侧链为长链烷基醚的聚硅氧烷的合成及其药物控制释放性能的研究

通过硅氢加成法合成了侧链为长链烷基醚的聚硅氧烷及共聚物，研究了其相转变性质以及由其组成的共混硅橡胶薄膜对避孕药物（左旋十八甲基炔诺酮）的释放性能．结果表明：聚硅氧烷的熔融温度随侧链烷基的增长而提高；共聚硅氧烷的熔融温度随较长烷基的比例增加而提高；聚硅氧烷的侧链烷基呈侧向有序性排列．药物分子透过薄膜的速率及其温度依赖性与共混膜中侧链烷基的有序状态有关，即由晶态转变为非晶态时，药物的透过速率加快     

苯乙烯—丙烯等规立构嵌段共聚物（iPS—b—iPP）的非等温结…

用ＤＳＣ法研究了苯乙烯－丙烯等规立构嵌段共聚物的非等温结晶动力学。结果表明，冷却速度在５－２０℃／ｍｉｎ范围内，共聚的非等温结晶动力学参数能很好地符合Ａｖｒａｍｉ动力学学方程，非等温结晶速率常数与冷却速率有关，动力学结晶能力则同时受到冷却速率和共聚物组成比的影响，文中还讨论了在非等温结晶条件下共聚物的结晶成核和生长方式与共聚物组成和结构的关系，联合Ａｖｒａｍｉ方程和Ｏｚａｗａ方程推导的非等温结晶动     

甲基丙烯酸甲酯-甲基丙烯酸无规共聚物的合成及其在乳液聚合中的应用

通过自由基共聚制备了不同组成的甲基丙烯酸甲酯-甲基丙烯酸无规共聚物,用碱中和后作为大分子乳化剂用于乳液聚合.研究了无规共聚物的组成、用量及反应温度对乳液聚合的影响.结果表明,在相同的反应条件下,乳化剂中聚甲基丙烯酸含量越多,乳液聚合速率越快;同一乳化剂,随乳化剂浓度的增加,乳液聚合速率增加;在乳化剂组成、浓度不变的情况下,反应温度越高,乳液聚合速率越大.     

橡胶相具有交联结构的新型抗冲聚丙烯合金

利用具有"颗粒反应器技术(RGT)"特征的Ziegler-Natta催化剂进行丙烯多相共聚(丙烯均聚+乙烯/丙烯无规共聚),通过在乙丙共聚阶段引入双烯烃单体1,9-癸二烯,使乙丙共聚物在聚合的同时实现交联,制备了新型抗冲聚丙烯合金.聚合反应结果表明,1,9-癸二烯可参与乙丙共聚,同时对聚合反应速率和共聚物组成影响较小;1,9-癸二烯使乙丙共聚物发生支化/部分交联,合金聚合物的熔体流动速率在引入1,9-癸二烯后显著降低,且凝胶含量随1,9-癸二烯用量的增加而增大.形态研究结果表明,乙丙共聚物的交联显著降低了其在聚丙烯基体中的分散尺度,提高了分散均匀性,分散相粒径随支化/交联程度提高而减小.力学性能测试结果表明,乙丙共聚物的交联使合金聚合物在保持较高韧性的同时显著提升了刚性,有利于实现抗冲聚丙烯合金的刚韧平衡.     

生物可降解聚丁二酸/苯基丁二酸丁二醇酯系列共聚物的合成及其结晶行为

合成了一系列聚丁二酸/苯基丁二酸丁二醇共聚酯(PBSBS),利用DSC、1H-NMR和X射线等测试手段对共聚物组成、热力学性能、结晶性能、等温结晶行为进行了表征和研究.结果表明,含苯基的共聚单元的引入显著改变了聚丁二酸丁二醇酯(PBS)的热力学性能4,利用Hoffman-Week曲线得到的共聚物平衡熔点随共聚组分含量的增加显著降低,玻璃化转变温度则明显升高,结晶熔点符合无规共聚物的Flory方程.此外,利用Avrami方程对均聚物PBS以及共聚物PBSBS-10分别进行了等温结晶行为研究,结果表明共聚使结晶速率降低,PBS和PBSBS-10的Avrami指数分别介于2.8~3.0和2.7~2.9之间,结晶方式为三维生长异相成核,X射线测试结果表明共聚不影响晶体结构.     

