低分子量聚噻吩结晶结构研究

用Ruland方法计算了氯仿可溶级分低分子量聚噻吩(PT_1)热处理前后的结晶度。热处理后结晶度及微晶尺寸均有明显提高。测量及计算晶胞参数证明,PT_1在晶态下具有近似平面伸展构象,提出了初步的结构模型。热处理前后的PT_1给出了明确可归属的红外吸收谱带。     

高结晶度氮掺杂介孔TiO2的制备及光催化活性（英文）

以钛酸丁酯为钛源,尿素为氮源,聚丙烯酰胺(PAM)和聚乙二醇(PEG)为复合模板剂,采用溶胶-凝胶法,在氮气和空气气氛中分段煅烧,制得高结晶度氮掺杂介孔TiO2光催化剂.利用X射线衍射、透射电镜、N2吸附-脱附、X射线光电子能谱和紫外-可见漫反射光谱等技术对其进行了表征.结果表明,当PAM和PEG的质量比为1:4时,先在氮气中600°C煅烧,后在空气中500°C煅烧所得样品是锐钛矿相,具有良好的孔隙结构和较高的结晶度,平均孔径为5.11nm,晶粒尺寸为12.5nm,比表面积110.8m2/g.掺杂介孔TiO2的氮主要以取代氮和化学吸附分子γ-N2的形式存在,少量以间隙氮形式存在.氮掺杂使TiO2的能带变窄,吸收带边明显红移,且使光吸收强度显著增大.光催化降解甲基橙实验结果表明,与未掺杂样品相比,氮掺杂介孔TiO2在可见光作用下表现出较高的催化活性.     

高结晶度氮掺杂介孔TiO_2的制备及光催化活性(英文)

以钛酸丁酯为钛源,尿素为氮源,聚丙烯酰胺(PAM)和聚乙二醇(PEG)为复合模板剂,采用溶胶-凝胶法,在氮气和空气气氛中分段煅烧,制得高结晶度氮掺杂介孔TiO2光催化剂.利用X射线衍射、透射电镜、N2吸附-脱附、X射线光电子能谱和紫外-可见漫反射光谱等技术对其进行了表征.结果表明,当PAM和PEG的质量比为1:4时,先在氮气中600°C煅烧,后在空气中500°C煅烧所得样品是锐钛矿相,具有良好的孔隙结构和较高的结晶度,平均孔径为5.11nm,晶粒尺寸为12.5nm,比表面积110.8m2/g.掺杂介孔TiO2的氮主要以取代氮和化学吸附分子γ-N2的形式存在,少量以间隙氮形式存在.氮掺杂使TiO2的能带变窄,吸收带边明显红移,且使光吸收强度显著增大.光催化降解甲基橙实验结果表明,与未掺杂样品相比,氮掺杂介孔TiO2在可见光作用下表现出较高的催化活性.     

茂金属聚乙烯的非等温结晶行为及其动力学研究

为探索分子量和支链含量对聚乙烯非等温结晶过程的影响,选用3组样品:(1)不同分子量的无支链线形聚乙烯;(2)低分子量的支链含量不同的试样;(3)高分子量的支链含量不同的试样.用DSC研究了这3组样品的非等温结晶动力学.结果表明:(1)与支链含量相比,分子量大小对结晶的影响是次要的,但高分子量样品的结晶度比低分子量样品低;(2)支链对聚乙烯的非等温结晶有重要影响,在支化聚乙烯中起决定作用;(3)无论是高分子量试样还是低分子量试样,支化含量增加,聚乙烯的结晶温度、结晶度、结晶动力学以及晶体的熔点等显著降低.     

基于2,6-二甲基萘的杂环聚芳醚酮的合成

由1,5-二(4'-氟苯甲酰基)-2,6-二甲基萘(1)和类双酚单体(2a～2d)通过N—C偶联聚合反应合成了一系列基于2,6-二甲基萘的新型杂环聚芳醚酮(3a～3d).采用FTIR、1H-NMR、DSC、TGA、GPC等手段对聚合物进行结构表征和性能测试,并研究了其溶解性及特性黏数.结果表明,聚合物在室温下易溶于氯仿、DMAc、NMP、吡啶和间甲酚等非质子极性有机溶剂,其氯仿溶液能形成无色透明、韧性较好的膜,特性黏数(ηinh)在0.76～1.40 dL/g范围内.聚合物3b～3d的数均分子量(Mn)和分散指数(PDI)分别在78000～104000和1.66～2.21范围内.该类聚合物的玻璃化转变温度(Tg)均大于280℃,在氮气氛围和800℃时的残余量在53%～69%范围内.该类聚合物在氮气中5%和10%的热失重温度分别在423～440℃和434～467℃范围内.     

