Blends of ultra high molecular weigth polyethylene and polypropylene (UHMWPE/PP)

• Grant number: 22/10070-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2022
• End date: September 30, 2023
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Leonardo Bresciani Canto
• Grantee: Vitória Bortolin Lucci
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The development of ultra-high molecular weight polyethylene (UHMWPE) blends with polyolefins, such as polyethylene (PE) or polypropylene (PP), is of great scientific and technological interest with regard to the possibility of molding in the molten state. The studies so far reported in the literature on the preparation of blends of UHMWPE with PE or PP by conventional melt-state extrusion demonstrate poor dispersion of UHMWPE particles into PE or PP matrixes, which is due to the high viscosity and elasticity of UHMWPE in the molten state. This research project proposes the use of solid-state extrusion (SSE) as a preparatory technique for the preparation of UHMWPE/PP blends aiming to improve the dispersion of the phase morphology and thus their mechanical properties. UHMWPE/PP blends with composition 90/10, 80/20, and 70/30 by weight will be prepared first by extrusion in the solid state at room temperature, then pelletized by melt extrusion, and finally, injection molded. Molded specimens will be subjected to tensile, impact, and abrasive wear mechanical tests. The crystallization of the UHMWPE and PP phases in the blends will be evaluated by the calorimetry differential scanning method (DSC) and the phase morphology by scanning electron microscopy (SEM). For the purpose of comparing the properties, samples of UHMWPE/PP blends and neat PP will be prepared solely by conventional melt-state extrusion and injection molding and those of UHMWPE by compression molded. The results will be analyzed seeking to correlate the properties of UHMWPE/PP blends with composition, processing conditions, degree of crystallinity of each phase, and the type and degree of dispersion of the phase morphology. (AU)