聚合物薄膜玻璃化转变及其分子松弛行为的研究进展

随着纳米技术的发展,受限聚合物的玻璃化转变以及分子松弛行为受到了高分子物理学家的关注.由于纳米尺度效应,高分子薄膜的玻璃化转变以及分子松弛行为偏离于本体,呈现出尺寸依赖性.研究聚合物薄膜的玻璃化转变及其相关分子松弛行为对聚合物纳米材料的结构设计,进一步理解聚合物玻璃化转变的物理本质具有重要意义.本文总结了近20年来聚合物薄膜玻璃化转变行为的研究成果,介绍了薄膜分子松弛行为偏离本体的主要物理机制、聚合物薄膜分子运动能力的深度分布特征以及薄膜分子松弛行为的相关理论模型,并对该领域研究进行了展望.     

含芳杂环的超支化聚合物的合成与性能研究

在紫外光照射的条件下,以CpCo(CO)2为催化剂,通过3,5-双-(4-炔苯基)-4-苯基-1,2,4-三唑和2,5-双-(4-炔苯基)-1,3,4-(噁)二唑的双炔分别与1-辛炔的[2 2 2]环三聚反应,合成了一类含芳杂环的可溶于普通有机溶剂的新型超支化聚合物.采用红外光谱、核磁共振谱、热失重分析、紫外吸收光谱、荧光光谱、循环伏安法等方法对聚合物进行结构表征和性能测试.结果表明,聚合物具有优异的热稳定性,尤其是含三唑的聚合物热失重5%的分解温度在450℃以上;在800℃时,残余碳化率高达75%.在光激发的条件下,这类聚合物在二氯甲烷溶液中发射深蓝光,其荧光量子效率可达80%.电化学测试结果表明,这类含芳杂环聚合物具有较好的电子传输能力.     

二甲基取代杂环联苯聚芳醚的合成与性能

由自制的二甲基取代类双酚4-(3,5-二甲基-4-羟基苯基)-2,3-二氮杂萘-1-酮(DM-HPPZ)单体和4,4'-二氟二苯酮、4,4'-二氯二苯砜进行亲核缩聚反应,制备了一类新型的二甲基取代聚芳醚酮、聚芳醚砜及其共聚物聚芳醚砜酮树脂材料.在适宜的聚合条件下,获得了高分子量的聚合物,其特性粘度为0.44～0.75DL·g^-1.利用DSC和TGA研究了聚合物的耐热性能,结果表明,新型聚芳醚玻璃化温度高(568～595K),耐热稳定性好(5%热失重温度大于416℃);拉伸强度为45.4～85.0MPa,力学性能优良.新型聚芳醚在氯仿、DMAc等极性有机溶剂中可溶解并浇铸得到透明、韧性高的薄膜.共聚物结合了聚醚酮好的力学性能和聚醚砜高的耐热性的特点,因此综合性能更佳.     

聚醚砜醚酮的合成与性能

以4,4′-二羟基二苯砜和4,4′-二氟二苯酮为单体, 通过溶液缩聚合成了聚醚砜醚酮(PESEK), 其分子结构相当于聚醚砜(PES)与聚醚醚酮(PEEK)的交替共聚物. 在共聚物分子中, 存在砜基、醚基和酮基, 整个结构单元形成了大共轭体系, 聚合物属无定形聚合物, 玻璃化转变温度(Tg)为198 ℃, 介于PEEK和PES的Tg之间, 其热稳定性和加工性能优于PES, 而力学性能与PES接近.     

