Synthesis and properties of novel epoxidized soybean oilmodified phenolic resin/montmorillonite nanocomposites

The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites（ESO-M-PR/ CN） was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N^＋（CH3）2C6H5Cl^- , B2MP] was adopted to modify the interface between the organic and inorganic phases. The effect of the nanocomposite structure on its physical and chemical properties was discussed. During the synthesizing process of ESO-M-PR/CN, the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments. Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-M- PR/CN. The thermal and mechanical properties exhibit a significant improvement. The temperature at which a weight loss of 5% occurs increases from 287.1 ℃ to 402.3 ℃. The flexural strength increases by 25%, while the flexural modulus increases by 39%. Moreover, the properties of resin were enhanced by the effect of the inorganic nanoparticles, while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope. The particle size of inorganic montmorillonites in the modified system is less than 100 nm.     

钼多金属氧酸盐催化脂肪酸甲酯环氧化研究

以钼多金属氧酸盐为催化剂,采用非溶剂法,在温和条件下制备环氧大豆油甲酯。在大豆油甲酯质量为20 g、过氧化氢与C=C物质的量比为1.5、催化剂[(C2H5)4N]4Mo8O26摩尔分数为1.50%、反应温度为55 ℃、反应时间为5.0 h的条件下,获得酸值为0.58 mg(KOH)/g、环氧值为3.73%的环氧大豆油甲酯。该方法催化剂易分离,后处理简便、快捷,产物不含无机酸,避免了无机酸对产品性质分析处理带来的影响。     

Mechanical Properties Amelioration of Hybrid Composites by Concomitant Synergy Between Graphene Oxide and Silica Nanoparticles

氧化石墨烯和二氧化硅纳米颗粒协同作用下的

复合材料力学性能改善

Anchalee Duongthipthewa, 杨树明*,王一鸣

（西安交通大学 机械制造系统工程国家重点实验室,西安 710049）

创新点说明：

本文提出将氧化石墨烯和纳米二氧化硅颗粒组成的纳米复合材料作为填充物添加到环氧树脂/碳纤维复合材料体系中,用于提升其机械性能和湿润环境下的抗腐蚀性。

研究目的：

通过实验研究了氧化石墨烯和纳米二氧化硅颗粒组成的纳米复合材料作为填充物对环氧树脂/碳纤维复合材料体系的机械性能增强作用,以及在湿润环境下的抗腐蚀性。

研究方法：

本文通过真空辅助树脂传递模塑（VARTM）方法制备了环氧树脂/碳纤维复合材料样品,同时也通过该方法向复合材料体系中添加了不同分量的氧化石墨烯和纳米二氧化硅颗粒组成的纳米复合填料;通过三点弯曲测试、冲击实验、硬度测试和动态力学分析等方法对所制备样品的弯曲强度、冲击强度、硬度等机械性能进行了测量;通过分别在纯水和盐水中浸泡2周,对样品的吸湿性、烘干后的重量保留和性能保留进行了分析测试。

结果：

实验结果表明,对于添加了氧化石墨烯和纳米二氧化硅颗粒组成的纳米复合材料作为填充物的环氧树脂/碳纤维复合材料体系,其机械性能表现出全面的明显提升,包括弯曲强度、冲击强度、硬度等;纳米二氧化硅分量的提高还会使其性能得到进一步提升;对于含有复合纳米填充物的样品,其暴露在湿润环境中时虽然吸湿度较高,但烘干后重量损失反而较小,而且再次对其机械性能进行测试后发现其性能保留程度也较高;同样的,含有高分量纳米二氧化硅的样品性能表现最优。为探究其增强原理,通过扫描电子显微镜对样品断面进行了分析。

结论：

实验结果显示,复合填充物的存在使整个复合材料体系的机械强度得到提升,其根本原因在于复合填充材料的存在使环氧树脂与碳纤维骨架的结合更加紧密,在收到外力作用时应力得以迅速传递避免累积,扫描电子显微镜的结果也支持该结论。

关键词：复合材料,纳米填充,机械性能,热分析,吸湿性

     

二氧化硅改性环氧树脂胶黏剂性能研究

采用聚氨酯增韧环氧树脂,并利用有机化的纳米SiO2为改性剂制备纳米改性环氧树脂胶黏剂.利用扫描电子显微镜( SEM)观察无机纳米粒子在聚合物基体中的分散性及复合材料的断面形貌,结果表明无机纳米粒子在复合材料中分散性良好,而且聚氨酯在环氧树脂基体中形成了“孔洞结构”.采用电子拉力机、TGA以及介电谱仪等方法测试了复合材料...     

