两亲性PS-b-PEG-b-PS三嵌段共聚物的合成及在水中的聚集行为研究

采用原子转移自由基(ATRP)合成了一系列两端为短的聚苯乙烯(PS)嵌段,中间为长的聚乙二醇(PEG)嵌段的PS-b-PEG-b-PS两亲性三嵌段共聚物。采用1H-NMR、荧光探针法和动态光散射研究了PS和PEG嵌段长度对三嵌段共聚物在水中聚集行为的影响。结果表明:三嵌段共聚物在水中可以形成以PS嵌段为核和以PEG嵌段为壳的球形胶束,其胶束化的临界胶束浓度(CMC)随着PS嵌段长度增加而减小,流体力学半径(Rh)随PEG嵌段长度增长而增大,调整PS嵌段长度能有效地调控胶束的形成。胶束对疏水分子芘具有很好的装载能力,芘在胶束中的分配平衡常数(Kv)为105,随PS嵌段长度增加而增大。     

ATRP法合成PMMA-b-PS-b-PFx-14三嵌段共聚物

首先通过原子转移自由基聚合(ATRP)得到了末端含卤素的聚甲基丙烯酸甲酯，以这种PMMA为大分子引发剂，引发苯乙烯的ATRP反应，得到了末端含卤素的PMMA-PSt双嵌段共聚物。再以这种双嵌段共聚物大分子为引发剂，引发含氟丙烯酸酯Fx-14的ATRP反应，得到了一种PMMA-PSt-Fx-14三嵌段共聚物．通过GPC、核磁、粘度等数据证实了该聚合物的结构，并详细讨论了由于PMMA-PSt-Fx-14在溶液中的线团行为所产生的GPC测试中出现的特殊现象。     

含氟丙烯酸酯嵌段共聚物乳液的合成及表征

以PEDB(二硫代苯甲酸苯乙基酯)为链转移剂,进行AA(丙烯酸)、BA(丙烯酸丁酯)可逆加成-断裂链转移(RAFT)自由基聚合,得到数均相对分子质量可控、相对分子质量分布窄的聚合物P(AA-BA).以得到的聚合物为大分子RAFT自由基聚合剂,进行舍氟丙烯酸酯的扩链反应,制得稳定的含氟嵌段共聚物P(AA-BA)-b-PTFEA(甲基丙烯酸三氟乙酯)乳液.为了克服RAFT链转移剂在水中迁移慢的缺点,引入了自发相倒置的实验过程,即先进行AA、BA的本体聚合,然后在温和搅拌条件下滴加NaOH溶液,体系发生自发相倒置,产生稳定的亚微型聚合物颗粒,DLS测量乳液颗粒平均大小为4nm.乳液经TEM、DLS观测,粒径为50～60nm,颗粒分布均匀.     

两亲性含氟嵌段共聚物的RAFT制备及其自组装行为研究

采用大分子RAFT试剂技术,通过可逆加成-断裂链转移(RAFT)溶液聚合法制备了丙烯酸和甲基丙烯酸三氟乙酯的两亲性嵌段共聚物[P(AA-b-TFEMA)].跟踪研究了聚合转化率与时间的关系及聚合反应动力学.通过红外光谱、核磁和DSC表征了嵌段聚合物的分子结构和Tg.探讨了在不同条件下P(AA-b-TFEMA)在溶液中的...     

含聚氧乙烯链段的嵌段共聚物和接枝共聚物的合成及性能

综述了由聚氧乙烯链段与聚二烯烃、聚异丁烯、聚乙烯基吡啶、聚丙烯腈、聚丙烯酰胺或聚丙烯酸链段组成的各种嵌段共聚物及接枝共聚物的合成,并对其各种性能,包括两亲性质、络合碱金属离子性及微观相分离等进行了总结。     

聚醚聚硅氧烷两亲性三嵌段共聚物的合成研究

以Si-H双封端硅油和烯丙基聚醚为原料,通过硅氢加成,进行无溶剂体系PEO-b- PDMS-b- PEO共聚物的催化合成.系统考察了氯铂酸分子中胺类分子的掺杂种类及用量、反应时间和反应温度对反应体系Si-H转化率的影响.结果表明:当Bu3N以n(N)/n(Pt)＝1的量对H2 PtCl6进行掺杂,且反应温度为90℃及反...     

