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Recycled carbon fiber reinforced polypropylene (PP) composites were fabricated by using high speed thermo‐kinetic mixer. The effect of recycled carbon fiber on the morphological, chemical, physical, thermal, and mechanical properties of PP composites was investigated. The results indicate that the tensile and flexural strength of PP increase with addition of recycled carbon fiber up to 20 wt%. When 40 wt% recycled carbon fiber was added into PP, the tensile and flexural moduli were increased by about 177 and 359%, respectively. The coefficient of thermal expansion was found to be decreased by increasing recycled carbon fiber weight fraction. The addition of low weight fraction of recycled carbon fibers (up to 5 wt%) increased the nucleation process on PP crystallization. POLYM. COMPOS., 39:3656–3665, 2018. © 2017 Society of Plastics Engineers

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Thermal conductivity of polymers can be increased by loading high thermal conductive materials like ceramic, carbon and metal-based or its mixtures. In this study, high thermal conductive and electrically insulating composites were manufactured using alumina/graphene hybrid filler mixtures. Graphene content of the filler mixtures was prepared at 0, 1, 3, 5 and 7% of total filler amount and alumina/graphene combinations of fillers loaded polypropylene (PP) matrix composites prototypes were produced at 3:2 polymer/filler weight ratio by high speed thermo-kinetic mixer. Thermal and electrical behaviors of the composites were investigated by differential scanning calorimeter, simultaneous differential thermal analysis, thermal conductivity measurement equipment and electrical resistivity measurement equipment. It was observed that the crystallization temperatures of the composites increased with increasing amount of graphene in the composite. At the same time, it was observed that the thermal conductivity values started to rise after 5% of the initial drop by the increase of the amount of graphene in the composite. The thermal conductivity of the composites increased with the addition of graphene. No significant change in the electrical conductivities of the composite materials was observed.

Micronized quartz powders reinforced polypropylene (PP) composites were fabricated by using high speed thermo-kinetic mixer. The effect of micronized quartz on the mechanical properties of PP composites was investigated. Mechanical tests were carried out to determine tensile and flexural properties of composites. Dynamic Mechanical Analysis of composites was performed to determine their thermo-mechanical properties, such as storage modulus and loss modulus. The results indicate that the tensile strength of PP decreased with addition of micronized quartz. Flexural strength, tensile modulus and flexural modulus of PP increased with the addition of 10 wt% micronized quartz.

2365 is hot work tool steel. In this study, pulsed plasma electrolysis technique has been used, in order to improve the surface hardness and wear resistance of the 2365 substrates. Polished-2365 samples were boronized by plasma electrolysis by using borax aqueous solutions at two different concentrations and two different test durations. The mechanical properties of both the modified and unmodified samples has been carried out by means of the micro-hardness, wear resistance and friction coefficient measurements. The modified samples were characterized by SEM (scanning electron microscope) and EDX (energy-dispersive X-ray spectroscopy).