Crystallization behavior and mechanical properties of bio-based green composites based on poly(L-lactide) and kenaf fiber

• Published in: Journal of applied polymer science Vol. 105; no. 3; pp. 1511 - 1520
• Main Authors: Pan, Pengju, Zhu, Bo, Kai, Weihua, Serizawa, Shin, Iji, Masatoshi, Inoue, Yoshio
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.08.2007; Wiley
• Subjects: Applied sciences; biocomposite; Composites; crystallization; Exact sciences and technology; Forms of application and semi-finished materials; kenaf fiber; mechanical properties; poly(L-lactide); Polymer industry, paints, wood; Technology of polymers; Strengthening; Ester polymer; Fiber reinforced material; biocomposite; Plant fiber; Mechanical properties; kenaf fiber; Experimental study; Lactone polymer; Composite material; Melt crystallization; Lactic acid polymer; Dynamic mechanical properties; Spherulites; poly(L-lactide); Natural fiber; Aliphatic polymer; Concentration effect; crystallization; Crystal morphology; Isothermal crystallization
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.26407

Bio‐based polymer composite was successfully fabricated from plant‐derived kenaf fiber (KF) and renewable resource‐based biodegradable polyester, poly(L‐lactide) (PLLA), by melt‐mixing technique. The effect of the KF weight contents (0, 10, 20, and 30 wt %) on crystallization behavior, composite morphology, mechanical, and dynamic mechanical properties of PLLA/KF composites were investigated. It was found that the incorporation of KF significantly improves the crystallization rate and tensile and storage modulus. The crystallization of PLLA can be completed during the cooling process from the melt at 5°C/min with the addition of 10 wt % KF. It was also observed that the nucleation density increases dramatically and the spherulite size drops greatly in the isothermal crystallization with the presence of KF. In addition, with the incorporation of 30 wt % KF, the half times of isothermal crystallization at 120°C and 140°C were reduced to 46.5% and 28.1% of the pure PLLA, respectively. Moreover, the tensile and storage modulus of the composite are improved by 30% and 28%, respectively, by the reinforcement with 30% KF. Scanning electron microscopy observation also showed that the crystallization rate and mechanical properties could be further improved by optimizing the interfacial interaction and compatibility between the KF and PLLA matrix. Overall, it was concluded that the KF could be the potential and promising filler for PLLA to produce biodegradable composite materials, owing to its good ability to improve the mechanical properties as well as to accelerate the crystallization of PLLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007