Study on the poly(3-hydroxybutyrate-co-4-hydroxybutyrate)-based composites toughened by synthesized polyester polyurethane elastomer

In this study, polycaprolactone(PCL)-based polyurethane (PU) elastomer containing 45 wt % hard segment component was synthesized and characterized by fourier transform infrared spectroscopy, gel permeation chromatography, and X-ray diffraction. As a toughening agent, the as-synthesized PU was incorporated into biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3,4)HB] by solution casting to prepare P(3,4)HB/PU composites. The microstructure and properties of P(3,4)HB/PU composites were investigated using transmission electron microscopy, X-ray diffraction, tensile testing, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and activated sludge degradation testing. The results show that PU can disperse well in a P(3,4)HB matrix. The elongation at break of P(3,4)HB/PU composites is remarkably increased while the yield strength and elastic modulus are decreased with an increase in PU content. At the same time, it is found that the fracture characteristic of P(3,4)HB is obviously transformed from brittleness into ductility with a gradual increase in PU loading. Moreover, the thermal stability of P(3,4)HB/PU composites is significantly improved compared with that of pure P(3,4)HB. In addition, the biodegradation rate of P(3,4)HB/PU composites is evidently reduced with the increase of PU content in the activated sludge degradation testing. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42740.