降冰片烯与丙烯共聚合的研究进展

继高活性茂金属催化体系成功开发以降冰片烯和乙烯共聚物为代表的高性能环烯烃共聚物以来, 降冰片烯与其他α-烯烃如丙烯的共聚物研究也备受学术界和工业界的重视。本文介绍了降冰片烯与丙烯共聚合的催化剂和聚合机理等方面的最新研究进展, 包括各种不同结构的茂金属催化剂催化降冰片烯与丙烯共聚合的特点及其共聚物的结构分析。C₂-对称和C_s-对称的茂金属催化剂催化降冰片烯与丙烯共聚合时链转移反应较多, 以致催化活性较低, 所得的聚合产物分子量偏低。采用限定几何构型茂金属柄型-二甲基亚甲硅基(芴基)(氨基)二甲基钛催化剂进行降冰片烯与丙烯共聚合时, 催化活性可高达10⁷ g polymer·(mol cat·h)^-1, 所得共聚物的相对分子质量超过20万, 降冰片烯含量可达70%(mol)且玻璃化转变温度高。     

丙烯与丁二烯共聚合

采用TiCl4/Mgcl2/芴二醚／Al(Et)3催化体系进行丙烯与丁二烯的共聚合,考察了n(Al)/n(Ti)、聚合温度、丁二烯的用量等聚合工艺条件对共聚反应活性的影响,通过傅里叶变换红外光谱、核磁共振氢谱和核磁共振碳谱对共聚物的结构进行了分析和表征。结果表明,丁二烯在共聚物中主要以嵌段形式存在,丁二烯的微观结构主要以反-1,4-结构和1,2-结构为主。当丁二烯用量从0增加到10 g时,共聚物的熔点从156．6℃降低到137．7℃,结晶度由39.3％降低到18．2％。     

极性单体/烯烃共聚合的研究进展

聚烯烃产品价格低廉,物理、化学性能稳定,使用寿命长,应用范围广。但因其分子链中不含极性基团,限制了其应用范围。极性聚烯烃备受青睐,可应用于催化剂负载、医药、光电转换材料、生物材料、光学材料、环境保护和能源等领域。主要综述了极性聚烯烃的合成方法和催化极性烯烃/非极性烯烃共聚合的催化剂,详述了非茂金属催化剂在催化乙烯或/(和)丙烯/极性单体共聚合中的应用及聚合机理。     

乙烯和丙烯的共聚合

用Ziegler-Natta催化剂系的低分子烯烃离子聚合法可用于乙烯和其他低分子烯烃或不饱和烃的共聚合。本文研究了乙烯-丙烯共聚物性质和丙烯含量关系。共聚物是用催化剂系:VOCl_3和AlCl(C_2H_5)_2、VO(OR)Cl_2,或VO(OR_2)Cl和AlCl(C_2H_5)_2得到的。这种催化剂特性是催化活性很高,使共聚合可在     

DQ催化剂催化丙烯共聚合

研究了DQ催化剂生产抗冲共聚物时均聚物(基体相)与共聚物(橡胶相)的相对分子质量之比(即特性黏数之比)对橡胶相分散度的影响。对于DQ催化剂,当共聚物与均聚物的特性黏数之比为2．7～3．0时,所得抗冲共聚物中橡胶粒子分散程度较好,抗冲共聚物的相对分子质量分布为7～8。     

钪配合物催化丙烯与月桂烯的共聚合

研究了两种钪配合物(C5Me4SiMe3)Sc(CH2C6H4NMe2-o)2(记作钪配合物1,Me为甲基)和(C5Me4SiMe3)Sc(CH2SiMe3)2(THF)(记作钪配合物2,THF为四氢呋喃)催化丙烯与月桂烯共聚合的性能.结果表明:在室温及丙烯压力为0.6?MPa时,通过调控月桂烯的用量,采用钪配合物1和...     

