【作者】 武伟红；

【导师】 高俊刚；

【作者基本信息】 河北大学 ， 高分子化学与物理， 2015， 博士

【摘要】 酚醛树脂具有较高的机械性能、耐热性、耐化学性等优异的性能而被广泛应用于军事、航天等社会各领域。含硼酚醛树脂具有比普通酚醛树脂更优异的热性能而被广泛关注。为了提高硼酚醛树脂的热性能,拓宽其应用范围,本文考虑双酚-S中存在刚性的砜基,具有更好的耐热性能,并能赋予材料良好的力学性能,合成了双酚-S型硼酚醛树脂(BBPSFR),并用纳米材料对其改性,探讨纳米材料对该酚醛树脂热性能的影响;并将其应用于环氧树脂的固化,分析了树脂的固化动力学及其性能,为获得兼具较好热性能和力学性能的改性环氧树脂提供了依据。第一部分,用甲醛水溶液法合成双酚-S硼酚醛树脂(BBPSFR),并利用1H NMR对树脂进行了表征。用动态力学分析、热重(TG)、热质联用(TG-MS)等测定了树脂的热性能,讨论了硼含量对酚醛树脂热性能和热降解过程的影响。研究发现,BBPSFR固化过程中形成了含硼酯键和硼氧配位键的六元环结构。硼的引入提高了双酚-S酚醛树脂的玻璃化温度(Tg)和热降解稳定性,双酚-S和硼酸摩尔比3:2的样品(2.0B),Tg为264.4℃,与不含硼的0B树脂相比提高了104℃;起始分解温度(Ti)为375.2℃,提高了43.2℃。用Flynn-Wall-Ozawa方法计算其热降解过程的活化能(Ea),其数值随失重量的提高而降低,硼的加入使得降解前期的活化能显著增加。TG-MS结果表明,在330℃之前的失重是由于小分子的脱附和脱端羟甲基引起的;330~560℃,失重原因为醚键、亚甲基和主链中的S─C键的断裂和氧化;560℃以后,硼氧酯键部分发生分解,释放出苯和苯酚等小分子物质。第二部分,采用纳米Al2O3和八苯胺基笼型倍半硅氧烷(OAPS)分别对BBPSFR进行改性,对改性后树脂的热降解稳定性进行了分析。研究发现,纳米Al2O3的加入提高了BBPSFR的Ti,纳米Al2O3含量为15 wt%复合材料Ti升高了26.0℃;但是分解开始后,纳米Al2O3催化了树脂的降解过程,热稳定性迅速降低;其降解过程为一级反应;从TG-MS结果可以看出,纳米Al2O3催化了BBPSFR的降解过程,尤其是后期的降解。OAPS的引入提高了BBPSFR的热稳定性,热降解起始分解温度随OAPS含量的增加而逐渐增大,含量为12wt%时,ti提高了25.3℃;降解过程分为三个阶段,均为一级反应,三个阶段的活化能均随着oaps含量的增加而逐渐增大,说明oaps抑制了bbpsfr的热降解过程,提高了树脂的热降解稳定性。第三部分用bbpsfr固化商用双酚-A型环氧树脂(e51),寻找了最佳质量比,并用原位生成纳米sio2对bbpsfr/e51进行改性,研究改性后树脂的固化动力学、动态力学分析、力学性能和电性能。结果表明bbpsfr和e51的最佳质量比为3:7;纳米sio2引入后,树脂的玻璃化温度下降,但储能模量升高、热降解稳定性提高,如纳米sio2含量为9wt%时,在25℃的储能模量最大,达11.8gpa,与不含纳米sio2的bbpsfr/e51树脂相比,提高了74.4%;ti在含量为3wt%时达到最大值,为335.1℃,提高了18.3℃。dsc结果说明纳米sio2促进了bbpsfr/e51的固化,固化过程满足二参数(m,n)?esták-berggren自催化模型。少量纳米sio2能显著提高树脂的拉伸强度和冲击强度,但对电学性能影响不大。用碳纳米管对bbpsfr固化双酚-A环氧树脂(e44)进行了改性,并研究了改性树脂的性能。研究发现bbpsfr和e44的最佳质量比为4:6;碳纳米管的加入也促进了树脂的固化,复合材料的非等温固化动力学满足?esták-berggren自催化模型;碳纳米管的加入使得材料的tg明显升高,含量为1.0wt%时的tg为212.4℃,与不含碳纳米管的bbpsfr/e44(189.6℃)相比,tg升高了22.8℃,碳纳米管含量为0.5wt%时,在树脂基体中分散更为均一,拉伸强度和冲击强度均为最高,分别达到了91.98mpa和89.34kj·m-2,与bbpsfr/e44相比,分别提高了21.45mpa和39.02kj·m-2。合成了邻甲酚醛环氧树脂(o-cfer),用bbpsfr做固化剂,分别讨论了纳米二氧化硅、碳纳米管和还原氧化石墨烯(r-go)三种纳米材料对树脂固化及性能的影响。结果表明bbpsfr可以用来固化o-cfer;bbpsfr和o-cfer的最佳质量比为3:7。三种纳米材料改性树脂的固化过程都遵从?esták-berggren自催化模型。纳米sio2的影响:纳米sio2显著增强了树脂的热稳定性,含量为12wt%时,600℃的剩余质量百分数为47.8%,与不含纳米二氧化硅的bbpsfr/o-cfer相比提高了34.3%。冲击强度随纳米sio2含量的增大,先升高后降低,含量为6wt%树脂的冲击强度达到最高为149kj·m-2,与bbpsfr/o-cfer相比升高了44kj·m-2;纳米sio2含量对电性能影响不大,含量较低时的各电性能指标较高。碳纳米管的影响:碳纳米管的加入,使得热性能明显提高,与BBPSFR/o-CFER相比,添加3.0 wt%的碳纳米管可使Tg提高43.9℃,Ti提高28.9℃;1.0 wt%的碳纳米管可使拉伸强度和冲击强度分别提高21.8%和12.4%,体积电阻和表面电阻也有所升高。还原氧化石墨烯的影响:少量r-GO的加入提高了树脂的玻璃化温度、热稳定性、拉伸强度和冲击强度,含量为0.5 wt%时Tg升高了11.3℃,含量为2.0 wt%时,Ti为239.3℃,与BBPSFR/o-CFER相比,升高了25.6℃;拉伸强度为180 MPa,冲击强度为143 kJ·m-2,分别提高了15.4%和36.2%;介电损耗随r-GO含量逐步升高。更多还原

【Abstract】 Phenolic resin which has good mechanical properties, heat resistance and chemical resistance has been widely used in many social fields including military and aerospace. Boron containing phenolic resin was studied because of its better thermal property than conventional phenolic resin. In order to improve phenolic resin’s thermal properties and broaden the scope of its application, in this thesis, boron containing bisphenol-S formaldehyde resin(BBPSFR) was synthesized in consideration of the rigid sulfonyl in bisphenol-S has higher mechanical properties and the attaching of better mechanical properties, BBPSFR was modified by nano materials, and the effect of nano materials on its thermal properties were discussed. BBPSFR and BBPSFR/nano materials composites were also used to cure epoxy resin, the curing kinetics and the properties of the composites were studied. The research provided the basis for the nanocomposite with both higher