有机硅改性AS—70环氧树脂固化反应的研究

本文报道用差示扫描量热法（DSC）研究自制的有机硅改性AS—70环氧树脂固化反应的结果．讨论该树脂与几种常用固化剂固化反应的温度，反应热和反应活化能及在一定温度下固化反应的速率．     

环氧树脂/改性纳米炭黑复合材料固化动力学

采用差示扫描量热法研究了表面改性纳米炭黑作为填料对环氧树脂非等温固化反应的影响,结果表明,改性纳米炭黑能促进环氧树脂的固化,降低固化反应的起始温度和峰温。运用Ozawa-Flynn-Wall等转化率法研究了复合材料固化活化能与转化率的关系,采用Malek法分析了动力学参数和反应机理。结果表明,固化反应符合两参数（m, n）自催化反应机理,模型预测与实验结果相吻合。     

EP/SiO_2/CF复合材料的动态热力学分析

为了研究纳米级SiO_2、碳纤维(CF)对环氧树脂(EP)基复合材料动态热力学性能的影响,制备了不同用量(分别为EP质量的0%和4%)纳米SiO_2、不同体积分数(分别为5%,10%,15%,20%)CF增强EP基复合材料弯曲试样,对试样进行了多频扫描动态热力学分析(DMA),研究了纳米SiO_2和CF对复合材料玻璃化转变温度(Tg)、储能模量、表观活化能和最大损耗因子的影响。结果表明,总体上添加4%的纳米SiO_2后复合材料的Tg下降2~6℃;100℃之前,测试频率对复合材料的储能模量影响较小,且未含SiO_2的试样储能模量曲线比含SiO_2的试样较为平坦;当CF体积分数分别为10%,15%,20%时,添加4%纳米SiO_2的EP/CF复合材料的在40℃下的储能模量较未加纳米SiO_2时提升31.2%,135.5%,13.6%,表明纳米SiO_2和CF展现出很好的协同效应从而提升了复合材料储能模量,而最大损耗因子分别下降3.7%,6.5%,14.8%,表明纳米级SiO_2有助于增强复合材料的刚性;当纳米SiO_2用量为EP质量的4%,CF体积分数为15%时,复合材料内部作用力最大,表观活化能达到569 k J/mol,呈现了很好的协同效果。     

Influence of Curing Agents Molecular Structures on Interfacial Characteristics of Graphene/Epoxy Nanocomposites: A Molecular Dynamics Framework

This paper presents a comprehensive molecular dynamics study on the effects of the stoichiometric ratio of epoxy:hardener, hardener's linear and cyclic structure, and number of aromatic rings on the interfacial characteristics of graphene/epoxy nanocomposite. The van der Waals gap and polymer peak density as a function of the type of the hardener is calculated by analyzing the local mass density profile. Additionally, steered molecular dynamics are used to conduct normal pull-out of graphene to study the effect of the mentioned features of hardeners on the interfacial mechanical properties of nanocomposites, including traction force, separation distance, and distribution quality of reacted epoxide rings in the epoxy. Influence of the hardeners on the damage mechanism and its initiation point are also studied by analyzing the evolution of local mass density profile during the normal pull-out simulation. It is seen that stoichiometric ratio and geometrical structure of the hardeners affect the interfacial strength. It is also revealed that the hardener type can change the epoxy damage initiation point. The damage occurs in the interphase region for a higher stoichiometric ratio or cyclic structure of hardener. In comparison, for hardener's lower stoichiometric ratio and non-cyclic structure, failure begins in the epoxy near graphene layers.     

玻纤织物/3068环氧树脂复合材料性能研究

采用流变仪、凝胶时间测试仪和DMA法研究了3068改性环氧树脂的流变性能、凝胶时间和玻璃化转变温度,结果表明,3068树脂在70～125℃粘度约为70Pa·s,80℃下凝胶时间达到160min,玻璃化转变温度为159.3℃,常温和70℃下复合材料具有良好的力学性能,经湿热试验处理后复合材料吸水率为0.96%,力学性能保持率75%。     

Curing Behavior of Epoxy Resin Using Controllable Curing Agents Based on Nickel Complexes

