硬脂酸-CaCO3协同改性对植物纤维/聚乳酸复合材料力学性能的影响

Effect of Stearic Acid-Calcium Carbonate Synergistic Modification on the Mechanical Properties of Plant Fiber /Polylactic Acid Composites

关键词:  植物纤维  聚乳酸  硬脂酸钙  力学性能

Key Words:plant fiber  polylactic acid  calcium stearate  mechanical properties

摘要:以硬脂酸、CaCl₂、NaHCO₃和NaOH为原料，对植物纤维进行硬脂酸-CaCO₃协同改性，在纤维表面沉积CaCO₃颗粒和疏水的硬脂酸钙层，并通过造纸法制备改性植物纤维/聚乳酸（PLA）复合材料。结果表明，协同改性生成的硬脂酸钙包裹了CaCO₃颗粒并覆盖在植物纤维表面，提高了纤维的疏水性，复合材料的力学性能随c(硬脂酸)∶c(NaHCO₃)的增加而先增加后减小；反应温度对复合材料强度影响较小；复合材料的抗张指数和耐破指数随c(NaOH)∶c(NaHCO₃)的增加而先增加后减小，耐折度则持续减小；最佳改性条件为：c(硬脂酸)∶c(NaHCO₃)∶c(NaOH)=4∶6∶6、反应温度75 ℃，此时制备的复合材料抗张指数、耐破指数和耐折度分别为51.0 N·m/g、3.56 kPa·m²/g、244次。

Abstract:Taking the stearic acid， CaCl₂， NaHCO₃ and NaOH were raw materials， the plant fiber was co-modified with stearic acid and calcium carbonate in this study. CaCO₃ particles and hydrophobic calcium stearate layer were deposited on the surface of plant fiber， then the modified plant fiber and polylactic acid were prepared into composites by a papermaking process. The results showed that calcium stearate encapsulated CaCO₃ particles and covered the surface of plant fiber， which improved the hydrophobicity of fiber. With the increase of c（stearic acid）∶c（NaHCO₃）， the mechanical properties of the composites first increased and then decreased. The reaction temperature had little effect on the mechanical properties of the composites. With the increase of c（NaOH）∶c（NaHCO₃）， the tensile index and bursting index of the composites first increased and then decreased， while the folding endurance continued to decrease. The best modification conditions were c（stearic acid）∶c（NaHCO₃）∶c（NaOH）=4∶6∶6 at 75 ℃. Under optimum conditions， the tensile index， bursting index and folding endurance of prepared composites were 51.0 N·m/g， 3.56 kPa·m²/g and 244 times， respectively.