多壁碳纳米管-丙烯酸酯嵌段共聚物共改性环氧树脂三元复合材料性能

采用多壁碳纳米管(MWCNTs)和丙烯酸酯嵌段共聚物(ACRBC)协同改性制备了多壁碳纳米管-丙烯酸酯嵌段共聚物/环氧树脂(MWCNTs-ACRBC/EP)三元复合材料。通过FTIR、 XPS和SEM对强酸处理后的MWCNTs的性能进行表征,利用DSC法对MWCNTs-ACRBC/EP复合材料的固化反应参数进行表征,采用DMA对MWCNTs-ACRBC/EP复合材料的耐热性进行表征,采用电子力学试验机对MWCNTs-ACRBC/EP复合材料的力学性能进行测试。结果表明:强酸处理后在MWCNTs表面成功形成反应官能团。采用150℃×1 h+180℃×3 h作为MWCNTs-ACRBC/EP复合材料的固化工艺, MWCNTs-ACRBC/EP复合材料的玻璃化转变温度可达197.5℃,提高了13.3%, MWCNTs-ACRBC/EP复合材料的力学性能提高,抗弯强度为144 MPa,弯曲模量为3662 MPa,冲击强度为19.5 kJ/m^2。     

可膨胀石墨/环氧树脂体系的固化动力学

采用非等温差示扫描量热(DSC)法分别对环氧树脂(EP)及可膨胀石墨/环氧树脂(EG/EP)体系的固化过程进行了研究。利用Kissinger和Crane法计算得到两种体系固化反应的表观活化能Ea、指前因子A、固化反应级数n等动力学参数,建立了固化反应动力学方程,并用T-β外推法确定了固化工艺温度。结果表明,EG的加入,降低了EP体系固化反应的完全程度,对固化反应时间的影响不大,体系的Ea由63.15 kJ/mol升高到65.89 kJ/mol,A由2.02×107提升到4.5×107,两种体系的反应级数基本一致,同时,EG的加入对体系固化工艺温度影响不大。     

Curing behavior and kinetic analysis of epoxy resin/multi-walled carbon nanotubes composites

The effect of multi-walled carbon nanotubes (MWNTs), both amino-functionalized (f-MWNTs) and unfunctionalized (p-MWNTs) on the curing behavior of epoxy resin (EP) cured with triethanolamine (TEA), was investigated using differential scanning calorimetry (DSC). Because the triethylenetetramine (TETA) grafted on the f-MWNTs could act as curing agent and the produced tertiary amine as negative ionic catalysts of curing reaction of EP, so the activation energy of the EP/TEA system was decreased by the addition of f-MWNTs. Viscosity played a key role in the curing behavior of the EP/TEA/MWNTs system, for high viscosity of the EP/TEA/MWNTs system could hinder the motion of the functional groups. The curing heat in EP/TEA/f-MWNTs (weight ratio 1/0.1/0.01) system was higher than the neat EP/TEA (weight ratio 1/0.1) system, while the curing heat in EP/TEA/p-MWNTs (weight ratio 1/0.1/0.01) was lower than the neat system. When the content of f-MWNTs was increased to 2 phr (weight ratio of 1/0.1/0.02), the curing heat became lower than that of the neat EP/TEA system, which was the result of the higher viscosity of the EP/f-MWNTs/TEA system. Since the curing heat indicated the curing degree of the system generally, the addition of the f-MWNTs was thought to increase the curing degree of the epoxy matrix at a relatively low content.     

