论文部分内容阅读
以玉米淀粉和马来酸酐(MAH)为原料,通过干法合成MAH酯化淀粉,通过熔融挤出法制备酯化淀粉/聚乳酸(PLA)复合材料。研究了MAH用量对复合材料结晶度和相容性的影响,同时考察了相容性和结晶度的变化对复合材料热性能、熔融流动性能、力学性能、耐水性能和流变性能的影响。FTIR结果证明通过干法成功合成了MAH酯化淀粉。酯化淀粉的取代度随MAH用量增多逐渐增大,反应效率高达90%。XRD和DSC结果表明:随着MAH用量增多,酯化淀粉/PLA复合材料的结晶度逐渐降低,淀粉和PLA的相容性逐渐提高。结晶度的降低和相容性的提高使复合材料的玻璃化转变温度逐渐降低,熔融流动性提高,耐水性提高。在力学性能和流变性能受相容性和结晶度的共同影响下,酯化淀粉中MAH用量从0增加到1.0wt%时,复合材料拉伸强度、弯曲强度、储能模量和复数黏度都逐渐增大,MAH用量超过1.0wt%后,性能逐渐降低。
MAH esterified starch was synthesized by dry method using corn starch and maleic anhydride (MAH) as raw materials, and esterified starch / polylactic acid (PLA) composite was prepared by melt extrusion. The effects of MAH content on the crystallinity and compatibility of the composites were investigated. The influences of the compatibility and crystallinity on the thermal, melt flow, mechanical, water and rheological properties of the composites were also investigated. FTIR results demonstrate the successful synthesis of MAH esterified starch by dry method. The degree of substitution of esterified starch increases with the amount of MAH increased, the reaction efficiency up to 90%. The results of XRD and DSC show that the crystallinity of the esterified starch / PLA composite decreases with the increase of the amount of MAH, and the compatibility of starch and PLA gradually increases. With the decrease of crystallinity and the increase of compatibility, the glass transition temperature of composites is gradually decreased, the melt fluidity is improved and the water resistance is improved. Under the influence of the compatibility and crystallinity of mechanical properties and rheological properties, the tensile strength, flexural strength, storage modulus and complex viscosity of the composites were increased when the content of MAH in esterified starch increased from 0 to 1.0wt% Are gradually increased, MAH amount of more than 1.0wt%, the performance gradually decreased.