Preparation and analysis of poly(l‐lactic acid) composites with oligo(d‐lactic acid)‐grafted cellulose

ABSTRACT α‐Cellulose extracted from jute fiber was grafted with oligo( d ‐lactic acid) (ODLA) via a graft polycondensation reaction in the presence of para ‐toluene sulfonic acid and potassium persulfate in toluene at 130 °C for 9 h under 380 mmHg. ODLA was synthesized by the ring‐opening polymerization of d ‐lactides in the presence of stannous octoate (0.03 wt % lactide) and d ‐lactic acid at 140 °C for 10 h. Composites of poly( l ‐lactic acid) (PLLA) with the ODLA‐grafted α‐cellulose were prepared by the solution‐mixing and film‐casting methods. The grafting of ODLA onto α‐cellulose was confirmed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The analysis of the composites was performed with FTIR spectroscopy, SEM, wide‐angle X‐ray diffraction, and thermogravimetric analysis. The distribution of the grafted α‐cellulose in the composites was uniform and showed better compatibility with PLLA through intermolecular hydrogen bonding. Only homocrystalline structures of PLLA were present in the composites, and the thermal stability increased with increasing percentage of grafted α‐cellulose. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47424.