丙烯生产工艺研究进展

丙烯是催化裂化和蒸气裂解装置的副产品,由于近年来国内外对丙烯的需求逐年增多,常规的蒸气裂解和催化裂化工艺生产的丙烯都难以满足丙烯快速增长的需求。目前主要生产丙烯的工艺有:1)蒸气裂解工艺;2)催化裂化工艺;3)易位反应工艺;4)丙烷脱氢工艺;5)甲醇制烯烃(MTP)工艺;6)重烯烃裂解工艺。其中对甲醇制丙烯(MTP)项目工艺包开发作了简要说明。     

乙烯-丙烯-1-丁烯三元共聚合

采用自制的ziegler-Natta催化剂催化乙烯-丙烯-1-丁烯三元共聚合.考察了1-丁烯/丙烯、铝钛比、反应温度和压力等对三元共聚合的影响.结果表明.三元共聚物中支化度约为26门000 C,其中乙基支链为18/1 000 C、丙基支链为8/1 000 C.在聚合温度为60℃、压力为0.8 MPa、乙烯分压百分数为70%、1-丁烯分压百分数为5.7%和丙烯分压百分数为24.3%时,催化活性最高,为10.5 kg/g.当n(Al)/n(Ti)大于100时,催化活性增加趋势变缓.聚合压力超过0.8 MPa时,催化活性变化不大.聚合平行实验结果表明,上述条件稳定,所得三元共聚物的表观密度为0.32g/cm3,拉伸强度为11～12 MPa、断裂伸长率为540%～560%.     

基于RAFT聚合策略合成功能化聚烯烃嵌段聚合物的研究进展

首先介绍了可逆加成-断裂链转移聚合（RAFT）的聚合机理及其常用的RAFT试剂,并与其它两种活性可控自由基聚合[氮氧化合物媒介的自由基聚合（NMP）和原子转移自由基聚合（ATRP）]进行了简单的优缺点对比。其次,介绍了近些年在基于RAFT聚合制备功能化聚烯烃嵌段聚合物研究中取得的进展,重点综述了制备功能化聚烯烃嵌段聚合物时所采用的6种方法,包括①烯烃配位聚合与RAFT聚合相结合;②阴离子聚合与RAFT聚合相结合;③阳离子聚合与RAFT聚合相结合;④Click反应与RAFT聚合相结合;⑤开环聚合与RAFT聚合相结合;⑥叶立德活性聚合与RAFT聚合相结合。最后,对基于RAFT聚合策略设计合成功能化聚烯烃嵌段聚合物的研究前景与实际应用进行了展望。     

新型聚硅氧烷嵌段共聚物的合成研究进展

聚硅氧烷作为一种有机硅高聚物,可通过嵌段共聚进行相应的化学改性。综述了国内外新型聚硅氧烷嵌段共聚物的研究进展,主要对纯聚硅氧烷嵌段型、聚醚型、聚烯烃型和聚氨酯型进行了叙述,并对其应用前景进行了展望。     

Controlled synthesis of amphiphilic siloxane-siloxane block copolymers with carboxyl functions

Summary Poly[2-(carboxymethylthio)ethyl]methylsiloxane-block-polydimethylsiloxane, 1, and poly{[2-(carboxymethylthio)ethyl]methylsiloxane-co-dimethylsiloxane}-block-polydimethylsiloxane, 2, were synthesized by ene-thiol addition of mercaptoacetic acid to respective precopolymers 3 and 4, containing vinyl groups bound to silicon. The precopolymers 3 and 4 were obtained by sequential anionic copolymerization of hexamethylcyclotrisiloxane, D₃, with 2,4,6-trimethyl-2,4,6-trivinyl-cyclotrisiloxane, 5, and D₃ with 2,4,4,6,6,-pentamethyl-2-vinylcyclotrisiloxane, 6, respectively. The method permits to synthesise the block copolymers with a narrow molecular weight distribution and a high block purity. The ene-thiol addition was performed on free radical route, using AIBN as initiator. The reaction proceeds selectively, leading to the transformation of vinyl groups in the precopolymers into the β-adducts. Received: 15 December 1999/Revised version: 25 February 2000/Accepted: 24 March 2000     

