傅立叶红外光谱法研究氰酸酯树脂及其改性体系的固化反应

借助傅立叶红外光谱对双酚 A型氰酸酯树脂、二月桂酸二丁基锡 /双酚 A型氰酸酯、环氧树脂 /双酚 A型氰酸酯树脂、酚醛环氧 /双马来酰亚胺 /双酚 A型氰酸酯树脂等体系的固化反应进行了在位监控分析 ,着重讨论了各体系的反应性。研究表明 ,未加催化剂的双酚 A型氰酸酯树脂体系固化反应的活化能为 175 .0 k J/ mol,频率因子 A=2 .5 5× 10 14 min-1;采用二月桂酸二丁基锡催化的氰酸酯树脂体系的活化能 Ea=5 1.7k J/ mol,A=6.12× 10 2 min-1;环氧树脂改性的氰酸酯树脂体系的固化反应温度明显降低 ,引入催化剂后转化率也明显提高 ;酚醛环氧树脂 /双马来酰亚胺树脂 /氰酸酯树脂体系具有良好的反应性。     

湿热老化对氰酸酯树脂/酚醛环氧树脂共混物结构与性能的影响

制备了不同摩尔比的双酚A二氰酸酯/酚醛环氧树脂共混物,测定了共混物和纯氰酸酯聚合物的吸湿曲线,用DMA和FTIR研究了湿热老化前后共混物结构与性能的变化。结果表明,氰酸酯基摩尔分数大于0.5的共混物具有明显比聚氰脲酸酯更低的平衡吸湿。老化后共混物的玻璃化转变温度保持率随氰酸酯含量的增加而降低。老化后聚氰脲酸酯的FTIR谱出现了降解产物的吸收峰,而共混物没有出现明显的结构变化。     

F-48环氧树脂改性双酚A型氰酸酯树脂的研究

采用FT-IR与DSC研究了F-48酚醛型环氧改性双酚A型氰酸酯树脂的固化行为及固化工艺,通过DMA、TGA、介电性能和冲击强度测试对F-48酚醛型环氧改性双酚A型氰酸酯树脂的热性能、介电性能和韧性进行了研究。结果表明,随着F-48环氧树脂含量的增加,改性氰酸酯的Tg总体呈升高趋势,最高达到255℃;改性后的氰酸酯树脂热分解温度逐渐降低;F-48环氧树脂加入量为氰酸酯质量的25%时,改性氰酸酯树脂具有较低的介电常数和介电损耗;改性氰酸酯的冲击强度较纯氰酸酯树脂提高25%。     

形状记忆氢化双酚A型环氧树脂的制备与性能

为研究聚丙二醇二缩水甘油醚(JH-230)对热固性形状记忆环氧树脂基本性能的影响,将异佛尔酮二胺(IPDA)与具有不同分子量比的氢化双酚A型环氧树脂(AL-3040)、聚丙二醇二缩水甘油醚(JH-230)共混,经完全固化制备出一种新型的形状记忆氢化双酚A型环氧树脂。借助傅里叶红外光谱仪(FT-IR)、差示扫描量热仪(DSC)、动态热机械分析仪(DMA)和拉伸-回复形状记忆测试分析了热固性形状记忆环氧树脂的分子结构以及JH-230对固化体系玻璃化转变温度、储能模量和形状记忆性能的影响。研究表明,JH-230可以增加固化体系链段的柔韧性;固化体系的玻璃化转变温度与动态模量随JH-230含量的增加而降低;该形状记忆氢化双酚A型环氧树脂体系具有良好的形状记忆性能,且形变完全回复时间随JH-230含量的增加而延长。     

双酚A缩水甘油醚/乙二胺环氧树脂的热分解行为

采用傅里叶红外光谱法研究了双酚A缩水甘油醚/乙二胺环氧树脂(DGEBA/EDA)在不同温度时分解残留物的红外吸收光谱;利用热分析技术考察了DGEBA/EDA从室温到600℃之间的热解反应。结果表明,DGEBA/EDA环氧树脂在氮气中分解时存在一个热解阶段,最低热解活化能为195.74 kJ/mol。色谱-质谱联用(GC/MS)分析DGEBA/EDA环氧树脂热解残留物,表明在热解过程中主要生成苯酚、对异丙基苯酚和双酚A。讨论了DGEBA/EDA环氧树脂热解的机理。经热解后的残留环氧树脂的热稳定性降低明显,环氧树脂发生了明显的化学裂解。     

聚醚酰亚胺对氰酸酯树脂/环氧树脂共混物的增韧作用

采用聚醚酰亚胺以提高双酚Ａ二氰酸酯／酚醛环氧树脂共混物的断裂韧性．实验结果表明，聚醚酰亚胺是氰酸酯／酚醛环氧树脂共混物的有效增韧剂，加入１５％的聚醚酰亚胺可使断裂韧性（ＫＩＣ）提高到１４５ＭＰａ·ｍ０．５，弯曲强度也有所提高．用扫描电子显微镜和动态粘弹谱研究了改性共混物的微观结构，具有双连续结构的共混物的耐溶剂性能大大下降，共混物的韧性和耐溶剂性主要与相行为有关， 固化工艺对含１０％聚醚酰亚胺的共混物的断裂韧性和形态没有明显的作用．     

