功能性工程化热塑性塑料增韧环氧树脂的研究Word文档下载推荐.docx

1、 An alternative approach to increasing the toughness and impact strength involves the use of functionalized engineering thermoplastics as toughening agents. 一种新的，提高体系韧性和强度的方法是使用功能性的工程热塑性塑料作为增韧剂。The improvement in toughness is accomplished in this case without significant sacrifice of properties at e

2、levated temperatures. 这种改性方法在提高韧性的同时并不会损害它的高温特性。In this chapter, a brief review of the state of the art of thermoplastic-modified epoxy resin networks is presented.在本文中，对热塑性塑料改性环氧树脂的目前工艺水平进行了一个简要的论述。 Emphasis is placed on the types of modifiers, morphological character, and the various mechanisms pr

3、oposed to be responsible for the toughening behavior.重点放在了改性步骤，形态特征，以及增韧后其机械性能的改变。EPOXY RESIN NETWORKS ARE CURRENTLY USED as coatings, structural adhesives, and advanced composite matrices in many applications involving both the aerospace and electronics industries.环氧树脂被广泛地应于于涂料，结构胶黏剂以及很多高新领域的复合材料中，

4、如航空航天和电子工业中。 In addition to their outstanding adhesive properties, these highly cross-linked networks possess excellent thermal and dimensional stability as well as high modulus and strength （I, 2）.除此之外，它们杰出的粘结性能，高的层间剪切强度使它们在具有高模量和强度的同时也有好的热稳定性（I, 2）。The widespread use of epoxies, however, is limite

5、d in many high-performance applications because of their inherent brittleness. 虽然环氧被广泛应用，但它们固有的脆性还是限制了它们在很多需要高性能环境中的应用。Several methods have been proposed to improve on this attribute of epoxy networks. 已经有几种方法被用来改性环氧树脂的这种脆性。The most common method involves the addition to the system of a second polym

6、eric component that phase-separates upon curing （3, 4）.最常用的方法就是向环氧树脂中加入第二种聚合物，在固化时发生相分离（3、4）。 Traditional modifiers include functionalized rubbers such as the widely known carboxyl terminated butadiene-acrylonitrile copolymers （CTBNs）.传统的改性剂 包括功能化的橡胶，比如众所周知的CTBNs（端羧基丙烯腈橡胶）。A two-phase morphology con

7、sisting of relatively small （O.l-） rubbery particles dispersed in and bonded to an epoxy resin network is produced by incorporating CTBNs into epoxy resins.这个将CTBNs和环氧树脂混合的两相体系包含细小的橡胶颗粒分散在环氧树脂中并且作为网状结构的结合点。 The toughness of the modified networks is dependent on the properties of the original epoxy,

8、the particle size, particle volume fraction,interfacial bonding, and the properties of the elastomeric component （5）.这个改性体系的韧性取决于原始环氧树脂的特性，橡胶颗粒的尺寸，颗粒的体积分数，界面粘附性以及弹性体橡胶的成分（5）。A major limitation to toughening epoxy resins with elastomers such as CTBNs is that increased toughness can be achieved only a

9、t the expense of high-temperature performance.使用诸如CTBNs类的弹性体改性环氧树脂的最大的问题是，增加的韧性必须以损失其高温性能作为代价。 Because of the low glass-transition temperature （Tg） of the rubbery phase, rubber modification often lowers both the use temperature and the thermoset modulus.因为橡胶相低的玻璃化转变温度，用橡胶进行改性会同时降低体系的使用温度和热固性模量。 With

10、 the growing demands of the aerospace industry for materials that display high thermal stability as well as toughness, alternative methods of toughening epoxy resins based on the incorporation of functionalized thermoplastics have emerged.随着航空航天工业对新材料的持续不断的需求以及对其热稳定性的要求越来越高，一种用功能性热塑性塑料来改性环氧树脂的方法出现了。

