新型冷拌冷铺沥青混合料路用性能研究

为了提高普通乳化沥青混合料的路用性能,将乳化沥青与水性环氧树脂有机结合,得到一种新型复合材料——水性环氧乳化沥青。通过试验研究水性环氧树脂用量对混合料的力学强度、水稳定性以及温度稳定性的影响。结果表明：混合料的初期强度、后期强度以及高温稳定性随着水性环氧树脂用量的增加而提高,但其水稳定性和低温稳定性随着水性环氧树脂用量的增加先增大后减小,分别在水性环氧树脂用量为10%和15%时达到最佳提升效果。在实际工程应用中将水性环氧树脂用量控制在10%~15%之间。     

功能化纳米SiO2-聚醚砜/BMI-酚醛环氧树脂复合材料的固化动力学与性能

以4,4’-二氨基二苯甲烷（DDM）为固化剂、双马来酰亚胺（BMI）和酚醛环氧树脂（F51）为基体、聚醚砜（PES）为增韧剂、硅烷偶联剂KH560功能化纳米SiO₂（KH-SiO₂）为改性剂,采用原位聚合法制备了KH-SiO₂-PES/BMI-F51复合材料,并通过非等温DSC确定了复合材料的固化工艺及固化反应动力学。根据Kissinger方程和Ozawa方程求得体系的表观活化能分别为96.03 kJ/mol和99.18 kJ/mol。FTIR测试结果表明:KH-SiO₂改性效果良好,不饱和双键和环氧基特征峰消失,BMI中C=C双键和F51中环氧基在DDM作用下参与了体系的固化反应。SEM结果表明:PES树脂和KH-SiO₂含量适当时,PES树脂和KH-SiO₂在树脂基体中分散均匀,断裂纹不规则杂乱发展,KH-SiO₂-PES/BMI-F51复合材料呈韧性断裂。力学性能测试和热失重测试表明:当PES含量为4wt%,KH-SiO₂含量为1.5wt%时,KH-SiO₂-PES/BMI-F51复合材料的弯曲强度、弯曲模量和冲击强度分别为156.23 MPa、4.18 GPa和20.89 kJ/m2,较BMI-F51基体分别提高了49.7%、29.4%和82.8%;KH-SiO₂-PES/BMI-F51复合材料的热分解温度为393.1℃,残重率为50%时,分解温度高达523.1℃,耐热性十分优异。KH-SiO₂-PES/BMI-F51复合材料的力学性能和耐热性有了较大提高,为拓展F51及BMI的应用范围提供了一定的理论数据。      

Effect of cure temperature on the structure and water absorption of epoxy/amine thermosets

Dielectric and rheological measurements are reported on the effect of cure temperature on the water absorption of tris[(2,3-epoxypropoxy)phenyl] methane cured with a 1 : 1 stoichiometric ratio of 4,4′-diaminodiphenylsulphone. Analysis of the water absorption characteristics of these materials using a combination of dielectric and gravimetric measurements has indicated that water molecules can be found in two distinctly different types of environments. There are water molecules which are strongly interacting with polar groups and water molecules clustered together into sub-micro-scale cavities within the matrix structure. Changes in the final cure temperature have the effect of changing both the extent and distribution of the types of water molecules present in the matrix. Validation of the diffusion coefficients obtained from the dielectric analysis is based on a comparison with gravimetric data and the implications are discussed. Differences observed between these two different types of measurement are related to peculiarity in the dielectric method and its extreme sensitivity to interfacial phenomena.     

Studies of temperature and time-dependent network formation in commercial epoxy resins using modified imidazole curing agents

Two commercial epoxy resins, MY750 and MY720, were cured over a range of cure temperatures with a series of novel curing agents based on modified imidazoles. A combination of techniques, including dynamic viscometry, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, high performance and gel permeation chromatography, were used to analyse the reaction mixture. It appears that for a given formulation and given resin, the viscosity behaviour near gelation is different for different cure temperatures and the mechanism appears to be dependent not only on the nature of the imidazole curing agent, but also on the cure temperature. Higher temperature cure appears to lead to the formation of a less ‘homogeneous’ reaction mixture at the gel point, containing oligomeric chain lengths of higher polydispersity, whereas in the lower temperature cure, oligomers of a smaller range of chain lengths are present.     

