对氯甲基苯乙烯与丙烯腈、甲基丙烯酸酯类的自由基共聚研究

<正> 对氯甲基苯乙烯(p-CMS)是合成功能高分子的一个非常有用的起始单体,利用它的均聚以及与其它烯类单体的共聚反应,可制得含活性基团的高分子材料。但以往对该单体的聚合及共聚研究,较多的是以邻、间、对位氯甲基取代苯乙烯的混合物作为研究对象。本文采用纯对氯甲基苯乙烯,在开展对其基本性质、均聚反应机理研究的同     

异丁烯与对氯甲基苯乙烯正离子共聚合研究

以四氯化钛(TiCl4)、二氯乙基铝(AlEtCl2)、倍半铝(AlEt1.5Cl1.5)、三氯化铝(AlCl3)等路易斯酸为共引发剂,水或枯基醇(CumOH)为引发剂,在-80℃下的正己烷/二氯甲烷(V/V=6/4)的混合溶剂内,研究了异丁烯(IB)与对氯甲基苯乙烯(p-CMS)的正离子共聚合.利用示差凝胶渗透色谱仪(GPCRI)以及核磁氢谱(1H-NMR)对共聚物的表观分子量及分子量分布、共聚组成等进行分析,采用KelenTüd?s与Yezreielv-Brokhina-Roskin法计算了单体竞聚率,初步探讨了p-CMS与IB正离子共聚合的反应机理.结果表明,AlEtCl2、AlEt1.5Cl1.5、AlCl3均可催化大分子间的烷基化反应,产生凝胶;TiCl4作为共引发剂,可以得到无凝胶单峰分布共聚物;邻位氯甲基苯乙烯(o-CMS)不能参与共聚,p-CMS的共聚活性较低,IB与p-CMS的单体竞聚率为rIB=4.67,rp-CMS=0.70;随反应时间延长,共聚物中p-CMS的含量及共聚物分子量均逐渐增加;p-CMS单体自身几乎不参与引发,共聚到大分子链后,苄基氯缓慢参与引发,形成支化.提高共聚合温度至-60和-40℃,聚合速率降低,p-CMS的引发活性未发生明显变化.     

新型超支化接枝共聚物的合成

以对氯甲基苯乙烯(CMS)为活性单体,CuCl/2,2′-联吡啶(bpy)为催化体系,利用原子转移自由基聚合(ATRP)方法,制备具有不同支化度的超支化聚对氯甲基苯乙烯(h-PCMS, 4);以4为大分子引发剂,引发第二单体进行聚合,合成了两个以4为核的新型星状多臂共聚物,其结构经¹H NMR, IR和GPC表征。     

PU大分子单体水溶液性质

双亲聚合物一般由亲水和亲油 2种链段构成 ,有嵌段型[1,2 ] 和接枝型[3 ] 2种 ,其中通过大分子单体法合成双亲接枝聚合物备受关注[4] 。如以亲水性大分子单体和亲油性小分子单体共聚 ,大分子单体构成共聚物主链上支链 ,具有较大活动性 ,亲水效能高。采用对氯甲基苯乙烯[5] 或甲基丙烯酰氯[6] 与聚氧化乙烯大分子的一端相反应 ,可得到亲水性大分子单体 ,但其分子量及结构变化有限。本文采用常规条件 ,合成了嵌段式水溶性聚氨酯大分子单体 ,其分子量较大 ,共聚接枝的支链较长。利用该大分子单体具有非离子高分子表面活性剂的性质 ,采用无皂乳…     

新型含环己烯结构的氮杂环聚醚聚合物的合成

用新型聚合单体 1 甲基 4,5 二 (4 氯代苯甲酰基 )环己烯与 4 (4 羟基苯基 ) 2 ,3 二氮杂萘 1 酮、4,4′ 二氯二苯砜单体经亲核共缩聚反应 ,成功地合成了含环己烯结构的杂环联苯型聚醚系列聚合物 .用FT IR、1 H NMR、DSC、X 射线衍射等方法对聚合物进行了表征 ,并研究了聚合物的溶解性能 .结果表明 ,这系列聚合物是具有较高的玻璃化温度的可溶性无规共聚物 .聚合物含有不饱和双键结构 ,可作为交联聚合物、接枝聚合物及其它特种高分子材料的中间体 .而且通过二元或三元聚合 ,来改变交联点和接枝点的密度 ,为进一步得到结构更加多样化与性能各异的聚芳醚的交联聚合物、接枝聚合物及其它特种高分子材料 ,提供一个良好的基础     

