吩噻嗪-1,4萘醌-乙二醇体系光化学过程的时间分辨ESR研究

用时间分辨ＥＳＲ方法研究了吩噻嗪（ＰＴＨ）－１，４－萘醌（ＮＱ）－乙二醇（ＲＨ）体系中的光化学过程．只观察到萘醌的中性半醌自由基ＮＱＨ．＊的全发射极化的ＣＩＤＥＰ（化学诱导动态极化）信号，并未观察到极化的萘醌负离子ＮＱ－·＊的ＣＩＤＥＰ信号，表明ＲＨ与三重态ＮＱ间的质子转移反应远比ＰＴＨ与ＮＱ间的电子转移反应为快．ＮＱＨ．＊的ＣＩＤＥＰ信号随ｐＨ值的变化表明体系中同时有极化自由基ＮＱＨ．＊与ＮＱＨ．＋＊２存在，并且其间有质子交换．     

硅（磷）中心自由基与2─丁烯二酸二乙酯的加合反应机理

用ＥＳＲ方法研究了硅（磷）中心自由基与２－丁烯二酸二乙酯的加合反应机理．具有顺式构型的马来酸二乙酯（ＤＥＭ）与硅（磷）中心自由基反应，生成自由基加合物。ＤＥＭ的聚合反应受到抑制。具有反式构型的富马酸二乙酯（ＤＥＦ）易发生聚合反应，ＤＥＦ与硅（磷）中心自由基的加合反应受到抑制．ＤＥＦ与ＤＥＭ在反应性能上的差异，主要来自ＤＥＦ有较大的空间位阻效应．     

含丙磺舒高分子药物纳米微球的制备

非甾体抗炎药丙磺舒与甲基丙烯酸 2 羟乙酯 (HEMA)反应制得含丙磺舒单体HP ,此单体在乙醇 /水体系中与甲基丙烯酸甲酯 (MMA)共聚得到含丙磺舒高分子药物纳米微球 ,聚合产物用1H NMR ,FTIR ,GPC和TEM进行了表征。结果表明HP中丙磺舒以酯键连接到甲基丙烯酸 2 羟乙酯上 ,微球由HP和MMA的共聚物构成 ,平均直径为 ( 90± 5 )nm ,含丙磺舒 4 7 4 % ,含药量较高。     

PDMAEMA多重环境响应行为的NMR研究

利用原子转移自由基聚合（Atom Transfer Radical Polymerization, ATRP）合成了分子量分布较窄的聚甲基丙烯酸N, N-二甲氨基乙酯{Poly\[2 (diethylamino)ethylmethacry-late], PDMAEMA}并通过对液体核磁共振氢谱（¹H NMR）化学位移以及弛豫时间（T₁、T₂）的测量,研究了聚合物PDMAEMA的温度敏感、pH敏感以及离子敏感3种环境敏感行为. 发现聚合物链段的运动性,以及温度和离子强度诱导的相变行为,都与体系的pH值具有强依赖关系. 室温下,聚合物链段的运动性随pH值的增大而降低. 酸性条件下,聚合物表现出离子敏感性,而不表现出温度敏感性. 碱性条件下,聚合物表现出温度敏感性,不表现出离子敏感性.     

含稀土铕(Ⅲ)配合物光学树脂的制备及光学性能的研究

报道了将多种稀土铕（Ⅲ）的二元及三元配合物复合于苯乙烯（St)／甲基丙烯酸（HMA）的共聚体系,制备得到具有发光功能的透明光学树脂,对其光学性能进行研究。同时,考察了稀土配合物的含量对聚合物 透明性、发光性能的影响。     

对－氯苯乙烯和丙烯酸甲酯梯度共聚物的微观结构表征

对由原子转移自由基聚合(ATRP)方法得到的具有“活性”聚合特征的对－氯苯乙烯(S)和丙烯酸甲酯(M)梯度共聚物结构进行了表征．通过¹H、¹³C 核磁共振(NMR)方法和对羰基¹³C峰峰面积的拟合积分研究了该共聚物的单体以及以M为中心的三元组序列结构的组成含量随转化率的变化．研究结果表明：共聚物链中S和M单体含量随着转化率的增加分别表现出减小和增大的变化趋势;三元组序列结构的含量变化中,SMS和MMM分别呈现出单调下降和上升的变化,而MM/MMS则随着转化率的增加达到一个最大值,然后呈现下降趋势．本文还尝试运用了以M为中心的五元组序列结构对羰基¹³C峰峰面积进行更精确的拟合积分,其拟合峰面积的计算结果显示了与上述三元组序列结果相同的变化规律．     