11、 Thermoplastic modifiers are tough, ductile engineering polymers possessing high Tgs.热塑性改性剂坚韧，柔软，以及工程聚合物具有高的Tgs。 Network systems based on this technology are toughened without negatively affecting their high-temperature performance.用这种工艺增韧后的体系对其高温性能没有消极的影响。 In this chapter, the aim is to provide a g

12、eneral overview of this relatively new class of material systemswith a focus on the variations in the modifier chemistry, aspects of phase separation and the resulting morphology, and some of the mechanisms that have been proposed to explain the toughening behavior.在本文中，旨在提供关于重点是改性剂化学变化的新材料体系的综述，探讨其

13、韧性行为在相分离和最终形态的方面和某些机械性能中的影响。Thermoplastic Modifiers热塑性改性剂Initial reports in the literature concerning the use of thermoplastics to toughen epoxy resins appeared in the early 1980s.涉及热塑性塑料增韧环氧树脂的最初文献报告出现在1980年代早期。 Raghava （6） and Bucknall and Partridge （7） were the first to publish the results of the

14、ir investigations in which a commercial poly（ether sulfone） （Vitrex 100P, Chart 1）, was employed as a toughening agent in epoxy resins. Raghava （6） and Bucknall and Partridge （7） 最早发表了他们的一个调研结果，商用的聚醚砜（PSF）被用于增韧环氧树脂体系。 Although the existence of a two-phase structure was evident from both dynamic mech

15、anical analysis （DMA） and scanning electron microscopy （SEM）, Bucknall and Partridge （7） observed no toughness improvement in systems in which both chemistry and stoichiometry of the resin and curing agent were varied.尽管可以用DMA和SEM清楚地得出它们存在两相结构 ，Bucknall and Partridge （7）还注意到不论是在化学还是再化学计量学方面，体系的韧性增加都

16、不会随着固化剂的量而变化。The lack of toughening agreed with the findings of Raghava （6）, who, in a later publication （8）, attributed it to poor adhesion between the phase-separated components.韧性的缺乏也在Raghava （6）稍后发表的发现所证实，Raghava 将之归因于相分离组分间微弱的粘结力。The importance of chemically pre-reacting a thermoplastic polymer

17、 into the epoxy resin to control the compatibility and interfacial adhesion of the phase-separated network was realized by McGrath and co-workers （9-11）. McGrath和他的同事们注意到热塑性聚合物和环氧树脂的预反应对相分离时两相的相容性和界面粘结力的控制的重要性。 In their approach, a phenolic hydroxyl-terminated bisphenol A polysulfone （PSF; Chart 1）

18、was incorporated into an epoxy resin system based on diglycidyl ether of bisphenol A and diaminodiphenyl sulfone （DDS） as depicted in Scheme I. 在他们的研究中，端基酚式羟基双酚A聚醚砜（PSF，图1）被加入到含有缩水甘油醚双酚A和DDS的体系中，方案1.The PSF was pre-reacted with a large excess of epoxyresin using a quaternary ammonium catalyst to fun

19、ctionalize the PSF oligomers with epoxide groups prior to the addition of the DDS curing agent. 预先反应得到的PSF和大量过量的环氧树脂在季铵盐的催化下于预先加入DDS固化剂的环氧体系反应成低聚物。The concentration and molecular weight of the PSF modifier were varied to investigate their effect on the properties of the resulting networks. 改变PSF改性剂的

20、浓度和相对分子质量来研究它们对最终体系性能的影响。Mechanical property results demonstrated that the fracture toughness （Klc） of the cured networks increased substantially （from 0.6 to 1.7 N/m3 / 2） when both the concentration and the molecular weight of the PSF were increased. 当PSF的浓度和相对分子质量增加的时候，改性体系的机械性能中已被证明的是其断裂韧性（KIc）会

21、大幅度提高（从0.6到1.7N/m3/2）。Moreover, the increase in fracture toughness was accomplished without significant reduction in the modulus, thermal stability, or solvent resistance （9-11）.而且，断裂韧性的增加对它的模量，热稳定性和耐溶剂性没有影响。Chu et al. （12） reported in patent literature similar results utilizingamino-functionalized

