复合引发剂体系引发下氯乙烯悬浮聚合动力学模型及应用

在建立复合引发剂分解动力学模型的基础上,推导了复合引发剂体系引发下的氯乙烯(VC)悬浮聚合动力学模型.用模型预测不同温度、引发剂复合体系引发的氯乙烯聚合动力学与实验数据能较好地吻合.其中TxEHP,Tx99,Tx23和Tx36在51和57℃下的引发效率由单一引发剂引发的VC动力学数据计算     

顶空气相法测定氯乙烯生产过程产生的盐酸溶液中的乙炔和氯乙烯

 采用顶空气相法测定了氯乙烯生产过程产生的盐酸溶液中的乙炔和氯乙烯。使用氢氧化钠将试样中的氯化氢中和 ,从而消除其在气相分析乙炔和氯乙烯中的影响。顶空平衡温度为 35℃ ,平衡时间为 4 5min ,柱为填充了GDX 2 0 2固定相的 2m× 3mmi d 不锈钢柱 ,柱温 14 0℃。顶空气体进样量为 1mL。以外标法定量 ,乙炔含量测定结果的相对标准偏差为 0 85 % ;当其含量为 30 0 μg/g～ 15 0 μg/g时 ,回收率为 98 9%～10 3%。氯乙烯含量测定结果的相对标准偏差为 1 4 % ;当其含量为 2 0 0 μg/g～ 10 0 μg/g时 ,回收率为 98 8%～10 2 %。     

History of Vinyl Chloride Polymers

In 1926 Semon tried to dehydrohalogenate high molecular weight poly(vinyl chloride) (PVC) in a high boiling solvent to get an unsaturated polymer which might bond rubber to metal. Unexpectedly, he obtained plasticized PVC, a flexible product inert both electrically and chemically. This discovery opened the door to the commercialization of PVC, a plastic with an annual United States production now exceeding 6 billion pounds. Special PVC's and PVC products have been developed taking advantage of the many favorable properties. Rigid structural products from house siding to pipes are becoming of increasing importance. Two main types of polymers have been utilized: 1) one prepared by suspension polymerization, and 2) a special variety prepared by colloidal polymerization and spray drying. This latter material has been especially useful for making plastisols. Plasticizers and stabilizers were developed to maximize useful and nontoxic properties. Vinyl chloride monomer (VCM) production and co-polymerization evolved as lower cost processes, higher quality products, and greater manufacturing safety were introduced. Recent challenges for the industry have included pollution and carcinogenic hazards which have been overcome by imaginative new technologies. The rate of growth of the industry is shown graphically.     

Primary Radical Termination in Vinyl Chloride Polymerization

The rate of vinyl chloride polymerization initiated by doubly labeled benzoyl peroxide ('H in the phenyl ring and ¹⁴C in the carboxyl group) in dichloroethane solution was measured by a dilatometric method. The relative significance of primary radical termination in polymerization is examined by kinetic analysis of the polymerization rate data and analysis of the polymer samples recovered at 10% conversion for combined initiator fragments.     

过氧化钠能否氧化氯化铵

从理论和实验2个方面探究了过氧化钠和氯化铵加热的反应, 得出过氧化钠不能氧化氯化钠但可以氧化浓盐酸的结论, 并对反应机理提出了假设。     

Corona-Poled Electrets Based on Vinyl Chloride/Vinyl Acetate Copolymer-Zinc White Composites

Electret properties of vinyl chloride/vinyl acetate copolymer and its composites with zinc oxide are studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 502–505.Original Russian Text Copyright © 2005 by Galikhanov, Deberdeev.     

Model for Kinetics of Vinyl Chloride Polymerization

This paper gives a critical review of recent models for the polymerization of vinyl chloride. In solution and bulk polymerization the effect of eventual degradative chain transfer to monomer, addition of chain transfer agents, and precipitation of polymer is discussed. A model for emulsion polymerization is described which includes particle formation and kinetics of polymerization where especially desorption and reabsorption of radicals in the particles are included.     

Copolymerization of 1-Vinylpyrazole with Vinyl Chloride

Copolymerization of vinyl chloride with 1-vinylpyrazole was studied. The copolymerization constants were determined. The chemical structure of the copolymers was studied by NMR and IR spectroscopy.     

Polymerization of Vinyl Chloride in the Presence of Alcohols

Precipitation polymerization of vinyl chloride in solution in the presence of alcohols was studied. The reaction mechanism was suggested, and the product composition was estimated by IR spectroscopy and selective extraction.     

Thermogravimetric Analysis of Vinyl Chloride/Acrylonitrile Copolymers

The dehydrohalogenation of several alternating and random vinyl chloride/acrylonitrile copolymers was characterized by thermogravimetry. The polymers were made in solution, and the conversions were kept below 5% to insure uniform sequence distributions. Hydrogen chloride was generated within a relatively narrow temperature range somewhere between 200 and 300°C depending on the sequence distribution, relative viscosity, and composition. The weight-loss during the dehydrohalogenation could be attributed completely to the hydrogen chloride available in the copolymer. Alternating copolymers were significantly more stable than random copolymers were significantly more stable than random copolymers at the same relative viscosity. For a given sequence distribution or composition, stability decreased with decreasing relative viscosity. The stability decreased as acrylonitrile content was increased from 23 to 57%.

The thermogravimetric analyzer was interfaced with a digital computer. The digitized data were smoothed and differentiated by convoluted integers. The differentiated data provided rates for a qualitative discussion of dehydrohalogenation kinetics.     