环氧树脂新型有机硅改性剂

研究了含酚羟基有机烷氧基硅烷及3,3',3"-三羟基苯氧基硅烷三缩水甘油醚两种新型有机硅改性剂对双酚F环氧树脂力学性能及热性能的影响.研究结果表明,两种改性剂均可有效提高环氧树脂浇铸体的韧性,提高其抗开裂指数,降低线胀系数.3,3',3"-三羟基苯氧基硅烷三缩水甘油醚改性剂在提高环氧树脂的力学性能的同时,保持固化物较高的玻璃化温度, 并可降低双酚系环氧树脂基体的粘度.     

固化促进剂对环氧共混体系相结构的影响

加入促进剂三氟化硼－乙基胺使双酚Ａ缩水甘油醚型环氧树脂（Ｅ５１）／聚砜（ＰＳＦ）／二氨基本基砜（ＤＤＳ）共混体系迅速达到凝胶点，使相分离早期固定，易于获得平均径较小的共混物相结构，促进剂使固化反应速度提高与降低温度相分离速度降低对共混物相结构的影响具有一致性。     

多官能度酚醛环氧树脂的合成表征及性能

苯甲醛和对羟基苯甲醛分别与双酚A反应,得到侧链含刚性苯环的酚醛树脂,然后环氧化,制备了侧链含刚性苯环的多官能度酚醛环氧树脂。以FT-IR1、H-NMR及GPC表征了环氧树脂的分子结构。以4,4′-二氨基二苯砜为固化剂,对环氧树脂固化物的热力学性能及热降解性能进行了研究,结果表明:由对羟基苯甲醛与双酚A反应制备的多官能度酚醛环氧树脂固化物的玻璃化转变温度、力学及耐热降解性能均比苯甲醛制备的酚醛环氧树脂固化物高,环氧树脂官能度的增加能提高环氧树脂固化物的综合性能。     

氰酸酯树脂/环氧树脂固化动力学研究

采用DSC和FTIR研究了氰酸酯树脂/环氧树脂共混体系的固化行为,考察了环氧树脂含量对体系的固化动力学参数的影响.纯的氰酸酯树脂及氰酸酯树脂/环氧树脂共混物(质量比为91,73,55)的表观活化能依次为74.3、72.1、60.8、72.7 kJ/mol,说明少量的环氧树脂可促进氰酸酯树脂的固化反应,过量则抑制.同时还发现,固化过程中氰酸酯树脂的转化速率远大于环氧树脂,固化反应对氰酸酯基和环氧基均是一级反应.     

Poly(ether ether ketone) with pendent methyl groups as a toughening agent for amine cured DGEBA epoxy resin

A diglycidyl ether of bisphenol-A (DGEBA) epoxy resin was modified with poly(ether ether ketone) with pendent methyl groups (PEEKM). PEEKM was synthesised from methyl hydroquinone and 4,4′-difluorobenzophenone and characterised. Blends of epoxy resin and PEEKM were prepared by melt blending. The blends were transparent in the uncured state and gave single composition dependent T _g. The T _g-composition behaviour of the uncured blends has been studied using Gordon–Taylor, Kelley–Bueche and Fox equations. The scanning electron micrographs of extracted fracture surfaces revealed that reaction induced phase separation occurred in the blends. Cocontinuous morphology was obtained in blends containing 15 phr PEEKM. Two glass transition peaks corresponding to epoxy rich and thermoplastic rich phases were observed in the dynamic mechanical spectrum of the blends. The crosslink density of the blends calculated from dynamic mechanical analysis was less than that of unmodified epoxy resin. The tensile strength, flexural strength and modulus were comparable to that of the unmodified epoxy resin. It was found from fracture toughness measurements that PEEKM is an effective toughener for DDS cured epoxy resin. Fifteen phr PEEKM having cocontinuous morphology exhibited maximum increase in fracture toughness. The increase in fracture toughness was due to crack path deflection, crack pinning, crack bridging by dispersed PEEKM and local plastic deformation of the matrix. The exceptional increase in fracture toughness of 15 phr blend was attributed to the cocontinuous morphology of the blend. Finally it was observed that the thermal stability of epoxy resin was not affected by the addition of PEEKM.     

