含间苯基聚醚醚酮酮的合成与性能研究

含间苯基聚醚醚酮酮的合成与性能研究林权，王一凡，张万金，吴忠文，尹玖梅（吉林大学化学系，长春，１３００２３）（中国科学院长春应用化学研究所）关键词聚醚醚酮酮，间苯基，熔点，玻璃化转变温度聚芳醚酮类高聚物具有优异的热、电、机械性能．全对苯基位聚醚醚酮酮...     

酞侧基聚芳醚酮的热学性能

酞侧基聚芳醚酮的热学性能谢红卫，李滨耀（中国科学院长春应用化学研究所长春１３００２２）关键词酞侧基聚芳醚酮，ｐｖＴ行为，导热系数，定压比热容酞侧基聚芳醚酮（ＰＥＫ－Ｃ）具有较高的玻璃化转变温度，其流变加工性能和力学性能已被广泛研究［１～３］，被证明是...     

含不同取代基的Cardo聚芳醚酮──合成与表征

含不同取代基的Ｃａｒｄｏ聚芳醚酮──合成与表征王忠刚,陈天禄,徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词Ｃａｒｄｏ聚芳醚酮,合成与表征,自由体积,玻璃化转变温度酚酞型Ｃａｒｄｏ聚芳醚酮（ＰＥＫ－Ｃ）是长春应化所合成的一种新型高一Ｔ,...     

氢键型聚芳醚酮共聚物的合成与表征

氢键型聚芳醚酮共聚物的合成与表征王忠刚，陈天禄，徐纪平（中国科学院长春应用化学研究所长春１３００２２０）关键词氢键，聚芳醚酮，合成，表征高分子链之间的氢键相互作用可以有效地提高聚合物的性能［１，２］．本工作通过共聚反应，在酚酞型聚芳醚酮ＰＥＫ－Ｃ分子...     

酞侧基聚芳醚酮的撕裂不稳定性

酞侧基聚芳醚酮的撕裂不稳定性韩艳春，杨宇明，李滨耀，冯之榴（中国科学院长春应用化学研究所长春１３００２２）关键词酞侧基聚芳醚酮，撕裂不稳定性，延性撕裂由Ｐａｒｉｓ等［１］根据弹塑性断裂理论发展的撕裂模量理论是表征延性材料失稳的重要理论之一。当裂纹扩展...     

分子结构对聚芳醚酮薄膜透气性的影响

分子结构对聚芳醚酮薄膜透气性的影响王忠刚，陈天禄，徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词聚芳醚酮，气体分离膜，结构－性能关系为了改善聚合物薄膜的透气性能，开发具有高透气性和高选择性的膜材料，人们对膜分子结构与透气性能间的关系进行...     

低温溶液缩聚合成聚芳醚酮酮的研究

低温溶液缩聚合成聚芳醚酮酮的研究宋才生，蔡明中，周丽云（江西师范大学化学系南昌３３００２７）关键词低温溶液缩聚，付一克或化反应，聚芳醚酮酮，二苯醚聚芳醚酮酮（ＰＥＫＫ）是一种新型的热塑性耐热高分子材料，具有优异的机械力学性能，耐溶剂抗化学腐蚀性能，抗...     

主链芳香型刚性链聚醚酮（砜）分子结构与其热性能的研究

通过模型化合物ＡｒＯＡｒＣＯＡｒＡｒＣＯＡｒＯＡｒ（Ａｒ为苯基或１，４－亚苯基）的全优化模型，得到芳环之间的平均二面角为３７．５°，由其结构参数建立了刚性链聚芳醚酮（砜）类均聚物分子结构与其熔点及玻璃化温度的关系式，据此较好地了预测了新品种均聚物的热性能。     

几种Cardo聚芳醚砜膜的气体透过行为

几种Ｃａｒｄｏ聚芳醚砜膜的气体透过行为王忠刚，陈天禄，徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词Ｃａｒｄｏ聚芳醚砜，膜，气体分离近年来的研究结果表明：同时增加聚合物的自由体积和限制分子链的链段活动性可以同时改善聚合物的气体透过系数和...     

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究李刚，殷敬华，李滨耀（中国科学院长春应用化学研究所，长春，１３００２２）关键词酞侧基聚芳醚砜，热致性液晶高聚物，原位复合材料，对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物将热塑性树脂与热...     

