Harmaen Ahmad Saffian
In this study, the effects of surface lignin modification on the properties of natural fiber reinforced poly (butylene succinate) biocomposites were examined. A weight percent gain (WPG) value of 4.5% was recorded after the lignin was modified with phthalic anhydride. Lower mechanical properties were observed for lignin composites because of incompatible bonding between the hydrophobic matrix and the hydrophilic lignin. Modified surface lignin (ML) was found to have a better interfacial bonding, since phthalic anhydrides remove most of the hydrophilic hydrogen bonding (this was proven by a ATR-Fourier-transform infrared (FTIR) spectrometer a reduction of broadband near 1743 cm-1,corresponding to the –C=C stretching vibration of hydroxyl groups for the ML samples). On the other hand, ML was found to have a slightly lower glass transition temperature, Tg, since reactions with phthalic anhydride destroy most of the intra- and inter-molecular hydrogen bonds, resulting in a softer structure at elevated temperatures. The addition of lignin was found to increase the thermal stability of the PBS polymer composites, while modified lignin showed higher thermal stability than pure lignin and possessed delayed onset thermal degradation temperature. Modified lignin also increased the mechanical properties in the lignin-based composites.
Published Date: 2020-11-13; Received Date: 2020-02-20