Thermal treatment of açaí (Euterpe oleracea) fiber for composite reinforcement

Abstract This work investigated the effect of thermal treatment in an autoclave on the chemical, physical, and morphological properties of lignocellulosic fibers from açaí (Euterpe oleracea Mart), and the behavior of this treated fiber in polypropylene (PP) matrix composites with polypropylene-graft-maleic anhydride (PPgMA) as the coupling agent. The treated and untreated fibers were characterized by chemical composition, x-ray diffraction, FTIR spectroscopy, and thermogravimetry, scanning electron microscopy and tensile tests were carried out for the composites. The results showed that the thermal treatment modified the hemicellulose and lignin content and increased the fiber surface roughness, without compromising the thermal stability. The composite prepared with thermally treated fibers and PPgMA exhibited an increase in tensile strength but a reduction in tensile modulus. In conclusion, the thermal treatment of vegetable fiber is a promising technique for improving the performance of composites.

摘要 本研究探究了高压釜（autoclave）热处理对巴西莓（açaí，学名Euterpe oleracea Mart.）木质纤维素纤维的化学、物理及形貌性能的影响，以及经该处理的纤维在以聚丙烯（polypropylene，PP）-g-马来酸酐（polypropylene-graft-maleic anhydride，PPgMA）为偶联剂的聚丙烯（PP）基复合材料中的界面行为。研究通过化学成分分析、X射线衍射（X-ray diffraction）、傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy，FTIR）及热重分析法对经处理与未处理的纤维进行了表征，并对复合材料开展了扫描电子显微镜观测与拉伸性能测试。结果表明，高压釜热处理可改变纤维的半纤维素与木质素含量，提升纤维表面粗糙度，且未损害其热稳定性能。采用经热处理纤维与PPgMA制备的复合材料，其拉伸强度有所提升，但拉伸模量出现下降。综上，植物纤维的高压釜热处理技术是改善复合材料综合性能的一种极具应用前景的方法。