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In this study, impact-resistant polypropylene (MPP), thermoplastic polyurethane (TPU) and polypropylene-grafted maleic anhydride (MA) are made into MPP/TPU/MA blends using melt-compounding and injection methods. The blending morphology, crystallization behavior, and melting and thermal behaviors of the blends are evaluated in terms of the content of TPU and MA, examining the influences of the parameters. The scanning electron microscope (SEM) observation shows that 1 wt% of MA can effectively enhance the interfacial adhesion and compatibility between MPP and TPU. The differential scanning calorimetry (DSC) results show that the crystallization temperature and melting temperature of the blends are not dependent on the content of TPU or MA. However, using TPU and MA adversely affect the crystalline and melting enthalpy of the blends. The thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) curve both show that the higher the MPP, the greater the thermal stability of TPU. Likewise, using MA as compatibilizer also has a positive influence on the thermal stability of the blends. The X-ray diffraction (XRD) analyses confirm that the addition of TPU decreases the diffraction intensity of MPP, but does not harm the crystalline structure of MPP. Moreover, the addition of MA improves the compatibility between MPP and TPU. MA marginally decreases the peak value and does not influence the crystallinity degree of MPP. It is expected that the results of SEM, DSC, TGA, DTG, and XRD can serve as a valuable reference for the design of composites with improved thermal and crystallization behaviors. Keywords: Impact-resistant polypropylene, Thermoplastic polyurethane, Maleic anhydride, Thermogravimetric analysis, Derivative thermogravimetry, Blends, Crystallization

The damage characteristics of dry sand erosion of fiber in a hot environment are important for bag filters for garbage incinerators. In this study, we use a newly developed measuring device and evaluation method to investigate the erosion resistance of three types of fiber used for bag filters at a site in a hot environment. We found that the erosion resistance of all three types of fiber decreased as the ambient temperature increased. The erosion resistance of fiber in a hot environment is largely influenced by the decrease in fiber strength in such an environment. [ABSTRACT FROM AUTHOR]

For the restitution behavior between the tennis strings and the ball, the setting unit which can set up the interval length and tension force of the string is produced, and identified the viscoelasticity characteristic of string side and ball by compression, vibration and impact tests experimentally. It was found that the restitution coefficient is increased with the increasing distance of string interval, but reduced with the increasing string tension at the impact velocity of 5.42m/s. The regularity about the viscosity characteristic is not very much obvious. Furthermore, the influences on restitution behavior are discussed by numerical simulation analysis. The simulation results are not only corresponded with the experimental results, but also revealed that string rigidity is great effective on restitution coefficient. The effect of viscoelasticity can be ignored due to its slight influence. [ABSTRACT FROM AUTHOR]

This study proposes fabric composites with improved static and dynamic puncture via increasing a friction force to restrain the slide of filaments as well as the compression and abrasion between the fibers and the puncture probe. The the bi-layered shell layers of composite fabrics are composed of aramid staple fibers and nylon staple fibers and a layer of low-melting-point polyester (LPET). The nonwoven layer consisting of recycled aramid and nylon staple fibers provides a shear effect to dissipate part of the puncture energy. Reinforcing interlayers include a woven fabric and PET filaments that are circularly aggregated between the surface layers, providing isotropic filament reinforcement and strengthening the resistance against the tip of the puncture probe. The reinforcing filaments may slide after the employment of needle punching, and to compensate for this disadvantage, the LPET layers are used to thermal bond the composite fabrics and the total thickness is controlled at 2 mm. The thermally bonded fabric composites are evaluated in terms of puncture resistance, thereby examining the effects of fabric structure and thermal bonding. According to the test results, the optimal composite structure is the sample N/L/W/F/L/N, which was reinforced by the LPET adhesive layer and irregularly aligned filaments. The sample which used the LPET adhesive layer had a positive influence on static puncture resistance and dynamic puncture resistance, preventing the slide of filaments, but the poor interfacial combination only contributed to limited reinforcement. [ABSTRACT FROM AUTHOR]