Latest breakthroughs with hybrid reinforced composites in lightweight applications

The shortage of landfill space, ocean pollution of plastics and the depletion of petroleum resources invigorated engineers and scientists to shift their focus on to the development of biobased plastics. Natural fibers are abundant and provide many advantages such as: weight reduction, process-friendliness (no wear of tools & skin irritation), biodegradability and good acoustic insulation properties. The limitations of natural fibers as reinforcement for thermoplastics are their low mechanical properties, limited thermal stability and shrinkage in comparison to traditional inorganic reinforced thermoplastics. In this study, the objective was to develop hybrid composites combining poly α-1, 3-glucan (DuPont’s NuvolveTM) along with long glass fiber in a polypropylene matrix to optimize the overall composite properties. The polysaccharide and glass fiber loadings (wt. %) were varied and the samples were prepared via twin-screw extrusion followed by injection molding. The results showed mechanical properties decreased with increasing polysaccharide content, however there is an optimum loading of the polysaccharide that is a promising alternative to reduce the utilization of inorganic fillers (e.g. glass fiber). Thermal & morphological analyses were also conducted to understand dispersive nature of the fillers, reinforcing capability and thermal behaviour of the overall composite. In general, the composites showed enhanced thermal stability with increasing glass fiber content with good to moderate filler distribution and dispersion within the PP matrix. The hybrid reinforced thermoplastic composites can lead to vast weight and potential cost savings with the promise to advance environmental stewardship within the automotive realm. Introduction Petroleum-based plastics have vastly contributed to quality of life in modern society such as the advent of Polyethylene (PE) which is widely used in consumer goods, wire & cable insulation, industrial piping, linings, coatings and was historically deployed in World War II for electrical insulation of submarines and radar shields [1]. In particular, the usage of plastics by mass in the automotive industry increased from 6% in 1970 to 16% in 2010 and it is due to reach 18% by 2020 [2]. The increased usage of plastics contributes to post-consumer waste where shortage of landfill space, ocean pollution and the depletion of petroleum resources inspired engineers and scientists to develop biodegradable & renewable plastics. Next generation materials should exemplify principles of sustainability, industrial ecology and green chemistry. Moreover, in the United States of America the corporate average fuel economy (CAFE) regulated by the national highway traffic safety administration (NHTSA) set the fuel economy standard for passenger vehicles and light-duty trucks to be 54.5 MPG by 2025 [2]. The projected added cost to a 2025 model vehicle is 1800 USD however, the improved fuel economy for those consumers who drive their vehicle for its entire lifetime would save on average 3400-5000 USD