氯乙烯-N-苯基马来酰亚胺(-丙烯腈)悬浮共聚物的耐热性能

用玻璃化转变前后储能模量的变化、储能模量的变化速率以及内耗的大小等参数来考察氯乙烯(VC) N 苯基马来酰亚胺 (PMI)以及氯乙烯 N 苯基马来酰亚胺 丙烯腈 (AN)悬浮共聚物的耐热性能 ,辅以维卡软化点测定进行比较 .用动态力学分析方法的研究结果表明 ,共聚物发生玻璃化转变时 ,储能模量随温度的最大变化速率的绝对值越小 ,则其耐热性能越好     

氯乙烯/N-苯基马来酰亚胺共聚物组成控制和优化

研究了氯乙烯 /N 苯基马来酰亚胺 (VC/PMI)共聚物组成随转化率的变化 ,体系中共聚物的累积组成偏差小于 0 0 5或 0 1的单体配比范围很小 ,采用加入第三单体丙烯腈 (AN)的方法进行改善 ,并以PMI在共聚物中的累积组成偏差作为控制参数 ,得到了PMI在共聚物中的累积组成偏差小于 0 0 5和 0 1的VC/PMIlAN较优的配比范围 .结合悬浮聚合工艺的特点 ,确定了VC/PMI/AN悬浮共聚的最佳单体配比范围为f1=0 72～ 0 84 ,f2 =0 0 2～ 0 0 4 ,f3 =0 1 2～ 0 2 4 .     

偏氯乙烯-氯乙烯悬浮共聚物的结晶与熔融性能

研究了聚合温度、共聚物组成、低分子助剂用量等对偏氯乙烯 (VDC) 氯乙烯 (VC)悬浮共聚树脂的结晶度、熔融峰温度的影响 ,并用Florry的聚合物熔点降低理论预测共聚树脂熔点随共聚组成、低分子助剂用量的变化规律 ,为VDC VC悬浮共聚树脂的合成工艺条件和加工性能的改善提供理论基础 .     

氯乙烯/N-苯基马来酰亚胺悬浮共聚合速率的研究

考察了单体配比、温度、引发剂浓度诸因素对氯乙烯（ＶＣ）／Ｎ－苯基马来酰亚胺（ＰＭＩ）悬浮共聚速率的影响．ＶＣ／ＰＭＩ共聚有显著的交叉终止,致使共聚速率降低,测得交叉终止速率常数的函数＝５．７７,ＰＭＩ均聚综合速率常数的倒数值δ２＝５３．６５,共聚表观活化能Ｅａ＝１２７．９ｋＪ／ｍｏｌ,增长活化能Ｅｐ＝６３．７ｋＪ／ｍｏｌ,聚合速率对引发剂浓度的反应级数为０．７８６．并对ＶＣ／Ｎ－环己基马来酰亚胺（ＣＨＭＩ）和ＶＣ／ＰＭＩ两个体系进行了比较     

Propagation Mechanism of Radical Copolymerization of Sulfur Dioxide and Vinyl Chloride

Radical copolymerization of sulfur dioxide and vinyl chloride (VC) has been studied by the comparison of the composition of copolymers obtaining from different reaction conditions, i.e., reaction temperatures, feed compositions, and total monomer concentrations. The composition of VC in copolymer is independent of comonomer composition except at high concentration of VC in feed; it increases with increasing reaction temperature or decreasing total monomer concentration. At lower temperature, the composition of copolymer becomes independent of total monomer concentration. The overall rate of polymerization is proportional to [VC]^1,7 and [SO₂]^0.5. These results were compared with those obtained in our previous study on the SO₂-styrene copolymerization. A propagation mechanism for radical copolymerization of SO₂ and VC is also proposed.     

氯乙烯/N-取代马来酰亚胺共聚竞聚率及共聚物组成

研究了氯乙烯(VC)与多种N-取代马来酰亚胺的溶液共聚合,求得各对单体的竞聚率.结果表明,各种马来酰亚胺的竞聚率都远高于VC的竞聚率,即N-取代马来酰亚胺单体的活性均比VC单体活性高.计算得到N-取代马来酰亚胺Q和e值.由于苯环的共轭效应,N-苯基及N-取代苯基马来酰亚胺具有较大的Q值.各对单体的e值差别较大,表明有形成交替共聚物的倾向.此外,还考察了聚合过程中共聚物组成的变化,用递推法预测了这类体系共聚物瞬时和累积组成随转化率的变化.     

