Daohai Zhang

Effects of compatilizers on mechanical and dynamic mechanical properties of polypropylene–long glass fiber composites:

The polypropylene–long glass fiber (PP/LGF) composites were prepared using self-designed impregnation device. The mechanical properties and dynamic mechanical properties of PP/LGF composites with two different compatibilizers including PP grafted with glycidyl methacrylate (PP-g-GMA) and maleic anhydride-grafted PP copolymer (PP-g-MA) were investigated on injection molding standard bars. The experimental results demonstrated that the addition of PP-g-GMA led to decrease in mechanical properties and storage modulus. However, it is found that the maximum mechanical properties and storage modulus are reached for the PP/LGF composites when PP-g-MA are 7 wt%. Moreover, PP-g-MA is better than PP-g-GMA in the PP/LGF composites.

Mechanical Properties, Morphology and Dynamic Mechanical Properties of LGF/TPU/SAN Composites

A series of the long glass fiber reinforced thermoplastic polyurethane elastomers and poly (styrene-acrylonitrile) (LGF/TPU/SAN) composites with different contents of long glass fiber were prepared by using self-designed impregnation device. Dynamic mechanical properties of TPU/SAN matrix reinforced with 10, 20 and 30 % by weight long glass fibers have been investigated by using dynamic mechanical thermal analysis (DMA). The results indicated that the content of long glass fiber and scanning frequency had some influence on dynamic mechanical properties and glass transition of LGF/TPU/SAN composites. In addition, the Arrhenius relationship has been used to calculate the activation energy of a-transition of the LGF/TPU/SAN composites. SEM demonstrates the relatively good dispersion of the long glass fiber in the TPU/SAN matrix. In addition, Effects of the content of long glass fiber on mechanical properties of the LGF/TPU/SAN composites are investigated.

Influence of Thermo-Oxidative Ageing on the Thermal and Dynamical Mechanical Properties of Long Glass Fibre-Reinforced Poly(Butylene Terephthalate) Composites Filled with DOPO

In this work, the long glass fibre-reinforced poly(butylene terephthalate) (PBT) composites filled with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were prepared by melt blending, and the influence of thermo-oxidative ageing on the static and dynamic mechanical properties, thermal behaviours and morphology of composites with different ageing time at 120 °C were investigated and analysed. The results showed that the mechanical properties decreased in the primary stage of ageing, while embrittlement occurs in the later period, and the crystallinity of PBT decreases first, and then recovers to some extent. The scanning electron microscopy (SEM) photos of the samples indicated that the obvious crack appeared on the sample surface and a deeper, broader crack occurred with a longer ageing time. The results of energy dispersive X-ray analysis (EDAX) proved the DOPO filler diffused to the sample surface by measuring the content of phosphorus. Thermal gravimetric analysis (TGA) curves showed that the thermal stabilities of composites increased with longer ageing time, as did the values of the limited oxygen index (LOI). Meanwhile, the results of dynamic mechanical analysis (DMA) indicated that the glass transition temperature shifted to a higher temperature after ageing due to the effect of crosslinking, and both the crosslinking and degradation of PBT molecular chains act as the main factors in the whole process of thermo-oxidative ageing.

Dynamic mechanical properties, thermal, mechanical properties and morphology of long glass fiber-reinforced thermoplastic polyurethane/acrylonitrile–butadiene–styrene composites

A series of the long glass fiber–reinforced thermoplastic polyurethane elastomers and acrylonitrile–butadiene–styrene (LGF/TPU/ABS) composites with different content of LGFs were prepared using self-designed impregnation device. Dynamic mechanical properties of the LGF/TPU/ABS composites have been investigated using dynamic mechanical thermal analysis. The results indicated that the content of LGFs and scanning frequency have some effect on the dynamic mechanical properties and glass transition of LGF/TPU/ABS composites. In the meantime, the Arrhenius relationship has been used to calculate the activation energy of α-transition of the LGF/TPU/ABS composites. The thermogravimetric analysis thermograms of the LGF/TPU/ABS composites were found to decrease in two steps. The good dispersion of the LGFs in the matrix resins is obtained from scanning electron micrographs. In addition, effects of the LGF contents on mechanical properties of LGF/TPU/ABS composites were investigated.

Mechanical, Heat-resistant, Crystallographic and Dynamical Mechanical Properties of Nylon 6/ P(N-phenylmaleimide-alt-styrene) Blends

In this work, nylon 6/ P(N-phenylmaleimide-alt-styrene) blends were prepared by melt blending, and the mechanical, heat-resistant, crystallographic and dynamical mechanical properties of nylon 6/ P(N-phenylmaleimide-alt-styrene) blends with different contents were investigated and analyzed. The results showed that the mechanical properties decreased with increasing PNS, while the heat deflection temperature (HDT), relative crystallinity (Xn), and storage modulus (G’) increased with increasing PNS. The results of differential Scanning Calorimetry (DSC) proved the PNS played the positive role of nucleating PA6. And the results of dynamic mechanical analysis (DMA) proved the PNS could improve the rigidity of PA6/PNS blends. From the SEM, these PNS domains were between 0.2 and 4 μm in diameter. The experimental results indicated that the addition of PNS improved the rigidity of PA6/PNS blends, and then improved the heat-resistant property.