无皂阳离子MMA/HEMA胶乳粒子的制备及表征

讨论了微波辐照下带正电荷的自由基引发剂偶氮二异丁基脒盐酸盐 (AIBA)引发甲基丙烯酸甲酯(MMA)和甲基丙烯酸 2 羟乙酯 (HEMA)共聚 ,用透射电子显微镜、红外光谱仪、差热分析仪等对聚合产物进行表征 .结果表明 :两种单体发生了共聚反应 ,制得均分散、表面洁净的无皂阳离子胶乳粒子 ;粒子的粒径随着单体HEMA浓度的增加先减小后增加 .在微波辐照下共聚反应的速率非常快 ,几乎所有的反应在 2 0min之内就能完成 .随着单体HEMA浓度的增加 ,乳液抗电解质稳定性提高     

丙烯酰胺在反向微乳液中聚合反应的研究

在水－ＡＯＴ－甲苯反向微乳液体系中，选用了四种引发剂ＡＩＢＮ，（ＮＨ４）２Ｓ２Ｏ３，ＮａＨＳＯ３，ＭｎＳＯ４－Ｏ２－ＮａＨＳＯ３，开展丙烯酰胺的聚合反应的研究，其中着重研究引发剂的浓度，反应温度等因素对聚合分子量的影响。     

纳米α-Fe/PS复合材料的制备及其热力学性能研究

 采用油包水(W/O)的微乳液体系制备了粒度为20~100 nm的α Fe。对纳米Fe进行表面有机改性后分散到苯乙烯（St）单体中，得到分散均匀的Fe/St分散体系，用本体聚合的方法制备了纳米Fe/PS复合材料。利用XRD，TEM，FTIR，SEM及TG DSC分别研究了所得纳米Fe的性能、复合材料的结构、纳米Fe在PS中的分散情况以及掺杂量对纳米Fe/PS复合材料的热力学行为的影响。研究结果表明：增加纳米α-Fe的掺杂量能提高PS的降解率，降低降解温度，增大热分解的焓变。     

傅里叶变换红外光谱对二氧化硅颗粒表面接枝含糖聚合物形成过程研究

在二氧化硅颗粒表面通过原子转移自由基可控聚合(ATRP)的方法接枝类天然碳水化合物簇,利用多个糖配体与多个蛋白受体的多价结合来获得稳定的相互作用,可以有效富集蛋白及其水解产物~([1])。基于此,设计了一种含糖聚合物单体2-葡糖酰胺基乙基甲基丙烯酰胺盐酸盐(GAEMA),通过ATRP的方法接枝到SiO_2表面,并通过湿法填柱,将木糖水解液实际体系注入。应用傅里叶变换红外光谱研究了含糖聚合物形成过程以及根据化学键的归属,对酰胺Ⅰ带进行解卷积处理,再对各个峰去指认,判断所属蛋白。     

Nitroxide-controlled free radical copolymerization of styrene and acrylonitrile monitored by electron spin resonance and fourier transform infrared technique in situ