22、thermoplastics. Chu et al. （12）在其专利文献中报道了使用氨基功能化的热塑性塑料得到相似的结果。Specifically, they demonstrated that amine-terminated aromatic polyethers, polysulfones, and poly（ether sulfone） of molecular weights in the range of 2000-10,000 g/mol and Tgs between 125 and 250 C produced multiphase morphologies and sig

23、nificant enhancements in the fracture toughness over the neat resin.特别的，他们证明了分子量在2000-10000g/mol以及Tgs在125-150之间端氨基芳香族聚醚，聚砜和聚醚砜在平整的树脂表面生成多相形态和断裂韧性有大幅的提高。In addition, Chu et al.（12） reported that the modified epoxy compositions resulted in stiff, tough thermoset composites with increased compression-a

24、fter-impact （CAI） strengths. 此外，Chu et al. （12）报道了改性环氧导致了强硬，坚韧的热固性材料的冲击后压缩（CAI）强度的提高。Other thermoplastics such as amino-functional poly（arylene ether ketone）s （PEKs） have been tested as toughening agents for epoxy resins. 其他的热塑性材料如氨基功能性聚醚酮（PEKs）也被用来尝试改性环氧树脂。The PEK oligomers, however, appear to be l

25、ess compatible with epoxy resins; inclusions of greater than 10-15 wt % （depending on the molecular weight） resulted in macrophase separation （13, 14）.聚醚酮低聚物，于环氧树脂的相容性不是很好，如果其含量超过10-15%（取决于其相对分子质量），就可以导致强烈的相分离（13, 14）。Recently, Bucknall and Gilbert （15） demonstrated that simple physical blends of po

26、ly（ether imides） （PEI; Chart 1） also can be used for effective toughening of epoxy resin networks. 最近，Bucknall 和 Gilbert （15）证明了聚醚胺（PEI）的简单物理混合也能用来有效地增韧环氧树脂体系。 They showed that fracture toughness increased linearly with PEI content up to 25 wt % with only modest reductions in Youngs modulus. 他们展示出随着

27、PEI含量的增加到25wt%的过程中，体系的韧性呈线性增加，其杨氏模量只会略微地下降。Whether the linear correlation between fracture toughness and modifier concentration is valid in the entire composition range has been of some interest.那么，是不是在改性剂在体系中的整个浓度范围内，断裂韧性都与其呈线性相关便变得有趣了。 For instance, Recker et al. （16,17）proposed that an optimum mo

28、rphology exists at intermediate compositions at which a maximum in fracture toughness is achieved.例如，Recker et al. （16,17）报道的得到的具有最大断裂韧性的中间组分也有最适宜的存在形态。 The work of Recker et al. involved correlating the fracture toughness of modified epoxy networks to damage tolerance in composite laminates. Recker

29、 et al. 的工作说明改性环氧体系的断裂韧性会损害复合材料的耐受性。 Fracture toughness as measured by fracture energy （GI c） and the strain energy release rate under shear （GI I c） was studied as a function of modifier molecular weight and concentration.由断裂能（GIc）测量得到的断裂韧性和剪切下的应变能释放速率（GIIc） 由改性剂的相对分子质量和浓度可以得到。The GI c was directly

30、 proportional to the number-average molecular weight up to about 10,000 g/mol, beyond which there was little or no change. GIc正比于数均分子量（数均分子量在10000g/mol内），当超过这个值以后，GIc只有很小或者没有变化。Additionally, the toughness appeared to have a sharp maximum at an intermediate modifier concentration （ca. 25 wt %）.此外，韧性在

31、改性剂浓度为一定值的时候有一个最大值（ca.25wt%）。 Similarly, Almen and co-workers （18） reported that fracture toughness achieves a maximum at intermediate compositions in thermoplastic-modified epoxies.类似的，Almen和他的同事（18）报道了在热塑性塑料改性的环氧中也会有一个断裂韧性与中间物组分相关的最大值。 Almen et al. correlated their results with morphological studies and proposed that a co-continuous morphology was responsible for the maximum and that this morphol