Which of the following are characteristics of thermosetting polymers?
(i) Heavily branched cross-linked polymers.
(ii) Linear slightly branched long-chain molecules.
(iii) Become infusible on moulding so cannot be reused.
(iv) Soften on heating and harden on cooling, can be reused.
The answer is the option (i, iii) Thermosetting polymers or thermoset are heavily branched and cross-linked molecules. They cannot be reused as they become infusible on the moulding.