高强高韧尼龙6复合材料的制备与性能

发布时间：2018-01-20 19:17

本文关键词： 尼龙6 马来酸酐接枝苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物有机改性蒙脱土聚苯醚聚合物共混物 “核壳结构”粒子　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：尼龙6(PA6)是一种重要的工程塑料,具有优良的耐磨性、强度和加工性能,广泛应用于机械部件、电气设备和汽车等领域。然而,PA6的裂纹增长能较低(缺口敏感性),导致其缺口抗冲击强度较低,此外,其热变形温度(HDT)较低,耐吸湿性较差,使其应用受到一定限制。一种常见的增韧PA6的方法是向其添加弹性体或者马来酸酐接枝的弹性体,但受限于弹性体自身的特性,这种增韧方法会大幅度降低PA6的拉伸强度和HDT。为提升PA6的HDT和耐吸湿性,聚苯醚(PPO)常用来与PA6共混。由于PA6和PPO的热力学完全不相容,通常需向PA6/PPO共混物添加增容剂,如苯乙烯-马来酸酐共聚物(SMA)。有机改性蒙脱土(OMMT)也是PA6常用的改性剂,可提高其HDT。本论文的主要研究目的是制备高强高韧的PA6复合材料,并对复合材料的结构和性能的关系进行研究。论文取得了以下创新结果:将OMMT和SMA通过熔融共混添加至PA6/PPO共混物中,发现OMMT和SMA能够协同增容PA6/PPO。OMMT和SMA都能减小PPO分散相的尺寸。SMA能使PA6/PPO/OMMT共混物中的OMMT团聚体均匀分散,OMMT可大幅度降低PA6/PPO/SMA共混物的粘度。对PA6/PPO/SMA/OMMT纳米复合材料的耐吸湿性、拉伸性能也进行了研究。将OMMT通过熔融共混引入马来酸酐接枝苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS-g-MA)增韧的PA6/PPO共混物中,并研究了 OMMT对PA6/SEBS-g-MA/PPO纳米复合材料的形貌、流变性能和机械性能的影响。OMMT能减小PPO分散相的尺寸,降低纳米复合材料的粘度。此外,剥离态的OMMT可显著提升PA6/SEBS-g-MA/PPO纳米复合材料的拉伸性能、HDT和抗冲击性能,最终获得了高强度、超韧性、较高HDT和良好加工性的PA6/SEBS-g-MA/PPO纳米复合材料。研究了 PPO和聚苯乙烯(PS)在PA6/SEBS-g-MA/(PPO/PS)纳米复合材料中的作用。通过扫描电子显微镜(SEM)和力学性能测试分别研究了 PPO和PS的质量比以及PPO/PS添加量对PA6/SEBS-g-MA/(PPO/PS)纳米复合材料的形貌和机械性能的影响规律。受界面张力和铺展系数驱使,PPO/PS和SEBS-g-MA在PA6基体中形成了“核壳结构”粒子(PPO/PS为核,SEBS-g-MA为壳)。“核壳结构”粒子对PA6的增韧发挥至关重要的作用。PS可提高“核壳结构”粒子在PA6基体中的分散性,PPO可提高PPO/PS相的分子链缠接密度,PPO和PS在质量比为3/1时PA6纳米复合材料的性能最佳。在一定范围内,提高PPO/PS添加量可为增韧PA6提供更多合适尺寸的“核壳结构”粒子,从而提高纳米复合材料的力学性能。因此,通过调节PPO和PS的质量比以及PPO/PS的添加量,可得到高强度、超韧性和较高HDT的PA6/SEBS-g-MA/(PPO/PS)纳米复合材料。研究了聚丙烯(PP)和SEBS-g-MA在PA6/SEBS-g-MA/PP共混物中的作用。PP和SEBS-g-MA能够通过熔融共混原位在PA6基体中形成“核壳结构”粒子。研究了 PP和SEBS-g-MA对PA6/SEBS-g-MA/PP共混物的形貌、流变性能、力学性能的影响。SEBS-g-MA能改善PA6和PP的相容性,有利于形成合适尺寸的“核壳结构”粒子,从而提升共混物的力学性能。PP可抑制PA6和SEBS-g-MA过量的扩链反应,从而降低共混物的粘度,提升共混物的力学性能。基于半韧性和韧性共混物的差别,提出了增韧机理。只有合适相尺寸的增韧粒子(大于0.1 μm)才能有效增韧PA6,且韧性共混物的冲击断面才能观察到PA6基体的剪切屈服。最终,在仅添加5-10份SEBS-g-MA的情况下,可获得高强度、超韧性的PA6/SEBS-g-MA/PP 共混物。通过熔融共混制备了耐高温、高强度、高韧性的(PPO/PS)/SEBS-g-MA/PA6共混物。PA6和SEBS-g-MA在PPO/PS基体中原位形成“核壳结构”粒子(PA6为核,SEBS-g-MA 为壳)。研究了(PPO/PS)/SEBS-g-MA/PA6 共混物与PA6/SEBS-g-MA/PPO纳米复合材料在形貌和性能等方面的差异。
[Abstract]:Nylon 6 (PA6) is a kind of important engineering plastics with excellent wear resistance, strength and processability, widely used in mechanical parts, electrical equipment and automotive fields. However, PA6 can lower crack growth (notch sensitivity), the notch impact strength is low, in addition, the heat deformation temperature (HDT) with low resistance, poor hygroscopicity, which limits its application. A common method is to add the PA6 toughened by elastomer or maleic anhydride grafted elastomer, but due to the characteristics of elastic body itself, the toughening method will greatly reduce the tensile strength of PA6 and HDT. HDT and PA6 to enhance the resistance to moisture, polyphenylene ether (PPO) is used to blend with PA6. The thermodynamics of PA6 and PPO completely incompatible, usually need to add to the compatibilizer for PA6/PPO blends, such as styrene maleic anhydride copolymer (SMA). The organic modified montmorillonite (OMMT) is PA Modifier 6 commonly used, can improve the HDT. the main purpose of this thesis is the preparation of PA6 composite material with high strength and toughness, and the relationship between the structure and properties of the composites were studied. The paper has made the following innovative results: OMMT and SMA by melt blending added to PA6/PPO blend, found OMMT and SMA to PA6/PPO.OMMT and SMA synergistic compatibilization can reduce the size of.SMA phase PPO dispersion can make OMMT aggregates of PA6/PPO/OMMT blends in uniform dispersion, OMMT can