硼酸季戊四醇缩聚物改性环氧树脂的性能研究

发布时间：2017-12-28 12:29

本文关键词：硼酸季戊四醇缩聚物改性环氧树脂的性能研究　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：环氧树脂的力学性,电绝缘性,粘合性优良,而且加工性较为灵活,因此在军事领域、航空航天领域及民用领域等得到应用。然而,环氧树脂的氧指数低(约19.8),其易燃性,使其应用非常有限,因此在一定条件下需要对环氧树脂阻燃。在阻燃的复合材料材料中,一般都是采用阻燃剂来改善材料的阻燃性。目前改性环氧树脂阻燃性能,大多数使用含卤阻燃剂、含磷阻燃剂及无机阻燃剂,但是无机阻燃剂对环氧树脂所制的复合材料的力学性能影响比较大,而含磷阻燃剂、含卤阻燃剂会对环境造成一定的污染,因此开发新型阻燃剂是势在必行。科学研究证明有机硼一类的阻燃剂具有阻燃性能好、低毒、低烟等优点。本文研究内容如下:(1)以硼酸、季戊四醇为原料,经脱水缩合反应,合成了新型的有机硼阻燃剂-硼酸季戊四醇缩聚物(BP),探讨其最佳耐热性能的合成条件为:硼酸:季戊四醇=1:1,于100℃下反应七小时;所得到BP可以溶解于水和乙醇中;BP初始分解温度368℃,高于大部分高分子的分解温度,可用于高分子阻燃。由DTG可知最大失重速率的温度为420.76℃,600℃的残炭率为41.5%,分解温度范围只有68℃,在较窄的温度范围内可以生成大量的炭层,有利于阻燃,是一种优良的阻燃剂。(2)制备了不同含量的BP/海茵环氧(EP)树脂体系,研究了树脂体系的粘度特性和凝聚特性;并制备了BP/EP浇注体固化物,对其力学性能进行测试。结果表明:不同组分的低粘度平台的粘度随着BP的含量增加而增大;在105~125℃之间BP/EP体系有较低的黏度,适合成型操作;在相同的温度下含BP高的树脂体系凝胶时间更短,计算得10%BP的反应活化能73.33KJ/mol、20%BP反应活化能62.89KJ/mol、30%BP反应活化能61.03KJ/mol、40%BP反应活化能58.89KJ/mol;增加一定BP的用量有利于降低体系的反应活化能;BP的加入有效地提高了环氧树脂的冲击强度,改善了环氧树脂的韧性,同时BP的加入对海因环氧树脂的拉伸、弯曲强度的改善效果不明显。(3)通过动态DSC对不同配比的BP/EP树脂体系测试,并推导特征固化温度,反应活化能和固化动力学方程;结果表明:动态DSC计算各配方的反应活化能,10%反应活化能最高为85.51kJ/mol,随着BP含量的增加,反应活化能下降,反应活性增加;联合Kissinger、Starink和Crane方程建立了BP/EP固化反应动力学方程。通过T-β作图外推法得到BP/EP各配方的特征固化温度,制定BP/EP的固化工艺为110℃固化2小时,125℃固化4小时,140℃固化4小时。(4)对BP/EP固化体系的阻燃性进行探讨,结果表明:阻燃固化剂BP的加入能够明显提高固化物的阻燃性能,随着BP含量的增加,固化物的氧指数增大,阻燃性能提高,当含量为40%时,氧指数达到30.5;随着硼酸季戊四醇缩聚物的的增加,膨胀度减小。通过对BP/EP树脂TG测试,10%BP树脂固化物在800℃的残炭率28.3%,比没有BP的环氧树脂固化物的残炭率高出74.4%;且随着BP含量的增加,固化物的残炭率增大,当含量达到40%时比没有BP的环氧树脂固化物的残炭率提高了220.6%,BP的加入能够显著的提高固化物的耐热性。通过扫描电镜观察BP(40%)/EP的燃烧表面可知,燃烧后的外表面炭层致密,内表面为多孔泡沫状,是一种典型的膨胀型阻燃现象。推测BP/EP自阻燃体系的阻燃的主要作用机理为为:形成玻璃体覆盖层,起隔绝作用的凝聚相阻燃;硼酸脱水吸热的吸热阻燃机理;体系受热分解产生氨气,二氧化氮的气相阻燃机理。
[Abstract]:The mechanical properties, electrical insulation and adhesion of epoxy resin are excellent, and the machinability is flexible. Therefore, epoxy resin has been applied in military, aerospace and civil fields. However, the oxygen index of epoxy resin is low (about 19.8), and its flammability is very limited, so it needs to be flame-retardant to epoxy resin under certain conditions. In the flame retardant composite materials, flame retardants are generally used to improve the flame retardancy of the material. At present, the properties of modified epoxy resin flame retardant, most of the use of halogen containing flame retardant, flame retardant and inorganic flame retardant, but the mechanical properties of composite material of flame retardant epoxy resin system is relatively large, while the phosphorus containing flame retardant, halogen containing flame retardant can cause the pollution to the environment, so the development of a new type of flame retardant the agent is imperative. It has been proved by scientific research that the flame retardants such as organic boron have the advantages of good flame retardancy, low toxicity, low smoke and so on. The contents of this paper are as follows: (1) with boric acid and pentaerythritol as raw materials by dehydration condensation reaction, organic boron - new flame retardant boric acid polycondensate synthesized pentaerythritol (BP) and explore the optimal synthesis conditions for heat resistance: boric acid: pentaerythritol =1:1, in 100 DEG C for seven hours; the BP can dissolved in water and ethanol; BP initial decomposition temperature is 368 degrees centigrade, the decomposition temperature is higher than most of the polymer, can be used for flame retardant polymer. According to DTG, the maximum weight loss rate is 420.76 C, the carbon residue rate at 600 C is 41.5%, the decomposition temperature range is only 