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The effects of maleic anhydride-grafted styrene-ethylene-butylene-styrene copolymer (SEBS-g-MAH) on the mechanical and morphological properties of polypropylene (PP) and poly(acrylonitrile-butadiene-styrene) (ABS) blends were investigated. Based on mechanical properties, including impact and tensile strengths, the PP/ABS (70/30) blends containing SEBS-g-MAH showed improved impact strength with minimal loss of tensile strength. As determined from morphological studies of the PP/ABS blends, addition of SEBS-g-MAH decreased PP/ABS blend droplet size more than the addition of SEBS. Additionally, the effects of SEBS-g-MAH and SEBS on the mechanical and morphological properties of the PP/ABS (70/30) blends were investigated during accelerated aging in an oven at 90 C for 72 h (one cycle). The impact strength of the PP/ABS (70/30) blends with SEBS-g-MAH (7 phr) decreased less than 10% after five cycles, but blends with SEBS (7 phr) and blends without compatibilizer decreased as much as 37%. The tensile strengths of the PP/ABS (70/30) blends after accelerated aging indicated a trend similar to that of the impact strength. The morphological studies indicated no significant changes in the PP/ABS (70/30) blends with SEBS-g-MAH; however, many cavities and damages were observed in the blend with SEBS. The above results suggest that SEBS-g-MAH acts as an impact modifier and as a good compatibilizer in the PP/ABS (70/30) blends.

The sound absorption properties and airflow resistivity of polyurethane foams (PUFs) with multiwall carbon nanotube (MWCNT), perfluoroalkane (PFA), dimethylsiloxane (HMDS), and MWCNT/PFA hybrid additives were investigated with varying additive content. The results show the close relationship of the sound absorption coefficient and airflow resistivity, and increasing flow resistivity was found to improve the sound absorption coefficient of the PUF. For the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) hybrid additives, the sound absorption coefficient and airflow resistivity were 0.80 (in the frequency range of 1,600–2,500 Hz) and 439,900 Ns/m4, respectively, which were the highest values among the investigated additive species and additive content. The sound absorption coefficient of the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) was increased by 82.0% compared to that of the PUF without additives, probably because the PUF has the smallest cell size among the additive species and compositions investigated in this study. The results of the sound absorption coefficient, airflow resistivity, and cell size of the PUF suggest that to decrease the cell size and to increase the tortuous paths of the foams, MWCNT/PFA hybrid additives appeared to be the most effective additives and showed synergistic effects in the formation of PUF, and its small cell size increased the sound absorption properties of PUF. POLYM. COMPOS., 39:E1087–E1098, 2018. © 2017 Society of Plastics Engineers

Blends of poly(ether imide) (PEI) and bisphenol-A polycarbonate (PC) have been investigated by differential scanning calorimetry, dynamic mechanical thermal analyzer, scanning electron microscopy, and transmission electron microscopy. Three different molecular weights of polycarbonate have been used in the PEI-PC blends. Blends were prepared by screw extrusion and solution casting with weight fractions of PEI in the blends varying from 0.90 to 0.10. From the measured glass transition temperature (T,), the maximum decrease of Tg(PEI) is observed for 0.9 weight fraction PEI in the PEI-PC blends. In the study of the morphology, the size of minor component domains (about 0.1 to 0.3 Fm) in the 90/ 10 PEI-PC blend is small compared to the size of minor component domains (about 0.2 to 2.0 Fm) in the 10/90 PEI-PC blend. This morphological behavior is attributed mainly to the difference of viscosity ratio between the dispersed phase and continuous phase. No considerable differences in the thermal behavior and morphologies have been observed among the blends of PEI and PC having different molecular weights.

Transesterification reactions between polyarylate (PAr) and a copolyester (PETG) have been investigated by proton nuclear magnetic resonance (NMR), Fourier‐transform infrared spectroscopy (FTIR), and differential scanning calorimetry. Blends of PAr and PETG were prepared by melt mixing and solution‐casting with weight fractions of PAr in the blends varying from 0.90 to 0.10. The PETG is a copolyester containing ethylene‐1,4‐cyclohexylene dimethylene terephthalate. From the thermal analysis of the PAr/PETG melt blends, a single glass transition temperature is observed, which indicates a miscibility between the PAr and PETG. The benzene insoluble fraction of the PAr/PETG (50/50) melt blends and solution‐cast blends were characterized using NMR and FTIR. The results of NMR and FTIR support the conclusion that transesterification reactions between the PAr and PETG occurred under the melt blending conditions applied.