无机胶粘贴CFRP布加固梁火灾后受力性能试验

目前粘贴碳纤维(CFRP)布加固混凝土结构多采用环氧类有机胶,但其软化温度过低,多为60～80℃,用环氧类有机胶粘贴CFRP布加固混凝土结构难以满足耐高温要求.为此,研发了600℃时强度不低于常温强度的无机胶,并用其粘贴CFRP布加固混凝土梁.对4根已进行过火灾下耐火性能试验的加固梁进行火灾后受力性能试验,描述加固梁火灾后受力破坏过程,获得了火灾后受弯承载力试验值和荷载-跨中位移变形曲线,进行了受弯承载力分析,提出正截面承载力计算公式和构件刚度计算方法.试验与分析表明,当CFRP布历经的温度高于300℃时,CFRP布的强度不能充分利用,加固性能有所下降.相关公式计算值与试验结果吻合较好,可用于该类加固梁火灾后正截面承载力和构件刚度的计算.     

环氧树脂/蒙脱土纳米复合材料的制备及性能研究

采用双子季铵盐对蒙脱土进行有机化处理，再与环氧树脂进行插层复合制备了环氧树脂／蒙脱土复合材料、借助XRD和FTIR等手段对改性蒙脱土进行了表征，对复合材料的力学性能进行测试。结果表明，改性使蒙脱土层间距增大，有机蒙脱土的加入改善了环氧树脂基体的力学性能，当有机蒙脱土质量含量为1％时，其弯曲强度、冲击强度等力学性能得到了最大的提高。     

基于桐油的环氧沥青增容剂的合成与表征

以桐油和环氧树脂为原料,通过皂化、酯化和环氧化三步反应制备了环氧沥青增容剂。研究了反应温度、反应时间、催化剂用量和反应物投料比等对各步反应的影响。结果表明:当皂化温度为70 ℃,回流时间为2 h,桐油与氢氧化钠的摩尔比为1∶3.6时,桐油反应转化率为76.3%;当反应温度为100 ℃,反应时间为5 h,环氧树脂与桐油酸的摩尔比为1∶2,环氧树脂与甲苯的质量比为1∶2时,四正丁基溴化铵用量为反应物质量的2.5%时,酯化产物具有较低的环氧值0.544 mol/100 g;环氧化反应的最优工艺条件为:反应温度 60 ℃,反应时间45 min,双氧水与甲酸、桐油酸酯树脂的摩尔比为3∶1∶1,硫酸的用量为桐油酸酯质量分数的1.5%。通过傅立叶变换红外光谱分析并确认了各步目标产物的结构。     

铜、铁席夫碱配合物的合成、晶体结构和性质

为了研究含席夫碱配体配合物的晶体结构及其热稳定性与选择的金属盐之间的关系,使用双2-羟基3-甲氧基苯甲醛缩邻苯二胺（H2L）与CuCl2.2H2O或与无水FeCl3在不同反应体系中反应,并分别得到配合物［Cu（L）（H2O）］·CH3OH（1）和配合物［Fe（L）（N3）（H2O）］·CH3COOC2H5（2）。晶体结构表明1和2均属于单斜晶系,它们分别属于P21和P21/c空间群。1和2都为单核配合物,其中Cu2+和Fe3+分别采取五配位四角锥构型和六配位八面体构型。热重分析研究表明:配合物1在温度达到150 ℃之前是稳定的,显示Cu2+与配位水之间配位能力较强;而对于配合物2,样品稳定温度只能到65 ℃左右,到104 ℃时乙酸乙酯溶剂分子完全失去。1和2热稳定性研究为今后使用该席夫碱配体合成其他配合物提供了一定的参考价值。     