氨基氮杂环荧光分子改性苯乙烯马来酸酐共聚物的研究

荧光高分子材料 ,由于其独特光学性质 ,成为功能高分子研究热点[1～ 3 ] .一般而言 ,荧光聚合物的合成有两种方法 ,一是首先合成荧光单体 ,然后与其他适宜单体聚合 ,得到荧光聚合物 ,然而荧光单体结构复杂 ,提纯困难 ,难以获得高分子量、成膜性能好的聚合物[4] ;另一种方法是通过官能团的反应 ,用荧光物质对聚合物进行化学改性来制备[5,6] .苯乙烯 马来酸酐共聚物 (ＳＭＡ)是一类成本低廉 ,性能良好的商品化聚合物材料 ,主链中含有具有反应性能的酸酐基团 ,这就使通过化学改性制备荧光聚合物成为可能 .本文通过 2 氨基苯并咪唑 ( 1 ) ,4 …     

RAFT试剂N-咔唑二硫代甲酸1,4-对二甲基苯双酯的合成及应用

以咔唑和对二氯甲基苯为原料, 合成了以咔唑为Z基团的双功能团RAFT聚合链转移试剂N-咔唑二硫代甲酸1,4-对二甲基苯双酯(PXCBD). 以PXCBD为链转移试剂, 以苯乙烯、丙烯酸甲酯及N,N-二丁基丙烯酰胺为单体, 考察了PXCBD在RAFT聚合中合成多嵌段共聚物上的应用, 并研究了PXCBD及由其合成的聚合物的荧光特性. 研究结果表明, PXCBD是一种性能优异的双功能团RAFT聚合链转移试剂, 可用于合成特殊结构并且带有荧光标识的功能高分子材料.     

含Iniferter微凝胶及星型聚苯乙烯的合成

借助于超声波振荡分散法,通过苯乙烯-二乙烯基苯-对氯甲基苯乙烯三元共聚合反应合成了可溶性聚苯乙烯微凝胶,用二乙基二硫代氨基甲酸钠(铜试剂)取代其中的氯原子得到具有Iniferter功能的多官能度自由基活性微凝胶,该活性微凝胶引发苯乙烯聚合得到星型高分子,星型高分子中仍有Iniferter功能的基团.     

“活”的α-甲基苯乙烯共聚物:聚合反应新化学和材料工程新技术

高于临界聚合反应温度时,α-甲基苯乙烯(AMS)单体和其聚合物处于聚合-解聚平衡.基于AMS聚合物在受热时可裂解生成大分子链自由基的特性,提出了含AMS结构单元的共聚物是一种"活"的,可作为大分子自由基引发剂的概念,并通过实验对AMS共聚物的引发性能和应用进行了研究.首先,合成了AMS与(甲基)丙烯酸酯类单体、丙烯酸、苯乙烯和马来酸酐等的共聚物.然后以上述共聚物为大分子引发剂,在90℃引发(甲基)丙烯酸酯类单体和苯乙烯等的本体聚合、溶液聚合和乳液聚合,得到了嵌段共聚物.用ESR谱证明了AMS的共聚物在加热时能裂解生成以碳原子为中心的大分子链自由基.此外,在聚合物的熔融共混中,AMS分解产生的大分子链自由基通过偶合反应形成接枝链,原位生成相容剂.AMS共聚物还可以对碳纳米管及无机粒子进行表面原位接枝改性.AMS共聚物是一类无小分子残留的绿色自由基引发剂,可以用于低成本制备两嵌段共聚物,也可以用于聚合物的熔融共混增容.     

