Synthesis and degradation of nontoxic biodegradable waterborne polyurethanes elastomer with poly(ε-caprolactone) and poly(ethylene glycol) as soft segment

In this study, in order to obtain waterborne polyurethanes (WBPUs) with biocompatibility, biodegradability as well as good mechanical properties, a series of nontoxic cross-linked waterborne polyurethanes were designed and synthesized with isophorone diisocyanate (IPDI), poly(ε-caprolactone) (PCL), poly(ethylene glycol) (PEG), 1,4-butandiol (BDO) and l-lysine without any other organic agent involved in the whole synthetic process. The bulk structures and properties were characterized by DSC, IR and Instron, mainly focused on the effect of amount of PEG. Their corresponding biodegradability was examined with Lipase AK. The result showed that the prepared waterborne polyurethanes had very good tensile properties, allowing them to be well used as biomaterials. And the change of tensile properties with increasing of amount of PEG in the polymers could be assigned to the change of microphase separation, as indicated by DSC and IR data. A quite good biodegradability was achieved as judged from the change of tensile properties as a function of time. The current work demonstrated a new synthetic approach that can be more promising to prepare both nontoxic and biodegradable polyurethanes for soft tissue engineering applications or drug delivery.