改性双马来酰亚胺树脂体系的固化工艺及热稳定性研究

采用差示扫描量热仪 (DSC)对价格低廉、配比不同的二苯甲烷型双马来酰亚胺(BMI) /二烯丙基双酚A(BA) /N -苯基马来酰亚胺 (NPMI)三元共聚树脂体系反应性能、反应动力学进行研究 ,确定了固化工艺。对固化树脂的热变形温度、热失重及耐湿热性能进行了分析。     

BT树脂

这是日本三菱瓦斯化学公司和西德拜耳公司发表的耐热树脂。BT树脂按照日本专利报道:是由三个组份混合加热反应而生成可固化的树脂组成物。第一个组份是由4,4′二氨基二苯甲烷和马来酸酐反应生成的双马来酞亚胺;第二个组份是由氯化氰ClCN和双酚A生成的异氰酸酯;第三组份为四溴双酚A的二乙二醇醚,即美国道化学公司的Der542。三者混合加热反应可生成含有S-三嗪环和正胺结构的新型耐热树脂。BT树脂的种类和性状如上表。     

3，3′-二乙基-4，4′-二苯甲烷型多马来酰亚胺改性聚苯醚树脂的制备和性能

首次将两种高性能印制电路板(PCB)用树脂--聚苯醚(PPO)和多马来酰亚胺(PMI)相结合,以烯丙基化PPO为基础树脂,采用质量为PPO的10%的3,3′-二乙基-4,4′-二苯甲烷型多马来酰亚胺(PEDM)作为交联剂,无引发剂热聚合得到一种新型热固性PPO树脂.PEDM改性烯丙基化PPO固化树脂的Tg为204.71℃,介电常数(ε,1 MHz)为2.69,介电损耗角正切(tanδ,1 MHz)为0.0032,吸水率为0.21%,能满足高性能PCB用树脂的要求.同时,对PEDM/丙基化PPO体系的非等温固化动力学进行了研究,并确定了该体系的固化工艺参数.     

单马来酰亚胺的合成和表征

本文合成了四种单马来酰亚胺树脂，并采用ＩＲ．ＮＭＲ．ＴＧ－ＤＴＡ对其结构和性能进行了表征，结果表明，单来酰胺酸和单马来酰亚胺在固化过程中无明显的固化峰存在，与普通未扩链的双马来酰亚胺有所区别，同时二胺的结构和固化过程中少量水份的存在都将在很大程度上影响其热稳定性能。     

一种新型紫外光固化涂料的性能研究

采用本体熔融聚合法制备了可紫外光固化的不饱和聚酯酰胺脲树脂,该类树脂可用作紫外光固化涂料,并对树脂进行了红外表征.研究了树脂反应的酸值与反应条件的关系,并研究了不同光引发剂体系对涂膜性能的影响.结果表明,该类树脂感光性好,用安息香双甲醚作为光引发剂,其用量为2%～3%时固化速度快、涂膜性能优异.     

酰亚胺键扩链的胺-马来酰亚胺的合成和表征

合成了４种酰亚胺键扩链的胺－马来酰亚胺。并采用红外光谱。核磁共振谱,差热分析对其结构和热稳定性进行了研究,结果表明扩链后的胺－马来酰亚胺在树脂的固化过程中未出现明显的固化峰。与未扩链的双马来酰亚胺有所区别,所采用二胺结构不同,将在很大程度上影响固化后树脂的热稳定性。     

纳米TiO2对改性BMI树脂固化反应及热稳定性影响

将芳香二胺、N-取代苯基马来酰亚胺等组分引入双马树脂以降低固化物交联密度,研究了纳米TiO₂对该改性双马树脂固化反应性和固化树脂热稳定性的影响。利用差热分析、凝胶特征曲线对树脂的固化反应性进行研究,采用热重分析和红外分析表征固化树脂的热稳定性和树脂固化前后IR光谱变化特征。结果表明:该系列树脂基体具有较低的熔点(70~90℃),良好的溶解性,大多数预聚体可溶解于丙酮溶剂;纳米TiO₂的引入可使固化温度下降45~105℃,固化物的耐热温度指数提高19~27℃。      

引发剂引发BMI/DP共聚双马树脂基体研究

在优选树脂组分的基础上，采用回归正交设计的实验方法优化低温固化双马树脂的配方。通过树脂体系的固化反应特性研究，确定树脂浇铸体和纤维增强复合材料的固化成型工艺，测定其主要力学性能和热性能。研究发现，固化工艺中的低温固化台阶对树脂的耐热性影响很大。引发剂引发改性使双马树脂的固化、后处理温度由２００℃、２５０℃降低到１６０℃、１８０℃，并提高了耐热性，但树脂韧性下降较大。改性树脂热变形温度３００℃，起始分解温度４１７．５℃，弯曲强度１１４ＭＰａ。     

