丁二烯本体聚合及与异戊二烯的共聚合

研究了负载钛催化剂引发丁二烯本体聚合合成高反式-1,4-聚丁二烯的条件,如催化剂组成、温度、时间、催化剂用量等对聚合过程和催化效率的影响.在Al/Ti摩尔比为70,30℃,8h条件下,在Ti/Bd(摩尔比)为(1～2)×10-5时,丁二烯的本体聚合具有最佳催化效率,聚丁二烯的反式-1,4-结构摩尔分数为99%.并对丁二烯和异戊二烯的共聚合进行了研究,结果表明二者发生了共聚合.     

Multifunctional Initiator with Platinum-Acetylide Dendritic Core for Living Polymerization of Isocyanides

A novel multifunctional initiator has been developed by peripheral modification of a Pt-acetylide dendrimer. Pd–Pt μ-ethynediyl units were introduced to the first-generation dendrimer by a divergent method. The dendritic initiator was applicable to the living polymerization of aryl isocyanides, producing high molecular weight polymers with a narrow polydispersity index in quantitative yields. The ³¹P NMR spectrum of the resulting polymer suggested that all Pd–Pt μ-ethynediyl units in the dendritic molecule actually functioned as an initiator.     

Grafting of polystyrene “from” and “through” surface modified titania nanoparticles

We report the surface modification of titania (TiO₂) nanoparticles with azo-based radical initiator and vinyl (acrylate) polymerizable groups. This is achieved through the reaction of the surface hydroxyl groups of the titania with acid halides. Polymer (specifically, polystyrene) was grafted “from” the surface using the azo-modified titania, and “through” the surface of the vinyl-modified surface. Both conventional radical and reversible addition-fragmentation chain transfer (RAFT) polymerizations were performed. The surface-modified titania and the polystyrene-titania nanocomposites were characterized using IR spectroscopy, thermogravimetric analysis and gel permeation chromatography.     

Chemoenzymatic synthesis of Y-shaped diblock copolymer

Y-shaped diblock copolymer polycaprolactone-block-(polystyrene)₂ [PCL-b-(PSt)₂] was synthesized successfully by the combination of enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP). CH₃O-terminated PCL was synthesized firstly by eROP of ε-caprolactone (ε-CL) in the presence of biocatalyst Novozyme 435 and initiator CH₃OH, subsequently the resulting PCL was converted to macroinitiator by the esterification of it with 2,2-dichloro acetyl chloride (DCAC). PCL-b-(PSt)₂ diblock copolymers were synthesized in an ATRP of the styrene with CuCl/2,2′-bipyridine as the catalyst system. The kinetic analysis of ATRP indicated a controlled/‘living’ radical polymerization. The structure and composition of obtained polymers were characterized with NMR, GPC and FTIR. The thermal behavior was characterized by differential scanning calorimetry (DSC).     

Adsorption behaviour of functional grafting particles based on polyethyleneimine for chromate anions

Polyethyleneimine (PEI) was first grafted on the surfaces of micro-sized silica gel particles in the manner of the coupling graft, forming the grafting particles PEI/SiO₂. Afterward, for the grafted PEI, two polymer reactions, tertiary amination reaction and quaterisation, were allowed to be carried out in turn, and a kind of functional composite particles, QPEI/SiO₂, was obtained. QPEI/SiO₂ particles were used as solid adsorbent in the removal of chromate anions from aqueous solution. The static adsorption experiments (batch method) were performed, the effects of various factors on the adsorption capacity of QPEI/SiO₂ were examined, and the dynamic desorption experiments were also carried out. The experimental results show that QPEI/SiO₂ particles have strong adsorption ability for CrO₄²⁻ ions by right of electrostatic interaction, and the saturated adsorption amount actually reach up to 0.14 g/g. The isothermal adsorption behaviour is fitted to Langmuir model. The adsorption ability of QPEI/SiO₂ particles for CrO₄²⁻ ions is affected greatly by the quaterisation degree of the grafted PEI macromolecules. The QPEI/SiO₂ particles with higher quaterisation degrees have greater adsorption capacities. The adsorption ability of QPEI/SiO₂ particles for CrO₄²⁻ ions is nearly independent of pH values of the medium. QPEI/SiO₂ particles have excellent eluting and regenerating property as a mixed solution of NaOH and NaCl is used as eluent.     