Gamma Ray Induced Low Temperature in Situ Polymerization of Vinyl Chloride and Copolymfrization of Vinyl Chloride-Vinyl Acetate in Taiwan-Produced Woods

Gamma radiation induced polymerization of vinyl chloride (VC) and copolymerization of vinyl chloride (VC)-vinyl acetate (VAc) in Taiwan cedars have been investigated at low temperatures. The polymerization-rate of VC and the copolymerization-rate of VC-VAc system in wood were found to be proportional to the n powers of the dose-rate, where n became close to the value of 1 as the polymerization temperature being lowered below 0°C. The oxygen in air was recognized to induce the delay of the induction period due to its retardation on the polymerization. The apparent activation energies of VC and VC-VAc for the polymerization and the copolymerization in wood were determined by use of the Arrhenius plotting as 4.0 Kcal/mole and 3.4 Kcal/mole respectively at the temperature-range of —15°C～20°C. The degree of polymerization of VC was greatly affected by the polymerization temperature, although it was observed to be independent on the total gamma dose within 1 Mrad and the kinds of wood. No graft reaction of PVC polymer and PVC-PVAc copolymer onto the wood cellulose was found, while low graft percentage of about 3% being obtained at 20° C in the case of using swelling agents. However, this value was found to be decreased to 0.1% at the temperature of —15°C. Based on the above-mentioned experimental results, the radiation induced low temperature polymerization of VC or copolymerization of VC-VAc system in Taiwan produced cedars are considered to proceed with radical polymerization mechanism.     

增塑化学微交联聚氯乙烯中化学交联和物理交联的协同作用

由氯乙烯／ 邻苯二甲酸二烯丙基酯（ＶＣ／ＤＡＰ） 悬浮共聚合成了化学微交联聚氯乙烯（ＰＶＣ） 树脂,并进行增塑加工．共聚得到的化学交联ＰＶＣ 具有溶胶／ 凝胶分配特性,交联密度较低;化学交联ＰＶＣ 的溶胶和凝胶均存在分子链缠结作用,尤其当凝胶含量较高时,物理缠结对凝胶交联密度有较大贡献．化学交联对增塑ＰＶＣ 结晶性的影响较小,因此在增塑化学微交联ＰＶＣ 中同时存在化学交联网络和以分子链物理缠结点和微晶为交联点的物理交联网络,两者协同影响增塑ＰＶＣ 材料的性能．     

Copolymerization of Vinyl Chloride and Sulfur Dioxide. II. Copolymerization Rates and Copolymer Compositions

The rate of copolymerization of vinyl chloride (VC) with sulfur dioxide and the composition of the poly (vinyl chloride sulfone) formed have been measured for comonomer liquid mixtures with X_VC = 0.1 to 1.0 and over the temperature range -95 to +46°C.

Polymerization was initiated by γ-irradiation (-95 to +46°C) and with the t-butyl hydroperoxide/SO₂/methanol redox system (-95 to -18°C). The copolymerization rates and copolymer compositions indicated two distinct temperature regions, with a change in mechanism around 0°C. For radiation initiation below 0°C, the rate versus comonomer composition relationship showed a maximum at an x_VC value which increased with increasing temperature. Above 0°C, the rate decreased with increasing temperature and was greatly retarded by SO₂. No high molecular weight copolymer or VC homopolymer was formed on irradiation of comonomer mixtures above ～55°C.     

Vinyl Chloride-Vinyl Bromide Copolymers

Abstract

Radical copolymerization kinetics of vinyl chloride (VC) and vinyl bromide (VB) lead to the following reactivity ratios r_VC=0.825 r_VB=1.05 Vinyl bromide acts as a chain transfer agent, more powerful than vinyl chloride, the transfer constant for VC radicals being 8.5 × 10^?3 at 40° C. Neither thermal nor ionic degrad-ation produce controlled distribution of short diene sequences in the copolymer. In the ionic process initiated with LiCl or LiBr in dimethylformamide solution, substitution of halogen atoms as well as acid elimination takes place.     

