嵌段聚氨酯脲的形态与性能——软链段结构和分子量的影响

合成了不同软链段长度的聚醚型、聚酯型嵌段聚氨酯脲弹性体,以及聚醚-聚酯软链段聚氨酯脲弹性体(PUU)。借助SEM、DSC以及拉伸试验机分析其结构、形态对力学性能的影响。研究表明,相分离程度随软链段分子量的提高而提高。在软链段分子量相同时,聚醚为基础的PUU的相分离程度较聚酯为基础的PUU高。以聚醚-聚酯为软链段的PUU呈现了聚醚型和聚酯型PUU的各自形态,有较大的相区尺寸和较明显的相界面。力学性能数据证实了形态研究的结果。     

(乙交酯-ε-己内酯)共聚酯为软段嵌段聚酯氨酯的合成、表征以及生物降解性

以辛酸亚锡为催化剂,1,4-丁二醇为引发剂,通过开环聚合,合成了双端为羟基,不同分子量、不同配比的(乙交酯-ε-己内酯)共聚酯。用红外、核磁、端基滴定、DSC等手段,对其组成、端基结构、分子量及热分析性能进行了测定,并进一步合成了以共聚酯为软段,4,4’-二苯甲烷二异氰酸酯-1,4-丁二醇链节为硬段的嵌段聚酯氨酯,进行了物性测定与体外降解试验,着重讨论了软段组成与分子量对嵌段聚氨酯性能的影响。     

扩链剂对水性聚氨酯乳液的影响

通过自乳化聚合引入低分子扩链剂制得具有嵌段结构的阴离子型水性聚氨酯乳液。研究了不同扩链剂及其用量对聚醚型和聚酯型聚氨酯乳液的影响。结果表明,以乙二醇为扩链剂制得的聚氨酯乳液稳定性较好,且所得的聚酯型聚氨酯涂膜的力学性能也较好,但耐水性较差。扩链剂的最佳用量为2.05%(质量分数)左右。     

具有内皮祖细胞捕获功能的聚氨酯的合成与研究

以聚碳酸酯二元醇(PCDL)为软段,1,6-六亚甲基二异氰酸酯(HDI)为硬段,二羟甲基丙酸(bis-MPA)为扩链剂合成了一种侧链含有羧基官能团的聚碳酸酯型聚氨酯材料。将氨基封端的四代树枝状聚酯大分子共价接枝到聚氨酯的侧链上,脱除树枝状分子表面缩酮保护基后得到了一种新型的侧链树枝化多羟基聚氨酯材料。此聚合物能有效黏附CD133抗体,黏附了抗体的材料可大大提高CD133内皮祖细胞的黏附。这一结果为通过加速血液接触材料表面内皮化来提高其血液相容性提供了可能。     

聚酯型聚氨酯结构与性能关系的研究

本文主要研究了在聚酯型聚氨酯中软链段的组成与分子量对聚氨酯物理及机械性能的影响，对聚酯型聚氨酯结构与性能的关系进行了探讨．     

聚酯型聚氨酯结构与性能关系的研究

本文主要研究了在聚酯型聚酯中软链段的组成与分子量对聚氨酯物理及机械性能的影响，对聚酯型聚氨酯结构与性能的关系进行了探讨。     

示差扫描量热法研究水性聚氨酯的微相分离

合成了一系列水性聚氨酯，考察了软段组成、二羟甲基丙酸(DMPA)含量及不同NCO／OH比值对产物微相分离的影响。实验结果表明：聚醚型水性聚氨酯的微相分离程度高于聚酯型水性聚氨酯。提高DMPA用量，软段玻璃化温度移向低温区，说明体系的微相分离程度加大。随着NCO／OH比值的增大，软段玻璃化温度也移向低温，软硬段的微相分离程度增大。     

PET—PCT共聚酯的微相分离结构

利用核磁共振(1H-NMR.13C-NMR)表征了聚对苯二甲酸乙二醇酯(PET)-聚对苯二甲酸-1,4-环己烷二甲酯(PCT)共聚酯的组成及序列结构;采用高级转矩流变仪和动态力学分析仪研究了共聚酯的动态流变性能和动态力学性能.结果表明:PET-PCT共聚酯为无规嵌段聚合物.其中PCT的实际摩尔含量高于投料比.各链段的数均序列长度与其摩尔含量成正比;共聚酯呈现明显的末端区效应,随PCT摩尔含量的增加,储能模量～频率曲线(G'～W)中,储能模量偏离线性关系的频率移向高频;动态力学分析图谱中出现了两个玻璃化转变温度,说明PET-PCT共聚酯中PET链段和PCT链段是不相容的.呈现微相分离的相态结构.     

DMTDA在聚氨酯弹性体中的扩链性能研究

在聚氨酯弹性体加工成型中必须加入一种兼起扩链和交联作用的固化剂,一般使用的扩链剂是3,3’-二氯-4,4’-二氨基-二苯基甲烷(英文缩写为MO-CA),在本文的研究中,以自制的二甲硫基甲苯二氨(英文缩写为DMTDA)作为扩链固化剂,并考察了它的扩链性能,研究发现:对聚酯型聚氨酯弹性体而言,制备的DMTDA的扩链效果与国外同类产品ETHACURE300的扩链效果相当;而且在邵氏硬度方面,自制的DMTDA要优于ETHACURE300.结果表明:自制的DMTDA可以替代国外同类产品ETHACURE300在聚酯型聚氨酯弹性体中使用.     

硬质聚氨酯泡沫塑料的开发

以废聚酯(瓶)为原料,研究了废聚酯瓶料醇解成芳香族聚酯多元醇的工艺。探讨了聚酯多元醇、泡沫稳定剂、发泡剂及催化剂等原料对硬质聚氨酯泡沫塑料制备的影响。     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has