经由三丁基锡化氢、炔基砜和炔基溴的锡氢化-Stille串联反应“一锅”立体选择合成( Z)-2-砜基取代的1,3-烯炔

炔基砜和三丁基锡化氢在四(三苯基膦)钯催化下于苯中室温下进行锡氢化反应4 h,经溶剂转换成DMF后,再在CuI助催化剂存在下与炔基溴化物于室温进行Stille偶联反应,以良好产率且立体选择性地合成了( Z)-2-砜基取代的1,3-烯炔。该“一锅”合成法具有起始原料易得、反应条件温和、操作简便、钯催化剂利用率高和产率好等优势。     

含氟聚酰胺酸热亚胺化过程的扭辫分析

用扭辫分析(TBA)研究了含氟聚酰胺酸的热亚胺化过程,用聚合物链段运动有利于小分子生成物的扩散,因而对缩合反应发生影响的观点,解释了剧烈的亚胺化反应总是在玻璃化温度以上发生;还观察到亚胺化反应使聚合物链刚性增加,玻璃化温度逐渐由120℃升高到310℃。因而提出了分段熟化的合理生产工艺。 对TBA谱中的溶剂蒸发,玻璃化转变、玻璃态中的次级转变,予聚物的亚胺化反应等多重转变进行了分析,解释了溶剂和水对亚胺化过程的影响。     

1,3-二(炔丙基氧)苯与4,4'-二叠氮甲基联苯的聚合反应及聚合物性能的研究

研究了1,3-二(炔丙基氧)苯(BPOB)与4,4'-二叠氮甲基联苯(DAMBP)的本体聚合行为. 核磁共振氢谱(¹H NMR)表征了聚合物的结构, 通过傅立叶红外技术(FT-IR)观察了反应过程中的基团变化情况, 采用差示扫描量热技术(DSC)研究了聚合反应动力学, 在较低温度(80 ℃)下二元叠氮与二元炔发生了1,3-偶极环加成聚合反应, 生成了主链含三唑环的聚合物; 利用Kissinger法和Crane法处理得到了反应的动力学参数: 反应级数为0.92, 反应活化能E_a为79.8 kJ• mol^－1, 频率因子A为1.26×10¹⁰ min^－1. 利用凝胶渗透色谱(GPC)、动态热机械分析(DMA)和热重分析方法(TGA)研究了聚合产物的性能. 结果表明, 聚合物的数均分子量达4.22×10⁴, 聚合物有较高的玻璃化转变温度和良好的热稳定性, 玻璃化转变温度达到131 ℃, 热分解温度(T_d5)达355 ℃     

基于炔类单体的点击聚合制备超支化聚合物

超支化聚合物由于其独特的树枝状结构和物理化学性质,已经得到了广泛关注及应用.而基于炔类单体的点击聚合作为一类简单、高效的聚合反应已被广泛用于超支化聚合物的制备.本文对近5年利用叠氮-炔和巯基-炔点击聚合制备超支化聚合物的工作进行了简要综述.其中,Cu(I)催化的叠氮-炔点击聚合可制备1?4-立构规整的超支化聚三唑;Ru(II)催化的叠氮-炔点击聚合可制备1?5-立构规整的超支化聚三唑;活化的炔类单体和叠氮单体的无金属催化点击聚合可得到1?4-异构体含量高(高达91.7%)的超支化聚合物;而光引发?热引发及自发的巯基-炔点击聚合可制备含硫的超支化聚合物.此外,对所制备的超支化聚合物的功能和应用进行了简单介绍,最后还简单讨论了点击聚合制备超支化聚合物方面的可能发展方向.     

新型超支化聚芳烃的合成与性能研究

3,6-二乙炔基-9-(三苯胺基)-咔唑、4,4′-二乙炔基-4″-(咔唑基)-三苯胺双炔和1-辛炔单炔在CpCo(CO)2-hν催化的条件下合成了新型超支化聚芳烃.所得的聚合物都溶于普通溶剂(甲苯、THF、氯仿、二氯甲烷等).在光激发的条件下,聚合物在428 nm左右发射蓝光,其荧光量子效率达到62%.所有超支化聚合物都表现出优异的热稳定性,它们的起始分解温度高达484℃.     