聚醚醚酮酮（PEEKK）－含联苯聚醚醚酮酮（PEBEKK）共聚物的T_g和T_m转变

不同联苯含量的ＰＥＥＫＫ－ＰＥＢＥＫＫ共聚物的ＤＳＣ结果表明，随着联苯含量的增加，共聚物的玻璃化转变温度几逐渐升高；共聚物的熔点Ｔｍ明显地依赖于联苯含量，当联苯含量ｎＢ＝０．３５时，Ｔｍ值最４小。热处理可以显著地改善共聚物的结晶性，并出现熔融重结晶双峰。     

Metastability release of the form alpha of trehalose by isothermal solid state vitrification

Kinetic investigations of the polymorphic form alpha of anhydrous trehalose have been performed below its apparent melting temperature (Tm) by differential scanning calorimetry (DSC) and X-ray diffraction. The results reveal a spontaneous isothermal vitrification process which indicates that the phase alpha is in a very unusual superheating situation. This behavior has been attributed to the fact that the effective melting temperature (Tm(eff)) of the phase alpha is likely to be located far below the glass transition temperature (Tg) of this compound. The high viscosity of the liquid trehalose between Tm(eff) and Tg is thus invoked to explain the long lifetime of the phase alpha in this temperature range.     

Progress of Polymerization of D,L-Lactide Through Differential Scanning Calorimetry and Gel Permeation Chromatography

Melt polymerization conditions for D,L-lactide initiated with tetraphenyltin were studied with regard to polymer molecular weight. The present study was undertaken to investigate the progress of polymerization of D,L-lactide through differential scanning calorimetry (DSC), and also to explore the correlation between melt polymerization conditions and molecular weight. The physical characteristics, such as glass transition temperature (Tg) of the polymer and melting transition (Tm) of D,L-lactide are correlated with GPC data. DSC data shows that the Tm of D,L-lactide is 122.8 at 150°C polymerization time. ΔHf is 83.2 J g-1, and Tg of polymer is untraceable. At 180°C the Tm is 101.4°C, ΔHf is 34 J g-1, and Tg is around 29.5°C. The drop in Tm and ΔHf clearly shows the conversion of D,L-lactide to polymer. The maximum increment to molecular weight of polymer is achieved at 160°C and 8 h. After a short induction period, the slow polymerization of D,L-lactide resulted in maximal molecular weight followed by an almost constant value of molecular weight. This revised version was published online in July 2006 with corrections to the Cover Date.     

反气相色谱法研究结晶聚合物的结晶行为

 :采用反气相色谱法(IGC)测定了结晶聚合物聚乙二醇(PEG)的熔点和结晶度,探讨了探针分子的性质、固定相中聚合物的涂布量对测定结果的影响,同时与热分析(DSC)方法测得的结果作了比较。结果表明,IGC法测定结晶性聚合物熔点和结晶度是一种非常实用可靠的技术,其优点在于并不依赖100%纯结晶聚合物的性质,PEG的熔点测得值为67℃,结晶度为89.7%,测定结果与DSC法的测得值(Tm=67.9℃,Xc=90.6%)相近,所测定的结果与探针分子的性质无关,但受PEG在担体上的涂布量的影响显著。     

Melting and Annealing Peak Temperatures of Poly(butylene succinate) on the Same Hoffman-Weeks Plot Parallel to Tm=Tc Line

The crystallization and melting behavior of polymers is of theoretical importance. In this work, poly(butylene succinate)(PBS) was selected as an example to study such behavior at low supercooling via introduction of the extended-chain crystal(ECC) of the same polymer as nucleating agent. The crystallization of PBS with its ECC as nucleating agent in a wide temperature range(90–127 °C) and the following melting behavior were studied. It is revealed that the melting point(T_m, for T_c≥113 °C) and the annealing peak temperature(T_a, for T_c=90–100 °C) show similar asymptotic behavior. Both T_m and T_a approach to a value of ca. 3.3 °C higher than the corresponding T_c when the crystallization time tc approaches the starting point. That is to say, the Hoffman-Weeks plot is parallel to T_m=T_c line. The crystallization line became parallel to the melting line when PBS was crystallized at T_c higher than 102 °C. Based on these results, we propose that the parallel relationship and the intrinsic similarity between the T_a and the T_m observed at the two ends of the T_c range could be attributed to the metastable crystals formed at the beginning of crystallization.     

偶氮型液晶冠醚的合成与表征

以4'-正烷氧基联苯-4-甲酸和顺(反)-4,4'-双(4-羟基苯基偶氮)二苯并-14-冠-4为中间体, 通过溶液缩合反应, 合成了一系列偶氮型液晶冠醚. 并用元素分析、核磁共振、紫外可见分光光度计、红外光谱、基质辅助激光解析电离飞行时间质谱、示差扫描量热法和偏光显微镜对其进行了表征. 随分子末端烷氧基碳原子数增加, 化合物4I和4II的熔点(T_m)和液晶态的清亮点(T_i)逐渐降低, 液晶态温度范围较宽.     