Summary: The curing reaction kinetics and mechanism of the diglycidyl ether of bisphenol A (DGEBA) with three complexes of Ni(II) with diethylentriamine (Dien), Pyrazole (Pz) and Pyridine (Py) as ligands have been studied using differential scanning calorimetry (DSC). The curing reaction was characterized by high cure onset and peak maximum temperatures. The kinetics of the curing reaction were evaluated using the Ozawa method. The average values of activation energy for the three nickel complexes increased in the order: Dien‐based curing agent > Pz‐based curing agent > Py‐based curing agent. Three main curing mechanisms (catalytic, complex cation and free ligand polymerization path) have been proposed depending on the cure temperature. It was also shown that the cure kinetics of DGEBA with Dien‐ and Py‐based complexes could be described by the Sestak‐Berggren equation. The water absorption, chemical resistance and thermal stability of the thermosets were also studied. The results showed that the thermoset obtained with the Py‐based complex was more thermally stable than those obtained with the other two curing agents.

Activation energy versus conversion plots for the epoxy systems studied.     

环氧树脂的精细化

介绍了各种专业用途的环氧树脂,如高纯度、低粘度、高溴含量、高分子量、透明化树脂的反应机理、合成方法以及相关的性能指标。     

聚硅氮烷/环氧树脂固化体系的研究

研究了聚硅氮烷(PSN-1)/双酚A型环氧树脂固化体系的固化温度、PSN-1用量对固化速度的影响;并利用热重分析(TGA)研究了PSN-1用量对固化树脂高温残余质量分数的影响,对固化机理进行了初步探讨.结果表明,PSN-1可作为双酚A型环氧树脂的高温固化剂,在170～180℃范围内、PSN-1用量为20～50份时,均可有效固化双酚A型环氧树脂;采用PSN-1固化的环氧树脂的初始失重温度略低于采用三乙烯四胺(TETA)固化的环氧树脂,但在800℃时的残余质量分数均远远高于采用TETA固化的环氧树脂;且随着PSN-1用量的增加,环氧树脂的高温残余质量分数也增加.     

环氧树脂的静电纺丝

研究了环氧树脂的静电纺丝,考察了纺丝电压、溶液浓度及共混溶剂等参数对纤维直径及分布的影响。研究结果表明:随纺丝电压增大,环氧树脂纤维直径减小,分布区间变窄;随环氧树脂溶液浓度升高,纤维直径增大,在高浓度时,纤维直径会产生分化而形成双峰分布;不同溶剂体系对环氧树脂纤维直径产生影响,在1-甲氧基-2-丙醇(MP)/丁酮(BT)体系中,随BT比例增加,溶液黏度上升,电导率下降,纤维直径增大。     

环氧树脂/纳米氢氧化铝体系固化反应动力学研究

本文对环氧树脂体系(EP)与加入纳米氢氧化铝(Nano-ATH)的环氧树脂体系进行了固化动力学研究,用n级反应模型分析了一系列差示扫描量热法(DSC)的试验数据,计算出了两个体系的反应活化能分别为63.15kJ/mol和66.43 kJ/mol,反应级数均为一级反应。并对两个体系的玻璃化转变温度(Tg)作了比较。研究结果表明:加入Nano-ATH的树脂体系活化能得到提高,Tg升高约12℃,具有更好的耐热性。     

高性能环氧树脂乳液的制备及性能研究

通过化学改性制备了一种性能优异的阳离子型环氧树脂乳液,对该乳液合成工艺进行了探讨,并研究了影响乳液及涂膜性能的因素。结果表明:采用环氧树脂E-51为原料制备的环氧树脂乳液稳定性好,分散相粒径为0.1～0.3μm,适用期为4 h,涂膜透明,硬度2H～3H,综合性能优良。     

PE—UHMW纤维／环氧树脂复合材料研究

对超高相对分子质量聚乙烯(PE-UHMW)纤维进行了铬酸液相氧化和纳米二氧化硅溶胶表面涂覆的复合化表面处理，并对PE-UHMW纤维／环氧树脂复合材料进行了界面性能研究。结果表明，单纯的液相氧化和表面涂覆均可以提高复合材料的界面性能，但液相氧化处理时间过长会使纤维强度降低，而复合化处理则具有协同效应，可以不降低纤维强度而大幅度提高复合材料的层间剪切强度，是一种有效的表面处理方法。     