引发剂引发BMI／DP共聚物双马树脂基体研究

在优选树脂组分的基础上，采用回归正交设计的实验方法优化低温固化双马树脂的配方。通过树脂体系的固化反应特性研究，确定树脂浇铸体和纤维增强复合材料的固化成型工艺，测定其主要力学性能和热性能，研究发现，固化工艺中的低温固化台阶对树脂的耐热性影响很大。引发剂引发改性使双马树脂的固化、反处理温度由２００℃、２５０℃降低到１６０℃１８０℃，并提高了耐热性，但树脂韧性下降较大。改性树脂热变形温度３００℃，起始分     

热分析在挤拉成型工艺中的应用

本文采用DSC固化实验和SPI凝胶实验的热分析方法,评价挤拉成型工艺中不同树脂反应活性、不同填料、填料用量、引发剂用量、温度对树脂固化性能的影响以及树脂混合物的固化性能。通过热分析寻找合适的工艺参数,从而获得成本较低、效率较高、性能较好的挤拉制品。      

Influence of curing agents on gelation and exotherm behaviour of an unsaturated polyester resin

A judicious choice of curing agents such as initiator and promoter and their ratio to the resin can avoid reduced gel-time and shortened exothermic reactions in applications such as liquid composite moulding processes. In this study, effects of different ratio of initiator and promoter to the unsaturated polyester resin on curing of the resin were investigated by measuring gel-time and peak exotherm using ASTM D2471 standards. Methyl ethyl ketone peroxide (MEKP) was used as an initiator and a cobalt salt was employed as an accelerator for the free radical polymerization of curing resin at ambient temperatures. It was observed that the resin gelation starts closely with the initial rise in exotherm temperature and time of gelation decreases with the increase in initiator or accelerator volume proportions. It was also found that the exotherm-peak and rate of temperature rise indicating that the curing rate increases with the initiator or accelerator proportions also increased. A nonlinear regression analysis of all gel-time and cure data were performed to quantify the dependence of curing parameters on the volume proportions of accelerator and initiator. Thus, for this polymerization initiation system, the gel-time and cure parameters can be predicted for any initiator and cobalt levels within the ranges studied.     

ES/CEP共混树脂紫外光固化行为及性能研究

以有机硅环氧树脂为增韧剂改性脂环族环氧树脂,研究了树脂组分比、固化时间、引发剂种类和含量等工艺参数对固化行为的影响;采用热失重(TG)和差示扫描量热(DSC)对固化产物进行了分析.结果表明:当引发剂820和T含量为2％、环氧树脂(CEP)与有机硅树脂(ES)比例为85∶15时,1 000W高压汞灯紫外光固化15 min,树脂体系可以达到较好的固化效果.与纯环氧树脂相比,添加15％含量ES的共混树脂的抗拉强度略有下降而韧性得到较大提高,玻璃化转变温度下降7.5℃,快速失重区热降解速率明显下降.     

Mechanical properties of nano-silica particulate-reinforced epoxy composites considered in terms of crosslinking effect in matrix resins

In this study, the mechanical properties of nano-silica particulate-reinforced epoxy composites with different crosslinking densities were clarified experimentally to consider the interaction effects between nano-particles and the network structure in matrix resin. The matrices were prepared by curing with an excessive mixture of diglycidyl ether of bisphenol A type epoxy resin as the curing agent for the stoichiometric condition. The volume fraction of the silica particles with a median diameter of 240 nm was constantly 0.2 for every composite. The crosslinking densities and glass transition temperatures of the neat epoxy resins were identified from thermo-viscoelastic properties measured by dynamic mechanical analysis. Elastic moduli and strengths of the composites and the neat epoxy resins were measured by three-point bending tests. The glass transition temperatures of the neat epoxy resins decreased linearly as the crosslinking densities decreased from the stoichiometric condition. The glass transition temperatures of the composites were reduced by adding the nano-silica particles. The bending moduli of the composites in the glassy state could be predicted by using a mixture law of the composites regardless of the crosslinking densities and glass transition temperatures. The bending strengths were found to be sensitive to the crosslinking densities: they were both higher (for composites with high crosslinking densities) and lower (for composites with low crosslinking densities) than those of the neat epoxy resin. These results demonstrate that the interaction between nano-particles and network structures reduces the bending strengths, especially for low crosslinking densities.     