Temperature-sensitive nonionic vesicles prepared from Span 80 (sorbitan monooleate)

Different types of nonionic vesicles were prepared from commercial Span 80 (also called sorbitan monooleate), as an inexpensive, biocompatible alternative to conventional phospholipid-based vesicles (liposomes). The vesicles were characterized by different techniques and comparison was made with vesicles formed from POPC (1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine) or DOPC (1,2-dioleoyl- sn-glycero-3-phosphocholine). Dynamic light scattering measurements, electron microscopy analyses, and two types of fusion assays indicate that Span 80 vesicles are stable for at least 7 days at 4 or 25 degrees C, while storage at 42 degrees C causes irreversible vesicle fusion. This indicates that Span 80 vesicles are thermoresponsive with vesicle fusion occurring at elevated temperature. This property may be related to headgroup dehydration and is certainly not directly linked to the phase transition temperature (Tm) of the vesicles, since the Tm is below -30 degrees C, as determined by differential scanning calorimetry (DSC). The measured Tm value for Span 80 vesicles is lower than in the case of DOPC or POPC, correlating with a higher fluidity of Span 80 vesicles as compared to POPC or DOPC vesicles, as determined with DPH (1,6-diphenyl-1,3,5-hexatriene) as fluorescent membrane probe. High fluidity correlates with increased leakage of entrapped water-soluble dye molecules. Addition of cholesterol and soybean phosphatidylcholine lowers the extent of leakage, allowing a tuning of the bilayer permeability.     

SYNTHESIS OF LIQUID CRYSTALLINE COPOLYESTERS WITH T-SHAPED TWO-DIMENSIONAL MESOGENIC UNIT AND CROWN ETHER CYCLE

A novel series of liquid crystalline copolyesters with T-shaped two-dimensional mesogenic unit and crown ether cycle of cis-4,4′-bis(4-hydroxyphenylazo)dibenzo-18-crown-6 was prepared via solution condensation polymerization from 4,4′-(α,ω-hexanedioyloxy)dibenzoyl dichloride(M_1),2-(4′-ethoxyphenyl)hydroquinone(M_2)and cis-4,4′-bis(4- hydroxyphenylazo)dibenzo-18-crown-6(M_3).The molecular weights of copolyesters are not high,and the intrinsic viscosity [η]of copolyesters ranges from 0.29-0.43.The monomer...     

热历史对尼龙1212熔融行为的影响

利用DSC方法研究了不同热历史条件对尼龙1212熔融行为的影响.不同的热历史条件下,在DSC曲线上,观察到尼龙1212产生2个或3个熔融峰,依据聚合物结晶理论,对各峰的来源进行了分析.在160℃下不同温度退火120 min的尼龙1212样品DSC曲线上,低温结晶熔融峰主要由低温结晶形成的一些微晶体或者片晶熔融产生,其晶体完善程度较差,熔融峰值较低,峰面积较小;主熔融峰是由样品在淬火过程中形成的晶体和升温过程中低温结晶形成的晶体的熔融重结晶形成较为完善的晶体熔融所产生,熔融峰值较高,峰面积较大.在不同的升温速率条件下,熔融峰温度有所移动,表明不同升温速率条件下产生的熔融峰的结晶晶型是相同的.在不同结晶时间下结晶,延长结晶时间对较高完善程度晶体的生长有利.在不同温度下依次退火处理的样品,熔融产生两个附加峰,这两个附加峰的峰温都比它们相应的退火温度高,而峰高和峰面积随退火温度降低而减小.根据等温结晶结果,由Hoffman方法确定了尼龙1212的平衡熔融温度为202.8℃.     

Predicting melting temperature directly from protein sequences

Proteins of both hyperthermophilic and mesophilic microorganisms generally constitute from the same 20 amino acids; however, the extent of thermal tolerance of any given protein is an inherent property of its amino acid sequence. The present study is the first to report a rapid method for predicting Tm (melting temperature), the temperature at which 50% of the protein is unfolded, directly from protein sequences (the Tm Index program is available at http://tm.life.nthu.edu.tw/). We examined 75 complete microbial genomes using the Tm Index, and the analysis clearly differentiated hyperthermophilic from mesophilic microorganisms on this global genomic basis. These results are consistent with the previous hypothesis that hyperthermophiles express a greater number of high Tm proteins compared with mesophiles. The Tm Index will be valuable for modifying existing proteins (enzymes, protein drugs and vaccines) or designing novel proteins having a desired melting temperature.