Investigating the Effect of Treated Rice Straw in PLLA/Starch Composite: Mechanical, Thermal, Rheological, and Morphological Study

The aim of this work is to use lignocellulosic wastes as low price additives in biodegradable polymers. The rice straw (RS) was treated by means of different methods, and then it was introduced to the poly(lactic acid)/starch composites. The effects of different treatments on RS properties were investigated using the Fourier transform infrared, tensile, charpy, hardness, differential scanning calorimetry, rheology, contact angle, and scanning electron microscopy. It was found that 5-10% of all the differently treated RS increases the overall properties. Moreover, silica and lignin were mainly affected by such treatments; however, a balance between silica and lignin shows the best results. The modified alkali-treated rice straw (ARS treatment) prevented cellulose from degradation by creating a balance between silica and lignin, which controls the opposing effects of lignin including paste-like and plasticating effects. Finally, the ARS-filled samples show improved overall properties among the other samples. The obtained composites with optimum filler content may be used in the biomembranes and food packaging applications.