Preparation and Characterization of Polymer/Date Pits Composites

This research reports the formulation and characterization of polymer/date pits composites. Polymers used in this study were high-density polyethylene (HDPE) and polystyrene (PS), while date pits used were locally called khlaas (K) and sekari (S), wastes of two types of date palm fruit grown in Saudi Arabia. Tensile strength (TS) and Izod impact strength (IIS) tests were conducted to assess the mechanical properties of the prepared composites. Thermal properties of the composites were measured and discussed in view of glass transition and melting temperatures, T(g) and T(m), respectively, as well as the heat of fusion, which reflects the degree of crystallinity of the polymer/date pits composites. Generally, mechanical properties, i.e., TS and IIS, were reduced upon date pits incorporation in the composites. Results showed that IIS of HDPE/date pits composites drastically suffered from the addition of as low as 5 wt% of date pits. Addition of date pits regardless of the type, either S or K, tended to reduce T(g) of the PS100/date pits composites and the heat of fusion of the HDPE/date pits composites at relatively higher date pits content, >10 wt%. The reduction in both degree of crystallinty represented by heat of fusion of the HDPE and mechanical properties of all composite systems used in this study at the high loading presence of date pits may be related to the anticipated coarse morphology of the composites evolved during the mixing of polymers, with date pits in the absence of an appropriate coupling agent system.