Nitroxide-mediated homopolymerization of styrene (St) and copolymerization of styrene and acrylonitrile (An) were monitored respectively by electron spin resonance and Fourier transform infrared technique in situ, and the polymerization kinetics was investigated in detail. Homopolymerization of St was well controlled in the presence of 4-hydroxyl-2,2,6,6-tetramethyl-l-piperidinyloxy (HTEMPO, N*) at high temperature. The initiation reactions and polymerization rates were changed by varying initiators, such as benzoyl peroxide (BPO), 2,2-azobis-isobutylonitrile (AIBN) and dicyclohexyl dicarbonate peroxide (DCPO) because of the different half-period values of the initiators. For the St system containing the DCPO with longer half-period value, the reaction rate was enhanced and the final conversion was increased because the larger amount of the DCPO residual released continuously the excess radicals to increase growing radical concentration. But the polydispersity of the resulting polymer became somewhat larger. The copolymerization of St and An with AIBN as initiator in the presence of HTEMPO was also tamed in the living fashion of stable free radical polymerization in the range of the total monomer conversion below 40%. The hydrogen-abstracting effect on the penultimate unit of the primary radicals or growing radical was observed through a copolymerization process. The larger amount of St was combined into the copolymers, leading to an increase of the An contents especially in the latter period of copolymerization, due to the inhibited addition of An on the growing radicals with end An unit. The normal random copolymerization was interrupted, resulting in the different virtual reactivity ratio. The dissociation and combination equilibrium between N* and the different end St and An units on propagating radicals affected the consuming rates of St and An. A possible copolymerization mechanism containing hydrogen-abstracting reaction was suggested.     

In situ monitoring of styrene polymerization using Raman spectroscopy. Multi‐scale approach of homogeneous and heterogeneous polymerization processes

Free radical polymerization of styrene was monitored in situ by combining Raman spectroscopy to other experimental techniques (gravimetry and rheology). Three different processes were investigated: bulk, emulsion and miniemulsion polymerization. A complete analysis of the evolution of Raman spectrum during the course of reaction showed that a lot of information about molecular dynamics could be extracted and related to chemical phenomena. In addition, we report for the first time the coupling of Raman spectroscopy to a rheometer in order to monitor styrene bulk polymerization both at the scale of chemical bonds and at the scale of macroscopic phenomena (viscosity variation). Copyright © 2013 John Wiley & Sons, Ltd.     

Time-resolved Fourier-transform and continuous-wave ESR studies on photo-initiated polymerization

Radical polymerization of vinyl monomers as initiated by the diphenylphosphinoyl (DPO) radical which is formed by the photo-cleavage of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TMDPO) was investigated by continuous-wave electron spin resonance (cw ESR) and Fourier-transform (FT) ESR. Well-resolved hyperfine structures (hfs’s) of the starting radicals were observed by the time-resolved cw ESR for vinyl acetate, ethyl vinyl ether, styrene, methyl methacrylate (MMA), and isoprene. The rates of formation and the spin-lattice relaxation were determined by time-resolved FT ESR for these starting radicals. In the polymerization of MMA and isoprene the primary propagating radicals were found for the first time by the observation of their well-resolved hfs’s with timeresolved cw ESR. On the basis of the kinetic analysis including the spin-lattice relaxation, the rates of formation and the spin-lattice relaxation were determined by simulation of the time profile of FT ESR for the primary propagating radicals of MMA and isoprene. The rate of the primary propagating step was found to be by two orders greater than an average value of whole propagating steps as obtained by a steady-state measurement.     

Enhancement of ultrasonically initiated emulsion polymerization rate using aliphatic alcohols as hydroxyl radical scavengers

Ultrasonically initiated emulsion polymerization of styrene was carried out in the presence of aliphatic alcohols, e.g. methanol, ethanol, n-pronanol and n-butanol, as volatile hydroxyl radical scavengers. With the addition of methanol, the polymerization rate of styrene increased, while the molecular weight and the average particle size of the produced polystyrene decreased because more radicals were produced in the presence of methanol. This is true also for the other polymerization system using other aliphatic alcohols, such as ethanol, n-pronanol and n-butanol, suggesting that the alcohols enter into cavitation bubbles and further react with hydroxyl radicals (*OH) from the sonolysis of water to produce hydroxyalkyl radicals, so as to reduce the recombination of *H and *OH radicals, therefore more radicals will be present in the systems for initiating polymerization. Obviously, it is an effective way to enhance ultrasonically initiated emulsion polymerization rate of styrene by adding volatile hydroxyl radical scavenger.     

Facile graft polystyrene onto multi-walled carbon nanotubes via in situ thermo-induced radical polymerization

A facile procedure was developed for the grafting of polystyrene onto the surfaces of multi-walled carbon nanotubes (MWNTs) via the in situ thermo-induced bulk radical polymerization of styrene at the different polymerizing temperatures, in the presence of MWNTs without any initiator added. The grafting products were validated by the dispersibility, TEM, TGA, FT-IR, and Raman analysis. The TGA results also showed the lower polymerizing temperature was propitious to the free radical addition reactions.     