环氧树脂改性双环戊二烯型氰酸酯树脂固化反应性

采用凝胶试验、 FTIR和DSC等手段研究了环氧E-51与双环戊二烯型氰酸酯(DCPDCE)共聚体系的固化反应性以及阶梯固化过程中—OCN基、 三嗪环、 唑啉、 噁唑啉酮的变化情况。结果表明, 环氧树脂既能够催化氰酸酯本身三聚成环反应, 又对氰酸酯三聚成环反应有稀释作用。当环氧树脂含量(环氧占混合物总量的质量百分比)大于5wt％时, 催化效果增加不明显, 稀释作用加强; 当环氧树脂含量约为25wt%时, 以上两种作用效果基本平衡, 改性体系的固化反应活性和纯DCPDCE相当。阶梯固化时, 低温阶段(160~180℃)主要发生生成三嗪环和唑啉的反应, 高温阶段(200~220℃)主要发生三嗪环和唑啉向噁唑啉酮的转化反应。另外, —OCN基的低温转化率随着环氧树脂含量的增大而提高, 固化树脂的最终结构组成和环氧树脂的含量有关。      

聚氨酯改性TDE-85/E-51环氧树脂的固化反应机理

以混合芳胺为固化剂,通过聚氨酯(PU)对4,5-环氧环己烷-1,2-二甲酸二缩水甘油酯(TDE-85)与二酚基丙烷缩水甘油醚(E-51)环氧树脂的混合树脂体系(EP)的改性,制备得到了一种高性能聚氨酯改性环氧树脂(PU/EP)。通过对材料样品结构的红外光谱表征,探讨了PU/EP的固化反应机理。研究结果表明,PU预聚体与1,4-丁二醇(1,4-BDO)及三羟甲基丙烷(TMP)发生了扩链、交联反应得到PU交联聚合物网络,TDE-85/E-51环氧树脂与混合芳胺固化剂反应生成了交联环氧聚合物。EP与PU之间存在的化学接枝、交联反应,提高了EP与PU之间的相容性及共混程度。     

CIP/GF/CF/EP吸波复合材料的制备及力学性能

为制备兼具力学性能和电磁吸收性能的结构型吸波材料,采用真空辅助成型工艺设计制备一种以羰基铁粉(CIP)为吸收剂,玻璃纤维(GF)为透波层,碳纤维(CF)为反射层,环氧树脂(EP)为基体的吸波复合材料。研究了不同质量比CIP/EP对吸波复合材料力学性能和微波吸收性能的影响。通过FTIR和DSC分析可知CIP未与EP发生化学反应。SEM结果表明CIP能够在EP树脂基体中均匀分散,不趋向于纤维表面。力学测试分析结果显示:当CIP/EP质量比达到30%时,CIP/GF/CF/EP复合材料的力学性能最佳,拉伸强度为347.56MPa,拉伸模量为25.99GPa,较纯GF/CF/EP复合材料提升了4.3%和5.7%;弯曲强度为339.6MPa,弯曲模量为23.7GPa,较纯GF/CF/EP复合材料提升了18.2%和71.2%。矢量网络分析可知复合吸波板的吸波性能随CIP含量的增加而增加,且吸波损耗反射峰值朝低频段移动。     

环氧树脂／PHMCD体系相区尺寸分布与冲击强度

用扫描隧道显微镜，扫描电子显微镜，透射电子显微镜，差示扫描量热分析等研究了环氧树奚（ＥＰ）／聚六亚甲基碳酸酯二醇（ＰＨＭＣＤ）增韧体系（ＥＰ／ＰＨＭＣＤ）的粒径分布与冲击强度的关系。结果表明，一步加料法得到的固化物中的ＰＨＭＣＤ的粒径呈单峰分布；予反应法得到的固化物中ＰＨＭＣＤ的粒径呈双峰分布，而且固化物的冲击强度较高。     