Pd–phosphinesulfonate bravely battles the “vinyl halide insertion copolymerization” barricade

This overview provides insights into the current state‐of‐the‐art solutions to insertion copolymerization of functional olefinic monomers. The challenges in insertion copolymerization of functional olefinic monomers, with a special emphasis on vinyl halides, are highlighted. The crucial design of the Pd–phosphinesulfonate [Pd(PO)] enables up to 3.6 mol % incorporation of vinyl fluoride (VF) in an ethylene–VF copolymerization reaction. In a significant development, insertion copolymerization of industrially relevant functional olefin, that is, vinyl chloride (VC), was unambiguously ascertained, and a detectable amount of VC (0.4 mol %) was incorporated (at the chain end). In a detailed investigation, the in situ existence of (PO)Pd? H species during the polymerization was revealed, and it was demonstrated that these are indeed responsible for VC incorporation. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1–6     

氯乙烯/邻苯二甲酸二烯丙基酯悬浮共聚特征

对４５℃时的氯乙烯／邻苯二甲酸二烯丙基酯（ＶＣ／ＤＡＰ）的悬浮共聚进行了研究，得到表观竞聚率ｒＶＣ＝０７６９、ｒＤＡＰ＝０３７４．凝胶点对应的ＤＡＰ临界起始浓度在０４６６～０４９３ｍｍｏｌ／ｍｏｌＶＣ之间（聚合转化率为８０～８５％），当ＤＡＰ起始浓度小于临界浓度时，ＶＣ／ＤＡＰ共聚物均为溶胶，溶胶平均聚合度随ＤＡＰ起始浓度和聚合转化率的提高而增大；当ＤＡＰ起始浓度大于临界浓度时，共聚物由溶胶和凝胶组成，凝胶含量随ＤＡＰ浓度和聚合转化率的提高而增加，溶胶聚合度则随ＤＡＰ浓度的提高而减小．在凝胶点前，共聚物的分子量分布随ＤＡＰ浓度的增加而变宽；凝胶点以后，分子量分布随ＤＡＰ浓度的增加而变窄．     

Reaction of vinyl chloride with group 4 metal olefin polymerization catalysts

The reactions of three types of group 4 metal olefin polymerization catalysts, (C(5)R(5))(2)ZrX(2)/activator, (C(5)Me(5))TiX(3)/MAO (MAO = methylalumoxane), and (C(5)Me(4)SiMe(2)N(t)Bu)MX(2)/activator (M = Ti, Zr), with vinyl chloride (VC) and VC/propylene mixtures have been investigated. Two general pathways are observed: (i) radical polymerization of VC initiated by radicals derived from the catalyst and (ii) net 1,2 VC insertion into L(n)MR(+) species followed by beta-Cl elimination. rac-(EBI)ZrMe(mu-Me)B(C(6)F(5))(3) (EBI = 1,2-ethylenebis(indenyl)) reacts with 2 equiv of VC to yield oligopropylene, rac-(EBI)ZrCl(2), and B(C(6)F(5))(3). This reaction proceeds by net 1,2 VC insertion into rac-(EBI)ZrMe(+) followed by fast beta-Cl elimination to yield [rac-(EBI)ZrCl][MeB(C(6)F(5))(3)] and propylene. Methylation of rac-(EBI)ZrCl(+) by MeB(C(6)F(5))(3)(-) enables a second VC insertion/beta-Cl elimination to occur. The evolved propylene is oligomerized by rac-(EBI)ZrR(+) as it is formed. At high Al/Zr ratios, rac-(EBI)ZrMe(2)/MAO catalytically converts VC to oligopropylene by 1,2 VC insertion into rac-(EBI)ZrMe(+), beta-Cl elimination, and realkylation of rac-(EBI)ZrCl(+) by MAO; this process is stoichiometric in Al-Me groups. The evolved propylene is oligomerized by rac-(EBI)ZrR(+). Oligopropylene end group analysis shows that the predominant chain transfer mechanism is VC insertion/beta-Cl elimination/realkylation. In the presence of trace levels of O(2), rac-(EBI)ZrMe(2)/MAO polymerizes VC to poly(vinyl chloride) (PVC) by a radical mechanism initiated by radicals generated by autoxidation of Zr-R and/or Al-R species. CpTiX(3)/MAO (Cp = C(5)Me(5); X = OMe, Cl) initiates radical polymerization of VC in CH(2)Cl(2) solvent at low Al/Ti ratios under anaerobic conditions; in this case, the source of initiating radicals is unknown. Radical VC polymerization can be identified by the presence of terminal and internal allylic chloride units and other "radical defects" in the PVC which arise from the characteristic chemistry of PCH(2)CHCl(*) macroradicals. However, this test must be used with caution, since the defect units can be consumed by postpolymerization reactions with MAO. (C(5)Me(4)SiMe(2)N(t)Bu)MMe(2)/[Ph(3)C]][B(C(6)F(5))(4)] catalysts (M = Ti, Zr) react with VC by net 1,2 insertion/beta-Cl elimination, yielding [(C(5)Me(4)SiMe(2)N(t)Bu)MCl][B(C(6)F(5))(4)] species which can be trapped as (C(5)Me(4)SiMe(2)N(t)Bu)MCl(2) by addition of a chloride source. The reaction of rac-(EBI)ZrMe(2)/MAO or [(C(5)Me(4)SiMe(2)N(t)Bu)ZrMe][B(C(6)F(5))(4)] with propylene/VC mixtures yields polypropylene containing both allylic and vinylidene unsaturated chain ends rather than strictly vinylidene chain ends, as observed in propylene homopolymerization. These results show that the VC insertion of L(n)M(CH(2)CHMe)(n)R(+) species is also followed by beta-Cl elimination, which terminates chain growth and precludes propylene/VC copolymerization. Termination of chain growth by beta-Cl elimination is the most significant obstacle to metal-catalyzed insertion polymerization/copolymerization of VC.     