Kinetic approach to modeling the radical polymerization of styrene in the presence dibenzyl trithiocarbonate

A mathematical model of the kinetics of the radical polymerization of styrene in the presence of dibenzyl trithiocarbonate by the reversible addition-fragmentation chain transfer mechanism with cross-termination of radicals and intermediates and quadratic termination of intermediates is developed. The adequacy of the polymerization mechanism underlying the model and the related mathematical formalism are tested by comparing the calculated and measured values of the average molecular-weight characteristics of resulting polystyrene.     

锗掺杂聚合物及其泡沫的制备与表征北大核心CSCD

采用稳定自由基聚合法合成了锗掺杂聚苯乙烯类聚合物,并利用聚合物溶液的热致相分离原理和冷冻干燥技术制备出具有多孔结构的锗掺杂泡沫材料。通过核磁共振氢谱、等离子体发射光谱及扫描电镜等测试手段表征了聚合物分子和泡沫结构。结果表明,聚合物分子具有极窄的分子量分布,锗掺杂原子分数为2．6％;泡沫具有多孔网络结构和薄片状骨架,骨架间的孔洞尺寸为1～10／zm,泡沫骨架随密度的降低趋于细化,孔洞变大。     

Preparation and characteristics of acrylic acid/styrene composite plasma polymerized membranes

Plasma polymerization has gained increasing interest for the deposition of functional plasma-polymerized membranes suitable for a wide range of applications on account of its advantageous features. In this work, acrylic acid/styrene composite plasma polymerized membranes were synthesized by plasma polymerization of a mixture of acrylic acid and styrene monomers in a low-frequency after-glow capacitively coupled plasma (CCP) discharge process. The structure and composition of the plasma polymerized membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the partial pressure ratio between acrylic acid (AA) and styrene (St), applied discharge power and the energy of the extracted particles have considerable effects on the structure and the content of functional groups of the deposited membranes.     

Nonisothermal Crystallization Behavior of Polypropylene Grafted Silane and Styrene Using γ-Ray Irradiation

Polypropylene grafted silane and styrene (named PP-g-Si/St in this article) was successfully prepared by radical graft polymerization initiated by γ-ray irradiation. The influence of total absorbed dose on the graft ratio of vinyltrimethoxysilane onto PP and the melt flow rate (MFR) of the PP-g-Si/St product were studied. The effect of graft ratios of vinyltrimethoxysilane on the melting point and nonisothermal crystallization kinetics of PP-g-Si/St was investigated by the method of differential scanning calorimetry (DSC). With increasing vinyltrimethoxysilane and styrene (used as viscosity modifier and free radical source) grafted on PP, the melting point of PP-g-Si/St became lower. Several different analysis methods, including those of Avrami, Jeziorny, and Mo and colleagues, were employed to describe the nonisothermal crystallization process of the grafted samples. The results indicate that the peak temperature of crystallization of PP-g-Si/St sample was lower than that of virgin PP. Crystallization kinetics revealed that the rates of nucleation and growth were affected differently by the graft ratio of vinyltrimethoxysilane onto PP. The activation energy was calculated on the basis of the method of Kissinger, and the values were 253.6 and 215.7 kJ/mol for virgin PP and PP-g-Si/St, respectively.     

A Quantum-chemical study of the mechanism of formation of styrene polymerization centers under initiation by the ferrocene—benzoyl peroxide system

The mechanism of formation of free polystyrene growth radicals and radicals bound to complexes with ferrocene when polymerization was performed in the presence of the ferrocene—benzoyl peroxide initiating system was studied by quantum-chemical calculations with the use of the PRIRODA program and the PBE/3z method. The calculated structure of the charge transfer complex between ferrocene and benzoyl peroxide was in agreement with the experimental data. The calculated heat effects of possible complex decomposition reactions showed that radical formation easily occurred in the presence of the monomer only. The most favorable energetically scheme of the formation of the active centers of the complex-radical polymerization of styrene, including the intermediate formation of the ferrocene—benzoyloxy radical complex, was suggested.