RTM改性苯并噁嗪树脂及复合材料性能研究

研究了RTM改性苯并噁嗪树脂及复合材料性能.用DMA研究RTM改性苯并噁嗪树脂体系的储能模量、损耗模量和玻璃化转变温度;用流变仪研究黏度特性;用TGA和TGA微分曲线研究热分解性能;并研究了RTM改性苯并噁嗪树脂及复合材料的力学性能.结果表明:RTM改性苯并噁嗪树脂体系的玻璃化转变温度是206℃;至少有400min的低黏度(η≤0.5Pa.s)时间作为工艺开放期;在氮气气氛下,RTM苯并噁嗪树脂体系热失重分两个主要阶段,在375℃时发生5％热失重,800℃残碳率是45.2％;RTM苯并噁嗪树脂基体拉伸强度72.4MPa,拉伸模量5.07GPa,弯曲强度173MPa,弯曲模量4.6GPa;碳纤维增强RTM苯并噁嗪树脂基复合材料的常规力学性能优异.     

苯并噁嗪树脂流变特性及工艺窗口预报研究

苯并噁嗪树脂是一种适宜RTM工艺的新型耐烧蚀开环聚合酚醛树脂,本工作对该树脂的流变特性进行研究.在粘度实验和DSC热分析实验的基础上,依据双阿累尼乌斯方程建立了与实验数据较为吻合的化学流变模型.模型可揭示树脂在不同工艺条件下的粘度变化规律,定量预报树脂的低粘度平台工艺窗口,为该树脂RTM工艺窗口的确定以及RTM工艺参数优化提供了的科学依据.     

用于RTM 成型工艺的苯并口恶嗪树脂及其复合材料

以苯酚、苯胺和甲醛为原料, 合成了三种不同结构的低粘度苯并口恶嗪中间体树脂。根据RTM 成型工艺中注塑和成型过程对基体树脂的特殊要求和不同组分的反应活性, 系统研究了树脂粘度和凝胶化时间与温度的关系, 及玻璃布层压板的力学性能和耐热性, 详细讨论了树脂组成和催化剂种类及用量的影响。结果表明, 以有机酸或环氧-叔胺为催化剂, 以低粘度苯并口恶嗪树脂为主体所构成的多组分树脂体系, 是一类可用于RTM 成型工艺的新型树脂; 该类树脂基复合材料可用做耐高温结构材料在155℃长期使用。      

高性能苯并(噁)嗪基复合材料研究进展

综述了近年来国内外在苯并(噁)嗪树脂基复合材料方面的研究进展,重点介绍了以苯并(噁)嗪为基体的复合材料在耐热、增韧、增强等方面包括化学改性和物理共混研究进展,并初步判断了今后以苯并(噁)嗪树脂为基体的复合材料的发展方向.     

一种RTM 用苯并噁嗪树脂的工艺性及其复合材料性能

制备了一种可用于树脂传递模塑( RTM) 工艺的高性能苯并噁嗪共混树脂体系( BA21) 。研究了BA21 的注射工艺性, 确定了其固化程序, 并考察了采用RTM 工艺制备的BA21 基复合材料的基本力学性能。升温及恒温黏度测试结果表明, BA21 树脂体系能够用于RTM 工艺。依据修正的双阿累尼乌斯方程建立了与实验数据较为吻合的化学流变模型, 利用该模型可以选择合适的注射温度。通过不同温度下的恒温DSC 测试及修正的Kamal 动力学模型计算得到BA21 树脂体系的固化反应级数, 并确定后固化温度为200 ℃。采用RTM 工艺制得的玻璃纤维/ BA21 复合材料表现出优异的力学性能, 弯曲强度达600 MPa , 弯曲模量达30 GPa , 冲击强度达210 kJ/ m2 。      

碳纤维/SiO2/聚苯并(噁)嗪复合材料的制备及性能研究

以纳米SiO2/聚苯并(噁)嗪(PBOZ)为基体树脂,与碳纤维(CF)复合,制备了CF/SiO2/PBOZ复合材料,研究了纳米SiO2含量对其弯曲强度、层间剪切强度以及断面形貌的影响.结果表明,纳米SiO2含量为4%时,CF/SiO2/PBOZ复合材料的性能最好,材料的弯曲强度和层间剪切强度分别达到835和72.1MP...     

