The strength of polylactic acid composites reinforced with sugarcane bagasse and rice husk

There are more than 1000 species of cellulose plants available in fiber form. A number of them are by-products from the major food crops contain lignocellulosic sources and being investigated as composite reinforcement materials. Sugarcane bagasse and rice husk are potential reinforcement materials and they were used to reinforce polylactic acid (PLA) matrix to make green composites. In this research work, sugarcane bagasse was given two different kinds of treatment; some were alkali treated using 8 wt.% NaOH at room temperature for an hour and some other were steam treated at 0.75 MPa for 30 minutes. The fiber content of the composites changed with weight percentage ratios of sugarcane bagasse/rice husk/PLA was 25/0/75, 25/5/70 and 25/10/65. Flexural strength was tested in accordance with ASTM D790-17 and structural evaluation was evaluated using scanning electron microscope (SEM) on the fracture section of the flexural test samples. Composites produced using steam treated sugarcane bagasse and rice husk have lower area density (1277-1385 g/m²) compared to the ones formed using NaOH treated bagasse and rice husk (1162-1500 g/m²). Both values of area density are below the density of neat PP and wood flour reinforced PP/PE composites used as reference materials. The flexural test shows the NaOH treatment on the bagasse fibers improve the flexural strength of the composites but the rice husk content introduced to the structure reduces the strength of the composites. SEM evaluation shows fiber fracture and few pull-out.