"LIVING" FREE RADICAL SYNTHESIS OF NOVEL RODCOIL DIBLOCK COPOLYMERS WITH POLYSTYRENE AND MESOGEN-JACKETED LIQUID CRYSTAL POLYMER SEGMENTS

The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.

On the Scaling Study for the A_f-A_g Type Free Radical Polymerization

根据Ａｆ－Ａｇ自由基加聚反应的数量分布函数，导出凝胶点附近的渐进分布函数和高分子矩的表示式．进一步应用标度变换，得到了描述溶胶－凝胶相变的广义标度律，从而揭示了Ａｆ－Ａｇ自由基加聚的固化反应是一个相变过程．

DESIGN AND SYNTHESIS OF NOVEL CHIRAL IONIC LIQUIDS AND THEIR APPLICATION IN FREE RADICAL POLYMERIZATION OF METHYL METHACRYLATE

Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Theirchemical structures were characterized by ~1H-NMR. Reverse atom transfer radical polymerization of methyl methacrylate(MMA) in these two ionic liquids was carried out using AIBN/CuCl_2/bipy as the initiating system. The resultant well-definedpolymethyl methacrylate (PMMA) was employed as a macroinitiator to induce the atom transfer radical polymerization ofmenthyl methacrylate (MnMA) in chlorobenzene, which yielded a PMMA-b-PMnMA diblock copolymer with narrow polydispersity.

SYNTHESIS OF HETEROARM STAR-SHAPED POLYMER BY THE USE OF POLYFUNCTIONAL CHAIN-TRANSFER AGENT via CONVENTIONAL FREE RADICAL POLYMERIZATION

Heteroarm star-shaped polymers were synthesized by conventional free radical polymerization in two steps by the use of polyfunctional chain transfer agent.In the first step,free radical polymerization of methyl methacrylate was carried out in the presence of a polyfunctional chain transfer agent,pentaerythritol tetrakis(3-mercaptopropinate).At appropriate monomer conversions,two-arm PMMA having two residual thiol groups at the chain center or three-arm PMMA having one residual thiol group at the core were o...

AQUEOUS STABLE FREE RADICAL POLYMERIZATION PROCESSES

An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.

Studies on the Self-condensing Vinyl Living Radical Polymerization of a Novel Acrylate Inimer

A novel acrylate inimer, 2-（2-chloroacetyloxy） ethyl acrylate, was prepared by the reaction of 2-hydroxyethyl acrylate with chloroacetyl chloride in the presence of triethylamine. The self-condensing vinyl living radical polymerization of the inimer was studied and the hyperbranched macromolecules containing ester linkages on their backbone were prepared. All the polymerization products were characterized by 1H NMR. The polymerization degree and the branching parameter were calculated based on the 1H NMR spectra. It has been shown that this inimer exhibits a very distinctive polymerization behavior. Similar to step-growth polymerization, the polymerization degree of the products formed increased exponentially during the early stage of the polymerization, and then the increasing rate slowed down. However, the inimer remained present throughout the polymerization consistent with conventional free radical polymerization. Also, if much longer polymerization time was used, the polymerization system would become gel due to the crosslinking reaction derived from radical-radical recombination. As a result of the unequal reactivity of -CH2Cl and >CHCl, an almost linear product was obtained at a molar ratio of bipy to inimer=0.05, while a relatively high ratio of bipy to inimer 1 favored the formation of the branched structure. The macromolecules formed at a high ratio of bipy to inimer 1 exhibited an excellent solubility in organic solvents such as acetone.

FREE RADICAL RING OPENING POLYMERIZATION OF CYCLIC ACRYLATES

Cyclic acrylates, 2,2- dimethyl-5-methylene-1 , 3-dioxolan-4 -one and 2- phenyl-5-methylene-1,3-dioxolan-4-one, were synthesized successfully. The monomers were characterized by ~1H NMR, ^(13)C NMR, IR and elemental analysis or HRMS. Polymerization of the monomers were carried out at 120℃ with di-t-butylperoxide as initiator. The polymers were studied by ~1H NMR, ^(13)C NMR, UV and hydrolysis. The molecular weights of the resulting polymers were estimated by viscosity measurement and the extent of ring opening was estimated also by ~1H NMR and hydrolysis of the polymers and further confirmed by UV spectra.

