Completely Biodegradable Composites of Poly(propylene carbonate) and Short, Lignocellulose Fiber Hildegardia populifolia X. H. LI, 1 Y. Z. MENG, 1,3 S. J. WANG, 1 A. VARADA RAJULU, 4 S. C. TJONG 2 1 Guangzhou Institute of Chemistry, Chinese Academy of Sciences, P.O. Box 1122, Guangzhou 510650, China 2 Department of Physics and Materials Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong 3 Institute of Energy and Environment Materials, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275, China 4 Department of Polymer Science and Technology, S.K. University, Anantapur-515003, India Received 27 November 2002; revised 29 September 2003; accepted 6 October 2003 ABSTRACT: The composites of biodegradable poly(propylene carbonate) (PPC) rein- forced with short Hildegardia populifolia natural fiber were prepared by melt mixing followed by compression molding. The mechanical properties, thermal properties, and morphologies of the composites were studied via static and dynamic mechanical mea- surements, thermogravimetric analysis, and scanning electron microscopy (SEM) tech- niques, respectively. Static tensile tests showed that the stiffness and tensile strength of the composites increased with an increasing fiber content. However, the elongation at break and the energy to break decreased dramatically with the addition of short fiber. The relationship between the experimental results and the compatibility or interaction between the PPC matrix and fiber was correlated. SEM observations indi- cated good interfacial contact between the short fiber and PPC matrix. Thermogravi- metric analysis revealed that the introduction of short Hildegardia populifolia fiber led to a slightly improved thermooxidative stability of PPC. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 666 – 675, 2004 Keywords: composites; polycarbonates; natural fiber; mechanical properties; biode- gradable INTRODUCTION Biodegradable plastics such as aliphatic polyes- ter, cellulose-based thermoplastics, and other po- lysaccharide-based plastics have attracted much attention in recent years from the point of view of environmental protection. 1,2 Most of the biode- gradable plastics, for example, the aliphatic poly- esters including poly(3-hydroxy-butyrate-co-3-hy- droxyvalerate) and poly(butylenes succinate), have poor mechanical strength and modulis than those of commercial thermoplastics. 3–8 Fiber re- inforcement is an effective way to improve the mechanical properties of thermoplastics. How- ever, conventional reinforcing materials such as glass fiber, carbon fiber, and aramid fiber are nondegradable and difficult to incinerate. In this Correspondence to: Y. Z. Meng, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, P. O. Box 1122, Guangzhou 510650, China (E-mail: mengyz@yahoo.com) Journal of Polymer Science: Part B: Polymer Physics, Vol. 42, 666 – 675 (2004) © 2004 Wiley Periodicals, Inc. 666