In this study, agave fiber/linear medium density polyethylene composites were manufactured by rotational molding. A laboratory scale biaxial machine was used, where the internal air temperature during the processing cycle was measured. Two sizes of agave fibers (50 and 100 mesh) were used separately and mixed together (50/50) at concentrations varying between 0 and 15 wt%. The initial mixtures were obtained by dry blending, rotomolded under different operation conditions (oven temperature, processing cycle time, and rotational speeds), and the final pieces were compared. For each process condition, a complete morphological analysis was performed to relate with mechanical properties in terms of tensile, impact, and flexural strength. The results show that there is an optimum fiber concentration around 10%, and blending fiber sizes gave better tensile properties than using each size alone.

No abstract

In this work, agave fibers were blended with polystyrene to produce foamed and unfoamed composites. The effect of fiber size and density reduction on the morphological, thermal, mechanical, and rheological properties, as well as crystallinity and water absorption kinetics of the composites was assessed. The results show that Young's modulus and tensile strength increased with increasing fiber content, but decreased with density reduction. Increasing fiber content and decreasing the size of the fibers both increased crystallinity of the composites. Finally, water uptake and diffusion coefficient were found to increase with increasing fiber content for all sizes.

In this work, the processing and properties of blown films prepared from thermoplastic corn starch (TPS) and polycaprolactone (PCL) were studied, in particular at high TPS content. The influence of processing parameters and material moisture content on the tensile properties was also studied. The results show that final film properties are mainly controlled by the draw ratio, blow-up ratio and PCL concentration in the blends.The results also show that PCL/TPS films are less hydrophilic as PCL content increases. Finally, it was found that a very narrow processing window exists for this blend.

The synthesis of poly(N-isopropylacrylamide) nanogels by semi-continuous inverse heterophase polymerization (SIHP) under monomer starved conditions is reported here. This process consists in adding a N-isopropylacrylamide (NIPA) aqueous solution at a controlled rate over a monomer-free oleic solution containing surfactant and initiator. The nanogels became smaller with narrower size distributions as the addition rate was decreased. Moreover, nanogel sizes, the size distributions and more importantly, the polymer/surfactant ratios were smaller than those of PNIPA nanogels synthesized by batch inverse microemulsion polymerization (BIMP). The swelling behavior of these nanogels in water as a function of temperature is reported. As expected, all nanogels have a volume phase transition temperature at ca. 33-34 • C.