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In this study, the relationship between wood cellulose crystallinity, influence of extractives on wood degradation, correlation between chemical composition, and physical properties of four wood species were investigated by chemical analysis, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry. The chemical analysis showed that Dipteryx odorata and Mezilaurus itauba (ITA) contained a higher quantity of extractives and lower quantities of holocellulose and lignin than Eucalyptus grandis (EUG) and Pinus elliottii. FTIR spectroscopy indicated that higher extractives content in ITA might be associated with more intense bands at 2920, 2850, and 1510 cm À1 . The lower values for hydrogen bond energy and hydrogen bond intensity showed that EUG contained more absorbed water than the other species. Thermogravimetry confirm that lower extractive contents leads to a better wood thermal stability. This study showed that through the methods used previous information about structure and properties of wood can be obtained before use it in composite formulations. V C 2012Wiley Periodicals, Inc. J Appl Polym Sci 126: E336-E343, 2012

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In this study Eucalyptus grandis (CEG) and Pinus taeda (CPT) cellulose fibers obtained from kraft and sulfite pulping process, respectively, were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetry (TGA). The degradation kinetic parameters were determined by TGA using Coats and Redfern method. FTIR results showed that CPT presented a more ordered structure with higher crystallinity than CEG. Thermogravimetric results showed that CPT had a higher thermal stability than CEG. The kinetic results revel that for CEG the degradation mechanism occurs mainly by random nucleation, although phase boundary controlled reactions also occurs while for CPT the degradation process is more related with phase boundary controlled reactions. Results demonstrated that differences between thermal stability and degradation mechanisms might be associated with differences in the cellulose crystalline structure probably caused by different pulping processes used for obtaining the cellulose fibers.

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This study investigates the feasibility of using recycled high density polyethylene (HDPE) and wood fiber from species Eucalyptus grandis (EU) to manufacture experimental composite panels. The use of maleated polyethylene as coupling agent (CA) improved the compatibility between the fiber and plastic matrix. The mechanical properties of the resultant composites were compared with polymer with and without compatibilizer. The influence of the coupling agent (CA) in the polymer matrices and composites were evaluated at different concentrations, checking the physical, mechanical and thermal properties of wood plastic composites (WPC). Results of mechanical, physical and thermal properties showed that concentration of 3% w/w CA in the polymer matrices was that which showed the best results, but in the composites properties were very similar in all formulations. Based on the findings in this work, it appears that recycled materials can be used to manufacture value-added panels without having any significant adverse influence on material properties.