Copolymerization studies of vinyl chloride and vinyl acetate with ethylene using a transition-metal catalyst

Since the advent of Ziegler-Natta polymerization of ethylene, attempts have been made to extend coordination polymerization to commercially important monomers with polar functionality. In this study we examined the copolymerization of perdeuterated vinyl chloride (VC) and perdeuterated vinyl acetate (VA) with ethylene using a tridentate Fe(II) dichloride pyridine diimine metal catalyst. The resulting ethylene oligomers were examined by GC/MS and 2H NMR spectroscopy. It was shown that VC was inserted once for every approximately 180 ethylene monomers and VA was inserted once for every approximately 350 ethylene monomers. VC and VA behave as comonomers for coordination/insertion polymerizations with ethylene. However, we find that insertion with either monomer leads to termination of the growing chain via beta-elimination processes. The deuterium atoms are exclusively located at the olefin terminus for each of the monomers.     

Nanocomposites of vinyl chloride–acrylonitrile copolymer and silica

Vinyl chloride–acrylonitrile (VC–AN) copolymer was synthesized through emulsion copolymerization. VC–AN copolymer/silica nanocomposites were prepared by solution blending of copolymer and silica in a common solvent, N,N‐dimethylformamide (DMF). The rheology studies show that the shear‐thinning behavior of the VC–AN copolymer solution becomes less distinct as nano particles are introduced. It was also found that the viscosity of the copolymer solution decreases with adding small amount of nano particles. Transmission electron microscopy observations indicate that the UV‐treated silica could disperse well in the copolymer matrix. Differential scanning calorimeter studies suggest that the presence of the silica suppresses crystallization of the AN segments in the copolymers. Because of the interactions between copolymer chains and inorganic particles, the thermal stability and mechanical strength of the VC–AN copolymers are improved considerably. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3127–3134, 2005     

Structural Defects in Poly(vinyl chloride) and the Mechanism of Vinyl Chloride Polymerization: Comments on Recent Studies

Investigations in the title areas within the past ten years are summarized and critiqued. The polymerizations studied were performed by conventional free-radical methods. A new mechanism, not yet confirmed, is suggested to explain a reported enhancement in the chloromethyl branch concentration of poly(vinyl chloride) (PVC) prepared at high conversions of monomer. This mechanism involves an intramolecular 1,5 hydrogen shift in a 1,3,5,6-tetrachlorohexyl radical. Evidence showing that most of the internal double bonds in PVC are not formed via intermolecular H abstraction from internal monomer units is tentatively rationalized, in part, by hydrogen transfer via at least one cyclic transition state containing more than eight members. The absence of free chlorine atoms from polymerizations of vinyl chloride (VC) is reaffirmed, and the copolymerization of VC with the chloroallylic chain ends of PVC is argued to be insignificant. New information in the literature does not invalidate the currently accepted mechanism of vinyl chloride polymerization.     

