▁the ▁North west ▁Territ ories ▁Category : E co z ones ▁and ▁e cor eg ions ▁of ▁N un av ut ▁Category : Ge ography ▁of ▁Quebec ▁Category : Ge ography ▁of ▁Man it oba ▁Category : Ge ography ▁of ▁S ask atch ew an ▁Category : Ge ography ▁of ▁New found land ▁and ▁Lab r ador <0x0A> </s> ▁A ▁therm op last ic , ▁or ▁therm oso ft ening ▁pl astic , ▁is ▁a ▁pl astic ▁polym er ▁material ▁that ▁becomes ▁p li able ▁or ▁m old able ▁at ▁a ▁certain ▁elev ated ▁temperature ▁and ▁solid ifies ▁upon ▁cool ing . ▁ ▁Most ▁therm op last ics ▁have ▁a ▁high ▁mole cular ▁weight . ▁The ▁polym er ▁ch ains ▁associate ▁by ▁inter m ole cular ▁forces , ▁which ▁weak en ▁rapidly ▁with ▁increased ▁temperature , ▁yield ing ▁a ▁vis c ous ▁liquid . ▁In ▁this ▁state , ▁therm op last ics ▁may ▁be ▁res h aped ▁and ▁are ▁typically ▁used ▁to ▁produce ▁parts ▁by ▁various ▁polym er ▁processing ▁techniques ▁such ▁as ▁injection ▁m old ing , ▁compression ▁m old ing , ▁cal ender ing , ▁and ▁extr usion . ▁Th erm op last ics ▁differ ▁from ▁therm os et ting ▁polym ers ▁( or ▁" ther mos ets "), ▁which ▁form ▁irre vers ible ▁chemical ▁b onds ▁during ▁the ▁cur ing ▁process . ▁Th erm os ets ▁do ▁not ▁m elt ▁when ▁he ated , ▁but ▁typically ▁de compose ▁and ▁do ▁not ▁reform ▁upon ▁cool ing . ▁ ▁A bove ▁its ▁glass