greatly reduce the viscosity of PA6/PPO/SMA blends. PA6/PPO/SMA/OMMT nano composite material resistance to moisture, tensile properties were also studied. OMMT by melt blending into maleic anhydride grafted styrene ethylene butadiene styrene block copolymer (SEBS-g-MA) blends of PA6/PPO toughening, and studied the morphology of the PA6/SEBS-g-MA/PPO nanocomposites OMMT, Effect of.OMMT rheological properties and mechanical properties of PPO can reduce the size of the dispersed phase, reduce the viscosity of nano composite materials. In addition, exfoliated OMMT can significantly improve the tensile properties of PA6/SEBS-g-MA/PPO composites, HDT and impact resistance, finally obtained high strength, high toughness, high HDT PA6/SEBS-g-MA/PPO nano composite materials and good processing the study of PPO and polystyrene (PS) in PA6/SEBS-g-MA/ (PPO/PS) nano composite materials in vitro. By scanning electron microscopy (SEM) and mechanical performance test on the quality of PPO and PS respectively the ratio and amount of PPO/PS PA6/SEBS-g-MA/ (PPO/PS) influence the morphology and mechanical properties of the nanocomposites. Driven by surface tension and spreading coefficient, PPO/PS and SEBS-g-MA formed a core-shell structure particles in the PA6 matrix (PPO/PS as core and SEBS-g-MA as shell). "Core-shell structure "Particle toughening PA6 play crucial role in the.PS can improve the dispersion in the PA6 matrix of the core-shell structure particles, PPO can improve the molecular chain of PPO/PS phase winding density, PPO and PS in the mass ratio of 3/1 PA6 nano composite material has the best performance. In a certain range, high PPO/PS additive toughening PA6 provide more suitable size of core-shell structure particles, thereby improving the mechanical properties of nano composite materials. Therefore, by adjusting the PPO and the mass ratio of PS and PPO/PS content, can obtain high strength, high toughness and high HDT PA6/ SEBS-g-MA/ (PPO/PS) nano composite materials research. Polypropylene (PP) and SEBS-g-MA in PA6/SEBS-g-MA/PP blends. The effect of.PP and SEBS-g-MA by melt blending in situ in PA6 matrix to form core-shell structure particles. The effects of PP and SEBS-g-MA on PA6/SEBS-g-MA/PP blends The rheological properties, morphology and compatibility of the mechanical properties of.SEBS-g-MA can improve the PA6 and PP, is conducive to the formation of suitable size of core-shell structure particles, so as to enhance the mechanical properties of.PP blends can inhibit the chain extension reaction of PA6 and SEBS-g-MA in excess, thereby reducing the viscosity of the blend, improved the mechanical properties of blends half. Toughness and toughness of the blends is different based on the toughening mechanism was proposed. The particle size is only suitable for toughening (greater than 0.1 M) can effectively toughened PA6 blends toughness, and impact fracture can be observed in PA6 matrix shear yield. In the end, only adding 5-10 phr SEBS-g-MA, can to obtain high strength, super tough. PA6/SEBS-g-MA/PP blends were prepared by melt blending of high temperature resistance, high strength, high toughness (PPO/PS) /SEBS-g-MA/PA6 blends.PA6 and SEBS-g-MA in the PPO/PS matrix in situ formation of nuclear shell structure "Particle" (PA6 as core and SEBS-g-MA as shell). The difference in morphology and properties between (PPO/PS) /SEBS-g-MA/PA6 blends and PA6/SEBS-g-MA/PPO nanocomposites is studied.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB33

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