SYNTHESIS AND FREE RADICAL POLYMERIZATION OF 2-OXO-3-METHYLEN E-5-PHENYL-1,4-DIOXAN

The novel cyclic monomer, 2-oxo-3-methylene-5-phenyl-1,4-dioxan, was synthesized by a set of reactions. Several intermediates were prepared and characterized in order to determine the monomer structure. The presence of chiral centers in the intermediates and resulting monomer makes it complicated to separate , purify and characterize them. It is a very reactive monomer which will polymerize even at room temperature if expose to moisture and air. This monomer can undergo essentially quantitative flee radical ring opening polymerization. The driving force for ring opening is the formation of new carbonyl group and benzylic radical. The monomer and polymer structure were established by IR, ~1H NMR, ^(13)C NMR and elemental analysis or high resolution mass spectrum. The molecular weight of the resulting polymer was estimated by viscosity determination.

CONTROLLED/"LIVING" RADICAL POLYMERIZATION OF STYRENE IN AN AQUEOUS DISPERSION SYSTEM

Atom transfer radical polymerization (ATRP) of styrene catalyzed by cuprous (CuX)/1,10-phenanthroline (Phen) and CuX/CuX2/Phen was conducted in an aqueous dispersed system. A stable latex was obtained by using ionic surfactant sodium lauryl sulfonate (SLS) or composite surfactants, such as SLS/polyoxyethylene nonyl phenyl ether (OP-10), SLS/hexadecanol and SLS/OP-10/hexadecanol, Among which SLS and SLS/OP-10/hexadecanol systems established better dispersed effect during the polymerization, It was found that Phen was a more suitable ligand than N,N,N',N',N'-pentamethyldiethylenetriamine (PMDETA) to maintain an appropriate equilibrium of the activator Cu(I) and the deactivator Cu(II) between the organic phase and the water phase, The effect of several initiators (such as EBiB, CCl4 and 1-PEBr) and the temperature on such a kind of ATRP system was also observed. The number-average molar mass (M-n) of polystyrene (PS) increased with the conversion and the molar mass distribution (M-w/M-n) remained narrow. These experimental data show that the polymerization could be controlled except for the quick increase of monomer conversion and the number-average molar mass of PS in the initial stage of polymerization. Furthermore, the initiator efficiency was found to be low (similar to57%) in CuX/Phen catalyzed system. To overcome this problem, Cu(II)X-2 (20 mol%-50 mol% based on CuX) was introduced into the polymerization system. In this case, higher initiator efficiency (60%-90%), low M-w/M-n of PS (as low as 1.08) were achieved and the molar masses of the PS fit with the theoretical ones.

“LIVING”/CONTROLLED RADICAL POLYMERIZATION OF ETHYL METHYLACRYLATE WITH 2,2’-AZOBISISOBUTYRONITRILE/FERRIC CHLORIDE/TRIPHENYLPHOSPHINE INITIATION SYSTEM

'Living'/controlled radical polymerization of ethyl methacrylate (EMA) was carried out with a 2,2'-azobisisobutyronitrile (AIBN)/ferric chloride (FeCl_3)/triphenylphosphine (PPh_3) initiation system at 85℃. Thc numberaverage molecular weight (M_n) increases linearly with monomer conversion and the rate of polymerization is first order withrespect to monomer concentration. The M_w of PEMA ranges from 3900 to 17600 and the polydispersity indices are quitenarrow (1.09～1.22). The conversion can reach up to～100% and M_w of the polymers obtained is close to that designed. Thepolymerization mechanism belongs to the reverse atom transfer radical polymerization (ATRP). The polymer was end-functionalized by chlorine atom, which acts as a macroinitiator to proceed extension polymerization in the presence ofCuBr/bipy catalyst system via an ATRP process. The presence of ω-chlorine in the PEMA obtained was identified by ~1H-NMR spectrum.