Strengthen flame retardancy of epoxy thermoset by montmorillonite particles adhering phosphorus-containing fragments

Phosphaphenanthrene derivative tri-(3-DOPO-2-hydroxypropan-1-yl)-1,3,5-triazine-2,4,6-trione (TGD) and organo-modified montmorillonite (OMMT) were jointly introduced into the diglycidyl ether of bisphenol A cured by 4,4-diamino-diphenylmethane (EP) to investigate their flame retardant behaviors. With only addition of 0.5%OMMT and 2.5%TGD, epoxy thermoset achieved a limiting oxygen index value of 33.7% and passed UL 94 V-0 rating test. Compared with the combustion behaviors of 3%OMMT/EP and 3%TGD/EP, an obvious synergistic flame retardant effect between OMMT and TGD can be concluded in OMMT/TGD/EP. Meanwhile, the FTIR spectra of gas-phase and condensed-phase products further proved this synergistic effect working in a physical way. On one hand, the co-existence of hydroxyl-containing TGD enabled montmorillonite (MMT) particles to filtrate and adhere more smoke fragments. On the other hand, the co-action of MMT help the polar phosphorus-containing fragments from TGD better strengthened char layer, enhancing the barrier and protective effect of residue. The synergistic flame retardant effect from OMMT/TGD system endowed themselves with higher flame retardant efficiency, and epoxy thermoset with better flame retardant performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47500.     

碳纳米管的氨基化对环氧树脂力学性能的影响

研究了三乙烯四胺(TETA)修饰的多壁碳纳米管(MWNT)对环氧树脂(EP)/MWNT复合材料力学性能的影响。结果显示,氨基化的短MWNT表面的TETA含量较高,修饰效果较好,在EP中分散性较好。添加1%左右的氨基化短MWNT复合材料的冲击强度、断裂伸长率、拉伸强度和弯曲强度较纯EP分别提高了163%、345%、80%和31%;氨基化的长MWNT比短MWNT复合材料的冲击强度和断裂伸长率分别高18.4%和10.2%;拉伸强度和弯曲强度则分别低4.2%和5.3%。     

紫外光固化环氧丙烯酸酯涂料的研究

合成了适于配制紫外光固化涂料的环氧丙烯酸酯,重点研究了反应温度对环氧树脂与丙烯酸反应的影响,并利用红外光谱观察了产物的结构,以及不同活性剂、辐射时间对固化涂膜性能的影响。     

Improvement of the electrical resistivity of epoxy resin at elevated temperature by adding a positive temperature coefficient BaTiO_3-based compound

The DC electrical resistivity-temperature characteristic is an important property for insulating materials to operate at a high stress level. In order to improve the DC electrical resistivity at elevated temperature in a targeted way, a positive temperature coefficient(PTC) material(Ba Ti O3-based compound(BT60)) was selected as the filler in this paper, whose electrical resistivity has a PTC effect when the temperature exceeds its Curie temperature. The BT60 was treated with hydrogen peroxide and(3-Aminopropyl) triethoxysilane. Epoxy composites with different loadings of BT60 fillers(0 wt%, 0.5 wt%, and 2 wt% of epoxy) were prepared, denoted as EP-0, EP-0.5, and EP-2. It was shown that BT60 was able to maintain the DC breakdown strength when its loading was less than 2 wt% of epoxy. As the temperature exceeds 60 °C,BT60 will compensate for the negative temperature coefficient effect of epoxy resin to some extent. The electrical resistivity of EP-2 was improved by 55% compared with that of neat epoxy at 90 °C. It was found that the potential barrier at the grain boundary of BT60 and the deep traps in the interface between BT60 and the epoxy resin hinder the migration of carriers and thus increase the electrical resistivity of epoxy composite.     

球形石英粉的制备方法及性能表征

文章介绍了球形石英粉的制备方法,分析得出了火焰法工艺简单最易实现工业化生产的结论,对球形石英粉的性能参数进行了阐述,通过实验对比了国产球形石英粉和进口石英粉对环氧模塑料性能的影响。     

废旧线路板中环氧树脂的辐射接枝改性

对废旧印刷线路板（PCB）上的环氧树脂粉末进行辐射接枝改性。通过IR证明了与顺丁烯二酸酐的反应的确发生,从而环钒树脂粉末得到了活化;并探索了辐射剂量对环氧树脂与苯乙烯接枝率的影响。最后得到结论：辐射剂量为12K时环氧树脂粉末、苯乙烯辐射聚合接枝率最大。