氯化聚乙烯对甲基丙烯酸甲酯／苯乙烯共聚动力学的影响

将甲基丙烯酸甲酯（ＭＭＡ）／苯乙烯（Ｓ）在氯化聚乙烯（ＣＰＥ）存在下进行悬浮溶胀接枝共聚，考察了ＣＰＥ对ＭＭＡ／Ｓ共聚动力学行为的影响．ＣＰＥ提高了聚合体系的粘度，使自动加速提前，扩散因素增加，对共聚有阻滞作用．ＣＰＥ是链转移剂，使ＭＭＡ／Ｓ共聚物分子量降低．ＣＰＥ对ＭＭＡ的吸附渗透优于对Ｓ的吸附，造成接技部分与非接技部分组成的差异．ＣＰＥ含量、溶胀时间、转化率、硫酸用量对共聚组成均有影响。     

光致变色液晶高分子研究（Ⅲ）──含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷的液晶行为

用热台偏光显微镜、Ｘ射线衍射和ＤＳＣ研究了含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷（ＰＳＩ）的液晶性．将非介晶基元并入液晶均聚物，所得共聚物的液晶态类型不变，仍显示近晶型织构，在ＰＳＩ共聚物中，保持液晶性的含介晶基元单体的最低极限组成为６０ｍｏｌ％．在液晶性存在的范围内，共聚物的清亮点由１３０℃升至１７０℃，液晶共聚物的热稳定性随非介晶组分含量的增加而增强．     

氯乙烯/邻苯二甲酸二烯丙基酯悬浮共聚特征

对４５℃时的氯乙烯／邻苯二甲酸二烯丙基酯（ＶＣ／ＤＡＰ）的悬浮共聚进行了研究，得到表观竞聚率ｒＶＣ＝０７６９、ｒＤＡＰ＝０３７４．凝胶点对应的ＤＡＰ临界起始浓度在０４６６～０４９３ｍｍｏｌ／ｍｏｌＶＣ之间（聚合转化率为８０～８５％），当ＤＡＰ起始浓度小于临界浓度时，ＶＣ／ＤＡＰ共聚物均为溶胶，溶胶平均聚合度随ＤＡＰ起始浓度和聚合转化率的提高而增大；当ＤＡＰ起始浓度大于临界浓度时，共聚物由溶胶和凝胶组成，凝胶含量随ＤＡＰ浓度和聚合转化率的提高而增加，溶胶聚合度则随ＤＡＰ浓度的提高而减小．在凝胶点前，共聚物的分子量分布随ＤＡＰ浓度的增加而变宽；凝胶点以后，分子量分布随ＤＡＰ浓度的增加而变窄．     

光致变色液晶高分子研究（Ⅲ）：含胆甾介晶基元和偶氮苯…

用热台偏光显微镜、Ｘ射线衍射和ＤＳＣ研究了含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷（ＰＳＩ）的液晶性。将非介晶基元并入液晶均聚物，所得共聚物的液晶态类型不变，仍显示近晶型织，在ＰＳＩ共聚物中，保持液晶性的含介晶基元单体的最低极限组成为６０ｍｏｌ％．在液晶性存在的范围内，共聚物的清亮点由１３０℃升至１７０℃，液晶共聚物的热稳定性随非晶组分含量的增加而增强。     

以丙烯为主体的二元及三元共聚研究——丙烯与乙烯和丁烯—1的共聚合

研究了ＭｇＣｌ２载体高效催化剂用于丙烯为主体的与乙烯和丁烯－１的二元及三元共聚合反应：选择最佳了共聚合条件；实验测定了共聚单体配比对共聚合活性，共聚物分子量和物理性能的影响；并用＾１３Ｃ－ＮＭＲ分析了共聚物组成、序列分布和支链结构等微观结构信息。     

谷氨酸赖氨酸无规共聚物和谷氨酸精氨酸无规共聚物的合成及性能

采用氨基酸-N-内羧酸酐(氨基酸-NCA)开环聚合的方法, 并通过改变开环聚合时谷氨酸-N-内羧酸酐(BLG-NCA)与赖氨酸-N-内羧酸酐[Lys(Z)-NCA]的投料比以及BLG-NCA与鸟氨酸-N-内羧酸酐[Orn(Z)-NCA]的投料比, 经过脱保护和胍基化反应得到一系列谷氨酸赖氨酸无规共聚物Poly(E,K)和谷氨酸精氨酸无规共聚物Poly(E,R). 核磁共振氢谱(¹H NMR)和核磁共振定量碳谱(¹³C NMR)分析结果表明, 合成了无规共聚物Poly(E,K)和Poly(E,R), 且二者中不同氨基酸的摩尔比接近开环聚合时相应NCA的投料比. 动态光散射(DLS)测定结果表明, 无规共聚物在pH=7.4的正常生理环境中形成的胶束粒径均一、 尺寸小于200 nm. Zeta电位表征结果表明, 无规共聚物Poly(E,K)和Poly(E,R)的Zeta电位值随着溶液pH值的变化而变化, 具有pH敏感性.     