Effect of Epoxy Resin on Mechanical Properties of Metakaolin based Geopolymer and Microscopic Analysis

By using NaOH and Na_2SiO_3 as the activator,the mechanical properties and shrinkage of the geopolymer after incorporation of 0%,10%,20%,and 30% epoxy resin were investigated.The mechanism of epoxy resin toughening metakaolin based geopolymer was analyzed by X-ray diffraction,scanning electron microscopy and Fourier transform infrared spectroscopy.It was shown that with the increases of epoxy resin,the shrinkage performance was obviously improved and the flexural strength increased by 53.5%.The compressive strength of EGP10,EGP20,and EGP30 increased by 49.12%,57.04%,and 65.34% after curing for 28 days,respectively.There were five obvious vibration peaks of 811 cm~(-1),1 000 cm~(-1),1 050 cm~(-1),1 590cm~(-1),and 3 400 cm~(-1) in the geopolymer and the undisturbed metakaolin.More geopolymer gels were formed in the material and the microstructure was more compact.     

应用于凹印版辊的环氧树脂

为了使凹印版辊降低成本、减轻重量、消除环境污染,本文以环氧树脂代替传统的金属材料制作凹印版辊表面材料,研究了环氧树脂固化物的表面硬度及其作为凹印版辊材料的使用性能.结果表明:不同的环氧树脂预聚体和不同的固化剂对其固化物的表面硬度有较大的影响,而不同的无机填料以及无机填料的不同用量对其表明硬度的影响并不明显.用扫描电镜观察其固化物的微观形态发现:纳米SiO2在体系中分散得很好,仍保持了100 nm以下的粒径.但SiO2与环氧树脂的界面结合力不高,致使环氧树脂的硬度没有较大提高.在环氧树脂固化物上进行的激光雕刻和转移印花实验结果表明,选择适当的组成、配比和固化条件,可使环氧树脂固化物达到制作凹印版辊的条件.     

Zn掺杂对SnO_2纳米线的气敏性能的影响

为了提高SnO2纳米线基气敏传感器在实际应用中存在着灵敏度低、选择性差等问题,采用物理热蒸发法制备纯SnO2纳米线和不同质量百分比（7%,8%,9%,10%）的Zn掺杂SnO2纳米线,将制得的气敏基料制备成旁热式气敏元件,应用静态配气法对浓度均为500ppm的无水乙醇蒸汽、CO及CH4分别进行气敏性能测试.实验结果显示,Zn掺杂SnO2纳米线相比纯SnO2纳米线的气敏性能有了明显提高（乙醇提高2.46倍,CO提高13.88倍,CH4提高1.43倍）,并得出无水乙醇气敏性能在工作温度为280℃最高,CO,CH4在300℃最好.当Zn的掺杂比例为质量百分含量为9%时,各种比例材料所制成的气敏元件气敏性能最高.     

Structural characteristics and properties of polyurethane modified TDE-85/MeTHPA epoxy resin with interpenetrating polymer networks

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate（TDE-85）/methyl tetrahydrophthalic anhydride （MeTHPA） epoxy resin was modified with polyurethane（PU） and the interpenetrating polymer networks（IPNs） of PU-modified TDE-85/MeTHPA resin were prepared. The structural characteristics and properties of PU-modified TDE-85/MeTHPA resin were investigated by Fourier transform infrared（FTIR） spectrum,emission scanning electron microscopy（SEM） and thermogravimetry（TG）. The results indicate that epoxy polymer network （Ⅰ） and polyurethane polymer network （Ⅱ） of the modified resin can be obtained and the networks （Ⅰ） and （Ⅱ） interpenetrate and tangle highly each other at the phase interface. The micro morphology presents heterogeneous structure. The integrative properties of PU-modified TDE-85/MeTHPA epoxy resin are improved obviously. The PU-modified TDE-85/ MeTHPA resin’s tensile strength reaches 69.39 MPa,the impact strength reaches 23.56 kJ/m,the temperature for the system to lose 1% mass （t1%） is 300 ℃,and that for the system to lose 50% mass （t50%） is 378 ℃. Compared with those of TDE-85/MeTHPA resin,the tensile strength,impact strength,t1% and t50% of the PU-modified resin increases by 48%,115%,30 ℃,11 ℃,respectively. The PU-modified TDE-85/MeTHPA resin has the structure characteristics and properties of interpenetrating polymer networks.     

