Infrared Spectral Functional Group and Thermal Properties of Acacia Wood Bio-composites

Abstract

This chapter discover spectral functional group and thermal properties of acacia wood bio-composites. A small peak at 2897.08 cm−1 for U-AW fiber and 2900.94 cm−1 for M-AW fiber was attributed to the C-H stretching and O-H stretching bond structure that contained functional group of alkanes (cellulose and lignin) and carboxylic acids. The small peak in the region of the C-H stretching bond structure can also include a functional group of methyl (CH3), methylene (CH2), and aliphatic saturated (CH). The peak at 607.58 cm−1 and 592.15 cm−1 for U-AW fiber, and 605.65 cm−1, 559.36 cm−1, 493.78 cm−1 and 472.56 cm−1 for M-AW fiber is characterized as the =CH bending bond structure from the functional group of alkenes (lignin). Few additional peaks in M-AW fiber spectrum were due to the esterification, which promotes additional free hydroxyl structure, which improves the AW fiber structure for better adhesion with polymer. The peak at 943.19 cm−1 and 727.16 cm−1 for PLA/PHA, and 875.68 cm−1 and 719.45 cm−1 for NCHB-PLA/PHA is characterized as the C-H “oop” bond structure from the functional group of aromatics. The peak at 480.28 cm−1 for NCHB-PLA/PHA is characterized as the =CH bending bond structure from the functional group of alkenes. The DSC result prove that the reduction in the crystallinity values was an indicator of improvement in the adhesion between fiber and polymer in the bio-composites. The TGA result demonstrated that M-AW-PLA/PHA blend showed two degradation steps. The first step was due to decomposition of hemicellulose, and lignin, weak PHA and PLA bonding and the second step was degradation of cellulose, strong PLA and PHA and other bonding in the polymer blend.