甲基丙烯酸丁酯和苯乙烯的原子转移自由基共聚

研究了甲基丙烯酸丁酯（ＢＭＡ）和苯乙烯（Ｓ）这两种不同极性单体的原子转移自由基嵌段共聚和无规共聚,得到了实测分子量与理论分子量相近,分子量分布较窄的嵌段共聚物和无规共聚物．聚合过程中分子量和单体转化率成比例增加,多分散性指数变化不大．用１Ｈ ＮＭＲ法测定共聚组成,Ｋｅｌｅｎ Ｔｕｄｏｓ法计算竞聚率．得到ｒＳｔ＝０９１,ｒＢＭＡ＝０３２．     

聚丙烯-聚乙烯嵌段共聚物的分子结构及性能的研究

本工作用核磁共振(~(13)C-NMR)、示差扫描量热(DSC)、动态力学分析(DMA)和扫描电子显微镜(SEM)等技术研究了将丙烯、乙烯单体两步分段共聚、预期为聚丙烯-聚乙烯嵌段共聚物的合成物(简称为聚丙烯-聚乙烯嵌段共聚物或嵌段共聚物)。结果表明,在嵌段共聚物中含有一定量的、能为正庚烷抽提出来的乙丙无规共聚物(EPR);分段共聚的产物并非预想的PP-b-PE两嵌段共聚物,而是含有多种组分的共混物;形态表征的结果表明了嵌段共聚物为多相体系,EPR和PE形成分散相以球形无规分布于PP基体中。     

乙烯丙烯嵌段共聚物的合成表征以及结构与性能的研究

第一部分 PP-EPR-PP嵌段共聚物的合成和表征 通过聚丙烯、乙丙共聚物和嵌段共聚物分子量随聚合时间的增大而在间歇加氢下不增大,肯定了本工作所用TiCl_3-Et_2AlCl催化剂有足够长的寿命,有合成嵌段共聚物的可能。由红外光谱确定了向单体和自动离析的链转移反应的存在,分级实验表明在嵌段共聚物中确实含有无规的低分子量的链转移产物,因此生成嵌段杂质是不可避免的。     

用双官能团引发剂进行的基团转移嵌段共聚研究

本文用二种双官能团引发剂进行基团转移嵌段共聚研究,得到了一系列实测分子量和理论分子量相近、分子量分布较窄的A-B-A型嵌段共聚物。用GPC、~1H-NMR、DSC等手段对嵌段共聚物进行了表征,证明确是两相嵌段共聚丙烯酸酯。发现位阻较大的单体作为第二单体时不利于聚合。过高的催化剂用量使嵌段共聚的总转化率降低。使用极性较大的溶剂可缩短第一步聚合的诱导期,但不影响第二步聚合的诱导期,即极性较大的溶剂有利于催化剂的离解。单体浓度增大使共聚物的分子量减小,多分散性指数增大。可通过单体投料比改变共聚物的热形变温度。     

含氟丙烯酸酯共聚物制备超疏水表面及其形成机理的研究

以丙烯酸全氟烷基乙基酯和甲基丙烯酸甲酯为共聚单体, 分别以用微乳液聚合法和溶液聚合法制备的无规共聚物和用可逆加成-断裂链转移制备的嵌段共聚物作为成膜共聚物, 并以1,1,2-三氟三氯乙烷作为溶剂, 采用溶剂挥发成膜法可以直接制备出超疏水膜, 聚合物膜对水的接触角可达160°. 改变聚合物结构和成膜条件, 探讨了该类超疏水膜的形成机理和影响因素. 发现膜的表面形貌和疏水性与共聚物的组成、结构、分子量以及成膜条件密切相关, 随着共聚物中氟含量的增大, 膜的表面形貌都趋于平滑; 而且, 无规共聚物比嵌段共聚物更易形成粗糙度好的膜; 同时, 较大的聚合物分子量和适宜的高的成膜温度都对形成粗糙结构有利.     

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第一部分 PP-EPR-PP嵌段共聚物的合成和表征 通过聚丙烯、乙丙共聚物和嵌段共聚物分子量随聚合时间的增大而在间歇加氢下不增大,肯定了本工作所用TiCl₃-Et₂AlCl催化剂有足够长的寿命,有合成嵌段共聚物的可能。由红外光谱确定了向单体和自动离析的链转移反应的存在,分级实验表明在嵌段共聚物中确实含有无规的低分子量的链转移产物,因此生成嵌段杂质是不可避免的。     

甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率

甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率邹友思郭金全戴李宗潘容华（厦门大学化工系，厦门，３６１００５）基团转移聚合是制备极性单体的嵌段或无规共聚物的有效方法。如用甲基丙烯酸甲酯（ＭＭＡ）和丙烯酸丁酯（ＢＡ）进行嵌段共聚，可制得热塑性弹性体［１...     