基于L-异亮氨酸衍生物的液晶单体及其聚合物的合成与结构表征

通过对L-异亮氨酸化合物进行扩展性研究及分子设计,本论文合成了四种含(2S,3S)-3-甲基-2-氯戊酰氧基的手性液晶单体(M1～M4),然后再以六氯合铂酸为引发剂,将四种单体通过接枝聚合,获得了对应的聚硅氧烷类液晶高分子(P1～P4),采用FT-IR、1 H-NMR与GPC表征了所合成的中间体、手性液晶单体及其聚合物的化学结构与分子量及分布,结果符合分子设计.此外,采用旋光仪测定了手性单体的旋光度,研究表明:它们均为右旋化合物,其比旋光度随化合物刚性的增加而降低,而对于端基相同、液晶核刚性大小接近的单体,其比旋光度比较接近.     

甲基丙烯酸三乙基锡酯的聚合反应动力学的研究

<正> 有机锡聚合物可以用于防污涂料,与低分子有机锡化合物相比,具有低环境污染、长效等特点。近年来,人们对有机锡单体的合成、纯化、聚合和共聚合进行了研究,但有关动力学的研究报道甚少,而甲基丙烯酸三乙基锡酯(TETM)的聚合动力学未见报道。     

Sulfur-Containing Vinyl Monomers. XV. Kinetic Study of Radical Polymerization of Vinyl Mercaptobenzothiazole and Its Copolymerization

A kinetic study of radical polymerization of vinyl mercaptobenzothiazole (VMBT) with α,α′-azobisisobutyonitrile (AIBN) at 60°C was carried out. The rate of polymerization (R_p) was found to be expressed by the rate equation: R_p = k[AIBN]^0.5 [VMBT]^1.0, indicating that the polymerization of this monomer proceeds via an ordinary radical mechanism. The apparent activation energy for overall polymerization was calculated to be 20.9 kcal/mole. Moreover, this monomer was copolymerized with methyl methacrylate, acrylonitrile, vinyl acetate, phenyl vinyl sulfide, maleic anhydride, and fumaronitrile at 60°C. From the results obtained, the copolymerization parameters were determined and discussed.     

Synthesis and polymerization of styrene monomer carrying isothiocyanate moiety and its copolymerization with HEMA based on chemo‐selectivity to nucleophiles

Isothiocyanate is a very useful functional group for post‐polymerization modification by the reaction with amine or alcohol. An isothiocyanate monomer, 4‐vinylbenzyl isothiocyanate, was synthesized from 4‐vinylbenzyl chloride without using any harmful reagents such as thiophosgene and CS₂. The obtained monomer was successively polymerized by the conventional radical polymerization (AIBN, 1,4‐dioxane, 60 °C) to afford the corresponding polymer. The obtained polymer was characterized by ¹H NMR, FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry. In contrast to the isocyanate group, the isothiocyanate group was relatively tolerant to alcohols, and this character enabled us to synthesize a copolymer of 4‐vinyl benzylisothiocyanate and (2‐hydroxyethyl methacrylate). The copolymer is transformed into networked polymer by 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as a promoter of the reaction between isothiocyanate and alcohol to afford thiocarbamate. The formation of networked polymer was characterized by FTIR and TGA. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5215–5220     

Synthesis and characterization of random hydrophilic/hydrophobic copolymers of styrene and D-lactose-O-vinylbenzylhydroxime

D -Lactose-O-(vinylbenzyl)oxime (LVO), prepared from α-D -lactose and [O-(vinylbenzyl)oxy]amine ( 1 ) was copolymerized with styrene (ST) in dimethylsulfoxide (DMSO)-toluene (1 : 1, v/v) at 65°C using 2,2′-azobisisobutyronitrile (AIBN) as a free radical initiator. The polymerization was rapid when using AIBN as the initiator. The resultant copolymers were characterized by elemental analyses, infrared, viscometry, TGA, DSC, and ¹H-NMR spectroscopy. The poly(ST-co-LVO) had an intrinsic viscosity in the range of 0.11–0.51 dL/g in DMSO at 30°C. The molecular weight was determined by gel permeation chromatography (GPC), and the molecular weight of the resulting polymers ranged from 2.11 × 10⁴ to 6.53 × 10⁷ with low polydispersities. The solubility of the copolymers with different monomer compositions in solvents of varied polarities was also studied. Incorporation of up to 65% (mol %) of lactose-based monomer onto polystyrene backbone led to a water-soluble polymer. Thermal behavior of the synthesized copolymers was evaluated by thermogravimetric analysis (TGA) and correlated very well with the polymer composition. Introduction of a pendant disaccharide compromised the thermal stability of the copolymer. The synthetic approach described in this report provides a route to prepare a novel disaccharide surfactant polymer with well-defined structures and hydrophilic/hydrophobic balances, by adjusting feed ratio of the lactose-based monomer ( 1 ) to styrene. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2971–2978, 1998     

