Supakanok Thongyai

Effects of sample preparation method on mixing and phase separation in binary polymer blends

Abstract Detailed studies of effects of sample preparation method on the kinetics of phase separation in a blend of polystyrene- co -maleic anhydride (SMA) with a commercial sample of polymethyl methacrylate containing ethyl acrylate as co-monomer (PMMAe) have been performed using light scattering techniques. Two preparation methods, viz. solution casting and melt mixing in a mini twin screw extruder were employed in this work. The blend, which shows lower critical solution temperature (LCST) behaviour, exhibits spinodal and binodal curves at higher temperatures in the case of solution casting than those from melt mixed samples. The relative values of the Cahn–Hilliard growth rate, R ( q ), obtained from the two preparation methods depend on blend concentration, R ( q ) being faster for solution cast samples at some concentrations and slower at others. Comparison of the data with recent theoretical developments for entangled polymer blends is reported.

Morphology and properties of poly(styrene-co-acrylonitrile)/poly(methyl methacrylate)/zinc oxide composites

The effect of zinc oxide (ZnO) 250 nm on the mechanical, thermal and morphological properties of the composites of poly(styrene-co-acrylonitrile) (SAN), poly(methyl methacrylate) (PMMA) and ZnO was investigated. The Youngs modulus of 20SAN/PMMA/ZnO and 40SAN/PMMA/ZnO increased at low ZnO content. Increasing content of ZnO up to 0.5–1.0 wt% increased the impact strength of PMMA/SAN blends and then decreased. The addition of ZnO improved the thermal stability of polymer blends. The dielectric constant of 20SAN/PMMA/ZnO and 40SAN/PMMA/ZnO composites increased with increasing ZnO content. The dispersion of ZnO particles was relatively good and uniform throughout the entire polymer matrix.

Mechanical and Thermal Properties of Polyoxymethylene Nanocomposites Filled with Different Nanofillers

The effect of the different nanofiller on properties of polyoxymethylene (POM) nanocomposites was investigated. The nanofiller containing CaCO3, Al2O3 and modified clay was used added in POM. The results showed that the Youngs modulus of the nanocomposites increased after adding the nanofiller. The tensile strength and stress at break of the nanocomposites increased by adding CaCO3 nanoparticles in a range of 1–2 wt.%. The addition of CaCO3 enhanced the thermal stability of the POM matrix. The microstructure of neat POM and POM nanocomposites was found that the dispersion of nanofiller particles was relatively good in a low content.

The crystallinity and miscibility of syndiotactic polystyrene blends after mixing with low molar mass liquid crystal or commercial lubricant

The quantities of the crystallinity of syndiotactic polystyrene (SPS) blended with another polymer in the group of poly(α-methyl styrene), poly(n-butyl methacrylate) or poly(cyclohexyl acrylate) with or without the additives were measured by X-ray diffraction and calculated by Ruland’s method. The SPS was synthesized by using metallocene catalyst and modified-methylaluminoxane as cocatalyst. The additive of low molar mass liquid crystal chemical (cyclohexyl-biphenyl-cyclohexane (CBC33)) or lubricant (glycerol monostearate (GMS)) was individually added to the blends of SPS in order to investigate the effects on the crystallinity of the blended SPS. From the experimental results, it was found that the percent crystallinities of the blends decreased with decreasing the percent of SPS in the blend because of the dilution of SPS. The depression of the percent crystallinity was in the order of PaMS > PCHA > PBMA according to the compatibility with SPS. The addition of GMS or CBC33 slightly decreased the percent crystallinity of the pure SPS. The addition of GMS impeded the depression of the SPS crystallinity in the blends, because their percent depression from pure SPS is similar (at around 25%) regardless to the components of the blends. The blends with added CBC33 have the similar depression of crystallinity as the pure blends because of the low concentration of CBC33 and the good compatibility of CBC33 with the SPS.

New concepts in material and energy utilization

New criteria in material and energy utilization are proposed. The potential index (Θ*) is assigned to explain some natural processes in the world and to identify reasonably the preferable process instead of the efficiency. In addition, this term can first integrate the independent knowledge of the fields of mechanical, electrical and chemical engineering. It not only describes satisfactorily the transformation processes that are well-known in mechanical and electrical engineering, but also the increasing potential processes familiar in chemical engineering.