酚醛环氧树脂水性化的研究

对酚醛型环氧树脂E-44进行化学改性引入亲水性基团，同时保留尽可能多的环氧基，成盐后制得水性环氧树脂体系。研究了各反应物用量对体系水溶性和水稳定性的影响，确定了最佳的原料配比、反应温度和时间。结果表明：该改性E-44环氧树脂可与水以不同的配比形成水溶液或水乳液，且体系具有优良的稳定性。     

水性环氧树脂的制备及表征

以乳酸和丁二酸酐对双酚A型环氧树脂E-51进行化学改性引入亲水性基团,研究乳酸和丁二酸酐的用量对改性树脂的水分散性、水稳定性及水分散液粒径的影响.确定了最佳的原料配比、反应温度、时间和催化剂;并利用红外光谱对产物的结构进行了表证,动态激光光散射测量水分散液粒径.结果表明:当投料比n(乳酸):n(琥珀酸酐):n(环氧基)在0.15:0.30:1和0.20:0.40:1之间时, 合成的水性环氧树脂具有优良的水分散性、稳定性和较小水分散液粒径.     

二苯基硅二醇改性环氧树脂耐热性的研究

为改善双酚A型环氧树脂的耐热性,采用二苯基硅二醇单体与环氧树脂E-44直接开环加成聚合的方法.以辛酸亚锡作催化剂、4,4'-二氨基二苯基砜(DDS)为固化剂,研究了反应条件和E-44与二苯基硅二醇的物质的量配比对改性产物耐热性能的影响.通过傅立叶红外光谱仪(FT-IR)、动态热机械仪(DMTA)、热失重分析仪(TGA)进行分析,得出最佳反应条件是150℃/2h,配比为3:1时,改性环氧树脂的玻璃化转变温度(Tg)为147.45℃,分解温度(Td)达到490.5℃(热失重50%).实验结果表明:二苯基硅二醇改性可以提高环氧树脂的耐热性能.     

水性环氧固化剂分散体的制备与应用

以聚乙二醇、环氧树脂、三乙烯四胺和单缩水甘油醚为原料,制备了水性环氧固化剂分散体.讨论了固化剂的合成原理和结构,研究了催化剂、反应温度、反应时间和原料配比对水性环氧固化剂合成的影响.催化剂三氟化硼乙醚溶液的最佳用量为2%,最适宜反应温度为60℃,环氧树脂与聚乙二醇合理的物质的量比为2∶1,得到的水性环氧固化剂分散体对防锈颜料、分散剂适应性较强.     

一种水性环氧固化剂的制备与涂膜性能测试

采用环氧树脂(E-51)改性三乙烯四胺(TETA),以单环环氧化合物(AGE)为封端剂,合成了一种水性环氧固化剂。结果表明:在温度为60℃时,物质的量n(E-51)∶n(TETA)∶n(AGE)为1∶0.5∶1时,反应4 h合成的水性环氧固化剂,与自制环氧乳液按1.1:1物料比进行涂膜,其具有硬度高、耐盐雾性强以及耐酸性和流平性好等优点。     

环氧树脂改性三乙烯四胺固化剂的合成及性能研究

采用环氧树脂E44对三乙烯四胺(TETA)固化剂进行改性及其性能的研究。实验结果表明:最佳改性条件为n(AGE):n(E44):n(TETA)=4.5:1:3,反应温度为50℃,反应时间为3h,可制备出水溶性优异,与环氧树脂乳液相容性优良的改性环氧树脂固化剂,其比未改性的三乙烯四胺有优异的物理化学性能和环保性能。该固化剂以水为溶剂,大大降低了制备出的涂料的VOC含量。     

水性环氧丙烯酸接枝共聚物的合成及固化

环氧树脂与丙烯酸类单体接枝共聚是制备水性环氧树脂的一条重要途径.本文作者研究了多元接枝水性环氧树脂的合成,及其与固化剂双氰胺的固化工艺.讨论了单体配比、接枝反应温度、反应时间等因素对水性环氧乳液接枝率的影响,确定了较佳的工艺条件,通过红外光谱分析证实了丙烯酸接枝环氧共聚物的结构,并考察了漆膜的固化条件.所得涂膜附着力、柔韧性、硬度很好,能达到溶剂型环氧树脂防腐蚀涂料水平.     

WPU/WEP共混乳液稳定性研究

初步探索了水性聚氨酯(WPU)与水性环氧树脂(WEP)共混乳液的制备工艺,研究了共混乳液的高温稳定性、机械稳定性、酸碱稳定性和盐稳定性,并通过对共混乳液性能的测试,寻求最佳配比.研究共混体系的含固粒径分布与固化行为和机理,WEP:WPU=3:1,对固化膜进行了TG分析.结果表明:凝胶时间与固化温度、固化剂含量有很大关系,共混物的固化速率受温度的影响很大.     

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2.71wt%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.     

一种水性环氧固化剂的合成与性能研究

合成了一种室温固化水性环氧树脂固化剂.采用聚乙二醇(PEG - 2000),双酚A型环氧树脂(CYD - 128)以及三乙烯四胺(TETA)为原料,将PEG - 2000和CYD - 128在Lewis酸的催化下反应,在固化剂分子中引入亲水性的柔性聚醚链段;用上述产物和低分子量的液体环氧树脂对三乙烯四胺进行改性,同时在固化剂分子中引入了环氧树脂分子链段,以提高固化剂与水性环氧树脂的相容性;加入去离子水,将其稀释至固含量为50%(质量分数)左右,得到一种稳定的无色透明的环氧固化剂水分散体.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with