丙烯腈嵌段共聚物的合成及其自组装研究进展

综述了含聚丙烯腈(PAN)嵌段共聚物的合成方法及其在溶液中的自组装技术。对常用的活性自由基聚合方法,如原子转移自由基聚合(ATRP)、可逆加成断裂链转移(RAFT)聚合、氮氧自由基聚合(NMP)以及钴调介自由基聚合(CMRP)等方面的研究进行了总结,同时对PAN类嵌段共聚物在溶液中的自组装技术进行了概括。最后提出了现有技术存在的问题,并对其今后发展方向进行了展望。     

Accelerated pressure synthesis and characterization of 2-oxazoline block copolymers

The cationic ring-opening polymerization of 2-oxazolines in acetonitrile was investigated under pressure conditions utilizing methyl tosylate as initiator of which the single crystal X-ray structure is described as well. The polymerization kinetics were studied and compared with previously reported microwave-assisted pressure polymerizations. Moreover, a series of block copolymers was synthesized in an automated parallel synthesis robot utilizing this pressure polymerization method. The resulting block copolymers were characterized with both differential scanning calorimetry and contact angle measurements to determine the effect of copolymer composition on glass transition temperature, melting point and surface energy. Atomic force microscopy was applied to further investigate the possible phase separation.     

Towards the synthesis of electroactive block copolymers via anionic-to-Ziegler-Natta transformation reactions

Summary Diblock copolymers of acetylene and styrene were prepared by treating Ti(OBu)₄ with polystyryl lithium followed by reaction with acetylene. Reliable evidence for the formation of block copolymers was derived from dual radiotagging experiments.     

Bisphenol-A-polycarbonate-bisphenol-A-polysulfone block copolymers

Multiblock , block copolymers of bisphenol-A-polycarbon ate and bisphenol-A-polysulfone were prepared by three different synthesis routes. The in situ method consisted of forming the polycarbonate block in the presence of hydroxyl terminated polysulfone oligorner. The coupled oligomer technique utilized phosgene to link up the two preformed oligomers to high molecular weight. In one case, a perfectly alternating block copolymer was formed by reacting a ～9, 000 M _n chloroformate terminated polycarbonate with a ～9, 000 M _n hydroxyl terminated polysulfone. Block sizes from ～4, 000 to ～26, 000 were investigated. The oligomers and copolymers were characterized by potentiometric titrations and UV end group analysis. Membrane osmometry and gel permeation chromatography were also employed. Dynamic mechanical behavior of solvent cast and compression molded films was assessed via rheovibron measurements. The copolymers were ductile and transparent and displayed essentially only a single intermediate glass transition temperature, that is, microphase separation was not observed. This is in contrast to simple physical blends of the homopolymers or oligomers, which are opaque and display two glass transition temperatures.     

All-conjugated block copolymers

All-conjugated block copolymers of the rod-rod type came into the focus of interest because of their unique and attractive combination of nanostructure formation and electronic activity. Potential applications in a next generation of organic polymer materials for photovoltaic devices ("bulk heterojunction"-type solar cells) or (bio)sensors have been proposed. Combining the fascinating self-assembly properties of block copolymers with the active electronic and/or optical function of conjugated polymers in all-conjugated block copolymers is, therefore, a very challenging goal of synthetic polymer chemistry. First examples of such all-conjugated block copolymers from a couple of research groups all over the world demonstrate possible synthetic approaches and the rich application potential in electronic devices. A crucial point in such a development of novel polymer materials is a rational control over their nanostructure formation. All-conjugated di- or triblock copolymers may allow for an organization of the copolymer materials into large-area ordered arrays with a length scale of nanostructure formation of the order of the exciton diffusion length of organic semiconductors (typically ca. 10 nm). Especially for amphiphilic, all-conjugated copolymers the formation of well-defined supramolecular structures (vesicles) has been observed. However, intense further research is necessary toward tailor-made, all-conjugated block copolymers for specific applications. The search for optimized block copolymer materials should consider the electronic as well as the morphological (self-assembly) properties.     

Acrytonitrile block copolymers

Summary Acrylonitrile was polymerized by an insertion process on being added to solutions containing the adduct of the reaction of tetrakis(dimethylamino) titanium (T4) and azobisisobutyronitrile (AIBN). The obtained azo-linked polyacrylonitrile has appropriate initiating functionality for a subsequent vinyl polymerization.