SYNTHESIS AND FREE RADICAL RING-OPENING POLYMERIZATION OF 2-METHYL-AND 2-METHYL-9-n-BUTYL-(-7-METHYLENE-1,4,6-TRIOXA-SPIRO (4, 4)NONANE)

This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.

Nonisothermal Kinetics of Free-Radical Polymerization of 2,2-Dinitropropyl Methacrylate

The 2,2-dinitropropyl methacrylate（DNPMA） was synthesized by esterification of α-methacrylic acid with 2,2-dinitropropanol.The free-radical bulk polymerization of DNPMA in the presence of 2,2-azobisisobutyronitrile（AIBN） was investigated by differential scanning calorimetry（DSC） in the nonisothermal mode.Kissinger,Ozawa and Barrett methods were applied to determine the activation energy（Ea） and the reaction order of the free-radical polymerization.The results showed that the temperature of exothermic polymerization peaks increased with increasing heating rate.With increasing the molar ratio of monomer/initiator and the heating rate,the reaction order of nonisothermal polymerization was approximately equal to 1.The average Ea value from Kissinger and Ozawa methods（77.74±1.07 kJ/mol） was smaller than the value from the Barrett method（Ea=102.36 kJ/mol）.

NITROXIDE-MEDIATED FREE RADICAL SYNTHESIS OF MESOGEN-JACKETED LIQUID CRYSTAL POLYMERS

The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.

Controlled Radical Polymerization of Styrene in the Presence of Different Copper Complexes and Organic Halides

The polymerization behaviors of Styrene (St) in the presence of CuX/L [X=Cl or Br; L= 2,2 bipyridine (bpy), 1,10 phenanthroline (phen) or 4,7 diphenyl 1,10 phenanthroline (DPP) ] and R X (R=trichloromethyl, benzyl or allyl; X=Cl or Br) have been studied and examined. In a CuCl/bpy/RCl/St system, a bimodal GPC peak at the early stage of polymerization was observed, and a concept of multi active species was proposed to explain this phenomenon. In a CuCl/phen (DPP)/RCl/St system, the \%M\%\-n of polystyrene (PS) increased linearly with St conversion and ln[M] o/[M] also increased linearly with time, indicating the living nature of this system. Furthermore, the stability of the propagating active species in a CuBr/phen/RBr/St system is higher than that in the CuBr/phen/RBr/St system.

REVERSE ATOM TRANSFER RADICAL POLYMERIZATION OF STYRENE WITH COPPER-BASED CATALYST

'Living'/controlled radical polymerization of styrene was carried out with diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS)/CuCl2/bipyridine (bipy) initiation system at 120 degreesC. The molecular weights of resultant PSt increased with the monomer conversion and the polydispersities were in the range of 1.37 similar to1.52. A linear ln([M](o)/[M]) versus time plot was also obtained indicating the constant concentration of growing radicals during the polymerization with this initiation system. End group analysis by H-1-NMR spectroscopic studies showed that the end groups of the polymer obtained is omega -functionalized by a chlorine group from the catalyst and alpha -functionalized by a (carbethoxy-cyano-phenyl)methyl group from the fragments of the initiator. Having CI atom at the chain end, the PSt obtained can be used as a macroinitiator to promote a chain-extension reaction with fresh St and block copolymerization reaction with a second monomer, such as methyl methacrylate, in the presence of CuCl/bipy catalyst via a conventional ATRP process.

PAC-P(AM-BA)杂化高分子絮凝剂制备及絮凝效能评价

针对油田化学驱污水难处理问题,采用水溶液自由基胶束聚合法,以聚合氯化铝(PAC)为无机组分,丙烯酰胺(AM)、丙烯酸丁酯(BA)为有机单体,合成一种新型无机-有机杂化高分子絮凝剂(PAC-P(AM-BA))。利用傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA)、扫描电子显微镜(SEM)和比表面积分析仪(BET)对絮凝剂进行表征。结果表明,BA以化学键连接在聚丙烯酰胺(PAM)长链中,无机组分与有机组分之间以离子键连接。PAC-P(AM-BA)热分解温度为233.93℃,比表面积为30.351m^(2)·g^(-1)。絮凝实验结果表明,PAC-P(AM-BA)最佳投加量为20 mg·L^(-1),沉降时间为10 h,其絮体分形维数为1.733。在絮凝效能对比实验中,PAC-P(AM-BA)的平均除油率为90.3%,较阳离子聚丙烯酰胺(CPAM)和复配型絮凝剂(PAC+PAM)分别高出16.4%和29.0%。