特高压气体绝缘金属封闭开关设备用Al2O3/环氧树脂复合材料的非等温固化动力学及蠕变性能

针对特高压气体绝缘金属封闭开关设备（GIS）用Al₂O₃/环氧树脂（EP）复合材料,采用非等温差示扫描量热（DSC）法研究了Al₂O₃/EP复合材料的固化行为,对其DSC曲线进行分峰处理,利用等转化率方法求得不同反应阶段的表观活化能。根据Málek判据得到Al₂O₃/EP复合材料的固化行为符合的模型类型,并求得不同反应阶段的各个动力学参数及固化动力学方程。利用SEM观察Al₂O₃/EP复合材料的微观形貌,通过动态热力学分析仪（DMA）分析其动态热力学性能和高温蠕变性能,利用时温等效预测了Al₂O₃/EP复合材料的长时蠕变行为。结果表明,DSC热流曲线表现为双峰分布;Al₂O₃/EP复合材料的两个反应阶段的表观活化能分别为35.3 kJ/mol及48.1 kJ/mol,Sestak-Berggren自催化模型能够很好地描述Al₂O₃/EP复合材料体系在不同固化阶段的固化行为。Al₂O₃颗粒均匀分散于树脂基体中,填料的加入使裂纹发生偏转。Al₂O₃/EP复合材料的储能模量（E'）随温度的升高而降低,损耗因子（tanδ）峰值对应的玻璃化转变温度（T_g）为120.03℃。Al₂O₃/EP复合材料的抗蠕变性能随着拉伸应力和温度的增加而减弱,随着时间的延长,其蠕变速率减小。      

Influence of addition of silica particles on reaction-induced phase separation and properties of epoxy/PEI blends

Polyether imides (PEI)/silica nanocomposites, prepared by sol–gel process, were used to modify the epoxy resin (ER), and the effect of silica particles on reaction-induced phase separation and mechanical properties of these systems were investigated. SEM images of the fracture surface of ER/PEI/silica composites showed an interesting morphology transformation with the increase of silica particle content. SEM–EDX results indicated that silica particles once formed in the PEI gradually migrated and concentrated in epoxy-rich region during the phase separation because of the better affinity between silica particles and epoxy resin. FTIR measurement and rheological test confirmed that the silica particles make the polymerization reaction of epoxy faster and the dynamic DSC results demonstrated that the activation energy of these systems decreased with the increase of the silica particles. Mechanical measurements approved that the introducing of PEI/silica nanocomposites into the epoxy could lead to great improvement of the impact strength and storage module.     

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。     

碳纤维-氧化石墨烯/环氧树脂复合材料的制备及表征

采用改进的Hummers法制备了五种具有不同氧化程度的氧化石墨烯（GO）。借助元素分析、X射线光电子能谱及FTIR红外光谱测试对所制备GO的组成及结构衍变进行了表征。利用光学显微镜对不同GO在固化剂异佛尔酮二胺（IPDA）中的分散状态进行观察,并将分散效果最佳的GO试样用于改性碳纤维/环氧树脂（CF/EP）复合材料。结果表明,随着氧化剂用量及反应时间的增加,GO的氧化程度也随之增加。在氧化程度较低时,GO表面官能团主要以羰基、羧基和酚羟基为主。随着氧化程度的不断提高,GO表面官能团主要为醚、环氧和醇羟基结构。GO在IPDA中的分散状态与其氧化程度密切相关,氧化程度最低和最高的GO均出现明显的聚集现象。另外,GO表面在分散过程中可被IPDA化学改性。在EP基体中加入分散效果最佳的GO（0.2wt%）后,与CF/EP复合材料相比,CF-GO/EP复合材料的弯曲强度、层间剪切强度和Ⅱ型层间断裂韧性分别提高了14%、17%和14%。     

甲基乙基次膦酸铝/环氧树脂阻燃复合材料性能

以甲基乙基次膦酸铝(Al(MEP))作为环氧树脂(EP)的阻燃剂, 制备了Al(MEP)/EP复合材料, 利用垂直燃烧和氧指数法研究了Al(MEP)/EP复合材料的阻燃性能; 探讨了不同组成的Al(MEP)/EP复合材料的弯曲强度和冲击强度; 采用红外光谱(FTIR) 、 TGA 、 DSC、 SEM分别对样品的结构、 热稳定性、 玻璃化转变温度(T_g) 和形貌进行了分析。 结果表明, Al(MEP)的质量分数为15%时, Al(MEP)/EP复合材料的氧指数值(LOI)即可达到32.5%, 垂直燃烧达到UL 94 V-0级。此外, 各种组成的复合材料的力学性能较好、 热稳定性能优良。     

