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| 1. |
What are thermosetting polymers ? |
| Answer» Solution :These are semi fluid SUBSTANCES with low molecular masses which when heated in a mould , undergo a permanent change in chemical composition to give a HARD , infusible and insoluble mass. This hardening on heating is due to extensive cross linking between POLYMER chains to give a three -dimensional network solid. Thus , a thermosetting polymer can be heated only once when it undergoes a permanent change and SETS into a solid which cannot be remelted and reworked. For example , bakelite , melamine-formaldehyde polymer , ETC. | |