液化雙氰胺的制備與評價以及預(yù)浸料應(yīng)用研究
發(fā)布時間：2018-11-21 21:26
【摘要】：環(huán)氧樹脂預(yù)浸料,通常是樹脂體系呈B階段復(fù)合材料的中間材料。雙氰胺是環(huán)氧樹脂預(yù)浸料最為常用的潛伏性固化劑,但由于其化學(xué)結(jié)構(gòu)極性高,在環(huán)氧樹脂中的分散性和溶解性差,并可導(dǎo)致固化后所得到的環(huán)氧樹脂組合物中分散狀態(tài)惡化,從而影響預(yù)浸料及其復(fù)合材料的質(zhì)量。為提高預(yù)浸料樹脂體系中雙氰胺與環(huán)氧樹脂的相容性,通常需要對雙氰胺進(jìn)行液化改性。本文利用固化劑聚醚胺對雙氰胺有較好溶解性的特點,將聚醚胺和雙酚A環(huán)氧樹脂的加成產(chǎn)物制備了液化改性雙氰胺固化體系(L-DICY),并與純雙氰胺(DICY)和聚醚胺與雙氰胺共混的固化體系(PEA/DICY)進(jìn)行了比較。相對于DICY和PEA/DICY固化體系,L-DICY固化體系的總胺值和伯胺值均降低,相對于DICY固化體系,PEA/DICY和L-DICY固化體系的結(jié)晶性下降,熔點降低,L-DICY靜置30天沒有明顯沉降,且5天內(nèi)的質(zhì)量沒有明顯變化,儲存穩(wěn)定性較好,L-DICY固化體系在環(huán)氧樹脂分散性得到改善。應(yīng)用三種固化體系制備了預(yù)浸料用樹脂體系,研究了三種樹脂體系的固化動力學(xué)和化學(xué)流變學(xué)。Kissinger-Akahira-Sunose(KAS)理論分析表明PEA/DICY固化體系活化能最低,L-DICY與DICY固化體系活化能相近,具有較低固化反應(yīng)活性,有利于保持預(yù)浸料的儲存期。利用Malek理論和SB(m, n)理論模擬了三種樹脂體系在不同固化速率下的速率方程,PEA/DICY和L-DICY體系都較好的預(yù)測了實驗數(shù)據(jù)�；瘜W(xué)動態(tài)流變學(xué)分析表明L-DICY與DICY體系有較長的低粘度平臺,預(yù)浸料加工窗口較寬,雙Arrhenius模型模擬了三種樹脂體系的等溫粘度曲線,在固化前期的低粘度區(qū)域能較好地預(yù)測樹脂體系的粘度。研究了上述三種樹脂體系的力學(xué)性能、耐熱性、透光率和雙氰胺在固化樹脂中的分散性。相比于DICY和PEA/DICY制備的樹脂體系,L-DICY樹脂體系的力學(xué)性能和玻璃化轉(zhuǎn)變溫度都沒有明顯降低,L-DICY樹脂體系固化物的透光率最好,說明L-DICY在固化物中基本沒有雙氰胺顆粒殘留,DICY固化物的微觀圖像中有未固化的雙氰胺顆粒,而PEA/DICY和L-DICY體系中基本沒有,說明提高分散性促進(jìn)了固化反應(yīng)的進(jìn)行。應(yīng)用上述三種樹脂體系,采用熱熔兩步法工藝制備了預(yù)浸料,討論了預(yù)浸料復(fù)合材料的力學(xué)性能和耐濕熱性能,評價了雙氰胺在復(fù)合材料表面的分散情況。相比于DICY和PEA/DICY制備的復(fù)合材料,L-DICY體系復(fù)合材料的力學(xué)性能沒有明顯下降。經(jīng)過濕熱處理后,L-DICY體系的力學(xué)性能下降幅度很小,DICY體系則降低明顯,說明L-DICY體系有較好的耐濕熱性。DICY體系復(fù)合材料板材微觀圖像中有未固化的雙氰胺顆粒存在,而在PEA/DICY和L-DICY體系幾乎沒有顆粒殘存,說明復(fù)合材料的耐濕熱性與雙氰胺在其中的殘留有關(guān)。
[Abstract]:Epoxy resin prepreg, usually the intermediate material of a B-stage composite of resin systems. Dicyandiamide is the most commonly used latent curing agent for epoxy resin prepreg. However, because of its high polarity of chemical structure, the dispersivity and solubility of dicyandiamide in epoxy resin are poor. Thus, the quality of prepreg and its composites is affected. In order to improve the compatibility of dicyandiamide and epoxy resin in prepreg resin system, liquefaction modification of dicyandiamide is usually needed. The liquefaction modified dicyandiamide curing system (L-DICY) was prepared by using the addition product of polyether amine and bisphenol A epoxy resin. The results were compared with pure dicyandiamide (DICY) and polyether amine / dicyandiamide curing system (PEA/DICY). Compared with DICY and PEA/DICY curing system, the total amine value and primary amine value of L-DICY curing system decreased, compared with DICY curing system, the crystallinity and melting point of PEA/DICY and L-DICY curing system decreased. There was no obvious sedimentation of L-DICY in 30 days, and the quality of L-DICY was not changed in 5 days. The storage stability was good. The dispersion of L-DICY curing system in epoxy resin was improved. The prepreg resin system was prepared by using three curing systems. The curing kinetics and chemical rheology of the three resin systems were studied. The Kissinger-Akahira-Sunose (KAS) theory analysis showed that the activation energy of PEA/DICY curing system was the lowest. The activation energy of L-DICY and DICY curing system is similar, and the curing activity is low, which is helpful to keep the storage period of prepreg. The rate equations of three resin systems at different curing rates were simulated by using Malek theory and SB (m, n) theory. The experimental data of PEA/DICY and L-DICY systems were well predicted. The chemical dynamic rheological analysis showed that L-DICY and DICY system had a long low viscosity platform, and the processing window of prepreg was wider. The isothermal viscosity curves of three kinds of resin systems were simulated by double Arrhenius model. The viscosity of the resin system can be well predicted in the low viscosity region in the early curing period. The mechanical properties, heat resistance, transmittance and dispersion of dicyandiamide in cured resin were studied. Compared with the resin systems prepared by DICY and PEA/DICY, the mechanical properties and glass transition temperature of L-DICY resin system were not significantly decreased, and the light transmittance of cured compounds of L-DICY resin system was the best. The results show that there is no dicyandiamide particle residue in the solidification of L-DICY, and there are uncured dicyandiamide particles in the microcosmic image of DICY solidified compound, but not in PEA/DICY and L-DICY system, which indicates that the increase of dispersion promotes the curing reaction. The prepreg was prepared by hot-melt two-step process using the three resin systems mentioned above. The mechanical properties and hygrothermal resistance of prepreg composites were discussed and the dispersion of dicyandiamide on the surface of composites was evaluated. Compared with the composites prepared by DICY and PEA/DICY, the mechanical properties of L-DICY composites did not decrease obviously. After hydrothermal treatment, the mechanical properties of L-DICY system decreased slightly, while that of DICY system decreased obviously, which indicated that L-DICY system had better resistance to moisture and heat. There were uncured dicyandiamide particles in the microscopic images of DICY composite plate. However, there was almost no particle residue in PEA/DICY and L-DICY systems, indicating that the resistance to moisture and heat of the composites was related to the residue of dicyandiamide in the composites.