氯乙烯聚合研究进展

聚氯乙烯(PVC)由于其低成本和通用性,应用领域广泛。自由基聚合在PVC工业生产上获得广泛应用,随着PVC市场竞争日趋激烈,具有低刺激性气味、高增塑剂吸收率和高热稳定性等性能的高品质通用型PVC更易受市场青睐,沉淀聚合法能够避免分散剂的使用,可以获得特殊性能PVC树脂;可逆失活自由基聚合技术具有潜在的应用前景,近年来获得广泛的关注,包括可逆加成-断裂链转移聚合、原子转移自由基聚合和氮氧稳定自由基聚合等。本文分别围绕自由基聚合和可逆失活自由基聚合两个方面总结了近期国内外氯乙烯聚合的研究进展,并提出发展建议。

基于Fe^(3+)-DA-APS自催化体系的Fe_(3)O_(4)/PAA水凝胶的制备及性能研究

以Fe_(3)O_(4)纳米粒子为磁性组分,基于AA(丙烯酸)与部分Fe3O4反应产生的Fe3+、多巴胺(DA)构建双重自催化过硫酸铵(APS)的自由基聚合体系,在低温下制备了Fe_(3)O_(4)/聚丙烯酸(PAA)水凝胶,并对其进行表征。研究结果表明:Fe_(3)O_(4)/PAA水凝胶具有良好的力学性能,断裂伸长率、拉伸强度分别为900%、251.1 kPa;同时,其可较好粘附不同基材,在钢材上粘附-剥离循环20次后粘附强度仍稳定在30.7 kPa左右;此外,其还可感应极小形变,并在166 ms内快速响应。该Fe_(3)O_(4)/PAA水凝胶综合性能良好,具备应用于柔性传感器等领域的潜力。

基于一磷酸腺苷的RAFT接枝棉织物的结构和阻燃性能

采用可逆加成断裂链转移自由基聚合(RAFT)方法,基于纤维基二硫代酸酯类RAFT链转移剂(Cell-CTA),以偶氮二异丁腈为引发剂,以改性一磷酸腺苷(AAMP)为阻燃单体,在纯棉织物上进行RAFT接枝聚合改性,制备了接枝阻燃棉织物(Cell-g-PAAMP)。采用红外光谱、扫描电镜、拉曼光谱等方法对Cell-g-PAAMP的化学结构、表面形貌及其燃烧后残炭的形态和石墨化程度进行了表征。采用热重分析仪、数显氧指数测定仪、织物强力仪、透气性能测试仪对Cell-g-PAAMP的阻燃性能和物理机械性能进行了分析。Cell-g-PAAMP红外光谱中,1199 cm^(-1)处新出现P=O双键的伸缩振动峰,说明已成功制备Cell-g-PAAMP。扫描电镜和拉曼光谱结果表明,Cell-g-PAAMP表面粗糙,有颗粒状物质附着于表面,燃烧后残炭形态保持基本完整且结构致密,石墨化程度提高。与纯棉织物对比,Cell-g-PAAMP初始分解温度降低,热稳定性提高,极限氧指数提高,获得了良好的阻燃效果。Cell-g-PAAMP透气性和断裂强力下降,但断裂伸长率却大幅增加。

SYNTHESIS AND POLYMERIZATION OF 2-OXO-3-METHYLENE-1,4-DIOXANES

A new kind of monomers was successfully synthesized by the reaction between 2-chloro methyl cycloketal and trimethylsilyl cyanide, followed by ring closure and dehaiogenation. Polymerizations of the monomers were carried out in benzene solution at 80℃ with benzoyl peroxide as initiator. Both the structures of monomers and polymers were characterized by IR, ~1H NMR, ^(13)C NMR and elemental analysis.