The effect of UV additives on thermo-oxidative and color stability of pistachio shell reinforced polypropylene composites

In this study, pistachio shell-polypropylene copolymer (PPc) biocomposites were prepared by using the melt compounding technique. Treated pistachio shell (TPS) (30%wt) was employed to increase mechanical and thermal properties of biocomposites. Maleation and filler pre-treatment processes improved the mechanical strength of the PPc-TPS composites. The UV additives, Chimassorb 944 (CHI) stabilizer, and the UV absorber Irganox 1010 (IRGV) were used to enhance oxidative and color stability of biocomposites after they were subjected to accelerated UV irradiation for 600 h. The mechanical properties of the UV additive containing composites were less affected after UV exposure. The oxidative induction time and discoloration analysis revealed that CHI and IRGV additives can be utilized in applications that require higher color stability while the former showed better performance for oxidative stability.