Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide

Abstract

In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes (with 10 and 30%wt amount of synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments) and their physical blends with poly([d,l]-lactide) (PDLLA) were investigated and then degraded under hydrolytic (phosphate buffer solution) and oxidative (CoCl2/H2O2) conditions. The rate of degradation was monitored by changes of samples mass, morphology of surface and their thermal properties. Despite the small weight losses of samples, the changes of thermal properties of polymers and topography of their surface indicated that they were susceptible to gradual degradation under oxidative and hydrolytic conditions. Blends of PDLLA and polyurethane with 30 wt% of R,S-PHB in soft segments and PUR/PDLLA blends absorbed more water and degraded faster than polyurethane with low amount of R,S-PHB.

Morphology and Physicochemical Properties of Branched Polyurethane/Biopolymer Blends

“…This makes it susceptible to degradation under natural conditions. Our previous research indicates that linear and cross-linked polyurethanes with poly([R,S]-3-hydroxybutyrate) are slowly degraded [12,13].…”

Bio-based, biodegradable and amorphous polyurethanes with shape memory behavior at body temperature

“…31,32 The biodegradable SMPUs reported recently mostly are based on PCL, co-oligoesters of (rac-) lactide and glycolide, or others. 33,34 They all exhibit good shape memory properties, but their weak points are obvious at the same time. Either they have poor processing properties because of their chemical crosslinking structure.…”

Branched Polyurethanes Based on Synthetic Polyhydroxybutyrate with Tunable Structure and Properties

“…Through the right combination of polycaprolactonetriol (PCL triol ) (Figure 1B) with polycaprolactonediol (PCL diol ), branched PURs with the highest possible molecular weight without reaching gelation and formed into foils could be obtained [5]. Knowing that introduction of amorphous R,S-PHB influences thermal, sorptive and surface [7] properties of linear and cross-linking PUR materials and their degradability profile [8], such effects are also expected in branched PURs.…”