thermal properties and higher mechanical properties.In the first part, boron containing bisphenol-S formaldehyde resin(BBPSFR) was synthesized by formalin method. The structure of BBPSFR was characterized by 1H nuclear magnetic resonance(1H NMR). The thermal properties of BBPSFR were investigated through dynamic mechanical analysis, thermogravimetric analysis(TG) and thermogravimetry and mass spectrum analysis(TG-MS). The effect of boron content on the thermal properties and the thermal degradation process of BBPSFR were studied. The results showed that the borate and the six-member ring containing boron oxygen coordinate structure were formed during the curing process of BBPSFR. The glass transition temperature(Tg) and the thermal degradation stability of BBPSFR were enhanced by the addition of boron. Contrast to the resin without boron, the Tg of 2.0B(the mole ratio of bisphenol-S and boric acid was 3:2) was 264.4oC, which increased 104.0oC, the initial decomposition temperature(Ti) was 375.2oC, which increased 43.0oC. The activation energy(Ea) calculated by Flynn-Wall-Ozawa method decreased with the conversion in the degradation process, and Ea at the early stage of the degradation increased markedly when boron was added. The TG-MS results showed that: below 330 oC, the mass loss was mainly caused by the volatilization of small molecules and shedding of the end-hydroxymethyl. In the range of 330~560 oC, the mass loss was mainly caused by the oxidation and the breakage of most ether linkages, methylene and S─C bond. Above 560 oC, B─O bond was broken, phenol and fragments were released.In the second part, BBPSFR was modified by nano Al2O3 and octa(aminophenyl) polyhedral oligomeric silsesquioxane(OAPS) respectively, and its thermal degradation process was investigated. The results showed that Ti of BBPSFR was increased by the addition of nano Al2O3, when nano Al2O3 content was 15 wt%, Ti increased 26.0oC. However, the thermal degradation stability of modified BBPSFR decreased immediately after the decomposition started, the decomposition was catalyzed by nano Al2O3. And the decomposition reaction order is one. TG-MS results showed that nano Al2O3 catalyzed the decomposition of BBPSFR, especially at the later stage. The addition of OAPS improved the thermal stability of BBPSFR,Ti increased with the content of OAPS, Ti was increased 25.3oC when the content of OAPS was 12 wt%. And the decomposition process was divided into three stages, the reaction order in each stage was one, Ea value increased with increasing of OAPS content in all the three stages. The results showed that OAPS inhibited the decomposition and enhanced its thermal degradation stability.In the third part, BBPSFR was used to cure the common bisphenol-A epoxy resin(E51), the optimal proportion of BBPSFR and epoxy was discussed. BBPSFR/E51 was modified by in situ formed nano Si O2. The curing kinetics, dynamic mechanical properties(DMA), mechanical properties and electrical properties of the composites were determined. The results showed that the optimal mass proportion of BBPSFR and E51 was 3:7. The glass transition temperature decreased with the addition of nano SiO2, however, the storage modulus and the thermal stability of the composites were increased, for example, when the content of nano SiO2 was 9 wt%, the storage modulus at 25 oC was the maximum, which was 11.8 GPa, that was increased 74.4%, Ti