CHEMICAL HEALING IN PARTIALLY CROSS-LINKED POLYAMIDES

Evidence is presented for chemical healing in linear polycondensates. In order to distinguish the contribution of the solid-state reaction from the healing effect, samples (nylon-11, nylon-12, and nylon-6,6) with strongly restricted chain mobility have been used. It has been found that under the same healing conditions the cross-linked samples display better welding than the un-cross-linked ones. The conclusion is drawn that the observed healing effect is due mainly to the solid-state chemical reactions at the contact surfaces and not to the diffusion of macromolecules.