两性星形嵌段共聚物的结晶及络合性质

研究了聚苯乙烯(S)-聚环氧乙烷(E)星形嵌段共聚物的结晶及络合性质.结果表明,结晶度随E含量及分子量增大而增大.共聚物熔融后在20℃淬火比0℃淬火的结晶规整,氯仿溶液浇铸的样品比乙苯浇铸的规整.共聚物在甲苯溶液中呈现特殊的介晶现象.紫外吸收光谱表明,它能与苦味酸碱金属盐络合,使不溶于氯仿及甲苯的钾盐或钠盐进入溶液.     

短链支化聚乙烯的合成与表征

合成了两类结构明确的乙烯共聚物, 通过FTIR, GPC, ¹H NMR和¹³C NMR表征了产物的分子结构, 分别研究了分子量和短链支化含量对两类共聚物结晶性能的影响. 采用阴离子聚合制备分子量(M_w)20000~110000、分子量分布为1.1的1,2-结构摩尔分数为7%左右的聚丁二烯. 加氢反应后得到乙烯/1-丁烯模型共聚物的熔点和结晶度随着分子量的增加而下降. 采用茂金属催化剂Et[Ind]₂ZrCl₂催化乙烯与1-己烯共聚合, 制备分子量为100000左右, 共聚单体摩尔分数为0~5.5%的乙烯/1-己烯共聚物, DSC结果表明其熔点和结晶度随着共聚物中1-己烯含量的升高而降低.     

ZIF-8的合成、表征及正己烷吸附性能

以甲醇为溶剂,硝酸锌六水合物为锌源,2-甲基咪唑为有机配体,通过溶剂热法合成了金属有机骨架材料ZIF-8;采用X射线衍射(XRD)、氮气吸附、热重-差热分析(TG-DSC)和扫描电子显微镜(SEM)等方法对ZIF-8样品进行了表征;研究了正己烷在ZIF-8上的液相吸附动力学和动态选择性吸附性能.结果表明,合成的ZIF-8晶体具有方钠石结构,结晶度较高,孔结构主要为0.37~1.10 nm的微孔,BET比表面积为1836 m2/g,孔体积为0.65 cm~3/g.TG-DSC和高温原位XRD分析结果表明,合成的ZIF-8具有良好的热稳定性能.283~313 K时,正己烷在ZIF-8上液相吸附的扩散系数为(2.53~8.88)×10-12cm~2/s,扩散活化能为31.11 k J/mol;308 K时,ZIF-8对正己烷的动态饱和吸附量为187.3 mg/g,由吸附穿透曲线计算得出Thomas速率常数为2.17×10~(-3)m L·min~(-1)·mg~(-1).与5A分子筛相比,ZIF-8对正己烷的吸附容量高出约1倍,液相吸附表观扩散时间常数高出约70%.     

快速增压制备非晶聚乳酸的等温冷结晶行为研究

通过快速增压法(RC)和自然冷却法(CN)分别制备出完全非晶的聚乳酸(PLA)样品,利用差示扫描量热仪(DSC)、偏光显微红外光谱仪(FTIR)和广角X-ray(WAXD)研究了2种非晶样品的初始结构、不同结晶温度下的等温冷结晶行为及最终的微观结构.结果表明,在温度为110、115、125、130、135及140℃下等温结晶时,RC样品的结晶速率明显高于CN样品;WAXD数据显示,结晶完成后RC样品的结晶度明显高于CN样品,但两者最终的晶粒尺寸大小相近,说明RC样品结晶过程中具有较高的成核密度;实验发现,PLA熔体在快速增压过程中很可能形成了某些类似物理老化样品中存在的局部有序结构,这些局部有序结构促进了晶核的形成,使冷结晶速率明显加快,结晶度提高.     

组合法优化Ti掺杂Zn-Al合金薄膜的耐腐蚀性能

应用组合技术, 通过离子束溅射法制备了Zn-Al-Ti合金薄膜材料芯片(其中wAl:wZn=55%:45%(w, 质量分数)), 表征了热处理后薄膜的耐腐蚀性能, 研究了Ti掺杂量对薄膜耐腐蚀性能的影响. 在Ar+5%(φ, 体积分数)H2混合气氛中, 经200 ℃扩散1 h, 再经370 ℃热处理2 h后可以得到高质量的合金薄膜. 通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)分别对热处理后的典型样品进行相结构和形貌表征. 使用电化学方法测试样品的耐腐蚀性能. 结果表明, Ti适量掺杂样品的腐蚀速率明显下降, 其中Ti掺杂量为6.0%(w)的Zn-Al-Ti合金薄膜(94.0%(w) Zn-Al, 其中wAl:wZn=55%:45%)具有最优异的耐腐蚀性能, 其原因在于, Ti适量掺入后晶粒明显细化, 表面更为致密, 且钝化作用增强.     

