Short answer questions
D. Answer in brief.
1. What is a polymer?
2. Why is nylon considered to be a good
material for making fishing nets?
3. Why is polyester considered to be a good
material for making the sails of ships?
4. What are blended fibres?
5. Name the component fibres for each of the
following: polycot, polywool and cotswool.
6. What are plastics?
7. Give the differences between thermoplastics
and thermosetting plastics.
Answers
polymer, any of a class of natural or synthetic substances composed of very large molecules, called macromolecules, that are multiples of simpler chemical units called monomers. Polymers make up many of the materials in living organisms, including, for example, proteins, cellulose, and nucleic acids.
Nylon is considered to be a good material for making fishing nets because; Nylon can absorb water and will not get weakened by being submerged in water for a longer duration. The nylon properties are such that it can withstand any change, whether it is dry or wet.
Polyester is widely used for makimg of boats and for sail material because it has good strength and durability, relatively low stretch and reasonable prices (lowprice, in budget).
Blended fibre means a mix of different fibres as it name denotes. ... Fibre blends and combinations are those fabrics in which two or more textile fibres are used. Polyester and cotton, which combines the properties of natural and synthetic fibres, is one of the most common blended fabrics.
The component fibre for polycot are Polyster&Cotton. The component fibre for Terrywool are Polyster&Wool. The component fibre for Cotswool are Cotton&Wool.
Plastics is the term commonly used to describe a wide range of synthetic or semi-synthetic materials that are used in a huge and growing range of applications. ... The raw materials used to produce plastics are natural products such as cellulose, coal, natural gas, salt and, of course, crude oil.
Thermoplastics have secondary bonds between molecular chains. Thermosetting plastics have primary bonds between molecular chains and held together by strong cross-links. Thermoplastics have low melting points and low tensile strength. Thermosetting plastics have high melting points and tensile strength.