纳米SiO_2改性EP/BMI/CE树脂体系固化动力学研究

采用非等温差示扫描量热(DSC)法对纳米二氧化硅/环氧树脂/双马来酰亚胺/氰酸酯(nano-SiO2/EP/BMI/CE)树脂进行了固化反应动力学和固化工艺研究。通过Kissinger法和Ozawa法求得了nano-SiO2/EP/BMI/CE树脂体系固化反应动力学的表观活化能。结果表明:改性CE树脂体系的固化工艺参数为凝胶温度112℃、固化温度195℃及后处理温度213℃,进而确定了改性CE树脂体系的最佳固化工艺条件为"150℃/3 h→180℃/3 h→200℃/2 h";改性CE树脂体系的平均表观活化能为59.90 kJ/mol。     

DDM/EP/CTBN增韧BMI耐高温胶合成工艺研究

以N,N-′4,4′-二氨基二苯甲烷型双马来酰亚胺(BM I)、环氧树脂(EP)、4,4′-二氨基二苯甲烷(DDM)为主要原料,合成了2种以BM I为基体的耐高温胶粘剂,分析了DDM、EP用量对胶粘剂性能的影响。采用差示扫描量热、红外光谱、热重分析表征了产物的反应程度、结构和热稳定性。结果表明,2种工艺都采用mBM I∶mEP∶mDDM=1∶1∶0.85时综合性能最优,在相同的固化条件下,共熔型体系耐高温实验强度(30.07 MPa)优于预聚型体系(27.33 MPa),但耐温冲击实验强度(29.83 MPa)不如后者(31.58 MPa)。     

CTBN对CB/EP基导电复合材料电性能的影响

以低结构CB(炭黑)为导电填料、EP(环氧树脂)为基体、CTBN(端羧基液体丁腈橡胶)为改性剂和2,4-EMI(2-乙基-4-甲基咪唑)为固化剂,采用超声分散法制备CB/EP基导电复合材料.研究结果表明:CB/EP基导电复合材料具有明显的导电渗流行为,其渗流阈值为w(CB)=7.1％;当w(CTBN)=12％时,含CT...     

CE/EP/CF复合材料的湿热性能研究

采用溶液预浸渍法分别制备了两种碳纤维(CF)增强环氧树脂(EP)改性氰酸酯树脂(CE)(CE/EP/CF)复合材料,研究了该复合材料的吸湿行为及湿热环境对其力学性能和微观结构的影响。结果表明,CE/EP基体具有比EP更小的吸湿能力;湿热环境对CE/EP/CF复合材料的纵向拉伸强度影响不大,但对其层间剪切强度的影响较为显著。     

CTBN结合纳米SiO_2改性环氧树脂及增韧机理

以端羧基液体丁腈橡胶(CTBN)结合纳米SiO2(n-SiO2)对环氧树脂(ER)增韧,采用正交法制备了室温固化双组分环氧胶粘剂。通过力学性能测试,红外、示差扫描量热及电镜分析对体系的性能进行了研究。结果表明,环氧树脂与双增韧剂质量比为8∶1,CTBN与n-SiO2质量比为2∶1,甲组分在180℃下反应2.5 h条件下制得的胶粘剂剪切强度、剥离强度、冲击强度分别达到33.85 MPa、5.92 kN/m、18.24 kJ/m2。CTBN和n-SiO2都与ER发生了作用,且双增韧剂增韧的固化产物热稳定性较好。CTBN、n-SiO2、双增韧剂增韧ER的机理分别为颗粒铆钉所诱发的剪切变形机理、银纹钝化机理、剪切变形与银纹钝化相结合形成的韧窝机理。     

基体种类对CTBN改性环氧树脂结构和性能的影响

研究了ＣＴＢＮ对不同种类的环氧树脂（Ｅ－５１、Ｆ－５１）力学性能的影响,通过扫描电镜观察了２种增韧体系的微观结构形态,并探讨了２种增韧体系的微观结构形态与力学性能间的关系。     

环氧树脂增韧改性氰酸酯树脂的研究进展

综述了近年来氰酸酯树脂增韧改性的研究进展,介绍了不同热固性树脂(环氧树脂、双马来酰亚胺)增韧改性氰酸酯树脂的方法以及共聚后具有优异力学、电学、耐水及热稳定性等性能的固化产物,并提出其将在电子产品及航空航天材料等高科技领域得到广泛应用。     

氰酸酯/环氧树脂体系的形状记忆效应研究

以不同配比的CE/EP(氰酸酯/环氧树脂)作为共聚体系制备耐温型SMP(形状记忆聚合物)。采用凝胶时间、红外光谱(FT-IR)和弯曲模型等测试手段,确定了合成CE/EP基SMP的最佳工艺条件和形状记忆行为。研究结果表明:当m(CE)∶m(EP)=1∶0.7、固化工艺为"抽真空/30 min→160℃/60 min→190℃/45 min"时,CE/EP共聚体系可完全固化,并能生成网状交联结构的无定形透明态SMP;此时,该SMP具有良好的形状记忆行为,并且其形状记忆行为的可恢复率相对最大。     