嵌段共聚物偶联剂的合成及其胶束化行为

采用阴离子聚合反应合成了可作为纤维增强聚合物复合材料界面改性偶联剂的苯乙烯/丁二烯/乙烯基三乙氧基硅烷及苯乙烯/异戊二烯/乙烯基三乙氧基硅烷嵌段共聚物,通过傅立叶红外光谱(FT-IR)、核磁共振氢谱(1H-NM R)等分析手段对合成产物进行了表征,并采用透射电镜(TEM)、动态激光光散射(DLLS)等技术研究了嵌段共聚物在溶剂中的组装行为。结果表明,反应合成了预定结构的嵌段共聚物偶联剂,该共聚物在选择性溶剂中能形成以可溶性链段为壳、难溶性链段为核的胶束结构,胶束的粒径与共聚物分子链及各嵌段的长度有关。     

嵌段共聚物增容共混聚合物的相形貌及胶束迁移行为研究

主要研究了对称性的聚苯乙烯-聚甲基丙烯酸甲酯嵌段共聚物(PS-b-PMMA,简称SM)对聚甲基丙烯酸甲酯/聚甲基丙烯酸环己酯(PMMA/PCHMA)熔融共混体系的增容。采用透射电子显微镜(TEM)表征了SM和PMMA分子量对共混体系微观相形态和胶束迁移行为的影响。研究表明,SM分别在PMMA与PCHMA均聚物中形成不同结构的胶束,当SM在PMMA/PCHMA界面上形成"湿刷"时,SM在PCHMA相中形成的胶束才能迁移到PMMA相中。SM的加入改善了PMMA与PCHMA之间的相容性,但其增容效果取决于SM的分子量。随着分散相PMMA分子量从19kg/mol增加到39kg/mol,PMMA粒子的平均粒径逐渐增加。     

Epoxy modified with triblock copolymers: morphology, mechanical properties and fracture mechanisms

The morphology, fracture toughness and mechanical properties of an anhydride-cured diglycidylether of bisphenol-A epoxy polymer modified with poly(methyl methacrylate)-b-poly(butylacrylate)-b-poly(methyl methacrylate) (MAM) have been investigated. The addition of three different MAM triblock copolymers (M22N, M52N and M52) to the epoxy polymer gives two different microstructures. A nanostructure with well-dispersed worm-like micelles (or a bicontinuous gyroid structure if the micelles are connected into a network) was obtained using M22N. The addition of M52N or M52 gives dispersed micron-size particles in the epoxy matrix for ≤7 wt% MAM, and a co-continuous microstructure at higher MAM contents. These triblock copolymers toughen the epoxy polymer significantly, with only slight reductions in the mechanical and thermal properties of the epoxy polymer. The maximum values of fracture toughness and fracture energy (1.22 MPa m^1/2 and 450 J/m², respectively) were measured using 12 wt% M22N, which is an increase of 100 and 350%, respectively, compared with the unmodified epoxy. The M52- and M52N-modified materials show a maximum toughness when a co-continuous microstructure is formed. The potential toughening mechanisms are identified and discussed.     

Synthesis and properties novel polyurethane-hexafluorobutyl methacrylate copolymers

Novel physically crosslinked polyurethane-hexafluorobutyl methacrylate (PU-M) copolymers were prepared by the macroiniferter-controlled radical polymerization method. The chemical structures of the PU-M copolymers were characterized by FT-IR, (1)H-NMR, GPC, DSC, and XPS. The self-assembly and surface properties of the PU-M copolymers have been investigated. The results revealed that PU-M copolymers have good hydrophobility, so the hydrophobility of polyurethane could be easily adjusted by controlling the content of the hydrophobic vinyl monomers. The mechanical evaluation shows that PU-M copolymers exhibit good mechanical properties. The effects of the fluorine content on the surface properties and self-assembly of the PU-M copolymers were investigated. The morphology of the PU-M copolymers' self-assembly was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and the mechanism of self-assembly was investigated. Antimicrobial property of the chlorinated PU-M copolymers against both Escherichia coli and Bacillus subtilis bacteria was examined and showed increase compared to that of pure polyurethane.     