got the maximum at the nano SiO2 content was 3 wt%, it was 335.1oC, which was 18.3oC higher than that of the resin without nano SiO2. The DSC results showed that nano SiO2 accelerated the cure of BBPSFR/E51, and the curing process of the composites could be described by the two-parameter(m, n) ?esták-Berggren autocatalytic kinetic model. The composites containing a small amount of nano SiO2 had higher tensile strength and impact strength, and the nano SiO2 content had no much effect on electrical properties of the composites. CNTs were used to modify the common bisphenol-A epoxy resin(E44) which was cured by BBPSFR, and the properties of the modified composite were investigated. The optimal mass proportion of BBPSFR and E44 was 4:6, the addition of CNTs also accelerated the cure of BBPSFR/E44, and the nonisothermal curing kinetics of the composite could be described by the ?esták-Berggren autocatalytic kinetic model. The addition of CNTs increased the Tg of the composite obviously, when CNTs content was 1.0 wt%, Tg was 212.4oC, which was 22.8oC higher than that of BBPSFR/E44 without CNTs. 0.5 wt% content of CNTs was dispersed uniformly in the matrix, so the tensile strength and the impact strength of the composites were the highest, the tensile strength was 91.98 MPa, and the impact strength was 89.34 kJ·m-2, which was 21.45 MPa and 39.02 kJ·m-2 higher than that of BBPSFR/E44 without CNTs, respectively.The o-cresol formaldehyde epoxy resin(o-CFER) was synthesized, and was cured by BBPSFR. The effect of nano SiO2, CNTs and reduced graphene oxide(r-GO) on the properties and curing of the resin were discussed, respectively. The results showed that o-CFER could be cured by BBPSFR and the optimal mass proportion of BBPSFR and o-CFER was 3:7. The nonisothermal curing kinetics of the three composites all could be described by the ?esták-Berggren kinetic model. The effect of nano SiO2: the thermal stabilities of the resin were improved significantly by nano SiO2, when the nano SiO2 content was 12 wt%, the residual weight at 600 oC was 47.8%, which was 34.3% higher than that of the residual weight of BBPSFR/o-CFER without nano SiO2. With the increasing of the nano SiO2 content. The impact strength increased firstly, then decreased, and it got the maximum value at 6 wt%, which was 149 kJ·m-2, and 44 kJ·m-2 higher than that of BBPSFR/o-CFER. The content of nano SiO2 content had no much effect on electrical properties, the electrical properties parameters were higher while the content of nano SiO2 content was less. The effect of nano CNTs: the thermal property of BBPSFR/o-CFER was improved significantly by the addition of CNTs. Tg increased 43.9oC and Ti increased 28.9oC by the addition of 3.0 wt% CNTs. The tensile strength and impact strength increased 21.8% and 12.4%, respectively by the addition of 1.0 wt%, the volume resistance and surface resistance of the composites were also improved. The effect of r-GO: the addition of a small amount of r-GO improved the Tg, thermal stability, tensile strength and impact strength of the composites. Tg increased 11.3oC when r-GO content was 0.5 wt%, and Ti of the composite with 2.0 wt% r-GO was 239.3oC, which was 25.6oC higher than that of BBPSFR/o-CFER, the tensile strength was 180 MPa, and the impact strength was 143 kJ·m-2, which increased 15.4% and 36.2%, respectively. The value of dielectric loss increased with the content of r-GO.更多还原