Self-assembly of pH-sensitive random copolymers: poly(styrene-co-4-vinylpyridine)

A series of pH-sensitive random copolymers, poly(styrene-co-4-vinylpyridine) (PSVP), with molecular weight about 10,000 and 4-vinylpyridine molar contents of 19-53%, were conveniently synthesized by free radical polymerization. The copolymers experience the formation, swell, and dissociation of multichain nanoparticles when the pH of the aqueous solutions/dispersions changes from 5.1 to 1.0. The nanoparticles have hydrodynamic diameters around 100 nm, a spherical shape, and a relatively uniform structure in a pH range of about 5-3 and a multicore structure at lower pH. The random distribution of the building units causes some of the hydrophilic units, protonated 4-vinylpyridine groups, to be trapped inside the nanoparticles. So the hydrophobicity of the nanoparticles is tunable by changing the 4-vinylpyridine content in the copolymers. For the copolymers with higher 4-vinylpyridine molar content, the pH range in which the multichain nanoparticles form shifts to higher values, the multichain nanoparticles dissociate, and the copolymers form single-chain hydrophobic domains at low pH.     

Synthesis of graft copolymers with polyisobutylene branch chains

<正>The copolymerization of 4-vinylbenzyl chloride(VBC) and vinyl acetate(VAC) was carried out in toluene at 75℃via radical polymerization using 2,2'-azo-bis-(isobutyronitrile)(AIBN) as an initiator.The random copolymers of poly(4-vinylbenzyl chloride-co-vinyl acetate)(P(VBC-co-VAC)) with number average molecular weight(M_n) from 2000 to 6900,relatively narrow molecular weight distribution(MWD,M_w/M_n ca.2.0) and with different copolymer composition of 4-vinylbenzyl chloride(VBC) from 17 mol%to 62 mol%could be obtained.The P(VBC-co-VAC) copolymers with an average number of 7 to 13 initiating sites of benzyl chloride per macromolecule could be used for the cationic polymerization of isobutylene(IB).The cationic polymerizations of IB were further conducted by using P(VBC-co-VAC) copolymers as macroinitiators in conjunction with TiCl_4 at -40℃in CH_2Cl_2.The effects of VBC/TiCl_4(molar ratio) on monomer conversion,M_n and MWD of the resultant copolymers were investigated under 3 sets of conditions.It is found that P(VBC-co-VAC)-g-PIB copolymers with relatively narrow MWD(M_w/M_n ca.2.0) and with terminal tert-chlorine functional groups in branched PIB chains could be successfully synthesized when VBC/TiCl_4(molar ratio) was set in the range from 0.10 to 1.12.The unimodal GPC curve of the P(VBC-co-VAC)-g-PIB copolymers by RI detector was almost in harmony with the GPC curve by UV detector.The TEM image of the P(VBC-co-VAC)-g-PIB copolymer stained by RuO indicated that the copolymer formed a two-phase morphology with P(VBC-co-VAC)-rich domains of 20-100 nm in size tethered by PIB branch segments.     

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.     

Synthesis of spherical particles by self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-co-acrylic acid] in supercritical carbon dioxide

Spherical particles were prepared from poly[2-(perfluorooctyl)ethyl acrylateco-acrylic acid] random copolymers (P(POA-co-AA)) by self-assembly in supercritical carbon dioxide (scCO2). The P(POA-co-AA) copolymers with 9:1, 8:2, 7:3, and 6:4 molar ratios of the POA/AA unit completely dissolved in scCO2, however, the solubility was dependent on the POA/AA ratio. The copolymer with the higher AA content had a lower solubility. The scanning electron microscopy (SEM) observations revealed that the spherical particles were obtained in a heterogeneous state at pressures lower than the cloud point pressure. Dynamic light scattering and 1H NMR studies demonstrated that the copolymers formed random copolymer micelles consisting of the shells of the CO2-philic POA units and the cores of the CO2-phobic AA units and main chains. It was found that the formation of spherical particles could be optimized by the manipulation of the CO2 pressure and temperature for the different compositions of the copolymers.     