新型含炔基苯并(口恶)嗪的合成及性能研究

为了提高苯并(口恶)嗪的热稳定性,以对碘苯胺、3-氨基苯乙炔、苯酚及多聚甲醛为原料合成了新型的含炔基苯并(口恶)嗪(PA-an-ba),并通过傅里叶变换红外光谱仪和核磁共振仪(~1 H-NMR,~(13) C-NMR)对其结构进行表征,通过差示扫描量热仪和热重分析仪对其固化行为和热性能进行了测试。结果表明:炔基的引入能显著提高聚苯并(口恶)嗪的耐热性,其失重率为5%和10%时的温度分别为437℃和464℃,800℃的残炭率为73%,比传统苯并(口恶)嗪提高了40%。     

苯并噁嗪树脂的应用研究进展

针对苯并噁嗪树脂的工业应用,综述了近年来苯并噁嗪树脂的单体合成、树脂改性及固化研究的现状.     

活性单体对苯并(口恶)嗪树脂性能的影响

通过加入活性单体E,对自制苯并口恶嗪(FBZ)及FBZ/E的反应性进行了研究,并制作了FBZ层压板和FBZ/E层压板,研究了其力学性能、阻燃性及热稳定性。实验结果表明,加入活性单体E后,FBZ的凝胶时间缩短、活化能降低;FBZ/E层压板的弯曲强度和冲击强度都比FBZ层压板提高3倍多;FBZ层压板和FBZ/E层压板的氧指数都大于50,为难燃材料,且其热稳定性也有所提高。     

RTM快速成型环氧树脂时间-温度-转变图的构建及其碳纤维/环氧树脂复合材料评价

针对自行研制的树脂传递模塑工艺（RTM）快速成型环氧树脂,利用唯象动力学模型、DiBenedetto方程和凝胶模型研究了树脂体系的等温及非等温固化动力学,构建了时间-温度-转变（TTT）的关系图,表明树脂体系兼具较长的适用期与快速固化特性。以此设计RTM快速成型工艺,考察了树脂体系对碳纤维织物的浸润流动行为,并评价了快速成型碳纤维/环氧树脂复合材料的界面力学性能与微观形貌。结果表明,注射温度下树脂体系的浸润填充性良好,RTM快速成型碳纤维/环氧树脂复合材料的力学性能和内部成型质量较好。      

碳纤维增强树脂复合材料细观蠕变性能

碳纤维增强树脂复合材料以其优异的性能,在各领域得到广泛应用。由于树脂基体具有黏弹性,使其合成的复合材料也表现出黏弹性行为。蠕变是材料黏弹性行为中最典型的一类现象,因此对碳纤维增强树脂复合材料细观蠕变性能的研究具有重要意义。室温下利用纳米压痕技术对碳纤维增强树脂复合材料中的基体、界面及纤维相在不同峰值载荷下的细观蠕变行为进行分析。结果表明:在相同的蠕变时间下,最大载荷为2 mN和10 mN的纤维蠕变位移约为基体蠕变位移的1/3和1/2,界面的蠕变位移介于两者之间;稳态蠕变阶段的蠕变速率小于0.1%;基体、界面、纤维的蠕变应力指数分别为3.6、2.9和2.1。同时根据Kelvin-Voigt模型得到了基体、界面及纤维的第一、第二复数模量、黏度系数及蠕变柔量。      

Electrical properties of short sisal fiber reinforced polyester composites fabricated by resin transfer molding

The electrical properties of sisal fiber reinforced polyester composites fabricated by resin transfer molding (RTM) have been studied with special reference to fiber loading, frequency and temperature. The dielectric constant (ε′), loss factor (ε″), dissipation factor (tan δ) and conductivity increases with fiber content for the entire range of frequencies. The values are high for the composites having fiber content of 50 vol.%. This increment is high at low frequencies, low at medium frequencies, and very small at high frequencies. The volume resistivity varies with fiber loading at lower frequency and merges together at higher frequency. When temperature increases the dielectric constant values increases followed by a decrease after the glass transition temperature. This variation depends upon the fiber content. Finally an attempt is made to correlate the experimental value of the dielectric constant with theoretical predictions.     