剥离型环氧树脂/蒙脱土纳米复合材料研究

采用阳离子交换的方法对蒙脱土进行了有机化处理,使蒙脱土由亲水性变成亲油性,并且使其层间距由原来的1.2nm扩大到2.2nm.采用X-射线衍射仪研究了有机蒙脱土在环氧树脂中的剥离行为,制备了环氧树脂/蒙脱土纳米复合材料并测试了其性能.实验结果表明,环氧树脂与有机蒙脱土的相容性好,蒙脱土在环氧树脂中完全剥离;环氧树脂/蒙脱土纳米复合材料的力学性能、热性能以及阻隔性能与纯环氧树脂固化物相比均有不同程度的提高和改善.     

电子束辐射固化环氧树脂的动态力学分析——辐射剂量、引发剂用量及热处理的影响

对电子束辐射固化的环氧树脂进行了动态力学分析。通过对不同样品凝胶含量、内耗tanδ及动态模量变化趋势的研究,得到电子束辐射剂量、引发剂用量和热处理等因素对环氧树脂辐射交联反应的影响规律。辐射剂量的增加使环氧树脂凝胶含量、玻璃化温度T_g及高温模量有所增加,但增长幅度在高辐射剂量下逐渐变小,且树脂交联体系的不均匀性随辐射剂量增大而有所增加。低剂量辐射下,环氧树脂固化物的玻璃化温度及高温模量随引发剂用量增加而增大,高辐射剂量下,引发剂的用量存在最佳值。经过热处理后辐射样品的交联程度得到提高,当热处理温度超过引发剂的热分解温度时,树脂体系中会存在因热固化反应而形成的局部交联网络。     

阳离子引发剂对环氧树脂电子束辐射固化的影响

研究了碘Weng盐引发剂对于环氧树脂电子束辐射固化效果的影响。在环氧树脂溶液的辐射反应过程中，反应体系的引发速率和增长速率迅速达到最大值，然后不断减小。随着电子束辐射的进行，加入引发剂的环氧树脂体系温度以较快速度达到一个峰值后回落，并逐渐保持在一个稳定值。引发剂用量增加，环氧树脂辐射固化厚度以及在相同位置的固化度呈现一种先上升后下降的趋势。     

A Fiber Optic Ultrasonic System to Monitor the Cure of Epoxy

A fiber optic ultrasonic system is described which monitors the cure of an epoxy resin. Ultrasound is generated using a high-power optical fiber to deliver high-energy pulses of light to the prepared surface of an aluminum mold that contains the curing epoxy resin. The generated ultrasound is detected using a local fiber optic ultrasound sensor embedded in the curing epoxy resin. The system was used to measure the ultrasonic signal velocity and ultrasonic attenuation throughout the cure of a neat epoxy resin at room temperature. Similar measurements also were performed using a piezoelectric transducer for ultrasound generation and an embedded fiber optic sensor for detection, which provided verification of the results using the complete fiber optic system. The complete fiber optic system demonstrated adequate sensitivity throughout the entire cure to measure the ultrasonic signal velocity and ultrasonic attenuation.     

LTM树脂及其复合材料的初步研究

报告一种研制的低温固化高温使用树脂体系Xufyg-44。用它成型复合材料层压制件时,固化温度低于70 ℃,最终固化产物的玻璃化转变温度高于200 ℃,浇注体力学性能以及复合材料制件在整个固化周期中的尺寸稳定性良好。     

CE改性及柔性膜性能

研究了催化剂、固化时间和温度对环氧树脂(EP)或丁腈橡胶(A)改性氰酸酯树脂(CE)固化反应的影响以及CE/A膜性能.不舍催化剂的CE/EP体系160℃不能有效固化,而含有二月桂酸二丁基锡(B)的CE/EP体系能有效固化,且固化反应速度随着B用量增加而提高.CE/A/B体系的固化程度随着固化时间延长和温度升高而提高.C...     

低粘度环氧树脂体系及其固化物性能的研究

为了满足环氧树脂在多种工艺中对低粘度的要求,使用了6002及618型两种普通双酚A型环氧树脂与低粘度XCT-802固化剂,设计出一种低粘度的环氧树脂体系,并对其粘度、固化物的力学性能等进行了表征。结果表明：该体系在常温下具有较长的适用期;在中温（80~C）条件下即可凝胶并固化,其固化物的力学性能优异。