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首页> 外文期刊>Journal of Applied Polymer Science >Toughening of epoxy resins by hydroxy-terminated, silicon-modified polyurethane oligomers
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Toughening of epoxy resins by hydroxy-terminated, silicon-modified polyurethane oligomers

机译：用羟基封端的硅改性聚氨酯低聚物增韧环氧树脂

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Epoxy resins are among the most versatile engineering structural materials. A wide variety of epoxy resins are commercially available, but most are brittle. Several approaches have been used to improve the toughness of epoxy resins, including the addition of fillers, rubber particles, thermoplastics, and their hybrids, as well as interpenetrating polymer networks (IPNs) of acrylic, polyurethane, and flexibilizers such as polyols. This last approach has not received much attention; none of them have been able to suitably increase resin toughness with out sacrificing tensile properties. Therefore, in an attempt to fill this gap, we experimented with newly synthesized hydroxy-terminated silicon-modified polyurethane (SiMPU) oligomers as toughening agents for epoxy resins. SiMPU oligomers were synthesized from dimethyl dichlorosilane, poly(ethylene glycol) (weight-average molecular weight similar to 200), and toluene 2,4-diisocyanate and characterized with IR, H-1-NMR and C-13-NMR, and gel permeation chromatography. The synthesized SiMPU oligomers, with different concentrations, formed IPNs within the epoxy resins (diglycidyl ether of bisphenol A). The resultant IPN products were cured with diaminodiphenyl sulfone, diaminodiphenyl ether, and a Ciba-Geigy hardener under various curing conditions. Various mechanical properties, including the lap-shear, peel, and impact strength, were evaluated. The results showed that 15 phr SiMPU led to better impact strength of epoxy resins than the others without the deterioration of the tensile properties. The impact strength increased continuously and reached a maximum value (five times greater than that of the virgin resin) at a critical modifier concentration (20 phr). The critical stress intensity factor reached 3.0 MPa m(1/2) (it was only 0.95 MPa m(1/2) for the virgin resin). (C) 2003 Wiley Periodicals, Inc. [References: 25]
机译：环氧树脂是最通用的工程结构材料之一。各种各样的环氧树脂是可商购的，但是大多数是易碎的。已经使用了几种方法来改善环氧树脂的韧性，包括添加填料，橡胶颗粒，热塑性塑料及其混合物，以及丙烯酸，聚氨酯和增韧剂（例如多元醇）的互穿聚合物网络（IPN）。最后一种方法并没有引起太多关注。它们中没有一个能够在不牺牲拉伸性能的情况下适当地提高树脂韧性。因此，为填补这一空白，我们尝试了新合成的羟基封端的硅改性聚氨酯（SiMPU）低聚物作为环氧树脂的增韧剂。 SiMPU低聚物由二甲基二氯硅烷，聚乙二醇（重均分子量与200相似）和甲苯2,4-二异氰酸酯合成，并用IR，H-1-NMR和C-13-NMR和凝胶表征渗透色谱。合成的不同浓度的SiMPU低聚物在环氧树脂（双酚A的二缩水甘油醚）中形成IPN。在各种固化条件下，用二氨基二苯砜，二氨基二苯醚和Ciba-Geigy固化剂固化所得的IPN产品。评估了各种机械性能，包括搭接剪切，剥离和冲击强度。结果表明，在不降低拉伸性能的情况下，15 phr SiMPU可以使环氧树脂的冲击强度更高。在临界改性剂浓度（20 phr）下，冲击强度连续增加并达到最大值（比原始树脂大五倍）。临界应力强度因子达到3.0 MPa m（1/2）（原始树脂仅为0.95 MPa m（1/2））。 （C）2003 Wiley Periodicals，Inc. [参考：25]

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