【作者】 冯威；

【导师】 金日光； 李佐邦；

【作者基本信息】 北京化工大学 ， 高分子材料， 1997， 博士

【摘要】 目前研究工程塑料合金正处在战略性转移的阶段，即同时进行化学增容与物理增容来制备高强超韧超级工程塑料合金。所采用的主要方法是通过添加各种增容剂和其它助剂、调节温场和剪切力场等重要加工参数，采用反应型双螺杆、四螺杆挤出机同时实现化学改性与物理改性。为了获得超韧聚苯醚(PPO)合金，本文分两个阶段对其增韧改性工作进行了研究。 第一阶段：PPO增韧工作的探索。 在该阶段，本文用多种冲击改性剂对PPO／PA6(49／41)体系进行增韧，所用冲击改性剂包括氢化苯乙烯—丁二烯—苯乙烯三元嵌段共聚物(SEBS，Kraton G 1651)、马来酸酐改性SEBS(SEBS-g-MA，Kraton FG 1901)、乙烯-1-辛烯共聚物(POE，Engage 8150)。该体系兼具非结晶性PPO的高Tg、尺寸稳定性、低吸水性和结晶性PA6的易加工成型、耐溶剂性等优点，是当代工程塑料合金开发的热点。 在PPO／PA6体系开发的过程中，首先需要解决的是PPO与PA6的相容性。为此本文采用熔融共混法制备了PPO-g-MA(马来酸酐)，用FTIR对所得产物进行分析，结果表明MA接枝到了PPO的分子链上。采用各种分析和测试手段对PPO-g-MA增容的PPO／PA6和PPO／PA6／SEBS体系的亚微形态、冲击性能、拉伸性能和流变性能进行了广泛的研究。透射电子显微镜(TEM)的研究结果表明PPO分散相的尺寸随着PPO-g-MA用量的增加而减小；扫描电子显微镜(SEM)的结果表明PPO／PA6／SEBS合金的冲击断面随着PPO-g-MA用量的增加由脆性断裂转变为韧性断裂；流变行为的测试结果表明合金的表观粘度随着PPO-g-MA用量的增加而增大；此外，PPO／PA6／SEBS体系的缺口冲击强度随着PPO-g-Mh用量的增加发生脆—韧转变。这些均说明PPO-g-MA与PA6在熔融挤出过程中发生反应，生成了PPO-g-PA6共聚物，该共聚物起到了原位增容作用。进一步的研究表明，合金的脆—韧转变受制于增容剂PPO-g-MA的用量和弹性体SEBS的用量，当PPO-g-MA用量为25％、SEBS用量为10～15％时，体系发生脆—韧转变，其缺口冲击强度达450J／m。 本文采用一种由金属茂催化剂制备的具有规整分子链结构的新型聚烯烃热塑性弹性体POE对PPO／PA6体系进行增韧。经过MA接枝改性的POE(POE-g-Mh)与PPO-g-MA增容的PPO／PA6体系进行共混，分析结果表明POE在PA6中的分散尺寸由未改性时的20μm下降到接枝率为0.46％时的0.2μm；缺口冲击断面由镜面状的脆性断裂到含有大量韧窝和空穴存在的韧性断裂；同时缺口冲击强度和拉伸强度明显提高。这些说明POE-g-更多还原

【Abstract】 In this paper, poly(phenylene oxide) (PPO) was modified by mixing it with various tougheners and compatibilizers in a twin-screw extruder. Processing parameters such as temperature and shear condition were controlled to achieve modification both physically and chemically. This research work was carried out in two stages to prepare super-toughened PPO alloys. Stage 1: The Toughening of PPO/PA6 AlloysThree elastomers were tried to improve the impact strength of PPO/PA6 alloys, including styrene/ethylene-butylene/styrene triblock copolymer (SEBS, Kraton G 1651), ethylene/octene-1 copolymer (POE, Engage 8150), and maleic anhydride grafted SEBS (SEBS-g-MA, Kraton FG 1901). The resulted alloys combine the high Tg, high dimension stability, and low water absorbability of PPO and the processibility and high solvent resistance of PA6.Maleic anhydride(MA) grafted PPO (PPO-g-MA) was also prepared via melt-mixing as a compatibilizer of PPO and PA6. FTIR determination of the PPO-g-MA showed that MA was indeed grafted onto PPO chains. This compatibilizer was applied to two alloys: PPO/PPO-g-MA/PA6 and PPO/PPO-g-MA/PA6/SEBS. Characterization with transmission electron microscopy (TEM) and scanning electron microscopy (SEM) indicated that an excellent compatibilization was achieved in these alloys. The size of dispersed phase (PPO) decreased with the increase of the amount of PPO-g-MA. The impact strength of the alloys increased with the PPO-g-MA content and a brittle-tough transition was observed. These results indicated that PPO-g-MA reacted with PA6 in-situ during the extrusion and copolymers PPO-g-PA6 was produced. The point of brittle-tough transition was dependent on the content of PPO-g-MA and SEBS, which was around the PPO-g-MA amount of 25 wt%, and that of SEBS of 10-15 wt%. The Izod impact strength of 450 J/m was achieved.PPO/PA6 alloys were further toughened by MA grafted POE(POE-g-MA). The grafting product improved the compability of POE and PA6. When the amount of grafted MA was 0.46 wt%, the average size of POE domains in PA6 matrix was 0.2μm compared with 20 μm of ungrafted POE. The addition of POE-g-MA greatly increased the impact strength of the alloys, which could be as high as 650 J/m. A brittle-tough transition was also observed, which was around the POE-g-MA content of 15wt% and that of 0.2～0.5wt% grafting degree.更多还原