氢气对负载型Z-N高效催化剂的乙烯-丙烯共聚产物链结构影响

用球形的负载型Ziegler-Natta（Z-N）高效催化剂，经丙烯均聚一乙烯丙烯气相共聚两段串联反应工艺制备的聚丙烯／乙丙共聚物（PP／EPR）合金具有优良的抗冲击性能，是聚丙烯的重要高性能化改性品种，已实现大批量生产，对这类反应器合金的结构表征和结构性能关系的研究表明，其共聚物组分中既有起弹性体作用的乙丙无规共聚物，也含有相当量的乙丙多嵌段共聚物．这种多嵌段共聚物既与无规共聚物（EPR）相容，又与PP基体相容，在合金中起相容剂作用，对材料高抗冲性能的形成起着重要作用．然而，负载型Z-N高效催化剂催化乙丙共聚合的产物结构及其影响因素至今鲜见系统的研究，调控PP／EPR合金中共聚物结构的原理尚不明确．氢气在聚烯烃生产中广泛用作分子量调节剂，在PP／EPR合金的生产中同样要用氢气调节PP和EPR组分的分子量．但是，加氢对共聚物的链结构有何影响则鲜见系统的研究．本文初步研究了用Z—N高效催化剂合成的乙丙共聚物的结构特征，着重考察了聚合体系中加入链转移剂氢气对共聚物结构的影响．     

基于聚乙烯的无规和嵌段接枝共聚物的制备

采用乙烯配位聚合和巯基-烯点击化学相结合的方法制备了羟基封端的线性聚乙烯,末端羟基含量接近100%;利用酰氯与羟基的高效反应,将羟基封端的聚乙烯转化为降冰片烯封端的聚乙烯大单体(PE-NB).使用Grubbs II代催化剂,将大分子单体与降冰片烯(NB)单体进行开环易位共聚,通过调整单体的投料比和加料方式制备了分子量和组成可控的聚降冰片烯-g-聚乙烯(PNB-g-PE)接枝共聚物.其中,无规共聚时,大单体的转化率接近100%,所得无规接枝共聚物的重均分子量为1.79×10~4~3.14×10~4,分子量分布指数为2.09~2.60,聚乙烯链段的质量分数为4.6%~16.8%;而嵌段共聚时,由于空间位阻原因,大单体的转化率约为80%.热分析研究发现,由于空间位阻,接枝共聚物的结晶度较聚乙烯前驱体略有下降,且接枝度越大,结晶能力下降得越多.     

等规聚苯乙烯与聚(乙烯/丙烯)嵌段共聚物的研究(Ⅱ)──嵌段共聚物的分离与表征

将配位聚合法合成的等规聚苯乙烯与聚(乙烯/丙烯)嵌段共聚反应产物进行溶剂车取分离,得到嵌段共聚物[iPS-b-Poly(E-co-P)]的含量约为总重量的20％～30％,并用¹³CNMR、FTIR、WAXD、DSC和电子显微镜进行表征．该共聚物是具有等规聚苯乙烯(iPS)与乙丙无规共聚链段结构的三元两嵌段共聚物,且iPS链段有一定的结晶度．由透射电镜可以看出,嵌段共聚物存在微相分离结构,相区尺寸在100nm数量级．     

Ethene-butadiene copolymers by single-site catalysts

Constrained geometry catalysts ([Me₂Si(N^tBu)(Me₄Cp)]TiCl₂) were used to copolymerize ethene and 1,3-butadiene. It is possible to incorporate 17 mol% of butadiene, other catalyst systems such as CpTiCl₃/MAO show much lower incorporation. More than 300 000 kg of copolymer can be obtained by one mol of the catalysts in one hour. The microstructure of the copolymers has been investigated by ¹H- and ¹³C-NMR spectroscopy. The butadiene is incorporated mainly in 1,4-trans- and 1,2-structure. The high amount of 9-29% of vinyl groups offers the possibility of an easy vulcanisation. The molecular weights of these elastomers are high with values of 250 000. Important is the low glass transition temperature of −28 °C of a copolymer with 7 mol% of butadiene.     

Ring-opening (co)polymerization of cardanol glycidyl ether

The anionic ring-opening copolymerization of commercially available bio-based cardanol glycidyl ether (CGE) was investigated without any prior purification. As a first step, anionic-ring-opening homopolymerization was attempted through active chain-end and monomer-activated mechanisms. Both strategies were unsuccessful. Conversely, in a second step, the anionic alternating ring-opening copolymerization (AAROP) of CGE with the renewable N-acetyl homocysteine thiolactone (NHTL) was successfully carried out in the presence of a strong base. Anisole, a solvent classified as sustainable and rarely used in anionic ring-opening polymerization, proved to be a suitable for the AAROP. This polymerization is an unusual example of synthesis of linear polyesters with cardanol-based monomers. The copolymers were carefully characterized by ¹H, ¹³C, COSY, HSQC, ¹H-¹⁵N NMR and MALDI-ToF, demonstrating an alternating structure. Then, CGE was copolymerized with NHTL and another additional epoxide. The cardanol-derived monomers enable the preparation of functionalizable poly(ester-alt-thioether) bearing multiple allyl and alkene groups. The AAROP method in anisole offers new opportunity for green anionic polymerization through the use of sustainable chemicals, witnessed by the valorization of cardanol-derived compounds and expands the scope of synthesized renewable polyesters.     

