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The characterizations of prepared low‐molecular‐weight polyhydroxybutyrate (LMWPHB) and the properties of LMWPHB photopolymerized with hydrophilic and hydrophobic acrylic monomers were studied with 1H‐NMR spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, Instron tensile testing, and biodegradation tests. The results of 1H‐NMR and FTIR spectroscopy confirmed that the prepared LMWPHB had transformed unsaturated ends that were photoreactive under UV light. The tensile strengths of the LMWPHB/acrylates decreased with increasing content of the added biodegradable LMWPHB because of the relatively long chains and large equivalent molar weights of LMWPHB. However, the flexibility of LMWPHB/acrylates changed differently with the type of acrylic monomer used. The LMWPHB/hydrophilic acrylate had a much more rapid biodegradation rate than the LMWPHB/hydrophobic acrylate because of the fast penetration of microorganisms. We demonstrated that the prepared LMWPHB could be used to control the biodegradation properties of acrylates and then could potentially be applied in biomedical fields. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39501.

The kinetics of the reaction between hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) of different molecular weights toward the synthesis of polyurethanes with versatile properties was studied using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). From the dynamic exotherms observed in DSC, it was found that the Kissinger equation modified by an additional temperature term in its frequency factor term was able to accurately describe the isothermal reaction kinetics of all HDI/PPG reactions. The modification can be justified by analyses with the Ozawa method and the modulus observed under DMA measurements. Regardless of the type of PPG used, the frequency factors changed with respect to the degree of conversion and maximized at near 70% conversion. The derivation of the modified kinetic equation is presented. In addition, the empirical equations describing the dependence of the activation energies and frequency factors on the molecular weights of PPG were also derived.