UV and thermal weathering of green composites: Comparing the effect of different agricultural waste as fillers

Abstract

In general, agricultural waste (residue) is left to nature or employed as fuel material in houses. However, such use of agricultural waste adversely affects the environment. To reduce the negative impact of agricultural waste on the environment, it can be utilized as natural filler in thermoplastic composites owing to its cellulosic structure. This research aims to determine ultraviolet (UV) and thermal ageing of natural fiber reinforced composites to investigate their potential of using in outdoor applications. Therefore, five kinds of agricultural waste were employed as natural fillers for fabricating polypropylene (PP) based composites in current research. Sunflower seed husk (dakota and white type), pumpkin seed husk, pistachio shell and hazelnut shell were utilized as natural fillers. Tensile behaviour of natural flour filled PP composites was characterized by a brittle failure. Though the natural fillers reduced the tensile and impact strength of pure PP, the mechanical properties were still acceptable for some applications and lower cost of natural filled PP composites made them feasible. It was concluded that sunflower seed husk (dakota and white type), pumpkin seed husk, pistachio shell and hazelnut shell flour filled PP composites could compete with pure PP when flexural strength was taken into consideration. Thus, more environmentally friendly composites with good flexural strength were developed. It was found that the influence of UV and thermal ageing on mechanical properties was not detrimental. In general, dakota type sunflower seed husk flour reinforcement gave the best mechanical properties among the natural composites, thus indicating better stress transfer.