After identifying the cloth materials made up of synthetic fibres, observe their characteristics such as strength, action of water and action of heat and write it.
Answers
Some of the most important properties of synthetic materials are as follows: 1. Tensile strength 2. Action of water 3. Action of heat and flame 4. Thermal conductivity 5. Electrical conductivity.
The usefulness or otherwise of a synthetic material depends upon the following properties.
1. Tensile strength:
This property gives us an idea of the strength a material shows when it is pulled.
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The pulling stress required to break a material is called its tensile strength:
The greater the tensile strength of a fibre, the greater is the load its yarn can bear. In respect of fibres, tensile strength is expressed in g/tex, where tex is the mass in grams of 1000 m of the fibre or its yarn.
The tensile strengths of different fibres can be compared in the following way:
Activity:
Do this activity in class. Tie one end of a cotton thread to a hook fixed to a rigid body and the other end to a pan of a balance. Put some weights on the pan and increase the weight in small steps, till the thread breaks.
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Note the total weight, including that of the pan, required to break the thread. Repeat the activity with other kinds of fibre, e.g., wool, silk, nylon and polyester, of similar thickness and the same length. The different weights required to break the threads will give comparative values of their tensile strength.
Answer:
nylon- poor absorption of water, melts and sticks to the surface when exposed to heat
rayon- readily melts at medium to high heat , recommended not to wear such clothes when in kitchen
spandex- recommended not to use in summer as it does not absorb sweat thus very less absorption of water
Explanation:
artificial fibres mostly melt when heated and stick to the surface but they don't burn and usually do not absorb water but they are to easier to clean and maintain