化学交联聚氯乙烯树脂的合成和结构

研究了氯乙烯/交联单体悬浮共聚时,交联单体种类、浓度和聚合温度对化学交联聚氯乙烯树脂结构的影响.对于氯乙烯/邻苯二甲酸二烯丙基酯(VC/DAP)悬浮共聚体系,凝胶含量和凝胶交联密度随DAP起始浓度的增加而增大;DAP浓度相同时,凝胶含量和凝胶交联密度随聚合温度上升而下降;当凝胶含量较高时,分子链物理缠结对凝胶交联密度有较大贡献,凝胶交联密度随凝胶含量增加而快速上升.在相同交联单体浓度下,氯乙烯/马来酸二烯丙基酯(VC/DAM)共聚物的凝胶含量最大,VC/DAP共聚物次之,氯乙烯/乙二醇二甲基丙烯酸酯(VC/EGDMA)共聚物最小,这是由于DAM单体的竞聚率小于1,且含有马来酸双键,EGDMA单体的竞聚率远大于1.     

Anisotropic Nanoparticles with Controllable Morphologies from Non‐Cross‐Linked Seeded Emulsion Polymerization

A simple and elegant approach to fabricate anisotropic P(VC‐co‐AAEM)/PS nanoparticles with controllable morphologies via emulsifier‐free seeded emulsion polymerization is presented. Non‐cross‐linked P(VC‐co‐AAEM) seeds with hydrophilic surface are first synthesized through copolymerization of vinyl chloride (VC) and acetoacetoxyethyl methacrylate (AAEM), which are used to prepare P(VC‐co‐AAEM)/PS NPs with multiple bulges by SEP of styrene. Electron microscopy observation indicates that the content of AAEM in seeds is crucial to control the phase separation and morphology of the composite NPs. Moreover, the thermodynamic immiscibility between PVC and PS is the driving force for the formation of PS bulges onto the P(VC‐co‐AAEM) seeds. The resultant anisotropic NPs with non‐cross‐linked feature may promisingly serve as compatibilizers for further polymer processing.

     

Copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride and alkyl methacrylates

Radical copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with methyl methacrylate and allyl methacrylate in the bulk and methanol solution in the presence of azobis-isobutyric acid dinitryle at 70–90°C has been studied. Copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with methyl methacrylate or allyl methacrylate in the bulk proceeds with formation of random copolymers enriched in methacrylate units; in the copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidiny chloride with methyl methacrylate in methanol, the copolymerization constants of the monomers become close. The kinetic parameters of the reaction have been studied, the relative activities of the monomers have been determined. It has been found that 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride is copolymerized with allyl methacrylate or methylmethacrylate to form pyrrolidinium structures in the cyclolinear polymer chain. At high degrees of conversion of the copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with allyl methacrylate, the viscosity increases and the side polymer chains are crosslinked by “allyl bonds” to form insoluble copolymers, swelling in benzene and DMSO.     

Copolymerization of Allilidene Diacetate with Vinyl Acetate

Abstract

The monomer reactivity ratios for vinyl acetate (VAc)-allilidene diacetate (ADA) copolymerization have never been obtained. The composition of VAc-ADA copolymers was determined by NMR spectroscopy, measuring CH protons corresponding to ADA at 3.1τ and VAc at 5.1τ. The monomer reactivity ratios were evaluated; r₁ = 1.34 ± 0.05 and r₂ = 0.48 ± 0.03, where M₁ = ADA and M₂ = VAc. From these values the Q and e values for ADA were calculated: Q = 0.047 and e = 0.44 by taking Q = 0.026 and e = ?0.22 for VAc. The H value [1] for copolymerization of ADA, VAc, and vinyl chloride (VC) is 0.87.