海因环氧树脂/DDS体系的制备与性能

合成了海因环氧树脂,采用红外光谱和核磁共振进行了表征,制备了海因环氧树脂/二氨基二苯砜(DDS)体系,研究了海因环氧树脂/DDS体系的固化反应特性及固化物的性能。结果表明,树脂体系在100℃~296℃有一放热峰,峰值温度为197℃,140℃的凝胶时间长于42 min,在180℃下仅8 min;树脂浇铸体的氧指数为26.6,弯曲强度为111MPa,弯曲模量为4.14 GPa,冲击强度为14.8 kJ/m2。     

日本吸水性树脂1991～1998年生产·销售量统计

（调查对象：日本吸水性树脂工业会所属１１家公司统计）（ｔ／ａ,％）１９９１１９９２１９９３１９９４１９９５１９９６１９９７１９９８生产量—————１５０,７３２１８７,１９６１９７,０９５日本国内销量（与上年度比）３６,５６７４６,１１０（１２６１...     

Self-healing epoxy composite with heat-resistant healant

To provide self-healing epoxy composite with adequate heat resistance for high-performance application, we developed a novel microencapsulated epoxy/mercaptan healing agent. The key measure lies in usage of diglycidyl ether of bisphenol A (EPON 828) as the polymerizable component and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as the catalyst. Because of the higher thermal stability of EPON 828 and lower volatility of DMP-30, the healing agent and the self-healing composite not only survive high-temperature curing and thermal exposure, but also offer satisfactory capability of autonomous properties restoration, as characterized by both fracture mechanics and fatigue tests. Especially when the operation temperature is not higher than 200 °C, the performance of the healing system is nearly independent of thermal history.     

海因环氧树脂/HHPA体系的制备与性能

合成了海因环氧树脂,采用红外光谱和核磁共振进行了表征,以六氢苯酐(HHPA)为固化剂,制备了海因环氧树脂/HHPA体系,研究了海因环氧树脂/HHPA体系的固化反应性及其固化物的性能。结果表明:树脂体系在升温速率为10℃/min的条件下,在90～210℃有一放热峰,峰值温度为152.5℃;100℃下的凝胶时间大于42min,在140℃下为8min;树脂浇铸体的氧指数为23,抗弯强度为122MPa,弯曲模量为2.7GPa,冲击强度为14.9kJ/m2。     

聚己内酯/ 环氧树脂/ SiO2杂化材料的制备及性能

采用端硅氧烷基聚己内酯( PCL-TESi) 作为无机前躯物, 通过环氧树脂/ KB-2 的固化反应和PCL-TESi的溶胶2凝胶过程, 制备了聚己内酯/ 环氧树脂/ SiO₂ ( PCL/ EP/ SiO₂ ) 有机-无机杂化材料。利用红外光谱、透射电镜( TEM) 、热失重分析( TGA) 及在甲苯溶液中的溶胀试验对不同SiO₂ 含量的杂化材料进行分析。研究发现, 随着PCL-TESi 含量增大杂化体系交联密度降低; 此杂化体系中存在环氧和Si —O —Si 两种交联网络, 微观上形成纳米两相结构; Si —O —Si 交联网络的形成显著提高了材料的耐热性能, 使失重5 %时的热分解温度从120.5 ℃(纯环氧树脂/ KB-2 体系) 提高到277.6 ℃(SiO₂质量分数为3. 84 %的杂化体系) 。      

Morphology, dynamic mechanical and thermal studies on poly(styrene-co-acrylonitrile) modified epoxy resin/glass fibre composites

Poly(styrene-co-acrylonitrile) (SAN) was used to modify diglycidyl ether of bisphenol-A (DGEBA) type epoxy resin cured with diamino diphenyl sulfone (DDS) and the modified epoxy resin was used as the matrix for fibre reinforced composites (FRPs) in order to get improved mechanical and thermal properties. E-glass fibre was used as the fibre reinforcement. The morphology, dynamic mechanical and thermal characteristics of the systems were analyzed. Morphological analysis revealed heterogeneous dispersed morphology. There was good adhesion between the matrix polymer and the glass fibre. The dynamic moduli, mechanical loss and damping behaviour as a function of temperature of the systems were studied using dynamic mechanical analysis (DMA). DMA studies showed that DDS cured epoxy resin/SAN/glass fibre composite systems have two T_gs corresponding to epoxy rich and SAN rich phases. The effect of thermoplastic modification and fibre loading on the dynamic mechanical properties of the composites were also analyzed. Thermogravimetric analysis (TGA) revealed the superior thermal stability of composite system.     

环氧树脂与氰酸酯共固化产物性能的研究

用DSC,介电和动态力学等分析方法研究了组成对乙酰丙酮过渡金属络合物催化促进的环氧树脂与氰酸酯共固化反应体系反应动力学参数,固化产物力学、电气和耐热性能以及玻璃化转变温度的影响。结果表明,随着共固化反应体系中氰酸酯含量的增加,其表观反应活化能和频率熵因子均随之升高;在相同的固化条件下,共固化产物中三嗪环结构含量增加,聚醚结构减少,玻璃化转变温度升高,耐热性能、介电性能提高。