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首页> 外文期刊>Journal of Applied Polymer Science >Toughening of epoxy resin using synthesized polyurethane prepolymer based on hydroxyl-terminated polyesters
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Toughening of epoxy resin using synthesized polyurethane prepolymer based on hydroxyl-terminated polyesters

机译：使用基于羟基封端的聚酯的合成聚氨酯预聚物对环氧树脂进行增韧

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Epoxy resins are increasingly finding applications in the field of structural engineering. A wide variety of epoxy resins are available, and some of them are characterized by a relatively low toughness. One approach to improve epoxy resin toughness includes the addition of either a rigid phase or a rubbery phase. A more recent approach to toughen brittle polymers is through interpenetrating network (TPN) grafting. It has been found that the mechanical properties of polymer materials with an IPN structure are fairly superior to those of ordinary polymers. Therefore, the present work deals with epoxy resin toughening using a polyurethane (PU) prepolymer as modifier via IPN grafting. For this purpose, a PU prepolymer based on hydroxyl-terminated polyester has been synthesized and used as a modifier at different concentrations. First, the PU-based hydroxyl-terminated polyester has been characterized. Next, an IPN (Epoxy-PU) has been prepared and characterized using Fourier transform infrared (FTIR) spectroscopy, thin-layer chromatography (TLC), and scanning electron microscopy (SEM) prior to mechanical testing in terms of impact strength and toughness. In this study, a Desmophen 1200-based PU prepolymer was used as a modifier at different concentrations within the epoxy resin. The results also showed that, further to the IPN formation, the epoxy and the PU prepolymer reacted chemically (via grafting). Compared to virgin resin, the effect on the mechanical properties was minor. The impact strength varies from 3-9 J/M and K-c from 0.9-1.2 MPa m(1/2). Furthermore, the incorporation of a chain extender with the PU prepolymer as a modifier into the mixture caused a drastic improvement in toughness. The impact strength increases continuously and reaches a maximum value (seven-fold that of virgin resin) at a modifier critical concentration (40 phr). K-c reaches 2.5 MPa m(1/2) compared to 0.9 MPa m(1/2) of the virgin resin. Finally, the SEM analysis results suggested that internal cavitation of the modifier particles followed by localized plastics shear yielding is probably the prevailing toughening mechanism for the epoxy resin considered in the present study. (C) 1998 John Wiley & Sons, Inc. [References: 37]
机译：环氧树脂在结构工程领域的应用越来越多。环氧树脂种类繁多，其中一些具有较低的韧性。一种改善环氧树脂韧性的方法包括添加刚性相或橡胶相。增韧脆性聚合物的最新方法是通过互穿网络（TPN）接枝。已经发现具有IPN结构的聚合物材料的机械性能相当优于普通聚合物。因此，本发明涉及通过IPN接枝使用聚氨酯（PU）预聚物作为改性剂的环氧树脂增韧。为此目的，已经合成了基于羟基封端的聚酯的PU预聚物，并以不同的浓度用作改性剂。首先，已经表征了PU基羟基封端的聚酯。接下来，在冲击强度和韧性方面进行机械测试之前，已经准备了IPN（Epoxy-PU）并使用傅里叶变换红外（FTIR）光谱，薄层色谱（TLC）和扫描电子显微镜（SEM）进行了表征。在这项研究中，基于Desmophen 1200的PU预聚物在环氧树脂中以不同浓度用作改性剂。结果还表明，除了IPN的形成以外，环氧树脂和PU预聚物还发生了化学反应（通过接枝）。与原始树脂相比，对机械性能的影响较小。冲击强度为3-9 J / M，K-c为0.9-1.2 MPa m（1/2）。此外，将增链剂与PU预聚物作为改性剂结合到混合物中引起韧性的显着改善。冲击强度在改性剂临界浓度（40 phr）下连续增加并达到最大值（是原始树脂的七倍）。 K-c达到2.5 MPa m（1/2），而原始树脂为0.9 MPa m（1/2）。最后，SEM分析结果表明，在本研究中，改性剂颗粒的内部空化以及随后的局部塑料剪切屈服可能是环氧树脂的主要增韧机理。 （C）1998 John Wiley＆Sons，Inc. [参考：37]

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