Nonisothermal shear-induced crystallization of polypropylene-based composite materials with montmorillonite

Material and mechanical characterization of recycled polypropylene reinforced with different weight percentages of short glass fiber developed by injection molding

The objective of this study was to develop short glass fiber-reinforced recycled polypropylene composites using injection molding technique with varying fiber percentages (0-50 wt%). The study aimed to evaluate the mechanical and material properties of the composites and their potential applications. To achieve this, polypropylene composite pellets were prepared using a low-cost and simple manufacturing method that involved plastic recycling using a crushing method and pelletizing with different weight percentages of short glass fiber using twin-screw extruder. The study conducted various analyses, such as melt flow index, capillary rhinometry, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Results showed that the recycled polypropylene/short glass fiber composites exhibited improved heat resistance, crystallization rate, and thermal stability compared to the pure polymer. The best impact mechanical (about 3.65 ± 0.09 J/m) properties were obtained at 50 wt% of short glass fiber in the fabricated composites. Scanning electron microscope analysis indicated a uniform dispersion of short glass fiber in the polypropylene matrix. The potential applications of these composites were found in household appliances, industrial plastic products, and other areas. Overall, this study demonstrates the potential of short glass fiber-reinforced polypropylene composites as a cost-effective, environmentally friendly and sustainable alternative for various applications.

Preparation and Characterization of Polypropylene/Sepiolite Nanocomposites for Potential Application in Automotive Lightweight Materials

Polypropylene (PP)/sepiolite nanocomposites were prepared using the melt blending technique. The effects of nano-sepiolite content on the mechanical property, thermal property, crystallinity, morphology and rheological property of PP/sepiolite nanocomposites were investigated. The organic modified sepiolites (OSep) were dispersed evenly in PP matrix after surface treatment. The addition of OSep improved the storage modulus and thermal stability, showing a strong interaction between OSep and PP matrix. With the increase of OSep content, the fluidity of PP/OSep composites first increased due to the lubrication of surface modifiers and then decreased due to the interaction between OSep and PP. The size of the toughening agent elastomer first increased and then decreased, and the impact notched strength of PP/Osep composites first decreased and then increased. The loading of OSep also reduced the crystallinity and shrinkage rate of PP. PP/OSep nanocomposites have potential applications in high-performance automotive lightweight materials.

Polypropylene/Short Glass Fibers Composites: Effects of Coupling Agents on Mechanical Properties, Thermal Behaviors, and Morphology

This study uses the melt compounding method to produce polypropylene (PP)/short glass fibers (SGF) composites. PP serves as matrix while SGF serves as reinforcement. Two coupling agents, maleic anhydride grafted polypropylene, (PP-g-MA) and maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer (SEBS-g-MA) are incorporated in the PP/SGF composites during the compounding process, in order to improve the interfacial adhesion and create diverse desired properties of the composites. According to the mechanical property evaluations, increasing PP-g-MA as a coupling agent provides the composites with higher tensile, flexural, and impact properties. In contrast, increasing SEBS-g-MA as a coupling agent provides the composites with decreasing tensile and flexural strengths, but also increasing impact strength. The DSC results indicate that using either PP-g-MA or SEBS-g-MA as the coupling agent increases the crystallization temperature. However, the melting temperature of PP barely changes. The spherulitic morphology results show that PP has a smaller spherulite size when it is processed with PP-g-MA or SEBS-g-MA as the coupling agent. The SEM results indicate that SGF is evenly distributed in PP matrices, but there are distinct voids between these two materials, indicating a poor interfacial adhesion. After PP-g-MA or SEBS-g-MA is incorporated, SGF can be encapsulated by PP, and the voids between them are fewer and indistinctive. This indicates that the coupling agents can effectively improve the interfacial compatibility between PP and SGF, and as a result improves the diverse properties of PP/SGF composites.