具有共轭主链聚合物单晶的低温电导测定

用自行组装的低温电导测定装置对77～373K温度范围内双(对甲苯磺酸)-2,4-己二炔-1,6-二醇酯(TS)及其聚合物PTS单晶体的暗电导进行了测定。在c方向上相应于它们低温相转变的温度,TS和PTS的电导均出现异常,此时TS的相变温度是163K和208K。     

STUDIES ON THE DYNAMIC MECHANICAL BEHAVIOR OF POLYMERIZATION OF BIS(4-(4-ETHYNYLPHENOXY)PHENYL)SULFONE AND ITS POLYMERS

The dynamic mechanical behavior and structural characteristics of polymerization bis(4-(4-ethynylphenoxy)phenyl)sulfine(ESF) and its polymers were investigated by means of tcrsional braid analysis(TBA) and infrared spectroscopy.Results show that the multiple transitions including the melting,low-temperature and high-temperature reactions of ESF oligomers,glass transition and decomposition reaction of resulted polymer can be characterized in the TBA spectra.The glass transition tempe: atures and structural characteristics of ESF polymers depend upon the conditions of polymerization.     

漆酶催化对苯基苯酚的聚合

漆酶(EC 1．10．3．2)是一种氧化还原酶,可应用于催化氧化还原反应和高分子合成领域．聚酚类物质由于具有丌电子共轭结构,通过掺杂可以表现出一定的导电性,而有机导电聚合物是一类有着广泛应用前景的功能材料．此外这类物质还具有较高的三阶非线性系数,是一类重要的有机非线性光学材料,是激光技术的重要物质基础之一．而取代苯酚类物质由于其结构的特殊性,一般很难用化学方法使其聚合．有报道用辣     

Copolymers of PBT and nylon 4T

Polybutylene terephthalate–nylon 4T copolymers (PBT–PA 4T) are synthesized from the diamide of diaminobutane and dimethyl terephthalate (DMT) with butane diol and more DMT in a concentration range of up to 50% PA 4T. The polymerization conditions were similar to those for PBT: first, a melt polymerization, followed by solid-state post-condensation. The materials were studied by differential scanning analysis (DSC) (melting and crystallization behavior) and dynamic mechanical thermal analysis (DMTA) (glass transitions and torsion moduli). The water absorptions were determined at 100% RH. By increasing the PA 4T content in the copolymers, melting temperatures increased strongly, heats of fusion decreased slightly, and glass transition temperatures increased linearly. The torsion moduli above the glass transition temperature were higher. © 1993 John Wiley & Sons, Inc.     

2-乙基-4-甲基咪唑固化环氧树脂体系动力学模型

由2-乙基-4-甲基咪唑(2,4-EMI)固化双酚A二缩水甘油醚型环氧树脂(DGEBA)的等温差示扫描量热(DSC)实验结果发现固化反应分两阶段进行,催化聚合反应有一诱导期.由DSC测试结果求得催化聚合反应的速率常数.从反应机理出发,以诱导期为边界,建立两阶段的微观固化动力学模型.从扩散的角度在模型中引入临界固化度(αc)和扩散因子,进一步建立扩散控制固化动力学模型,对不同2,4-EMI含量和固化温度(Tc)的体系,计算得到αc.研究发现扩散因素对固化动力学影响较大,固化反应前期由化学动力学控制,后期由扩散因素控制;αc主要由体系的玻璃化转变决定,Tc越高,体系玻璃化转变时对应的固化度越大,cα越大.     

Novel high temperature resins based on bis(4-maleimido-phenyl)methane

A novel high temperature thermosetting resin system based on the addition polymerization of bis (4-maleimidophenyl)methane and o, o′-diallyl-bisphenol A is presented in this paper. This system offers the combination of easy solventless processing and the high temperature and toughness performance characteristics demanded for the fabrication of C-fibre laminates. The mechanism of the polyaddition reaction is unusual. In a first step an ENE addition reaction of the maleimide to the allyl group occurs to give a 1:1 adduct with a propenyl phenol type of structure. This is then followed by a Diels-Alder addition reaction of another maleimide functional group to the ENE adduct (by the so-called Wagner-Jauregg reaction) to give a densely crosslinked polymer with glass transition temperatures well over 280°C.     