碳纳米管对环氧树脂固化反应和力学性能的影响

通过动态DSC扫描技术,结合等转化率方法分析了碳纳米管对环氧树脂体系(EP828/DDM)固化反应的影响。发现碳纳米管加入到环氧固化体系后,对体系的固化产生促进作用。尤其在反应初期,少量的碳纳米管可降低环氧固化反应活化能,但过多的碳纳米管阻碍树脂分子接触,反而使活化能升高。此外还对碳纳米管对环氧树脂力学性能的影响进行了探讨。     

湿热老化对玻璃纤维/环氧树脂复合材料性能的影响

为研究玻璃纤维(GF)/环氧树脂复合材料湿热老化机制, 首先, 利用称重法、动态热机械分析仪(DMA)、SEM和矢量网络介电分析仪研究了湿热老化对GF/环氧树脂608(EP608)复合材料性能的影响;然后, 分析了复合材料的吸湿率、力学性能、介电性能与老化时间的关系, 并对其老化机制进行了探讨。结果表明:随老化时间延长, GF/EP608复合材料的力学性能和介电性能均有不同程度的下降;湿热老化对GF/EP608复合材料吸湿率的影响符合Fickian扩散定律;树脂基体的塑化、水解和基体-纤维界面的破坏是造成GF/EP608复合材料力学性能和介电性能下降的主要因素。所得结论可为GF增强环氧树脂基复合材料的应用提供科学依据。      

PP/PP-g-MAH/Talc/EP复合材料的性能

通过熔融共混制备聚丙烯(PP)/马来酸酐接枝聚丙烯(PP-g-MAH)/滑石粉(Talc)/环氧树脂(EP)复合材料,研究了E-51/504/554(55.6/42.4/2,E1)、E-51/EDA/554(92.2/7.8/0.01,E2)、E-20/2E4MZ(100/4,E3)三种EP体系及其含量对复合材料力学性能的影响,结果表明,E-1对复合材料的弯曲模量改善最显著,当加入4%的E1时,复合材料的弯曲模量达到最大值,提高了29.1%。傅里叶红外光谱(FT-IR)分析表明,EP与PP-g-MAH发生了酯化反应。观察复合材料的微观结构,发现EP阻止Talc的凝聚,加强了两相界面作用力。     

动态固化PP/MAH-g-PP/EP共混物的等温结晶动力学

分别用Avrami方程和Hoffman结晶理论研究了马来酸酐接枝聚丙烯(MAH-g-PP)增容的动态固化聚丙烯(PP)/环氧树脂(EP)共混物中PP等温结晶动力学。实验结果表明,动态固化PP/MAH-g-PP/EP共混物中环氧颗粒可作为PP的成核剂,能显著促进PP的结晶。根据Avrami方程,动态固化PP/MAH-g-PP/EP共混物中PP的结晶速率常数K(T)明显大于纯PP的K(T)。依据Hoffman理论研究动态固化PP/MAH-g-PP/EP共混物结晶热动力学,动态固化PP/MAH-g-PP/EP共混物折叠链表面自由能(σe)明显小于PP折叠链表面自由能(σe)。     

DOPO-PHBA反应型阻燃剂的合成及其与TGIC复配体系对环氧树脂性能的影响

以9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物（DOPO）和对羟基苯甲醛（PHBA）为主要原料,合成了一种新型的反应型阻燃剂DOPO-PHBA,利用FTIR和核磁共振谱（¹H-NMR、³¹P-NMR）对其分子结构和组成进行了分析表征。将DOPO-PHBA与异氰尿酸三缩水甘油酯（TGIC）复配用于制备DOPO-PHBA-TGIC/环氧树脂（EP）复合材料,通过极限氧指数（LOI）、动态热机械测试（DMA）和TGA分别对DOPO-PHBA-TGIC/EP复合材料的阻燃性能和热性能进行了研究。结果表明：成功制备了DOPO-PHBA,且DOPO-PHBA-TGIC复配型阻燃剂能显著改善EP的阻燃性能,当体系磷元素的质量分数为0.6wt%时,氧指数（LOI）由24%提高至32.5%;此外不同磷含量的DOPO-PHBA-TGIC/EP复合材料的玻璃化转变温度（T_g）均保持在200℃以上并且在800℃时的残炭量不断提高,其初始分解温度和最大热失重速率均有所下降;燃烧后残炭的红外分析表明,该体系满足凝聚相阻燃机制,且DOPO-PHBA-TGIC的加入不会削弱EP的力学性能。     

