In this study, we prepared chitosan-coated Poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles. Specifically, we utilized a double emulsion-solvent evaporation technique to formulate nanoparticles containing paclitaxel as a model macromolecule and 6-coumarin as a fluorescent marker. SEM images verified that all nanoparticles were spherical in shape with smooth surfaces. Chitosan coating slightly increased the size distribution of the PLGA/PVA nanoparticles, from 202.2+/-3.2 nm to 212.2+/-2.9 nm, but the encapsulation efficiency was not significantly different. In contrast, coating with chitosan slowed the in vitro drug release rate and significantly changed the zeta potential from negative (-30.1+/-0.6 mV) to positive (26+/-1.2 mV). At the initial burst time, the drug release rate from chitosancoated nanoparticles was slightly slower than that of the uncoated nanoparticles. Chitosan-coated nanoparticles were also taken up much more efficiently than uncoated nanoparticles. This study demonstrated the efficacy of chitosancoated PLGA nanoparticles as an efficient delivery system.

No abstract

The effects of strain rate and water absorption properties can be used to evaluate the environmental degradation of sisal fiber reinforced polymer–matrix composites. Composites of vinylester and epoxy resin, reinforced by sisal fiber, were manufactured using the RTM method. To examine how the mechanical properties change with different surface treatments of a fiber, three fibrous composites with nontreated, permanganate, and silane treatments were compared in this experiment. Material fracture occurred as the brittleness hardened due to an increase in strain rate. The tensile strength was the largest in the permanganate‐treated epoxy composites, while the untreated vinylester had high elongation and fracture energy. The highest tensile strength value occurred at a 30% absorption ratio. POLYM. COMPOS., © 2011 Society of Plastics Engineers.

No abstract