隔热环氧树脂的研究及其在电缆桥架上的应用

选用导热系数很小的无机填料和增韧效果好的石棉纤维对环氧树脂进行填充改性；采用硅烷偶联剂对无机填料和石棉纤维进行表面处理，提高无机填料与聚合物基体的界面相互作用；用自行设计的方法测试材料的隔热性能，结果表明：导热系数小的无机填料明显地改善了环氧树脂复合材料的隔热性能，石棉纤维极大地提高了环氧树脂的冲击韧性，环氧树脂复合材料做成的电缆桥架已投入试运行，并且运转效果良好．     

AA/AMPS接枝环氧树脂E-44的水性化改性研究

为改善环氧树脂E-44的水溶性,以丙烯酸（AA）和2-甲基-2-丙烯酰胺基-丙磺酸（AMPS）为接枝共聚的单体对环氧树脂进行水性化改性.研究了引发剂、不同单体及比例和反应条件对接枝共聚物水分散稳定性的影响并通过红外光谱对产物进行了表征.结果表明,以2.71 wt％的BPO为引发剂、以体积比1∶1的无水乙醇-乙二醇单甲醚为混合溶剂,在接枝共聚反应温度110℃,下用质量比为1∶1的AA/AMPS对等质量的环氧树脂E-44进行改性,得到的改性环氧树脂水性化改性效果最好,乳液离心稳定性和贮存稳定性最高.     

Mechanical behavior and failure mechanism of 2.5D (shallow bend-joint,deep straight-joint) and 3D orthogonal UHWMPE fiber/epoxy composites by vacuum-assistant-resin-infused

Ultra-high molecular weight polyethylene(UHMWPE) fiber/epoxy composites were fabricated by a vacuum assisted resin infused(VARI) processing technology. The curing condition of composites was at a cure temperature of 80 ℃ for 3h in a drying oven. The characteristics of 2.5D(shallow bend-joint and deep straight-joint) structure and 3D orthogonal structure were compared. The failure behavior, flexural strength, and microstructures of both composites were investigated. It was found that the flexural property was closely related to undulation angle θ. The flexural strength of 3D orthogonal structure composite was superior to the other two structures composites with the same weave parameters and resin.     

Strength of copolymer grouting material based on orthogonal experiment

Using the orthogonal experimental design method involving three factors and three levels, the flexural strength and the compressive strength of copolymer grouting material were studied with different compositions of water-cement ratio (mass fraction of water to cement), epoxy resin content, and waterborne epoxy curing agent content. By orthogonal range and variance analysis, the orders of three factors to influence the strength, the significance levels of different factors, and the optimized compound ratio scheme of copolymer grouting material mixture at different curing ages were determined. An empirical relationship among the strength of copolymer grouting material, the water-cement ratio, the epoxy resin content, and the waterborne epoxy curing agent content was established by multivariate regression analysis. The results indicate that water-cement ratio is the most principal and significant influencing factor on the strength. Epoxy resin content and waterborne epoxy curing agent content also have a significant influence on the strength. But epoxy resin content has a greater influence on the 7-day and 28-day flexural strength, and waterborne epoxy curing agent content has a greater influence on the 3-day flexural strength and the compressive strength. The copolymer grouting material with water-cement ratio of 0.4, epoxy resin content of 8% (mass fraction) and waterborne epoxy curing agent content of 2% (mass fraction) is the best one for repairing of cement concrete pavement. The flexural strength and the compressive strength have good correlation, and the ratio of compressive strength to flexural strength is between 1.0 and 3.3. Foundation item: Projects(40728003, 40772180, 40802064) supported by the National Natural Science Foundation of China; Project (07JJ4012) supported by the Hunan Provincial Natural Science Foundation of China; Project(20080430680) supported by China Postdoctoral Science Foundation; Project(B308) supported by Shanghai Leading Academic Discipline Project     

