In this study, the effects of a coupling agent and additive on the physicomechanical (morphological, mechanical, thermal, and swelling) properties of tea dust (TD)–polypropylene (PP) composites were studied. TD–PP composites were prepared with untreated tea dust (UTD) and tetraethylsilane (TES)‐treated TD or silanated tea dust (STD) particles at ratios of 0:100, 10:90, 20:80, 30:70, and 40:60 w/w. Initially, TD particles were grafted by TES as a coupling agent, and these STD particles were then modified with graphene oxide (GO) as an additive to study their effects on the STD–PP composites; these were compared to the STD–PP and UTD–PP composites in accordance with a study of improvements in the mechanical properties. All of the TD–PP composites were analyzed with Fourier transform infrared spectroscopy, scanning electron microscopy, and mechanical, thermal, and physical tests. The thermal and mechanical properties of both the STD–PP and GO‐modified STD–PP composites were found to be improved as compared to those of the UTD–PP composites. So, the recycling of a large amount of TD as a waste material could be useful in the preparation of TD–PP composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42927.

This study investigat the effectiveness of reduced graphene oxide as nanofiller in enhancing epoxy/carbon fiber-reinforced composite at varying temperature conditions. The graphene oxide is synthesized using modified Hummer's method and then is chemically reduced to yield reduced graphene oxide (rGO). The rGO is dispersed in epoxy matrix system through combination of mechanical and sonication methods. The flexural and shear test samples are manufactured using resin infusion technique. These samples are then tested to determine their shear and flexural properties at varying temperatures (À10 C, 23 C, 40 C) and the results correlate to neat samples. It is found that the composites' flexural strength and flexural modulus increase with rGO wt% content up to 62% and 44%, respectively. The shear testing results show improvement on the shear strength and modulus at maximum of 6% and 40%, respectively. The rGO improvements advantage is lost for flexural strength, shear strength, and modulus at elevated temperatures while flexural modulus withheld at 40% improvements over virgin epoxy/carbon fiber-reinforced composite. An interesting observation is that all samples with rGO exhibit reduced damage characteristics superior to the neat samples under flexural and shear loading conditions. This study indicates that the addition of rGO significantly alter the flexural and shear properties, failure modes, damage characteristics, and they are overall sensitive to elevated temperature conditions.

In this research work, the recycling of waste tea dust particles was done by preparing the injection moulded polypropylene (PP) composites using different (10–40 wt.%) loadings of tea dust particles as a filler. The tea dust particles were treated with maleic anhydride (MA) and its esterification effect was studied on physico-mechanical (morphology, mechanical, thermal and swelling) properties of tea dust:polypropylene (TD:PP) composites. Surface modification of tea dust particles was observed due to the MA treatment i.e. the esterification effect. The surface morphology of the composites showed better interfacial bonding between the maleated tea dust particles and PP than the untreated particles. The mechanical properties of the maleated TD:PP composites were found to be improved (200–300% higher tensile strength, 250% higher tensile modulus, 43% higher flexural strength and 10% higher hardness) as compared to untreated TD:PP composites. Crystallinity and thermal properties of the maleated TD:PP composites showed increasing trend with increase in filler content. Water absorption tests showed that maleated TD:PP composites absorb less water than that of untreated one. The increment in all these properties is due to the greater compatibility in tea dust particles and PP by MA treatment. Thus, tea dust particles can be suggested for preparation of composite materials.