Self-assembly of metal-polymer analogues of amphiphilic triblock copolymers

Organized arrays of anisotropic nanoparticles show electronic and optical properties that originate from the coupling of shape-dependent properties of the individual nanorods. The organization of nanorods in a controllable and predictable way provides a route to the fabrication of new materials and functional devices. So far, significant progress has been achieved in the self-assembly of nanorod arrays, yet the realization of a range of different structures requires changing the surface chemistry of the nanoparticles. We organized metal nanorods in structures with varying geometries by using a striking analogy between amphiphilic ABA triblock copolymers and the hydrophilic nanorods tethered with hydrophobic polymer chains at both ends. The self-assembly was tuneable and reversible and it was achieved solely by changing the solvent quality for the constituent blocks. This approach provides a new route to the organization of anisotropic nanoparticles by using the strategies that are established for the self-assembly of block copolymers.     

Self-assembly of functional nanostructures from ABC triblock copolymers

The spontaneous formation of nanostructured materials by molecular self-assembly of block copolymers is an active area of research, driven both by its inherent beauty and by a wealth of potential technological applications. Thin films of block copolymers have attracted increasing interest, particularly in view of possible applications in nanotechnology. Although much of the work has concentrated on block copolymers consisting of two components, the insertion of a third block greatly enlarges the structural diversity and allows incorporation of additional chemical functionality. Here we describe a highly ordered hexagonally perforated lamella structure based on an ABC triblock copolymer thin film. By suitable choice of the three blocks a versatile structure is formed. The perforated lamella can serve as a lithographic mask, it can be chemically converted into an amphiphilic structure without losing its order, and after selective removal of one of its constituents it could be used as a responsive membrane. Intriguingly, the particular choice of the blocks ensures that the structure is formed irrespective of the chemical nature of the solid substrate. The experimental results are supported by mesoscale computer simulations.     

氟硅氧烷共聚低表面能杂化材料的研究

通过溶液聚合和溶胶-凝胶法复合工艺,采用甲基丙烯酸十二氟庚酯(FA)为含氟单体、乙烯基三乙氧基硅烷(VTES)为硅单体和正硅酸乙酯(TEOS)为无机相前驱体直接合成了一种分子级复合,最外层含氟侧链定向于空气,中间层是碳碳主链,底层为硅氧网络结构的氟硅氧烷共聚低表面能杂化材料.结果表明,溶剂含量对含氟侧链向表面的迁移速度以及材料疏水性能有着非常重要的影响.     

Nanoparticles with tunable internal structure from triblock copolymers of PAA-b-PMA-b-PS

Polymer nanoparticles containing their own inherent nanostructure (lamellar, bicontinuous-like, or porous) were formed via the self-assembly of a triblock copolymer complexed with a multiamine counterion in mixed solvents. The internal nanostructure is due to local phase separation of the block copolymers and can be tuned by varying the solvent composition, the relative block composition, and the valency of the organic counterion.     

主链含三苯胺链段的TPA-DHPPV共聚物的合成及表征

合成了2,5-二氯甲基-1,4-二己氧基苯、1,4-二己氧基-2,5-二甲苯双(三苯基氯化季膦)和4',4-三苯胺二醛3种单体.通过聚合反应制得了聚1,4-二己氧基对苯乙炔(DH-PPV)和含三苯胺链段的PPV类共聚物(TPA-DHPPV),对聚合物进行了结构表征和性能测试.DH-PPV和TPA-DHPPV聚合物物质结构准确,在紫外光激发下能发出强的蓝绿光,荧光光谱表征说明该类聚合物均能发射较强的荧光,电致发光器件的伏安特性测试表明该类聚合物具有较低的驱动电压和较高的发光亮度,并且该类聚合物具有较高的热稳定性.     

Synthesis and properties of caprolactone and ethylene glycol copolymers for neural regeneration

Copolymer networks from poly(ethylene glycol) methacrylate (PEGMA) and caprolactone 2-(methacryloyloxy) ethyl ester were synthesized and the resulting structure of the copolymer network was characterized by differential scanning calorimetry, thermogravimetry, Fourier transform infrared spectroscopy, equilibrium water gain and dynamic mechanical analysis, results which were employed to conclude about the network structure of the resulting copolymers. The new material is a random copolymer with a good miscibility and increasing hydrophilicity as the PEGMA content increases in the composition. Physical data suggest an excess free volume and synergistic interactions between the lateral chains of both comonomers. Olfactory ensheathing cells were cultured on the different networks, and cell viability and proliferation were assessed by MTS assay. The copolymers with a 30?wt% of PEGMA showed the best results compared with the other compositions in this respect, indicating the relevance for biological performance of a balance of hydrophilic and hydrophobic functionalities in the polymer chain.