【作者】 孟庆辉；

【导师】 顾嫒娟；

【作者基本信息】 苏州大学 ， 材料学， 2010， 硕士

【摘要】 先进树脂基复合材料(Advanced Polymeric Composite,APC)以其轻质、高比强、高比模、耐高温和极强的材料-性能可设计性而成为发展迅猛的高技术材料之一。基体树脂是决定复合材料性能优劣的一个关键因素。双马来酰亚胺(BMI)树脂既有聚酰亚胺(PI)的耐高温、耐辐射、耐湿热等多种优良特性,又有类似于环氧树脂(EP)的易加工性能,在许多方面满足了APC的要求,国外对其需求正以每年15%的速度增长。但是,未改性的BMI存在着熔点高、溶解性差、成型温度高、固化物脆性大等缺点,其中韧性差是阻碍BMI发展和应用的关键,因此增韧改性是BMI改性的前沿课题。作为APC基体树脂,不仅要有优良的机械性能(尤其是断裂韧性)、耐热、耐湿热、耐老化、耐腐蚀等,而且还要有优良的加工性。但现有树脂存在的主要问题是不能将高温性能、耐湿热性、韧性及加工性有机地统一起来。聚硅氧烷是一类具有突出耐热性、韧性和介电性能的聚合物,有望成为热固性树脂优良的增韧剂,但是聚硅氧烷的粘度大、与BMI的相容性差,使得增韧效果一直难以发挥。超支化聚合物是一类结构规整性低、质量分布宽,末端聚集大量活性官能团的化合物,具有结构和性能独特、聚合条件简单的特点,已成为近年来高分子材料领域研究的一个热点。超支化聚合物已用于环氧树脂的增韧改性,但是尚未有关于超支化聚合物用于BMI改性的研究报道。BMI的增韧改性的重点之一是必须兼顾BMI耐热性以及介电性能等,因此超支化聚合物是否能够在保证BMI突出耐热性以及优异介电性能的基础上实现BMI的增韧改性是一个值得探究的科学问题,这也正是本文的研究目的。我们选取了较为常见的、含不同活性端基、与BMI有不同反应机理的硅氧烷,分别是端基为环氧基团的γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560),端基为活性双键的γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570),以及端基为氨基的γ-氨丙基三乙氧基硅烷(KH550),分别经水解合成了三种端基为不同活性基团的超支化聚硅氧烷(HBPSi),以期不仅集成超支化聚合物和聚硅氧烷的特点,而且通过活性端基解决聚硅氧烷和BMI的相容性问题。在此基础上,探索了HBPSi改性BMI树脂的制备方法,全面评价了BMI改性体系的结构与性能。实验数据证明,HBPSi的加入能显著提高体系的冲击强度、耐热性能等,使体系的综合性能有较大幅度的提高。更多还原

【Abstract】 Advanced polymer matrix composites (APCs) have been one kind of high-tech materials owing to their light weight, large specific strength and modulus, outstanding thermal resistance, and high designability. The matrice is a key factor to determine the performances of a composite. Bismaleimide (BMI) resin has the advantages of polyimide such as including outstanding thermal and radiation resistance, and the similar processing characteristics of epoxy (EP) resins. BMI meets the requirements of the APCs in many aspects. However,BMI has big brittleness and poor processing characteristics including high melting point, poor solubility, and high curing temperature. Among them, brittleness becomes the biggest barrier to impede the applications of BMI. Therefore, the toughening is one of the most important subject on the modification of BMIs.In general, APCs should have not only excellent mechanical properties (especially fracture toughness),heat resistance,damp-heat,anti-aging,corrosion resistance and so on,but also have excellent processability. However,it seem not possible to overcome the contradiction between the processability.and performances of cured resins such as thermal resistancance, moisture resistance, and toughness.Polysiloxane is a kind of high performance polymers with outstanding heat resistance, toughness and dielectric properties, so it is expected to be used as an excellent tougher of thermosetting resins. But polysiloxane has big viscosity, poor compatibility with BMI, so the toughening effect of polysiloxane is difficult to be taken effect.Hyperbranched polymers are a class of polymers with low structural regularity, wide mass distribution, and a large number of active groups, which have been a hot spot of researches in the field of polymer materialsin recent years due to their unique structure and properties as well as simple polymerization conditions. Some hyperbranched polymers have been used for toughening of epoxy resins,but no similar researches are carried out for the modification of BMIs. More importantly, toughening of BMI resins should be carried out without sacrificing the original advantages of BMI resins including outstanding heat resistance and excellent dielectric properties, etc, whether the modification of BMIs by hyperbranched polymers can get the target is a worthy subject to be addresses, this is the object of this research.Three hyperbranched polysiloxanes (HBPSi) with different active end groups (epoxy, C=C double bonds and amine groups) are designed and synthesized by the hydrolyzation. These hyperbranched polysiloxanes are expected to combine the advantages of both hyperbranched polymers and polysiloxanes, but also get good compatibility with BMI through active-terminated groups. On this basis, new method for preparing HBPSi modified BMI resins is developed, and the structure-property relationship of modified resins is evaluated. Results show that the addition of HBPSi into BMI can effectively improve the impact strength and therma resistance of the resin, so that the overall performances of resins are greatly enhanced.更多还原