Self-assembly behavior of A-B diblock and C-D random copolymer mixtures in the solution state through mediated hydrogen bonding

We have synthesized poly(methyl methacrylate- b-4-vinylpyridine) (PMMA- b-P4VP) and poly(styrene- r-vinylphenol) (PS- r-PVPh) copolymers by using anionic and free radical polymerizations, respectively. Well-defined micelles through hydrogen bonding have been prepared by mixing PMMA- b-P4VP diblock copolymer and PS- r-PVPh random copolymer in a single solvent. Block copolymers were mixed with random copolymers, with various [N]/[OH] ratios (4/1, 2/1, 1/1, and 1/4) in which "[N]/[OH]" represents the molar ratio of pyridine groups on P4VP to hydroxyl groups on PVPh. The presence distribution of PVPh/P4VP and PVPh/PMMA hydrogen bonding depends on the feeding ratio of PVPh to P4VP. When the PVPh content is lower than that of P4VP, hydrogen bonding occurs only between PVPh and P4VP; with excess PVPh, additional hydrogen bonding between PVPh and PMMA would occur. Furthermore, the effect of the solvent quality on the self-assembly behavior of PMMA- b-P4VP/PS- r-PVPh blends is investigated by considering tetrahydrofuran (THF) and dimethylformamide (DMF) as common solvents. We can mediate the strength of hydrogen bonding in blend systems by adopting different solvents and inducing different morphology transitions.     

Rapid synthesis of biodegradable poly(epsilon-caprolactone-co-p-dioxanone) random copolymers under microwave irradiation

<正>Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO) random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL) and p-dioxanone(PDO) under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP) of PCDO have been discussed.The resultant products were characterized by ~1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In the presence of different CL/PDO molar feed ratios,the conversions of both monomers were kept relatively constant.DSC sturdy suggested that with increasing the content of PDO in the copolymers,the crystalline degree of the copolymers decreased gradually.It is believed to be a promising biodegradable material.     

含苯并咪唑酮结构双酚A型聚芳醚酮共聚物的制备和表征

通过双酚A-4, 4'-二氟二苯甲酮-苯并咪唑酮(BPA-DFK-HBI)无规共聚得到一系列聚芳醚酮共聚物。 采用亲核缩聚和C-N偶联缩聚的方法, 获得了高相对分子质量聚合物。 通过红外、核磁等技术手段表征了聚合物的结构, DSC、TGA分析了聚合物的热性能。 结果表明, 随着苯并咪唑酮加入量的增大, 共聚物对DMF、NMP等极性溶剂的耐溶剂性能得到提升, 热稳定性增强, 玻璃化转变温度(T_g)也明显提高, T_g最高可达236 ℃。 当苯并咪唑酮与双酚A的摩尔比大于7:3时, 溶解性降低, 反应出现前期沉淀, 难以得到高相对分子质量的聚合物。     

Biofouling resistance of ultrafiltration membranes controlled by surface self-assembled coating with PEGylated copolymers

Block and random PEGylated copolymers of poly(ethylene glycol) methacrylate (PEGMA) and polystyrene (PS) were synthesized with a controlled polydispersity using an atom transfer radical polymerization method and varying molar mass ratios of PS/PEGMA. Two types of PEGylated copolymers were self-assembly coated onto the surface of poly(vinylidene fluoride) (PVDF) ultrafiltration membranes for enhancing biofouling resistance. It was found that the adsorption capacities of random copolymers on PVDF membranes were all higher than those of block copolymers. However, the specific and overall protein resistance of bovine serum albumin (BSA) on PVDF membranes coated with block copolymers was much higher than that with random copolymers. The increase in styrene content in copolymer increased the amount of polymer coating on the membrane, and the increase in PEGMA content enhanced the protein resistance of membranes. The optimum PS/PEGMA ratio was found to be close to 2 for the best resistance of protein adsorption and bacterial adhesion on the PEGylated diblock copolymer-coated membranes. The PVDF membrane coated with such a copolymer owned excellent biofouling resistance to BSA, humic acid, negatively surface charged bacteria E. coli, and positively surface charged bacteria S. maltophilia.     

Synthesis,characterization, and properties of poly(ester‐phosphoester)s by lanthanum triphenolate‐catalyzed ring‐opening copolymerization

The ring‐opening copolymerization of methyl ethylene phosphate (MEP, 2‐methoxy‐2‐oxo‐1,3,2‐dioxaphospholane) and ε‐caprolactone (CL) was performed in bulk with lanthanum tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s as single‐component catalyst, resulting in poly(ester‐phosphoester) random copolymers with high molecular weight and moderate molecular weight distribution. The properties of the copolymers were characterized by differential scanning calorimetry, X‐ray diffractometer, dynamic mechanical analysis, and static water contact angle measurement. The crystallinities of the copolymers were reduced with the increase of MEP molar fraction in the products. Moreover, copolymers with enhanced hydrophilicity and lower glass transition temperature could be obtained with higher MEP content, which may provide potential applications in biomedical field. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.