Quantification of Wood Flour and Polypropylene in Chinese Fir/Polypropylene Composites by FTIR
LAO Wan-li1, LI Gai-yun1*, ZHOU Qun2*, QIN Te-fu1
1. Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China 2. Department of Chemistry, Tsinghua University, Beijing 100084, China
Abstract：The ratio of wood and plastic in Wood Plastic Composites (WPCss) influences quality and price, but traditional thermochemical methods cannot rapidly and accurately quantify the ratio of wood/PP in WPCss. This paper was addressed to investigate the feasibility of quantifying the wood flour content and plastic content in WPCss by Fourier Transform Infrared (FTIR) spectroscopy. With Chinese fir, polypropylene (PP) and other additives as raw materials, 13 WPCs samples with different wood flour contents, ranging from 9.8% to 61.5%, were prepared by modifying wood flour, mixing materials and extrusion pelletizing. The samples were analyzed by FTIR with the KBr pellets technique. The absorption peaks of WPCss at 1059, 1 033 and 1 740 cm-1 are considered as characteristic of Chinese fir, and the absorption peaks at 1 377, 2 839 and 841 cm-1 are typical of PP by comparing the spectra of WPCss with that of Chinese fir, PP and other additives. The relationship between the wood flour content, PP content in WPCss and their characteristic IR peaks height ratio was established. The results show that there is a strong linear correlation between the wood flour content in WPCss and I1 059/I1 377, I1 033/I1 377, R2 are 0.992 and 0.993 respectively; there is a high linear correlation between the PP content in WPCss and I1 377/I1 740, I2 839/I1 740 R2 are 0.985 and 0.981, respectively. Quantitative methods of the wood flour content and PP content in WPCss by FTIR were developed, the predictive equations of the wood flour content in WPCss are y=53.297x-9.107 and y=55.922x-10.238, the predictive equations of the PP content in WPCss are y=6.828 5x+5.403 6 and y=8.719 7x+3.295 8. The results of the accuracy test and precision test show that the method has strong repeatability and high accuracy. The average prediction relative deviations of the wood flour content and PP content in WPCss are about 5%. The prediction accuracy has been improved remarkably, compared to thermochemical methods. More importantly, FTIR is more easy-handing. This experiment may provide a simple, rapid and accurate method for quantification of wood flour and PP in Chinese fir/PP composites.
[1] XU Min, LI Jian(许 民, 李 坚). Biomass-Plastic Composite Technology(生物质塑料复合工艺学). Beijing: Science Press(北京: 科学出版社), 2006. 2. [2] XIAO Ze-fang, ZHAO Lin-bo, XIE Yan-jun, et al(肖泽芳, 赵林波, 谢延军, 等). Journal of Northeast Forestry University(东北林业大学学报), 2003, 31(1): 39. [3] Reneckar S, Zink-Sharp A G, Ward T C, et al. Journal of Applied Polymer Science, 2004, 93(3): 1484. [4] Jeske H, Schirp A, Cornelius F. Thermochimica Acta, 2012, 543: 165. [5] Windt M, Meier D, Lehnen R. Holzforschung, 2011, 65(2): 199. [6] Rohman A, Che Man Y B. Journal of Applied Sciences Reasearch, 2009, 5(7): 717. [7] Tucker M P, Nguyen Q A, Eddy F P，et al. Applied Biochemistry and Biotechnology, 2001, 91-93(1-9): 51. [8] Pandy K K. Journal of Applied Polymer Science, 1999, 71(12): 1969. [9] Pandey K K, Pitman A J. International Biodeterioration and Biodegradation, 2003, 52(3): 151. [10] Fackler K, Schwanninger M, Gradinger C, et al. FEMS Microbiology Letters, 2007, 271(2): 162. [11] Morent R, De Geyter N, Leys C, et al. Surface and Interface Analysis, 2008, 40(3-4): 597.