Catalytic Purification of Gases to Remove Vinyl Chloride

The catalytic purification on spinel-like catalysts containing no noble metals of ventilation exhaust gases formed in manufacture of PVC film was studied in the thermal and sorption modes.     

The Formation of Terminal Double Bonds in Vinyl Chloride Polymerization

The determination of double bonds in PVC is achieved with an increased accuracy in comparison with earlier methods by the addition of iodine monochloride (Wijs reaction) to PVC coupled with x-ray fluorescence analysis to determine the iodine content of the polymer. The number of double bonds per unit weight of polymer increases on increasing the polymerization temperature and is proportional to the number of polymer molecules. It is not affected, however, by the presence of the chain transfer agent tetrahydrofuran (THF). At the technically important polymerization temperatures of 30 to 80°C and in the absence of the chain transfer agent, 0.9 double bonds per polymer molecule are found. The number of double bonds per polymer molecule is lowered using the chain transfer agent THF. These results support the theory that the chain transfer to monomer and possibly the termination reaction are coupled with the formation of terminal double bonds. Contributions by internal double bonds formed by dehydrochlorination of the polymer during polymerization are excluded by investigating the Cl^θ content of the water phase in the oxygen-free VC suspension polymerization. No hydrogen chloride is formed. In IR spectra of PVC, the stretching vibration of the double bonds is detected at 1667 cm^?1 by the correlation of the double bond contents and the intensities of the absorption bands. The stretching vibration at 1667 cm^?1is in accordance with those of model compounds with a 1-chloro-2-alkene structure.     

Studies in Vinyl Polymerization. Reinitiation by Allyl Chloride Transfer Radicals in the Polymerization of Vinyl Acetate

The kinetics of vinyl acetate polymerization in the presence of allyl chloride were studied by a dilatometric method. The retardation of the rate of polymerization was explained in terms of degradative chain transfer to allyl chloride. Analysis of the polymerization rate data indicates that a relatively large proportion of the allyl chloride transfer radicals is reactive toward initiation.     

Effect of Oxygen on the Polymerization of Vinyl Chloride

The effects of oxygen on the liquid-phase polymerization of vinyl chloride at 55°C in the presence of an added initiator, bis(4-tert-butylcyclohexy1) peroxydicarbonate, (Perkadox 16), have been studied by tumbled dilatometry. A conventional kinetic scheme involving a predominant cross-termination reaction is proposed to explaine the dependence of the induction period on initial oxygen concentration and initiator concentration. The degree of conversion of the initial oxygen to peroxidic compounds did not exceed 30% by weight under any experimental conditions employed, and the existence of other oxidation products such as formaldehyde, carbon monoxide, and methanol has been demonstrated. Radical decomposition reactions may produce some of the oxidation products. At 55°C, the average velocity constant for decomposition of vinyl chloride polyperoxides in dichloromethane solution was 8 × 10^?5 sec^?1 compared with 6.6 × 10^?5 sec^?1 for Perkadox 16. Perkadox 16 has been used as an initiator in a dilatometric study of the homogeneous polymerization of styrene at 60°c. Molecular weights of the polymers were determined viscometrically or by the use of gel-permeation chromatography. The results indicate that no transfer to initiator occurs in this systems.     

C2H3Cl分子近阈值处真空紫外光离子谱研究

The photoionization efficiency curve (PIE) of C2H3Cl+ formation from C2H3Cl has been measured in wavelength region 105.0- 130.0nm, by using synchrotron radiation single- photon ionization and a quadrupole mass spectromemter as a detector. A series of peaks in region 106.0-117.0nm arise from Rydberg autoionization converging to A2A' state of the vinyl chloride ion, the average quantum defects are δ(ns) = 1.87, δ(np) = 1.51,δ(nd) = 0.22 respectively. The Rydberg transitions of π(2a") → 4d, π(2a") →5d, π(2a")→6s, π(2a") →7s have been assigned also.     

Vinyl Chloride Copolymerization. Penultimate Effects with Conjugated Comonomer

A kinetic study of the radical copolymerization of vinyl chloride with acrylonitrile, methyl methacrylate, or styrene, using the chromatographic method, shows that penultimate effects are observed in all cases, chiefly for the acrylonitrile case (r_cc = 0.03, r_ac = 3.0). The conjugated monomer induces a stronger penultimate effect than the unconjugated vinyl chloride; this effect might be correlated with the e values of the Q-e scheme. A strong antepenultimate effect is observed on the styrene ended radicals (r_sss = 3.0, r_css = 20.0, r_scs = 18.5, r_ccs = 2.7), which might be related to a steric effect.     

Emulsion Polymerization of Vinyl Monomers in Presence of Chitosan with Peroxide Groups

Peroxychitosans with ditertiary peroxide fragments were synthesized via radical reactions of chitosan and 5-tert-butylperoxy-5-methyl-l-hexen-3-in. They can be used as macroinitiators and coemulsifiers for emulsion polymerization of vinyl monomers. It is shown that peroxychitosans are grafted to the surface of latex particles and impart antibacterial properties to emulsion polymer.     

Synthesis and Properties of Copolymers Based on Vinyl Chloride

Radical copolymerization of 1-vinylazoles with vinyl chloride and the composition and properties of the resulting copolymers were studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 647–651.Original Russian Text Copyright © 2005 by Shaglaeva, Lebedeva, Sultangareev, Trofimova.     

Copolymerization of Vinyl Chloride with 1-Vinyl-1,2,4-triazole

Copolymerization of vinyl chloride with 1-vinyl-1,2,4-triazole was studied. The copolymerization constants were determined. The chemical structure of the resulting copolymers was studied by NMR and IR spectroscopy.