纳米CaCO_3对CE及CE/EP基体的改性研究

通过力学性能测试和扫描电镜、热重分析以及红外光谱测试研究了纳米CaCO3的加入量对氰酸酯(CE)及CE/环氧(EP)基体力学性能及热性能的影响。结果表明,适量的纳米CaCO3的加入,可有效地改善CE或CE/EP基体的韧性和强度。当纳米CaCO3的质量分数为3%时,两改性体系的冲击强度和拉伸模量均达到最大值,CE/EP/CaCO3体系较CE/CaCO3体系具有更高的冲击强度(7.8kJ/m2)和较低的拉伸模量(100.5GPa)。纳米CaCO3的加入有利提高基体的热稳定性,但CE/EP/CaCO3三元体系的热稳定性仍明显低于纯CE或CE/CaCO3二元体系。     

环氧基硅烷改性氰酸酯树脂的性能研究

采用环氧基硅烷(ESi)对双酚A型二氰酸酯树脂(BCE)进行改性,研究了ESi用量对ESi/BCE体系力学性能和动态力学性能等影响。结果表明:适量的ESi可以明显提高BCE的韧性和强度;当w(ESi)=6%时,ESi/BCE改性体系的力学性能最好,其冲击强度和弯曲强度分别从10.1 kJ/m2、94.11 MPa提高到14.49 kJ/m2、110.94 MPa;ESi/BCE体系的交联密度降至适度是其韧性提高的主要原因,并且其玻璃化转变温度(Tg)低于纯BCE体系(但降幅不大)。     

Effect of the addition of aramid-CTBN block copolymer on adhesive properties of cured epoxy resins modified with CTBN

To improve the bond strength of carboxy-terminated butadiene acrylonitrile (CTBN)-modified epoxy resin, aramid-CTBN block copolymer was used as an additive to a bisphenol-A-type epoxy resin modified with CTBN. With the addition of aramid-CTBN block copolymer, the fracture energy values of the adhesive joints were more than twice that of the CTBN-modified system and about twelve times that of the unmodified system. Observations of the adhesive layers using an optical microscope revealed that the width of the damage zone near the crack-tip in the double cantilever specimen increased with the addition of the aramid-CTBN block copolymer. TEM micrographs showed that the diameter of the CTBN-dispersed phases decreased and a number of fine CTBN phases were dispersed in the epoxy matrix with the addition of the block copolymer. It is concluded that addition of the block copolymer leads to an increase in the dispersibility of the CTBN elastomer into the epoxy matrix and thus the bond strength of the block copolymer-added system is increased due to the increase in the area of the damage zone and the occurrence of shear deformation of the epoxy matrix.     

锚固处理对SiO_2/CE复合材料静态力学性能的影响

采用偶联剂SEA-171对纳米SiO2表面进行了处理(M-1),再由偶氮异丁腈对M-1进行锚固表面处理(M-2),对产物进行了红外,元素分析和热失重分析。研究了上述2种纳米SiO2的含量对其氰酸酯树脂复合材料静态力学性能的影响,并采用扫描电镜和透射电镜分析研究了材料界面结构特征,探讨了其作用机理。结果表明,当M-1的添加质量分数为3%时,复合材料的冲击强度增长61.9%;弯曲强度增长44.2%,添加4%M-2时,增幅分别为89.0%和53.8%。经锚固处理后,纳米SiO2颗粒团聚程度减小,在高分子有机相中的分散更加均匀。     

Thermal and dielectric properties of epoxy/DDS/CTBN adhesive modified by cardanol-based benzoxazine

Cardanol-based benzoxazine (Bz-C) was introduced to a ternary resin system to substitute carboxyl-terminated butadiene–acrylonitrile (CTBN) partially and improve the thermal and dielectric properties of the diglycidyl ether of bisphenol-A (epoxy)/4,4′-diaminodiphenylsulfone (DDS)/CTBN adhesive resin system. The effect of Bz-C on the curing behavior of blends was studied, and factors that affect the thermal, mechanical, and dielectric properties were discussed systematically. Results show that reactions between Ep, DDS, and Bz-C decrease the curing temperature of the quaternary blends and increase the cross-linking densities of the network, leading to higher glass-transition temperature and enhanced mechanical properties. The flexibility of the copolymer films was maintained by the introduction of the aliphatic side chain of Bz-C. Substitution of Bz-C for some group of CTBN in the cross-linked network resulted in decreased dielectric constant and dielectric loss in the copolymer films.     

CTBN增韧改性热固性树脂研究进展

综述了活性液体端羧基丁腈橡胶(CTBN)增韧热固性树脂的优势和增韧机理,分别介绍了CTBN在环氧树脂、酚醛树脂、氰酸酯树脂(CE)和双马来酰亚胺树脂(BMI)增韧改性方面的研究现状,分析了目前CTBN增韧热固性树脂存在的问题,并指出了今后增韧体系研究的发展方向.     