68 centigrade, and a large number of carbon layers can be generated in a narrow temperature range, which is good for flame-retardant and is an excellent flame retardant. (2) different content of BP/ Hai Yin epoxy (EP) resin system has been prepared. The viscosity and agglomeration characteristics of the resin system have been studied, and the solidified material of BP/EP casting body has been prepared, and its mechanical properties have been tested. The results show that the different components of the low viscosity platform viscosity increases with the increase of the content of BP; in 105~125 DEG BP/EP system has low viscosity, suitable for molding operation; at the same temperature with time shorter gel resin system with high BP, 10%BP calculated the reaction activation energy of 73.33KJ/mol and 20%BP activation energy 62.89KJ/mol, 30%BP 61.03KJ/mol 40%BP, the activation energy of the reaction activation energy of 58.89KJ/mol; increase the amount of BP can reduce the activation energy of the reaction system; the addition of BP can effectively improve the impact strength of the epoxy resin, improve the toughness of epoxy resin, while the addition of BP the tensile strength and flexural strength of hydantoin epoxy resins with improved the effect is not obvious. (3) by dynamic DSC BP/EP resin system with different proportion of the test, and is characteristic of curing temperature and curing reaction kinetic equation; the result shows that the dynamic DSC calculate the formula of activation energy, 10% activation energy up to 85.51kJ/mol, with the increase of BP content, the activation energy decreased, the reaction activity increased combined with Kissinger, Starink and Crane; BP/EP equation kinetics equation was established. The characteristic curing temperature of each formula of BP/EP was obtained by T- beta drawing and extrapolation. The curing process of BP/EP was set at 110 C for 2 hours, curing at 125 C for 4 hours, and curing at 140 C for 4 hours. (4) of flame retardant of BP/EP curing system. The results showed that the flame retardant curing agent BP can significantly improve the flame retardant properties of the cured, with the increase of BP content, the oxygen index of curing increases, flame retardant performance, when the content is 40%, the oxygen index reached 30.5; with the increase of boric acid pentaerythritol polycondensation the degree of swelling, decrease. Through the test of BP/EP TG resin, 10%BP resin, carbon residue in 800 C was 28.3%, 74.4% higher than the rate of residual carbon epoxy resin without BP; and with the increase of BP content, carbon residue rate of solidified material increases, when the content reaches 40% carbon residue ratio of cured epoxy resin without the BP rate increased by 220.6%, the addition of BP can improve the heat resistance of the cured markedly. Scanning electron microscope (SEM) was used to observe the combustion surface of BP (40%) /EP. It is known that the carbon layer on the outer surface after combustion is porous, and the inner surface is porous foam, which is a typical intumescent flame retardant phenomenon. It is presumed that the main mechanism of BP/EP self flame retardant system is: forming glass covering layer, flame retarding condensed phase, heat absorbing and flame-retardant mechanism of boric acid dehydration, absorbing gas and flame retardant mechanism of ammonia nitrogen.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ323.5

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