المجلة الدولية للعلوم والتقنية

The study investigates the effect of adding castor oil (CO) as the coupling agent on the mechanical properties of linear low density polyethylene (LLDPE)/cement kiln dust (CKD) composites. Composites containing various amounts of the CKD (2, 4, 6, and 8 wt% relative to polymer) were initially prepared by melt mixing method and their mechanical properties, namely the tensile strength, elastic modulus, elongation at break, impact strength and shore D hardness were studied. The addition of CKD clearly affected the stress-strain curves of the composites, where 6 wt% CKD relative to polymer seems to be the threshold value at which the mechanical properties of the composite downgraded dramatically. At this CKD content, the composite changed from soft/tough material to hard/brittle material with high tensile strength, high elastic modulus, high shore D hardness, low impact strength and low elongation at break value. The effect of adding CO as the coupling agent on the mechanical properties of the obtained composites was investigated. Results indicate that the addition of CO led to increase the CKD content and the formation of soft/tough material with improved impact resistance and better elasticity. CO acted as a coupling agent as well as a plasticizer, which led to increase the amount of CKD content in the composite without affecting the mechanical properties of the polymer. The latter was attributed to a better CKD particle distribution in the polymer matrix at the presence of CO molecules. CO played a vital role in increasing the interaction between CKD particles and polymer chains, therefore good dispersion of CKD particles in the polymer matrix could be achieved, leading to composites with good mechanical properties.