Hybrid C/Pet/epoxy composites

Hybrid carbon/PET/epoxy composites were prepared by a wet layup technique and characterized by standard methods of fracture and impact tests. The influence of PET fibre surface treatment with polyfunctional amine on the composite properties has been studied in order to determine the role of the fibre/matrix interface. The state of the fibre/matrix interface has been examined by several techniques, such as SEM, differential scanning calorimetry (DSC) and contact angle measurements. A significant hybrid effect of the PET/aminated fibres on the curing reaction and T _g of the epoxy matrix in the composites was established. It is probably due to the reaction between the amine groups of the fibre surface and the epoxy component of the resin, as determined by DSC.     

Effect of nanoclay and carboxyl-terminated (butadiene-co-acrylonitrile) (CTBN) rubber on the reaction induced phase separation and cure kinetics of an epoxy/cyclic anhydride system

The effects of nano clay, carboxyl-terminated (butadiene-co-acrylonitrile) (CTBN) liquid rubber and the combination of both on the cure kinetics of diglycidyl ether of bisphenol-A (DGEBA)-based epoxy resin/nadic methyl anhydride were studied. Cure kinetics studies were carried out by performing dynamic and isothermal differential scanning calorimetric (DSC) experiments. The dynamic DSC experiments were carried out at four different heating rates. Dynamic kinetic modeling was performed using Kissinger and Ozawa approaches. Since these methods are based exclusively on the maximum rate of cure, which occurs approximately at the beginning of the cure reaction, the activation energy calculated using these methods is valid only for the initial stage of the cure. The clay (3 phr) filled epoxy system has an activation energy 24 % lower than the unfilled system. The role of the surfactant chemistry on the initial stage of the cure reaction was also studied. A plausible reaction mechanism which involves the effect of the nanoclay surfactant as an accelerator of the cure reaction was proposed. The phase separated CTBN rubber hindered the cure reaction and has 3 % higher activation energy for epoxy/CTBN system than the unfilled system. In the ternary epoxy/3 phr clay/15 phr CTBN system, the accelerating effect of clay on cure was highlighted. The cure activation observed in the presence of clay overshadows the hindrance created by the phase separated CTBN. Isothermal DSC scans were carried out at five different temperatures. The experimental datas showed an autocatalytic behavior of the reaction, and the isothermal modeling was carried out by Kamal autocatalytic model. The results showed a very good agreement within the whole conversion range for the unfilled and all the filled systems. The evolution of the morphology and phase separation was also studied using optical and scanning electron microscope. Faster cure reaction resulted in smaller phase-separated CTBN particles in epoxy/clay/CTBN ternary system as compared with those observed in epoxy/CTBN binary blend.     

氰酸酯/环氧树脂CE-40体系的固化反应

采用差示扫描量热(DSC)方法计算得到氰酸酯/环氧树脂CE-40体系反应动力学常数,分析了温度和浓度对反应速率的影响,同时结合红外光谱对各温度段发生的反应进行了推断。研究表明,CE-40体系有两个反应温度区——低温区(150℃-180℃)和高温区(200℃-250℃)。低温区是环氧与氰酸酯直接反应,产物为三聚氰酸酯和口恶唑啉,反应速率对浓度敏感,随反应物浓度下降而降低;高温区是低温区的生成物与环氧的进一步反应,主要产物为口恶唑烷酮和异氰酸脲,反应温度决定了反应速率。