Tuning the parameters of the suspension polymerization of styrene,divinylbenzene, and N‐(p‐vinylbenzyl)‐ 4,4‐dimethylazlactone

Azlactone‐functionalized microporous polystyrene resins were synthesized by suspension polymerization of styrene, divinylbenzene and N‐(p‐vinylbenzyl)‐4,4‐dimethylazlactone (VBM). A fractional factorial design of experiments (DOE) has been used to evaluate the influence of several parameters (factors) on the physical and chemical properties (responses) of the resins. Six factors were considered: (i) the organic/aqueous phase ratio, (ii) the amount of the functional monomer N‐(p‐vinylbenzyl)‐4,4‐dimethylazlactone, (iii) the amount of stabilizer, (iv) the amount of initiator, (v) the stirring speed, and (vi) the equilibration time. The process responses were the yield of polymerization, the diameter of the beads and their polydispersity, their swelling ratio in dichloromethane and the accessibility ratio of the immobilized azlactone sites. This methodology enables the determination of an optimal combination of the six factors to synthesize beads in high yield (92%) with remarkable properties for SPOS applications (azlactone sites loading = 1.57 mmol/g, swelling ratio in dichloromethane = 5.0 mL/g and 100% accessibility ratio). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3677–3686, 2007     

Kinetic study of high-conversion copolymerization of butyl acrylate with methyl methacrylate in solution

Butyl acrylate (BA) and methyl methacrylate (MMA) have been copolymerized in a 3 mol/L benzene solution using 2,2′-azobis(isobutyronitrile) (AIBN) as initiator over a wide composition and conversion range. The overall copolymerization parameter k_p/k_t^1/2 and the composition of the copolymer formed have been measured as a function of conversion. Theoretical values of the coupled parameter k_p/k_t^1/2 calculated from the implicit penultimate unit model and those of cumulative copolymer composition, determined from the Mayo—Lewis terminal model, have been correlated with those experimentally obtained. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1961–1965, 1997     

利用大分子单体技术合成接枝共聚物

大分子单体和小分子共单体共聚是合成接枝共聚物的重要途径之一。本文综述了大分子单体通过各种聚合方式(自由基共聚、离子型共聚、配位共聚、基团转移共聚和逐步共聚)和普通小分子单体的共聚反应,详细讨论了大分子单体和小分子单体的自由基共聚反应动力学,并简要介绍了接枝共聚物的应用背景。     

L—丙氨酸与甘氨酸的N—羧基—环内酸酐共聚合的研究

从模拟蚕丝素蛋白的角度,研究了L-丙氨酸的N-羧基-环内酸酐(L-Ala-NCA)与甘氨酸的N-羧基-环内酸酐(Gly-NCA)在硝基苯溶剂中,正丁胺引发下的共聚合反应。讨论了单体投料比,反应温度对聚合速率及产物分子量的影响。并从实验中发现,在不加入引发剂的情况下,L-Ala-NCA和Gly-NCA共结晶能在甲苯介质中顺利地进行非均相的热开环共聚,且产物的分子量远高于采用引发剂的均相聚合体系产物的相应值。     

A New,Practical Formulation of the Multicomponent Copolymerization Equation

A general and rigorous new formulation of the multicomponent extension to the Mayo Lewis copolymerization equation is presented based in matrix notation. In contrast to the original Walling and Briggs formulation, which was based on determinants and difficult to apply in practice, this new formulation is explicit, easy to implement, and introduces a natural scaling to the problem. The approach is illustrated with calculation of instantaneous composition and compositional drift with conversion for 4 and 6 monomers.

     

悬浮法合成聚丙烯接枝丙烯酸

用过氧化二苯甲酰作引发剂以水相悬浮法合成聚丙烯接枝丙烯酸。通过反应条件、组分等因素对PP的接枝率和接枝效率的影响研究,确定较佳配比工艺条件：溶用莳8-0min;反应温度90℃;反应时间90min;在氮气气氛中,丙烯酸7％;过氧化二苯甲酰3．3％;二甲苯25％;水和聚丙烯的重量比为3：1;若加入适量催化剂（1－1．7％0异氰尿酸三烯丙酯能显著提高接枝率。用此PP－g-AA作CaCO3、PP/PA6和合物的相容剂,材料的力学性能有很大的提高。