Chemical treatment of cotton stalk and its effects on mechanical, rheological and morphological properties of Polypropylene/cotton stalk bio‐composites

Cotton stalk as commercially viable bio fiber for preparing bio‐composites is explored of late, and the effects of various chemical treatments of cotton stalk fiber on mechanical, rheological and morphological properties of Polypropylene (PP)‐Cotton stalk (CS) bio‐composites are reported in this study. PP‐CS bio‐composites were prepared by varying the amount of cotton stalk from 10 to 50% by melt mixing in twin screw extruder and then injection molded to make specimen. PP‐CS bio‐composites with 50 wt% untreated CS were found to have maximum improvement in tensile modulus (83%), flexural modulus (120%), impact strength (39%). Similar to tensile and flexural modulus, the storage modulus of the PP‐CS composites was also increased with incorporation of CS into the PP matrix. To further increase the interaction between CS and PP matrix, four different chemical treatments (alkali, silane, permanganate solution and stearic acid) were tested for mechanical properties of CS‐PP bio‐composites. Among them KMnO4 treatment was found most effective on overall enhancement of bio‐composite properties. Chemically treated CS‐PP bio‐composites could be an economic viable option to prepare high quality low cost composites for suitable applications in various interior parts of automotives and house hold products. POLYM. COMPOS., 39:E286–E296, 2018. © 2017 Society of Plastics Engineers