Polylactide-Based Renewable Green Composites from Agricultural Residues and Their Hybrids

• Published in: Biomacromolecules 2010-06, Vol.11 (6), p.1654-1660
• Main Authors: Nyambo, Calistor, Mohanty, Amar K, Misra, Manjusri
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Applied sciences; Biocompatible Materials - chemistry; Biocompatible Materials - isolation & purification; Biological and medical sciences; Calorimetry, Differential Scanning; Chemical Phenomena; Composites; Crops, Agricultural - chemistry; Crops, Agricultural - growth & development; Exact sciences and technology; Forms of application and semi-finished materials; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Glycine max - chemistry; Glycine max - growth & development; Mechanical Phenomena; Microscopy, Electron, Scanning; Plant Components, Aerial - chemistry; Plant Components, Aerial - growth & development; Polyesters - chemistry; Polyesters - isolation & purification; Polymer industry, paints, wood; Surface Properties; Technology of polymers; Transition Temperature; Triticum - chemistry; Triticum - growth & development; Use of agricultural and forest wastes. Biomass use, bioconversion; Zea mays - chemistry; Zea mays - growth & development
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm1003114

Agricultural natural fibers like jute, kenaf, sisal, flax, and industrial hemp have been extensively studied in green composites. The continuous supply of biofibers in high volumes to automotive part makers has raised concerns. Because extrusion followed by injection molding drastically reduces the aspect ratio of biofibers, the mechanical performance of injection molded agricultural residue and agricultural fiber-based composites are comparable. Here, the use of inexpensive agricultural residues and their hybrids that are 8−10 times cheaper than agricultural fibers is demonstrated to be a better way of getting sustainable materials with better performance. Green renewable composites from polylactide (PLA), agricultural residues (wheat straw, corn stover, soy stalks, and their hybrids) were successfully prepared through twin-screw extrusion, followed by injection molding. The effect on mechanical properties of varying the wheat straw amount from 10 to 40 wt % in PLA−wheat straw composites was studied. Tensile moduli were compared with theoretical calculations from the rule of mixture (ROM). Combination of agricultural residues as hybrids is proved to reduce the supply chain concerns for injection molded green composites. Densities of the green composites were found to be lower than those of conventional glass fiber composites.