Structure, Morphology And Adhesion Of The Polyester Polyurethane Adhesive Performance

Three series of linear segment polyurethanes (PU-PHA, PU-PBA, PU-PEA) based on three polyesters (PHA, PBA, PEA), MDI and chain extenders (ethylene glycol, 1,4-butanediol, 1,6-hexanediol and m-tolyl diethanolamine) were synthesized by bulk polymerization. The PUS were characterized using gel permeation chromatography, differential scanning calonmetry and TEM. The PUS were dissolved in solvent (MEK) forming solvent-based adhesives, the adhesion properties of which were evaluated by T-peel test of polyvinyl chloride (PVC)/polyurethane adhesive joints. The influence of polyester types and molecular weight, chain extender types and catalyst on the crystallinity of PUS and the influence of compatibility on adhesion are discussed. The results showed that on condition that the hard-segment content was not high , the crystallinity in PU was mainly caused by the polyester soft-segment, the crystallinity of PUS was in the order of PU-PHA> PU-PBA> PU-PEA. The use of short-chain extender resulted in high phase separation, high crystallinity, and high adhesion properties. The use of catalyst can improve the crystallinity of PUS and increase the adhesion properties of PUS.