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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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One of the materials most commonly found in municipal plastic waste (MPW) is High Density Polyethylene (HDPE), which is used particularly for food packaging and cleaning product containers. Postconsumer HDPE is generally contaminated with other impurities and, therefore, a cleaning process is necessary before it can be reprocessed. The aim of this study was to investigate the influence of the cleaning conditions on the oxidative degradation of postconsumer HDPE. These plastic materials were washed in NaOH solution, liquid detergent (D), and a mixture of NaOH/D (1 : 1). Results for the melt flow rate (MFR) and capillary rheometry showed that NaOH has a great influence on the oxidative degradation of HDPE. The HDPE treated with NaOH solution had a lower decomposition temperature, observed through Thermal Gravimetric (TG) analysis, and a lower the Oxidative Induction Time (OIT), obtained via Differential Scanning Calorimeter (DSC). Finally, the oxidative degradation of HDPE was verified through a higher carbonyl index.

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