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.

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.