After alkali treatment of bamboo fiber with NaOH solution as modifier,bamboo fiber/PLA biodegradable composite was prepared by melt blending with polylactic acid (PLA).The effects of NaOH solution concentration,alkali treatment time and alkali treatment temperature on tensile strength,flexural strength and water resistance of composite were investigated,and the surface morphology of bamboo fiber after alkali treatment was observed by scanning electron microscopy (SEM).The results showed that the surface roughness and the strength of single fiber of bamboo fiber were increased after alkali treatment,which effectively improved the mechanical adhesion between bamboo fiber and PLA matrix.However,when the alkali concentration was too large,the treatment time was too long or the treatment temperature was too high,the molecular arrangement of cellulose chains was compacted and the mechanical properties of the whole fiber decreased.The bamboo fiber/PLA composite has the best tensile properties,bending properties and water resistance with 3 ％ of the concentration of NaOH solution,4 h of the treatment time and 60 ℃ of the treatment temperature.%以NaOH溶液为改性剂对竹纤维进行碱处理,再与聚乳酸(PLA)熔融共混制备竹纤维/PLA可降解复合材料.探讨了NaOH溶液浓度、碱处理时间和碱处理温度对复合材料拉伸强度、抗弯强度和耐水性能的影响规律,并采用扫描电子显微镜(SEM)对碱处理竹纤维的表面形貌进行了观测.结果表明,碱处理使竹纤维表面粗糙度增大,单纤维的强度提高,有效提高了与PLA基体的机械黏接力.但碱浓度过大、处理时间过长或处理温度过高时,纤维素分子链排列致密程度降低,整体纤维的力学性能下降.NaOH溶液浓度为3％,处理时间为4h,处理温度为60℃时,所制得竹纤维/PLA复合材料拉伸性能、弯曲性能和耐水性能均最佳.
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