Acetylenic polyesters containing either residues of 2-butyne-l,4diol, acetylenedicarboxylic acid, or both of them, were prepared and characterized. Polyesters of 2butyne-1,Pdiol with succinic, adipic, and phthalic acids were obtained aa soluble polymers by use of known methods. The polymaleate ester of 2-butyne-l,4-diol waa obtained either aa a soluble or aa an insoluble polymer, depending on the experimental conditions. Relatively high temperature or long reaction periods led to the formation of insoluble polymers. Polyesters of acetylenedicarboxylic acid with diethylene glycol, tetra-and hexamethylene glycols, 2-butene-l,Pdiol, and 1,Pcyclohexane dimethanol were prepared by melt polycondensation in bulk. These polyesters were obtained aa insoluble, rubbery materials, except those of Zbutene-1,Pdiol and 1,Pcyclohexane dimethanol, which were obtained both aa linear or aa nonlinear polymers. The insolubility of the polyesters of acetylenedicarboxylic acid waa due to crosslinking reactions involving the conjugated system -C&-C=O.
While the melt polycondensations in bulk involving either 2-butyne-l,4diol or acetylenedicarboxylic acid were entirely controlled reactions, those carried out between acetylenedicarboxylic acid and Zbutyne-1,Pdiol were very often associated with highly exothermic decompositions involving carbonization. The decompositions could be eliminated when the melt polycondensation in bulk waa preceded by a fore-condensation in solution. Solid, soluble, powdery low polymers (DP = 2-3) having softening temperatures of about 150-175ยฐC. were thus obtained.