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ226;TB33
本文編號：2348296
[Abstract]:Epoxy resin prepreg, usually the intermediate material of a B-stage composite of resin systems. Dicyandiamide is the most commonly used latent curing agent for epoxy resin prepreg. However, because of its high polarity of chemical structure, the dispersivity and solubility of dicyandiamide in epoxy resin are poor. Thus, the quality of prepreg and its composites is affected. In order to improve the compatibility of dicyandiamide and epoxy resin in prepreg resin system, liquefaction modification of dicyandiamide is usually needed. The liquefaction modified dicyandiamide curing system (L-DICY) was prepared by using the addition product of polyether amine and bisphenol A epoxy resin. The results were compared with pure dicyandiamide (DICY) and polyether amine / dicyandiamide curing system (PEA/DICY). Compared with DICY and PEA/DICY curing system, the total amine value and primary amine value of L-DICY curing system decreased, compared with DICY curing system, the crystallinity and melting point of PEA/DICY and L-DICY curing system decreased. There was no obvious sedimentation of L-DICY in 30 days, and the quality of L-DICY was not changed in 5 days. The storage stability was good. The dispersion of L-DICY curing system in epoxy resin was improved. The prepreg resin system was prepared by using three curing systems. The curing kinetics and chemical rheology of the three resin systems were studied. The Kissinger-Akahira-Sunose (KAS) theory analysis showed that the activation energy of PEA/DICY curing system was the lowest. The activation energy of L-DICY and DICY curing system is similar, and the curing activity is low, which is helpful to keep the storage period of prepreg. The rate equations of three resin systems at different curing rates were simulated by using Malek theory and SB (m, n) theory. The experimental data of PEA/DICY and L-DICY systems were well predicted. The chemical dynamic rheological analysis showed that L-DICY and DICY system had a long low viscosity platform, and the processing window of prepreg was wider. The isothermal viscosity curves of three kinds of resin systems were simulated by double Arrhenius model. The viscosity of the resin system can be well predicted in the low viscosity region in the early curing period. The mechanical properties, heat resistance, transmittance and dispersion of dicyandiamide in cured resin were studied. Compared with the resin systems prepared by DICY and PEA/DICY, the mechanical properties and glass transition temperature of L-DICY resin system were not significantly decreased, and the light transmittance of cured compounds of L-DICY resin system was the best. The results show that there is no dicyandiamide particle residue in the solidification of L-DICY, and there are uncured dicyandiamide particles in the microcosmic image of DICY solidified compound, but not in PEA/DICY and L-DICY system, which indicates that the increase of dispersion promotes the curing reaction. The prepreg was prepared by hot-melt two-step process using the three resin systems mentioned above. The mechanical properties and hygrothermal resistance of prepreg composites were discussed and the dispersion of dicyandiamide on the surface of composites was evaluated. Compared with the composites prepared by DICY and PEA/DICY, the mechanical properties of L-DICY composites did not decrease obviously. After hydrothermal treatment, the mechanical properties of L-DICY system decreased slightly, while that of DICY system decreased obviously, which indicated that L-DICY system had better resistance to moisture and heat. There were uncured dicyandiamide particles in the microscopic images of DICY composite plate. However, there was almost no particle residue in PEA/DICY and L-DICY systems, indicating that the resistance to moisture and heat of the composites was related to the residue of dicyandiamide in the composites.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ226;TB33
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