高羟基含氟丙烯酸乳液的合成及性能研究

以丙烯酸酯类单体作为原料,以过硫酸钾为引发剂,采用预乳化半连续乳液聚合方式合成了高羟基丙烯酸乳液,并在后期补加氧化还原体系引发剂,提高了单体的转化速率。系统地研究了乳化剂用量、羟基单体、氟单体、硅单体含量等因素对涂膜性能的影响。最后,将制备的丙烯酸羟基组分同水性固化剂配制成双组分水性丙烯酸聚氨酯清漆,并分析清漆的性能。     

聚吡咯/凹凸棒石纳米复合材料的制备及导电性能

以三氯化铁(FeCl_3)为氧化剂,十二烷基磺酸钠(sodium dodecylsulfonate,DSNa)为掺杂剂,使吡咯单体(pyrrole,Py)在凹凸棒石(attapulgite,ATP)的表面发生原位聚合反应,制备出聚吡咯/凹凸棒石(polypyrrole/attapulgite,PPy/ATP)纳米导电复合材料.研究了毗咯用量、聚合温度、聚合时间、FeCl_3用量以及DSNa用量对纳米导电复合材料体积电阻率的影响,确定了制备纳米导电复合材料的工艺条件.通过X射线衍射、热重-差热分析、Fourier红外光谱、Raman光谱和透射电子显微镜对纳米复合材料进行表征,结果表明:当吡咯用量(以ATP的质量计)为30%,FeCl_3与Py的摩尔比为2.3,DSNa的浓度为0.02g/mL时,20℃反应3h得到的PPy/ATP复合材料的体积电阻率可达7Ω·cm,聚吡咯以非晶态形式存在于凹凸棒石表面,两者之间的作用为物理作用.     

Preparation and properties of alkoxysilane/butyl acrylate/methyl methacrylate copolymer latices

The incorporation of alkoxysilanes into latex systems is of major interest in the field of colloidal science. Two kinds of vinyl‐containing alkoxysilanes, methacyloxypropyltrimethoxyl silane and vinyltriethoxysilane, were copolymerized with butyl acrylate and methyl methacrylate by seeded emulsion polymerization, and copolymer latices were obtained. The morphologies of the latex particles were characterized with transmission electron microscopy. Dynamic light scattering showed that the particle size increased and the particle size distributions of all the copolymer latex particles were alike with increasing amounts of organosilane. The effects of the organosilane content on the morphology of the particles, the rheology, and the swelling properties were also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Methyl acrylate/1‐octene copolymers: Lewis acid‐mediated polymerization

Copolymerization of methyl acrylate (MA) with 1‐octene (1‐Oct) was conducted in the presence of free radical initiator, 2,2′‐azobis(2‐methylpropionitrile) (AIBN) using heterogeneous Lewis acid, acidic alumina. The polymers obtained were transparent and highly viscous liquids. The copolymer composition calculated from ¹H NMR showed alkene incorporation in the range of 10–61%. The monomodal nature of chromatographic curves corresponding to the molecular weight distribution in gel permeation chromatography (GPC) further confirmed that the polymers obtained are true copolymers. The number–average molecular weights (M_n) of the copolymers were in the range of 1.1 × 10⁴–1.6 × 10⁴ with polydispersity index of 1.75–2.29. The effects of varying the acidic alumina amount, time of polymerization, and monomer infeed on the incorporation of 1‐Oct in the polymer chain were studied. Increased 1‐Oct infeed led to its higher inclusion in the copolymer chain as elucidated by NMR. DEPT‐135 NMR spectral analysis was used to explicate the nature of arrangement of monomer sequences in the copolymer chain. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and flocculation properties of poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane)

A novel hydrophobically modified and cationic flocculant poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane) (P(AM‐DMC‐MAPMS)) was synthesized by inverse emulsion polymerization. The molecular structure of hydrophobically cationic polyacrylamide (HCPAM) was characterized by FTIR and ¹H‐NMR. The effects of DMC and MAPMS feed ratio on intrinsic viscosity and solubility were measured. The effects of hydrophobically cationic flocculants on reactive brilliant red X‐3B solution and kaolin suspension were studied. It was found that the introduction of MAPMS could increase the intrinsic viscosities of P(AM‐DMC‐MAPMS) and enhance the flocculation properties to anionic dye solution and kaolin suspension, but reduced their water‐solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009