Theses and Dissertations Collection

Abstract

The elevated amount of polyolefin production, low recycling rate and increased landfill has created an environmental concern, and more innovative studies are still ongoing to reuse and reduce this waste efficiently. One out of many remedies, is the manufacture of composites with a polyolefin matrix and a reinforcing filler. The use of natural fibers as fillers for polyolefins has evidently proven to improve physical, mechanical, thermal and flow properties. Different factors affect the final product properties of a composite from fiber particle size, interfacial bonding between matrix, processing temperature amongst many. Hence, this research was done to investigate the influence of rice hulls of different sizes (<0.5 mm and <1 mm) used as reinforcement for common polyolefins of recycled high-density polyethylene (rHDPE) and polypropylene (rPP) rice hulls composites. Mechanical characterization of the composites was done using dynamic mechanical analysis (DMA) and tensile testing. Thermal characterization was achieved via differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). Flow properties were determined using melt flow rate (MFR), dynamic and capillary rheological methods. Surface chemistry analysis was performed using Fourier Transform Infrared (FTIR) Spectroscopy. Results showed an increase in tensile and viscoelastic properties for the <0.5 mm rice hull composites for both polyolefins. These results were compared to those of virgin polyolefin rice hull composites and wood plastic composites (WPC). It was evident that recycled polyolefin rice hulls composites can be used as replacements for wood and virgin polyolefin composites since they exhibited similar properties.