端脂肪氨基聚醚改性环氧树脂的性能研究

用自制的一种既含聚醚柔性链段又含苯脂肪氨基刚性链段的端脂肪氨基聚醚(APPEG)作为固化剂对环氧树脂进行增韧改性。扫描电子显微镜和力学性能测试结果表明,固化剂对环氧树脂具有明显的增强、增韧效果,且改性的环氧树脂胶粘剂具有很好的填充性能,填充比高达50%。与羰基铁粉组成的涂层材料具有优异的力学性能和热稳定性能。     

Study on the structure and properties of cyanate ester/bentonite nanocomposites

Cyanate ester (CE)/bentonite (BT) nanocomposites were prepared by melt blending of CE with NH₄⁺‐BT. The nanostructure of CE/BT nanocomposites was studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that partially intercalated and partially exfoliated structures coexisted in CE/BT nanocomposites containing 2.5 wt % BT with respect to that of bulk CE. Below 2.5 wt % BT content, a totally exfoliated and disordered structure was formed in the nanocomposites. The exfoliated BT enhanced the toughness of CE/BT nanocomposites. The impact strength showed a maximum of 7.1kJ/m² at 1 wt % BT, compared to 3.8kJ/m² of pure CE. Furthermore, results of thermogravimetric analysis (TGA) suggest that CE/BT nanocomposites have higher thermal stability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 632–637, 2005     

聚丙烯酸酯液体橡胶增韧环氧树脂体系研究

采用溶液聚合法合成了以丙烯酸丁酯、丙烯酸乙酯、丙烯酸缩水甘油酯为主链的液体橡胶,将其用于增韧改性环氧树脂/间苯二甲胺(EP 828/mXDA)体系,研究了聚丙烯酸酯液体橡胶用量对共混体系的微观形态、力学性能和玻璃化温度的影响。电镜观察显示液体橡胶改性EP828/mXDA的共混物呈海岛结构,连续相为环氧树脂,分散相为液体橡胶。随着丙烯酸酯液体橡胶用量增加,海岛相区的粒径和数量均呈增长趋势。当丙烯酸酯液体橡胶质量分数为15%时,共混物中海岛相区的尺寸为1μm左右,共混体系的冲击强度增加151.8%,玻璃化温度下降11.3℃。以丙烯酸液体橡胶改性EP828/mXDA环氧树脂体系,可以较大程度提高其韧性,同时其耐热性基本保持不变。     

Effect of poly(etherimide) chemical structures on the properties of epoxy/poly(etherimide) blends and their carbon fiber‐reinforced composites

Poly(etherimide)s (PEIs) with different chemical structures were synthesized and characterized, which were employed to toughen epoxy resins (EP/PEI) and carbon fiber‐reinforced epoxy composites (CF/EP/PEI). Experimental results revealed that the introduction of the fluorinated groups and meta linkages could help to improve the melt processability of EP/PEI resins. The EP/PEI resins showed obviously improved mechanical properties including tensile strength of 89.2 MPa, elongation at break of 4.7% and flexural strength of 144.2 MPa, and good thermal properties including glass transition temperature (T_g) of 211°C and initial decomposition temperature (T_d) of 366°C. Moreover, CF/EP/PEI‐1 and CF/EP/PEI‐4 composites showed significantly improved toughness with impact toughness of 13.8 and 15.5 J/cm², respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermophysical properties of CTBN and HTPB liquid rubber modified epoxy blends

Thermal conductivity and diffusivity of carboxyl‐terminated copolymer of polybutadiene and acrylonitrile (CTBN) and hydroxyl‐terminated polybutadiene (HTPB) liquid rubber‐ modified epoxy blends were investigated. A good agreement was observed between the calculated values of the specific heat estimated from thermal conductivity, diffusivity, and density measurements and the DSC results. Measurements of the thermal conductivity values of HTPB/Epoxy blends were in good agreement with three simple theoretical models, which have been used thereafter for the estimation of the unknown value of the thermal conductivity of CTBN (k_CTBN = 0.24 Wm^?1K^?1). The morphology of the rubber‐modified epoxy blends has been quantified and indicate a tendency towards co‐continuous phase upon the inclusion of higher weight percentage of rubber (≥30 wt %). Moreover, we notice a significant enhancement of the thermal conductivity during this morphological shift. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effect of different metallic catalysts on the coreaction of cyanate/epoxy

The curing reaction between the diepoxy and dicyanate mixed resins in the presence of three different catalysts Cu(AcAc)₂, manganese octoate, and copper octoate was investigated. The thermal behavior was monitored using differential scanning calorimeter; the transformations of structures during the isothermal and heating process were explored by Fourier transform infrared spectroscopy; the changes of the carbonic‐framework of polymer and intermediate products were analyzed by nuclear magnetic resonance. Conclusions can be drawn as follows: Similar to noncatalyzed system, the overall reaction still occurs in two steps: cyclotrimerization of cyanate ester to produce triazine rings, coupled with the formation of some secondary intermediate products, and coreaction of epoxy and triazine rings to form oxazolidinone rings at high temperature. The catalysts can accelerate the curing process and decrease the curing temperature as well as gel time, and manganese octoate presents the best effect on curing rate. But the mechanisms and the structures of intermediate products of metallic‐catalyzed epoxy/cyanate are not changed by the addition of catalysts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2293–2302, 2006