Study on the Kinetics of Polymerization of Tributyltin Methacrylate

The kinetics of polymerization of tributyltin methacrylate (TBTM) has been studied in benzene solution in the temperature range 60–75°C in the presence of azobisisobutyronitrile (AIBN). We have obtained the following polymerization rate equation: R _p = K _p [TBTM]^1.5 [AIBN]^0.5. It shows that the dependence of the polymerization rate on the concentrations of the monomer TBTM and the initiator AIBN are 1.5 and 0.5 order, respectively. The activation energy of polymerization was found to be 18.1 kcal/mol. The activation energy for the degree of polymerization is approximately -12.3 kcal/mol.     

Polymerization of 1,3‐dienes with functional groups. II. Free‐radical polymerization of N‐(2‐methylene‐3‐butenoyl)piperidine

The free‐radical homopolymerization and copolymerization behavior of N‐(2‐methylene‐3‐butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 °C for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels–Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2′‐azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be R_p ∝ [AIBN]^0.507[M]^1.04, and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure that included both 1,4‐E and 1,4‐Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 °C with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r₁ = 6.10 and r₂ = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1545–1552, 2003     

Multinuclear NMR studies of end-groups in polymers—III. Search for abnormal end-groups derived from azoisobutyronitrile

Samples of azoisobutyronitrile (AIBN), labelled with deuterium and nitrogen-15, have been used to initiate polymerizations and copolymerizations of styrene and methyl methacrylate. As in the case of [¹³C]-AIBN, the chemical shift associated with an end-group labelled with a particular isotope depends upon the nature of the attached monomer unit but there is no evidence of more than one type of end-group.     

Reversible Addition Fragmentation Chain Transfer Polymerization of Isobutyl Methacrylate

Abstract

The reversible addition fragmentation chain transfer (RAFT) bulk polymerization of isobutyl methacrylate (i‐BMA) has been studied using 2‐cyanoprop‐2‐yl dithionaphthalate (CPDN) as RAFT agent in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The results of polymerizations of i‐BMA show that i‐BMA can polymerize in a controlled way by RAFT polymerization using CPDN as RAFT agent; i.e., the polymerization rate is first order with respect to monomer concentration, molecular weight increases linearly with monomer conversion, and polydispersities are relatively low (PDI?<?1.2). The structure of the polymer was characterized by ¹H‐NMR. A chain‐extension experiment of the resulting polymer was successfully carried out. The influences of [i‐BMA]₀/[CPDN]₀/[AIBN]₀ molar ratio and reaction temperature were investigated.     

Styrene miniemulsion polymerization initiated by 2,2′-azobisisobutyronitrile

The effects of various parameters on the dodecyl methacrylate (DMA) or stearyl methacrylate (SMA) containing styrene miniemulsion polymerizations were investigated. These parameters include the type of initiators [2,2′-azobisisobutyronitrile (AIBN) vs. sodium persulfate (SPS)], the size of the homogenized monomer droplets, the AIBN concentration, and the SDS concentration. A small quantity of a water-insoluble dye was also incorporated into the polymerization system to study the related particle nucleation mechanisms. The oil-soluble AIBN promotes nucleation in the monomer droplets, whereas homogeneous nucleation predominates in the reaction system with the water-soluble SPS. Homogeneous nucleation, however, cannot be ruled out in the DMA or SMA containing polymerizations with AIBN as the sole initiator. Increasing the level of AIBN or SDS enhances formation of particle nuclei via homogeneous nucleation. The reaction kinetics is primarily controlled by the competitive events of monomer droplet nucleation and homogeneous nucleation. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2537–2550, 1999