Isocyanate-terminated Polyethers Toughened Epoxy Resin:Chemical Modification,Thermal Properties,and Mechanical Strength

The toughening of the diglycidyl ether of bisphenol A epoxy resin with isocyanate-terminated polyethers(ITPE)was investigated.The progress of the reaction and the structural changes during modification process were studied using FTIR spectroscopy.The studies support the proposition that TDI(tolylene diisocyanate)acts as a coupling agent between the epoxy and polyethers,forming a urethane linkage with the former and the latter,respectively.Me THPA-cured ER/ITPs blends were characterized using dynamic mechanical analysis(DMA)and thermogravimetric analysis(TGA).It is indicated the glass transition temperature(T g )of systems was lower than the T g of pure epoxy resin and overfull ITPE separated from the modified epoxy resin and formed another phase at an ITPE-content of more than 10wt%.The thermal stability was decreased by the introduction of ITPE.The impact strength and the flexural strength of the cured modified-epoxy increased with increasing the ITPE content and a maximum plateau value of about 24.03 kJ/m2 and 130.56 MPa was measured in 10wt%ITPE.From scanning electron microscopy(SEM)studies of the fractrue surfaces of ER/ITPE systems,the nature of the micromechanisms responsible for the increases in toughness of the systems was identified.     

磷氮阻燃固化剂对环氧树脂阻燃性能的影响

为了提高环氧树脂固化体系的阻燃性能,以1,3-丙二胺(DPAN)和苯膦酰二氯(PPDC)为主要原料合成一种新型磷氮反应型阻燃固化剂(PPDPA),对合成化合物的组织结构和热性能进行了表征.以不同比例PPDPA为固化剂,制备一系列具有不同磷含量的阻燃环氧树脂,并对其进行热性能分析和阻燃性能测试.结果表明,添加PPDPA的环氧树脂体系的500 ℃残炭明显高于EP/DPAN体系,且残炭表面磷碳层具有明显的发泡现象.当磷的质量分数达到2.12%时,EP-2样品成功通过UL94 V-0阻燃等级测试,LOI值达到28.3%,PPDPA在环氧树脂材料中表现出了良好的阻燃性能.     

环氧树脂涂料的水溶性改性

利用丙烯酸环氧树脂的接枝共聚反应制备了环氧-丙烯酸自乳化自交联水性防腐乳液。研究了反应温度、反应时间、环氧树脂相对分子质量、合成树脂的酸值、引发剂浓度、溶剂、中和剂等对合成树脂水乳液稳定性及单体转化率的影响。实验结果表明,合成环氧-丙烯酸树脂选用的共溶剂是质量比为2∶3的乙二醇单丁醚与正丁醇,用相对分子质量大于2 900的环氧树脂,合成树脂的酸值80 mg(KOH)/g(固体)以上,过氧化苯甲酰用量为接枝单体量的6%,在120℃反应5 h。用N,N-二甲氨基乙醇和水混合液中和,中和度为70%~80%,pH值为7.5~8.5,制得水分散乳液。在该条件下所制得的乳液的固含量为20%~40%,并且乳液的储存、稀释、机械和冻融等稳定性好。     

端异氰酸酯基聚醚接枝环氧树脂的性能研究

合成了端异氰酸酯基聚醚（ITPs）改性双酚A型环氧树脂，通过红外光谱（IR）、动态热机械分析（DMA）研究了ITPs和EP之间的化学反应及改性环氧树脂酸酐固化体系的热性能，并测试了固化体系的力学性能。结果表明：ITPs作为枝链接枝到环氧树脂上：随着加入ITPs质量分率增加，其固化体系的冲击强度和弯曲强度上升，当ITPs含量为10％时，两者达到最大值：动态热机械分析（DMA）结果表明改性环氧树脂固化体系的玻璃化转变温度（Tg）随ITPs的含量增大而降低：当ITPs质量分率大于15%时，过量的ITPs与改性环氧树脂会形成相分离。