Effect of Graphene on Mechanical and Morphological Properties of Coconut Shell Reinforced Unsaturated Polyester Composite

Abstract

Coconut shell (CS) reinforced unsaturated polyester (UPE) composites have been prepared by using hand lay-up and compression molding techniques. To improve fiber matrix adhesion, the CS (30 wt%) was chemically treated by two chemical treatments which are alkaline (NaOH) and alkaline-silane with concentration NaOH (6%) and silane (2%). To enhance the performance of CS-UPE composites, graphene nanoplatelets (GNP) was also added as a nano filler. Scanning electron microscopy (SEM) was used to investigate the morphology of the composite samples. Mechanical properties such as tensile and flexural tests of untreated and chemical treated CS-UPE composites was also studied and compared. Overall, the use of alkalized treated CS-UPE composites showed the best mechanical (strength and modulus). Therefore, alkaline treated CS was selected to be re-prepared with graphene as nano filler in UPE composites at 0.5, 1.0 and 1.5 wt% filler loading, respectively. The presence of GNP in CS-UPE composites have demonstrated a significant enhancement in modulus properties but at the expense of tensile strength. The use of 1.0 wt% of GNP seems more optimize loading since the increment of GNP has reduced the tensile strength, which might be due to the agglomeration issue.

Thermoset/graphene polymer composites—A review of processing and properties

“…Attiya et al [ 99 ] produced graphene composites with unsaturated polyester and reported an improvement in mechanical and thermal properties with graphene 1.5 wt.%, flexural strength increased from 45 to 65 MPa, and thermal conductivity increased from 0.2 to 0.5 WmK −1 . Abdullah et al [ 100 ] studied the mechanical properties of GNP/unsaturated polyester composites, and at 1 wt.% of GNP loading, they found that flexural strength decreased from 72 MPa (at 0.5 wt.%) to 60 MPa (1 wt.%), and they attributed this to the agglomeration of GNP, which might act as steric barriers.…”