核壳结构改性剂改性尼龙的研究

发布时间：2018-08-22 08:47

【摘要】：本文采用种子乳液聚合方法合成了核壳比为60/40的核壳结构改性剂ABS,在接枝过程中,共聚GMA单体制备了官能化ABS改性剂。采用超速离心分离技术去除了不同改性剂中的游离SAN聚合物链。与尼龙6进行熔融共混,考察了改性剂用量和游离链的存在对PA6/ABS共混物流变性能、力学性能、动态力学性能和共混物形态的影响。结果表明:1、随着胶含量的增加,平衡扭矩均逐渐增大,游离SAN链段存在与否PA6/ABS共混体系的加工粘度相差不大。同等条件下,GMA的引入,增加了共混体系的平衡扭矩,ABS-co-GMA改性剂中游离SAN链段的存在,在一定程度上缩短了共混物达到熔融平衡时所需要的时间,使共混物的加工粘度略有降低。2、PA6/ABS共混体系的冲击强度随改性剂用量增加逐渐增加。除去改性剂中的游离链段后,共混物在相同橡胶含量时的冲击强度明显升高,但仍属于脆性断裂。引入官能化单体GMA后,共混物的冲击强度随ABS-co-GMA改性剂用量的增加,迅速增加,共混物发生脆韧转变。在相同橡胶含量时,去除改性剂中的游离SAN链后,共混物的冲击强度均有所降低。3、PA6/ABS共混物体系的弹性模量和屈服强度随着橡胶含量的增加逐渐降低,游离链段的存在对共混物的弹性模量和屈服强度影响不大。随着橡胶含量的增加,共混物的断裂伸长率略有降低,去除改性剂中的游离SAN链断在不同胶含量时可以提高共混物的断裂伸长率。引入环氧化单体GMA后,同一橡胶含量下,ABS-co-GMA改性剂中的SAN游离链段基本没有使共混物的弹性模量以及屈服强度发生变化,ABS-co-GMA改性剂中游离SAN链段的存在,可以使共混物的断裂伸长率显著提高。4、对于PA6/ABS体系,去除ABS改性剂中的游离SAN链段,ABS改性剂中SAN相的Tg与PA6的Tg分别向低温和高温方向移动,分散相对变好,提高了两相间的相容性,使共混物的性能得到改善。对于PA6/ABS-co-GMA体系,游离SAN链段起到了一定的作用,使得PA6的Tg与ABS-co-GMA改性剂中SAN相的Tg相对靠拢,相容性得到改善,共混物的性能变好。
[Abstract]:In this paper, the core-shell structure modifier ABS with core-shell ratio of 60 / 40 was synthesized by seed emulsion polymerization. In the process of graft copolymerization of GMA monomer, functionalized ABS modifier was prepared. The free SAN polymer chains in different modifiers were removed by ultracentrifugation. The effects of the content of modifier and free chain on the physical properties, mechanical properties, dynamic mechanical properties and morphology of PA6/ABS blends were investigated. The results show that the equilibrium torque increases with the increase of rubber content, and the processing viscosity of free SAN chains is similar to that of PA6/ABS blends. Under the same conditions, the introduction of GMA increases the equilibrium torque of the blend system and the existence of free SAN segment in the ABS-co-GMA modifier, and to some extent shortens the time required for the blend to reach the melting equilibrium. The processing viscosity of the blends decreased slightly. The impact strength of PA6 / ABS blends increased with the increase of the content of modifier. After the free chain segment was removed, the impact strength of the blends increased obviously at the same rubber content, but still belonged to brittle fracture. When the functionalized monomer GMA was introduced, the impact strength of the blends increased rapidly with the increase of the amount of ABS-co-GMA modifier, and the brittle and ductile transition of the blends took place. When the free SAN chain in the modifier was removed, the impact strength of the blends decreased with the increase of rubber content, and the elastic modulus and yield strength of the blends decreased with the increase of rubber content. The existence of free chain has little effect on the elastic modulus and yield strength of the blends. With the increase of rubber content, the elongation at break of blends decreased slightly, and the breaking of free SAN chain in modifier could increase the elongation at break of blends with different rubber content. With the introduction of epoxide monomer GMA, the free segment of SAN in ABS-co-GMA modifier with the same rubber content did not change the elastic modulus and yield strength of the blend. The elongation at break of the blend increased significantly by .4.For the PA6/ABS system, the TG of the SAN phase and the TG of the PA6 phase in the free SAN chain segment modifier of the ABS modifier moved to low and high temperatures, respectively, and the dispersion was relatively better. The compatibility between the two phases was improved and the properties of the blends were improved. For the PA6/ABS-co-GMA system, the free SAN segment played a certain role, which made the TG of PA6 and the TG of SAN phase in the ABS-co-GMA modifier relatively close together, the compatibility was improved, and the properties of the blends were improved.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631

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