测定环氧值方法的改进

研究了环氧值的表征，优化了时间、温度和盐酸-丙酮溶液的过量百分数等因素，并确定了乙醇-水-氢氧化钠溶液的配制比例，将环氧值的滴定步骤具体化，从而更加精确地测定环氧值。     

麦秆液化物环氧树脂的制备与表征

以苯酚为溶剂,浓硫酸为催化剂液化麦秆得到麦秆液化产物,并以其为原料与环氧氯丙烷反应制备出以麦秆液化物为基材的环氧树脂。考察了液比(苯酚与麦秆质量比)、反应温度和反应时间对液化反应的影响。采用凝胶渗透色谱(GPC)对比分析了麦秆液化物及其环氧树脂的相对分子量分布。以聚酰胺为固化剂进行固化并进行力学测试。结果表明:在液比为4∶1,反应温度为150℃,反应那个时间为60min时,麦秆液化效果最佳,此时,麦秆液化物环氧树脂固化物的剪切强度可达4.1MPa。     

丙烯酸改性环氧水性树脂合成工艺的优化研究

在详细分析酯化工艺制备丙烯酸改性环氧树脂合成路线的基础上,讨论了两步酯化工艺的可行性和必要性;并对两步酯化工艺中的两个关键步骤进行了详细研究。通过对酯化过程中环氧基团开环过程的控制,得到了环氧树脂单酯化过程中催化剂的最佳用量为0.2%(相对于总质量)、最佳反应时间为105 min;同时通过凝胶渗透色谱对产物数均相对分子质量的测定,得出自由基聚合反应过程中引发剂和链转移剂用量与聚合树脂相对分子质量之间的关系;并由此制备出具有一定功能官能团数量、最佳相对分子质量和链结构的丙烯酸改性环氧树脂。最后,通过对该树脂的性能测试证实该方法所合成树脂综合性能优良。     

改性环氧酯树脂的研制

采用价格便宜、原料易得、贮存稳定性好的豆油酸与环氧树脂酯化,并拼用210松香改性酚醛树脂进行改性,制得改性环氧酯树脂。讨论了210松香改性酚醛树脂添加量对环氧酯树脂,以及用其配制色漆漆膜性能的影响。     

固体环氧树脂水性涂料的研制

利用双酚A型固体环氧树脂、二乙烯三胺、三乙烯四胺、正丁基缩水甘油醚和聚乙二醇二缩水甘油醚合成了自乳化环氧树脂乳液和水溶性固化剂。并制备了水性环氧树脂涂料,考察了水性环氧树脂的稳定性和涂料组分对性能的影响。     

Epoxy adhesive shear mechanism on the molecular level

The tensile and shear performances of epoxy adhesive were evaluated both experimentally and using molecular dynamics (MD) simulations to understand the shear mechanism operating at the atomic level. A sandwich structure composed of pure epoxy and two copper layers was established based on the standard stretching mode. This three-layer model was first stretched in the perpendicular direction to examine the dynamic evolution of the epoxy molecules. The epoxy was then adhered onto both smooth and rough copper surfaces to determine their shear strengths. Adhesive failure involving interfacial slippage and slight shear deformation of the epoxy matrix was observed on the smooth copper surface, while the epoxy was strongly bound to the rough surface and fractured under shear stress. MD simulations provided data that are consistent with experimental values. Finally, the shear mechanism was investigated by calculating the interaction energies between the epoxy and copper. This study provides significant insight into the shear-failure mechanisms of epoxy adhered to copper surfaces.     

水性环氧乳化剂环氧值测定方法的改进

探讨了反应时间和温度等因素对水性环氧乳化剂环氧值测定结果的影响。实验结果表明:在45℃下,试样与盐酸-丙酮溶液反应2 h,水性环氧乳化剂环氧值的测定值与理论值最接近,相对误差在0.4%以下,比国标GB 1677—1981方法产生的相对误差(6.5%以上)有明显降低。     

环氧树脂的清洁生产

介绍了生产环氧树脂的高浓度废水处理新工艺——闭路循环废水处理工艺。与传统生产方法相比，该工艺解决了严重污染问题，并实现了清洁生产，同时产生明显的经济效益。