Poly 4-(3-chloropropyl)styrene: Syntheses of monomer,polymerization, characterizations,and thermal degradation of polymer

4-(3-Chloropropyl)styrene, a new functionalized styrene, has been synthesized in three steps from 3-chloropropylbenzene or in two steps from 4-chlorostyrene, and the polymerization has been carried out in bulk, with azobisisobutyronitrile as an initiator. The polymer has been characterized by its molecular weights, glass transition temperature, and NMR spectra. Thermal degradation has also been studied and volatile fractions characterized by GC-MS. A mechanism of depolymerization, very similar to those of various polystyrenes, can be proposed.     

含吡咯烷酮基的衣康酸酯聚合物及其水凝胶的热响应性

含吡咯烷酮基的衣康酸酯聚合物及其水凝胶的热响应性潘怀忠阎雁唐莉吴志强李福绵（北京大学化学学院北京１００８７１）关键词衣康酸 １ （２ Ｎ （２ 吡咯烷酮） 乙）酯 ４ 甲酯，温敏水凝胶，转变温度，溶胀比近年来，对智能型水凝胶方面的研究已成为功能高分...     

Poly(aryl ether)s containing o‐terphenyl subunits. II. Random poly(ether sulfone)s

The synthesis of a new A₂X‐type difluoride monomer, N‐2‐pyridyl‐4′,4″‐bis‐(4‐fluorobenzenesulfonyl)‐o‐terphenyl‐3,6‐dimethyl‐4,5‐dicarboxylic imide ( 3 ), is described. The monomer 3 was incorporated into a series of copoly(aryl ether sulfone)s by polymerization of 4,4′‐isopropylidenediphenol and 4,4′‐difluorophenylsulfone. The incorporation of monomer 3 had an observable effect on both the glass‐transition temperature of poly(aryl ether sulfone)s and the tendency for macrocyclic oligomers to form during polymerization. Replacement of the pyridyl imide group via a transimidization reaction with propargyl amine proceeded quantitatively and without polymer degradation. The acetylene containing copoly(aryl ether sulfone) could be crosslinked by simple thermal treatment, resulting in an increase in the glass‐transition temperature and solvent resistance. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 9–17, 2000     

ATRP合成星型聚4-乙烯基二苯乙烯及性能研究

本文以2-溴异丁酸季戊四醇四酯(PT-Br)为引发剂,CuBr为催化剂,五甲基二亚乙基三胺(PMDETA)为配体,引发荧光单体4-乙烯基二苯乙烯(VS)进行原子转移自由基聚合,合成了星型荧光聚合物,且分子量分布较窄(1.37～1.50).通过与线性聚4-乙烯基二苯乙烯(line-PVS)的性能比较,发现星型聚4-乙烯基二苯乙烯的溶液粘度和玻璃化转变温度都相对较低.另外,还通过荧光光谱对星型聚合物的光学性能进行了表征.     

Azo polymers for reversible optical storage. 11 poly{4,4′-(1-methylethylidene)bisphenylene 3-[4-(4-nitrophenylazo)phenyl]-3-aza-pentanedioate}

Poly{4,4′-(1-methylethylidene)bisphenylene 3-[4-(4-nitrophenylazo)phenyl]-3-aza-pentanedioate} (pMNAP) was synthesized through the condensation polymerization of 4,4′-isopropylidene-bis-phenol and N-[4-(4-nitrophenylazo)phenyl]imido diacetyl chloride. The polymer solution in tetrahydrofuran (THF) was spin-coated onto a glass substrate to form a film and the process of reversibly photoinduced birefringence was tested. The birefringence induced in the film was observed to a level of 0.04. The biexponential fitting of the birefringence growth and relaxation curves shows two kinds of processes. A fairly low birefringence relaxation occurs after the light is turned off, about 12% at room temperature and less than 50% at 138°C, close to the glass transition temperature (152°C). pMNAP decomposes at about 160°C which prevents its use as a material for optical storage. © 1996 John Wiley & Sons, Inc.