No abstract

No abstract

Environmentally Degradable Parameter (Ed K) is of importance in the describing of biodegradability of environmentally biodegradable polymers (BDPs). In this study, a concept Ed K was introduced. A test procedure of using the ISO 14852 method and detecting the evolved carbon dioxide as an analytical parameter was developed, and the calculated Ed K was used as an indicator for the ultimate biodegradability of materials. Starch and polyethylene used as reference materials were defined as the Ed K values of 100 and 0, respectively. Natural soil samples were inoculated into bioreactors, followed by determining the rates of biodegradation of the reference materials and 15 commercial BDPs over a 2-week test period. Finally, a formula was deduced to calculate the value of Ed K for each material. The Ed K values of the tested materials have a positive correlation to their biodegradation rates in the simulated soil environment, and they indicated the relative biodegradation rate of each material among all the tested materials. Therefore, the Ed K was shown to be a reliable indicator for quantitatively evaluating the potential biodegradability of BDPs in the natural environment.

No abstract

The poly(e-caprolactone) (PCL)-coated microsized calcium carbonate (CaCO 3 ) was prepared by high-speed hybrid mechanical coating. Polylactide (PLA) was melt-blended with neat and modified CaCO 3 particles. Phase morphology, microstructure, and thermal dynamic rheological and mechanical properties of the composites were investigated. Differential scanning calorimetry reveals that the addition of coated CaCO 3 remarkably makes the cold crystallization temperature decrease but has little influence on the final degree of crystallinity of PLA. Dynamic rheological tests indicate that complex viscosity and loss modulus of modified CaCO 3 system are lower than those of neat CaCO 3 system. Scanning electron microscopic results show that the coated CaCO 3 micropar-ticles disperse more uniformly in the PLA matrix compared with neat particles. The smooth and round coated particles promote the dispersion of CaCO 3 particles in the PLA matrix, and PCL enhances the interfacial adhesion between CaCO 3 particles and the PLA matrix. From mechanical tests, it is found that toughness of the composites is greatly improved by the incorporation of PCL-coated CaCO 3 microparticles. It is glad to see that the elongation at break of the composite with 15 phr coated CaCO 3 is as high as 310%. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 125: 952-958, 2012