末端为噻吩基的聚苯乙烯大分子单体的合成及其氧化偶联聚合

以丁基锂为引发剂、四氢呋喃为溶剂 ,在氮气气氛和 - 78℃下进行苯乙烯 (ST)阴离子聚合 ,并加入 3 溴噻吩作为终止剂 ,从而合成出末端含噻吩基的聚苯乙烯 (PST Thp) ,它可以进行氧化偶联聚合 ,是一类新的大分子单体 .在无水三氯化铁作用下 ,PST Thp可以进行均聚反应或与噻吩进行共聚反应 ,共聚反应生成主链刚性、支链分子量分布窄的聚 (噻吩 接枝 苯乙烯 ) (PThp g ST) ,凝胶渗透色谱、红外光谱和吸收光谱证实接枝共聚物的生成     

Effect of synthetic route on structural and morphological properties of poly(thiophene-co-indole)

In this study, homopolymers of polythiophene (PT), polyindole (PIN) and their composites and copolymers were synthesized by chemical polymerization and were characterized by FTIR and UV-spectroscopy, and conductivity measurements. The conductivities of polymers, composites and copolymers were measured by a conventional four probe method at room temperature and different temperatures. Among the products, PT-PIN copolymer which was synthesized at polythiophene conditions revealed the highest conductivity with a value of 0.28 S cm^?1. The thermal properties of the samples were investigated by using thermogravimetric analyses, and it was found that they have quite good thermal stability. X-ray diffraction spectra showed that the amorphous nature of the polymers. Morphological properties of the polymers, composites and copolymers have been investigated by scanning electron microscopy.     

Peptide Chirality Sensing by a Cyclodextrin–Polythiophene Conjugate

A new cyclodextrin–polythiophene conjugate ( CDPT ) has been prepared by attaching permethyl-α-cyclodextrins to polythiophene (PT) through a hexamethylene tether. Circular dichroism spectral examination of CDPT revealed that only a weak positive Cotton effect (Δε=0.1 M ⁻¹ cm⁻¹) was induced at the main band of the PT in dimethyl sulfoxide and similarly weak bisignate signals in pure and aqueous methanol solutions, which indicates that the α-cyclodextrins appended to PT with a long tether are ineffective in inducing a homochiral structure in the PT backbone. Nevertheless, enantiomeric amino acids and dipeptides added to an aqueous methanolic solution of CDPT caused chirality-dependent hypochromic changes in the UV/Vis spectra, which enabled us to sense these species and quantitatively determine the enantioselectivity by observing the difference in absorbance upon interaction with pairs of enantiomers. Enantiomeric d,d /l,l -dipeptide pairs rather than D /L -amino acid pairs were better differentiated in general, the highest dd /ll selectivity of 13.7 being observed for Phe-Phe.     

Photochemical control of photoluminescence property of photoactive polythiophenes

Azobenzene‐functionalized polythiophene derivatives, Poly[4‐((4‐(phenyl)azo)phenoxy)alkyl‐3‐thienylacetate] (alkyl=hexyl and octyl) (P6 and P8) and the copolymers of 3‐hexylthiophene and 4‐((4‐(phenyl)azo)phenoxy)alkyl‐3‐thienylacetate (alkyl=hexyl and octyl) (P66 and P86) were synthesized. The composition, structure, and thermal property of these polythiophene derivatives were fully characterized by NMR, FTIR, GPC, MDSC, and XRD. The structural dependence of the photochromic features and thermochromic behaviors were also investigated by means of photoluminescence and UV‐Vis absorption spectroscopy. The results have shown that the azobenzene substitution renders the homopolymer (P6 and P8) some interesting optical properties that can be modulated by UV light irradiation. In these azobenzene‐modified polythiophenes, the intensity of photoluminescent emission associated with the conjugated polythiophene main chain was found to decrease significantly upon UV irradiation. The finding suggests that the photo‐induced trans–cis isomerization of the azobenzene pendant groups has significant effect on photoluminescent emission. However, the effect becomes less prominent for copolymer P66 and P86 due to the lower content of azobenzene chromophore in the side chain of the copolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1421–1432, 2005     

