding.
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Cannot be remoulded or reused on heating.
Some characters of thermosetting polymers:
- these polymers are cross-linked or heavily branched molecules,
- on heating it undergoes extensive cross-linking in moulds and again become infusible,
- these cannot be reused
Some common examples are bakelite, melamine and urea formaldehyde resin
Which among the following is a cross-linked polymer?
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Polyesters
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Glycogens
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Melamine-formaldehyde
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Polyvinyl chloride
Melamine-formaldehyde polymer is cross-linked polymer or thermosetting polymer which on heating undergo extensive cross linking in moulds and again become infusible. These cannot be reused. Some common examples are bakelite, urea-formaldelyde resins, etc.
Which of the following polymers does not involve cross-linkages?
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Vulcanised rubber
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Bakelite
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Melamine
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Teflon
Bakelite, melamine( thermosetting) and vulcanised rubber( elastomer) have cross-linkages in the structures whereas Teflon is linear addition or chain growth polymers that have not cross-linkages.
Match the column I with column II and mark the appropriate choice.
| Column I | Column II | ||
|---|---|---|---|
| (A) | Buna-S | (i) | Thermosetting |
| (B) | Polyamides | (ii) | Fibres |
| (C) | Polyvinyls | (iii) | Elastomers |
| (D) | Urea-formaldehyde | (iv) | Thermoplastics |
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(A) $\rightarrow$ (iv), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (i), (D) $\rightarrow$ (ii)
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(A) $\rightarrow$ (ii), (B) $\rightarrow$ (i), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (iv)
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(A) $\rightarrow$ (iii), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (iv), (D) $\rightarrow$ (i)
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(A) $\rightarrow$ (i), (B) $\rightarrow$ (iv), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (iii)
| Buna$-S$ | (iii) Elastomers |
|---|---|
| Polyamides | (ii) Fibers |
| Polyvinyls | (iv) Thermoplastic |
| Urea-formaldehyde | (i) Thermosetting |
[A] Elastomers - these are rubber like solids with elastic properties
Teflon is a special plastic on which oil and water do not stick.
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True
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False
Teflon is a synthetic polymer (polytetrafluoroethylene) that can be used to cover the surface of certain object and imparts nonstick properties to it. Teflon is used for Non Stick material because the monomer units are hydrophobic in nature (tetrafluoroethylene) and thus oil and water do not stick to it.
option A is correct.
Cooking pans have plastic handles.
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True
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False
Plastics are categorized into thermosoftening/thermoplastic and thermosetting/thermoset plastics.
In thermosoftening plastics, the forces between the polymer chains are weak, so they can easily be remoulded
into new shapes. This makes it possible to recycle this type of
plastic. whereas in thermosetting plastics there are strong covalent
bonds forming cross-links between the polymer chains, making these
plastics hard and rigid. Once set into its original shape, a
thermosetting plastic can't be softened and remoulded. The strong bonds between polymers also mean that thermosetting plastics are much more heat resistant than thermosoftening ones.
Cooking pans' handle are made from thermosetting plastic like bakelite as this is resistant to heat.
option A is correct
Plastics are generally good conductors of electricity.
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True
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False
Plastics are high molecular weight (macromolecular or polymeric) organic substances that have usually been synthesized from low molecular weight compounds. Being organic origin have no ionic character in them and thus can not conduct electricity. They are insulators.
Hence, option $B$ is correct.
Plastics are mainly used by everyone because :
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They are cheap
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Easy to handle
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Do not break
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Light weight
Plastics find many applications in day-to-day life because of various reasons as :
1) They are economical, thus are cheap.
2) Easy to handle unlike ceramics and glass which are brittle.
3) Light weight materials and easy to carry.
4) High durability but they are breakable.
Therefore option A, B and D are correct.
Plastic containers can resist decomposition for:
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50000
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3000
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1000
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40000
Plastic waste is one of many types of wastes that take too long to decompose. Normally, plastic items can take up to 1000 years to decompose in landfills. But plastic bags we use in our everyday life take 10-1000 years to decompose, while plastic bottles can take 450 years or more.
Which of the following takes so many years to degrade?
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Jute
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Cotton
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Wool
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Plastic