Blends of two biocompatible polymers: thermoplastic polyester‐urethane (TPU) and polylactic acid (PLA) were studied. The effect of the blending ratio on blend morphology and properties was examined by running a series of blends from 10 to 80 wt % of PLA. Increasing TPU concentration in the blends lowered the glass transition and melting point of PLA indicating that the components were compatible and partially miscible. The blends with 10–40 wt % PLA are hard, reinforced elastomers, while those with 60–80 wt % PLA are tough plastics. Cocontinuous morphology was suggested in samples with 40 and 50 wt % PLA. Inversion points between 30 and 40 wt % PLA (from globular phase is dispersed in the matrix to a cocontinuous morphology) and between 50 and 60 wt % PLA (a transition from cocontinuous to TPU dispersed in the PLA matrix) were observed. Elastomers with higher PLA content and intermediate morphology displayed a combination of high tensile strength, hardness, relatively high elongation and modulus. New materials have potential applications in the medical field. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41104.

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Blends with varied ratio of polylactic acid (PLA) and thermoplastic polyurethane (TPU) were prepared by melt blending. The PLA content in blends was 20, 40, 60 and 80 wt%. Samples of pure PLA and TPU that underwent the same thermal treatment were also prepared.Biodegradation was examined by respirometry. Pure TPU started to degrade immediately due to degradation of the low molecular weight plasticizer in the polymer. Pure PLA, on the other hand, exhibited an incubation period after which degradation progressed rapidly and was almost complete after 70 days. The degradation profile of the blends can be correlated to their morphology. Samples with a co-continuous morphology initially degrade at a higher rate than the rest of the samples due to the higher exposure of the TPU phase in these blends.

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The free-radical bulk polymerization of many monomers is characterized by a sudden rise in the rate of polymerization, a phenomenon called autoacceleration. Many mathematical models have been developed to describe this phenomenon. In this paper, the development of a new kinetic model is described. The model very successfully describes experimental data obtained by differential scanning calorimetry of the bulk free-radical polymerization of methyl methacrylate. The proposed model is composed of two contributions to the conversion of the monomer, one originating from polymerization according to the classical theory of radical polymerization and the other originating from polymerization during the autoacceleration. The rate constant of the autoacceleration (second contribution) is about eightfold higher than the rate constant of the first-order reaction (first contribution).