THERMOSETTING PLASTICS - thermosetting plastics are heated and moulded into shape. if re-heated they cannot soften as the polymer chains are interlinked. indervidual monomers are joined together to form a massive polymer.
THERMOPLATICS - thermoplastics will soften when they are heated, and can be shaped when hot. the plastic will harden when it is cooled, but can be reshaped if heated up again.