| 摘要 |
<p>A polymer product consists of polyamide acid pre-polymers of formula (I): and/or polyimide prepolymers of formula (II): (where A = n = 1-20 etc., R is H or 1-5C alkyl, R1 is (subst.) aryl, (subtd.) alkyl, cycloalkyl, (subtd.) aralkyl, alkaryl, alkylene, arylene or a heterocyclic aryl group from a polyfunctional amine, and R2 is (substd.) aryl, substd.) alkyl, a cycloalkyl, a (substd.) aralkyl, alkaryl, alkylene, arylene or a heterocyclic aryl group from a polyfunctional anhydride). The prepolymers have relatively low molecular weight and are stable at room temperature. They can easily be converted into high-molecular polyimides of great mechanical strength. Hardening is rapid and volatile matter is not liberated. The pre-polymers can be used to produce heat-stable moulding powders, possibly containing fillers. Laminates which are almost free from hollow spaces can be produced. The polymers can also be used in varnishes.</p> |
