Epoxidized soybean oil (ESO) was blended as a novel plasticizer with polybutylene succinate (PBS) in a twin-screw extruder. The effects of ESO on the mechanical and thermal properties of the PBS/ESO blends were investigated by means of tensile test, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electronic microscope. ESO improved elongation at break for PBS, which increased and then decreased with the increase in ESO. Elongation at break reached a maximum of 15 times than that for pure PBS when the ESO loading was 5 wt%. The tensile strength and modulus for the blends were lower than those for pure PBS. Compared with pure PBS, the blends exhibited lower glass transition temperature, crystallization temperature, and melting temperature. The storage modulus and tan d peaks for the blends were lower compared with that for pure PBS. ESO had very limited compatibility with PBS, and phase separation was observed when more ESO was added.

The flammable and the mechanical effects of silica (SiO 2 ) on the halogen-free, flameretarded ethylene-octene copolymer (POE)/polypropylene (PP) composites were investigated. Through the thermal stability analysis and the combustion test, it was found that the SiO 2 had a synergistic effect on the intumescent flame retardant (IFR), especially when the SiO 2 content was 3 wt%. According to the results of mechanical properties, the tensile strength of composites increased with the rising SiO 2 content and most of the impact strength is retained. The fracture morphology showed the state of SiO 2 /IFR particles in the POE/PP blends, which reflected that with the increasing SiO 2 content and the decreasing IFR content, the aggregates became less compact and the size of aggregates became smaller.

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A 30 wt % high-density polyethylene (HDPE)/70 wt % polystyrene (PS) blends and 5 wt % HDPE/95 wt % PS blends were prepared via polymer vane plasticating extruder, which can generate elongational force field, in different rotation speeds. The fracture surface of the HDPE/PS blends was observed by a scanning electron microscope, and the dispersion of the HDPE in the PS matrix was evaluated by multifractal programs. The multifractal spectrum width Da, and the dimension difference of maximum and minimum probability subset Df ðaÞ were defined to discuss the homogeneity and the diameter of the HDPE particles. The results showed that the multifractal method was an effective tool to quantitatively describe the special distribution and diameter of the dispersed particles.

In this work, the synergistic effect of Nano‐ZnO and intumescent flame retardant (IFR) on polypropylene/ethylene‐propylene‐diene monomer (PP/EPDM) composites was researched using an elongational flow field. The results were then compared to shear flow field. The flame retardant mechanism was characterized using thermogravimetric‐Fourier transform infrared spectroscopy (TG‐FTIR). Furthermore, the flame retardant properties and morphologies of the composites using different flow fields were characterized using cone calorimeter (CC), limited oxygen index (LOI), vertical combustion test (VCT), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicated that the mixture of 1 wt% Nano‐ZnO and 29 wt% IFR which based on the elongational flow field (VZ1) catalyzed the esterification and charring effect more efficiently than that based on the shear flow field (TZ1). The TGA indicated that VZ1 exhibited higher decomposition temperature, and resulted in more char residues than those for TZ1. Furthermore, VZ1 resulted in longer delay for the ignition, and the ignition time was 105 s longer than that for TZ1, which was the longest of all samples. The fire performance index (FPI) was the highest, while the fire growth index (FGI) was the second lowest of all the samples, and resulted in the smallest fire. The digital photos showed that the char layer of VZ1 was more compact than that of TZ1. With the proposed flame retardant exhibited better dispersion and unique “bee‐comb” microstructure in the matrix through elongational flow field, and showed better retarding characteristics than that using shear flow field. POLYM. COMPOS., 40:2819–2833, 2019. © 2018 Society of Plastics Engineers