链解缠结聚对苯二甲酸乙二酯的结晶行为研究

采用冷冻萃取聚对苯二甲酸乙二酯(PET)溶液(0.1～10g/dL7种不同浓度,3种不同性能溶剂)的方法制备了解缠结PET试样.与链相互穿透且缠结的熔体骤冷试样相比,解缠结PET试样的结晶能力明显增强,且随着制样溶液浓度的降低,链间解缠结程度增加,PET的结晶能力逐渐增强,有序结构含量明显增加,但是如果制样溶液浓度太低,溶液中链间距离太大,则又不利于萃取过程中链间的有序堆砌而结晶.采用接触浓度c*附近的溶液,既可确保链间的有效解缠结又有利于链间的有序堆砌而结晶.PET的结晶能力甚至还受制样所用溶剂性能的影响,这是因为溶剂性能影响了溶液中链间的相互作用以及链的解缠结程度.     

红外光谱法研究镍顺丁橡胶分级样品及凝胶的微结构

顺丁橡胶的链结构与其溶液性质和物理性能有密切关系,凝胶的存在往往影响加工和使用性能。付里叶变换红外光谱技术的发展使我们有可能考察顺丁分子链微结构与分子量的关系,研究凝胶与线性分子链结构的差别。     

Self-Adaptive Re-Organization Enables Polythiophene as an Extraordinary Cathode Material for Aluminum-Ion Batteries with a Cycle Life of 100 000 Cycles

Aluminum-ion batteries (AIBs) have attracted great attentions in recent years. Organic materials such as polythiophene (PT) are promising cathode for AIBs. However, the capacity and cyclic stability of conventional organic cathode such as PT are limited by the inadequate degree of reaction and the unstable nature of organic materials. To obtain high-performance organic cathode, a new PT with the ability of self-adaptive re-organization was prepared. During cycling, its molecular chain can be re-organized, and the polymerization mode will change from C_α−C_α (α-PT) to C_β−C_β (β-PT). This change leads to smaller steric hindrance and faster kinetics during ion insertion which can lower the reaction energy barrier and stabilize the molecular structure. Benefited by this, AIBs with this cathode can deliver a specific capacity of 180 mAh g⁻¹ (@2 A g⁻¹) and a superb stability of 100 000 cycles at 10 A g⁻¹. High energy density and power density can also be achieved with this cathode.     

振磨降解制备的低分子量聚氯乙烯形态结构的研究

本文首次通过ＦＴＩＲ和扫描电镜等手段研究了振磨作用对聚氯乙烯（ＰＶＣ）颗粒尺寸、微晶结构、表现密度和增塑剂吸收量的影响。结果表明，该聚合物位于６３５ｃｍ＾－１处结晶吸收谱带的强度随振磨时间的增加而降低，逐步趋于消失。随振磨时间的增加，ＰＶＣ的颗粒尺寸减小，比表面积增加，增塑剂的吸收量增加。通过振磨可以制得用一般化学方法难于制得的超细、低微量含量、易于加工的较低分子量ＰＶＣ。     

2-苯基噻吩的电化学聚合

聚噻吩及其衍生物是一类重要的导电高分子材料,它们具有良好的导电性、高度稳定性以及易于调控的分子链结构．因此,自从人们发现聚噻吩以来,噻吩类化合物,尤其是3-取代噻吩的聚合和表征一直受到人们的广泛关注[1,2]．相对而言,关于2-取代噻吩的聚合几乎还是空白,以往人们对其进行电化学聚合的尝试是不成功的[3]．     

In-situ Microscopic FT-IR Spectroelectrochemical Investigation of Polythiophene Film Modified Electrode

ＩｎｔｒｏｄｕｃｔｉｏｎＰｏｌｙｔｈｉｏｐｈｅｎｅｉｓａｃｏｎｄｕｃｔｉｖｅｐｏｌｙｍｅｒｗｉｔｈｓｔａｂｌｅ ｐｒｏｐｅｒｔｉｅｓａｎｄｖａｒｉｏｕｓｓｔｒｕｃｔｕｒｅｓ ,ｗｈｉｃｈｉｓｉｎｐｒｏｓｐｅｃｔｏｆｂｅｉｎｇｕｓｅｄｉｎｍａｎｙｆｉｅｌｄｓｓｕｃｈａｓｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌｓ ,ｏｒｇａｎｉｃｓｅｍｉｃｏｎ ｄｕｃｔｏｒｓ ,ｃｏｒｒｏｓｉｏｎｉｎｈｉｂｉｔｏｒ ,ａｎｄｅｎｅｒｇｙｒｅｓｅｒｖｅｅｔｃ .Ｍｅａｎｗｈｉｌｅ ,ｐｏｌｙｔｈｉｏｐｈｅｎｅｉｓａｌｓｏａｍｏｄ ｅｌｏ…