Constraints on monitoring resin flow in the resin transfer molding (RTM) process by using thermocouple sensors

In this study, a thermocouple sensor system was used to monitor the resin transfer molding (RTM) process. These sensors are low-cost and durable; and they do not disturb the resin flow. They can be used if the inlet resin is either hotter or colder than the mold walls. In experiments of this study, much of the hot resin’s internal energy was transferred to cold mold walls by conduction, when the mold parts were made of a material with high thermal conductivity, such as aluminum. A mathematical model based on 1D flow and 2D unsteady energy conservation was developed to investigate the heat transfer between resin and mold walls. The numerical solution of this model is in qualitative agreement with the results of our experiments. The thermocouple sensor system developed is more useful with the following process parameters: low thermal conductivity of mold material, high resin flow rate, high temperature difference between inlet resin and initial mold walls, and high specific heat of resin. However, for the typical use of RTM materials and typical injection parameters, thermocouples should not be preferred over other sensor types and should be used with caution due to the shortcomings investigated in this study.     

Numerical study of resin transfer molding (RTM) curing process

It is a very important phase in resin transfer molding (RTM) process that resin is cured. The result of the curing process determines the quality of a part, including mechanical properties, lifecycle of the part under high temperature and chemical properties. Therefore, it is very meaningful to discuss the curing process. In our work, the code is prepared based on unstructured mesh using divergence theorem. A case is used to verify properness of the code and the results are in good agreement with the published experiment data. In the paper, some factors of materials and numerical calculation, e.g., time step, reaction heat, the whole heat conductivity of fiber and resin and fiber initial temperature, which affect result of simulation, are emphatically investigated and carefully revealed. The conclusion shows that time step, the reaction heat and heat conductivity have an important effect on the curing process, while fiber initial temperature has very little impact. These are helpful to understand and adopt the curing process in order to produce good products.     

Numerical study of resin transfer molding (RTM) curing process

It is a very important phase in resin transfer molding (RTM) process that resin is cured. The result of the curing process determines the quality of a part, including mechanical properties, lifecycle of the part under high temperature and chemical properties. Therefore, it is very meaningful to discuss the curing process. In our work, the code is prepared based on unstructured mesh using divergence theorem. A case is used to verify properness of the code and the results are in good agreement with the published experiment data. In the paper, some factors of materials and numerical calculation, e.g., time step, reaction heat, the whole heat conductivity of fiber and resin and fiber initial temperature, which affect result of simulation, are emphatically investigated and carefully revealed. The conclusion shows that time step, the reaction heat and heat conductivity have an important effect on the curing process, while fiber initial temperature has very little impact. These are helpful to understand and adopt the curing process in order to produce good products.     

玄武岩增强硼酚醛树脂基复合材料工艺性能研究

利用正交试验方法,讨论冷却方式、成型压力、增强纤维百分含量、成型温度对玄武岩增强硼酚醛树脂基复合材料拉伸强度和弯曲强度的影响.结果表明:复合材料中增强纤维百分含量对其力学性能影响最大,成型压力增大有利于复合材料力学性能的改善,成型温度对基体材料的结构有较大影响,当成型温度较高时,复合材料具有较大的弯曲强度,延长冷却时间有利于复合材料力学性能的提高.     

镀金属炭毡/树脂复合材料的电磁屏蔽性能

采用镀金属炭毡与环氧树脂、聚丙烯（PP）、ABS、聚苯乙烯（PS）、聚乙烯（PE）复合制备电磁屏蔽（EMS）复合材料,镀金属炭毡复合材料在1－1000MHz范围内的屏蔽效率可达40dB以上,不同的树脂体系对复合材料的屏蔽效率无显著影响,在炭毡纤维表面镀不同的金属对复合材料的屏蔽效率有较大的影响。     

Monitoring of resin flow in the resin transfer molding (RTM) process using point-voltage sensors

Multiple point-voltage sensors were used to monitor the mold filling stage of the resin transfer molding (RTM) process. Both lineal- and point-voltage sensors are electrical circuits in which the two poles of the sensor are closed when liquid thermoset resin arrives at the sensor location in the mold cavity. The electrical conductance of the liquid resin causes an increase in the output voltage, V_sens of the circuit. Although the gradually varying in situ data of a lineal sensor is more informative than a point-voltage sensor, lineal-voltage sensors might mislead the user if the resin covers the wires at multiple sections, or if the resin covers the wires starting from an unexpected section. Two kinds of sensors were developed: a set of similar, wrapped and compact lineal-voltage sensors acting as point-voltage sensors; and a point-voltage sensor with voltage amplification. Without this amplification, the increase in V_sens might be difficult to detect if the resin system has a low electrical conductivity and there is noise in the DAQ system. The accuracy and reliability of the new sensor system was verified by comparing the in situ sensor data with the visually recorded resin flow.