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1.
以自制的二胺-二(3-胺基苯)-3,5-二(三氟甲基)苯基氧化膦(mDA6FPPO),4,4’-(1,3-苯二醚)二胺( PDODA)和二酐二苯酮四酸二酐(BTDA)进行共聚制得了高耐热高附着力的难溶性聚酰亚胺.测定了其特性粘度为0.414 dL/g;在氮气氛中5%的热分解温度(Td)高达580℃,10%热分解温度(T...  相似文献   

2.
透明、可溶性聚酰亚胺的合成与性能研究   总被引:5,自引:0,他引:5  
采用带有侧基的柔顺性二胺单体3,3′-二甲基-4,4′-二氨基二苯甲烷分别与3,3′,4,4′-二苯醚四羧酸二酐和3,3′,4,4′-二苯酮四段酸二酐共聚,合成了可容于DMF、DMAc、NMP等强权性溶剂的可溶性聚酰亚胺,研究中发现,制备的聚酰亚胺薄膜有一定的透明性,通过和常规聚酰亚胺对比,也有良好的耐热性,热分解温度均在500℃以上。因而作为液晶显示器的光学补偿膜具有实际的应有价值。  相似文献   

3.
以3-氯代邻苯二甲酸酐和间苯二酚为初始原料,研究了反应时间、反应温度对合成3,3'-(间苯)二醚二酐(3,3'-Rs DPA)单体的影响.以邻苯二甲酸酐(PA)为封端剂,将合成的3,3'-Rs DPA与1,4-双(4-氨基苯氧基)苯(TPEQ)、1,3-二氨基苯(MPD)、4,4'-二氨基二苯醚(4,4'-ODA)和1,4-二氨基苯(PDA)发生缩聚反应,经化学亚胺化制备了一系列聚酰亚胺(PI)模塑粉,并对聚酰亚胺的热性能、力学性能进行了表征.结果表明:合成的聚酰亚胺具有良好的热稳定性,其质量损失5%的热分解温度在空气中为525~531℃,在氮气中为526~538℃;玻璃化转变温度(Tg)随着二胺单体刚性的增加从218℃升高到261℃.当二胺单体为PDA时,PI(3,3'-Rs DPA-PDA)具有明显的熔融结晶行为,其熔融温度(Tm)为327℃.良好的耐热性及优异的可加工性能使该聚酰亚胺材料有望用于3D打印技术中.  相似文献   

4.
含羧基活性基团的聚酰亚胺制备和表征   总被引:2,自引:1,他引:1  
合成了一种4,4′-二氨基-4″-羟基三苯甲烷的二胺单体,用该单体分别和芳香性二酐、酯环二酐以及含氟二酐制备了三种含羟基聚酰亚胺,并对其溶解性能和热性能进行了初步研究,发现含羟基二胺单体和含氟二酐生成的聚酰亚胺能溶解在极性非质子溶剂中,且显示出良好的耐热性能,这种聚酰亚胺可通过羧基引入功能基团制备功能性聚酰亚胺。  相似文献   

5.
新型均苯型芳香族聚酰亚胺的研究   总被引:10,自引:3,他引:10  
以二步法制备了一种新型均苯型芳香族聚酰亚胺。测定了聚酰亚胺的预聚体--聚酰胺酸特性粘度(Iυ)随反应时间的变化曲线,聚酰亚胺以N-甲基-2-吡咯烷酮(NMP)中的特性粘度在1.2dL/g左右,玻璃化温度高于250℃,在氧气中失重5%的温度在500℃以上。经红外光谱测定,样品在1780cm^-1和1380cm^-1附近观察到聚酰亚胺的特征峰。  相似文献   

6.
高性能聚酰亚胺树脂热固化过程及热分解机制的研究   总被引:2,自引:0,他引:2  
用高分辨裂解气相色谱-质谱(HR PyGC-MS)研究了以降冰片烯为端基的聚酰亚胺(PMR-Ⅱ)的热固化过程和热分解行为.PMR-Ⅱ预聚体在330~390℃经不同时间(0~20h) 固化后,根据其在315~590℃裂解产物的组成与分布,讨论了聚酰亚胺树脂的热固化和热分解反应机制.  相似文献   

7.
长链聚酰亚胺的制备与表征   总被引:4,自引:0,他引:4  
以长链二胺4,4′-二(4-氨基苯氧基)二苯砜(BAPS)为单体,采用两步法分别与二酐PMDA、ODPA、BPADA合成了3种链长的聚酰亚胺。实验利用GPC监测0.05mol/L聚酰胺酸(PAA)的数均聚合度(Xn)及相对分子质量分布随缩聚时间的变化关系,结果表明该反应为一逐步缩聚反应,缩聚速率随二酐电子亲和性(EA)的递增而增加;与预聚体聚酰胺酸相比,热处理环化得到聚酰亚胺其数均分子质量(Mn)和特性粘度[η]均有所下降,而分布指数(D)增大。此外还利用红外光谱(FTIR)、差分扫描量热法(DSC)、热重分析(TGA)等对聚酰亚胺进行了表征,结果表明聚酰亚胺(PI)的玻璃化温度(tg)和热分解温度(td)随着聚合单元长度的增加而降低。  相似文献   

8.
对由对苯二甲酰氯与二苯醚在常规条件下经傅氏亲电取代反应制得的聚(氧-1,4-亚苯基对苯二酰基-1,4-亚苯基)[聚芳醚酮(PEK)]进行了结构表征与性能研究。PEK的T_g=152℃,T_m=374.1℃,热分解温度T_d=545.9℃。热分解活化能E_d=193.5 KJ/mol,表明该聚合物具有优良的热稳定性。  相似文献   

9.
共缩聚聚酰胺酸和聚酰亚胺的合成与表征   总被引:1,自引:0,他引:1  
以4,4′-二氨基二苯甲烷(MDA)为二胺单体,均苯四甲酸酐(PMDA)和3,3′,4,4′-二苯酮四羧酸二酐(BTDA)为二酐单体,低温溶液聚合生成一种共缩聚聚酰胺酸(PAA).然后亚胺化脱水环化生成共缩聚聚酰亚胺.通过特性粘度([η])、红外光谱(FT—IR)、热重分析(TG)和X衍射分析(XRD)等对聚合物进行了一系列的结构表征和性能测试.FT-IR表明,在1777 cm~(-1)和1723 cm~(-1)处观察到聚酰亚胺特征峰;TG表明.PI的10%热失重温度为568℃;XRD表明,PI的结晶度较低且分子链间距d为0.5069 nm.  相似文献   

10.
质子导电离子交换膜由于其高导电率和优异的化学性质而广泛应用于H2/O2燃料电池,但是全氟化膜的昂贵的价格限制了它的市场应用,为此,研究者尝试生产廉价的代替品,磺化聚酰亚胺就是被人们看好的代替品之一.用3,3′-二磺酸钠基-4,4′-二氟二苯酮和对氨基苯酚为原料合成一种新型芳香族二胺,再将新型芳香族二胺和二酐以间甲酚为溶剂一步法合成一系列具有不同磺化度的聚酰亚胺,从而避免了由聚合物磺化改性引起的聚合物链的交联与降解.用红外吸收光谱和H NMR核磁共振光谱对新型芳香族二胺单体进行了表征,并用红外吸收光谱表征了聚合物.研究了共聚物的组成结构,溶解性,及磺化度对共聚物的影响.结果表明DMF,DMAc,NMP等均是该磺化聚酰亚胺的良溶剂,聚合物粘度随着磺酸基含量的增加而降低.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
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。  相似文献   

15.
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.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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-  相似文献   

20.
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-  相似文献   

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