丙烯腈/甲基丙烯酸正丁酯/衣康酸三元共聚体系竞聚率的研究

根据丙烯腈/甲基丙烯酸正丁酯/衣康酸三元共聚体系特征,利用KT法测定了该体系竞聚率,利用元素分析仪测定了共聚物组成。用KT法拟合实验数据计算竞聚率,得到了以二甲亚砜为溶剂、偶氮二异丁腈为引发剂的丙烯腈/甲基丙烯酸正丁酯/衣康酸三元溶液聚合体系的竞聚率。     

丙烯腈/醋酸乙烯酯/甲基丙烯磺酸钠共聚体系竞聚率的研究

利用核磁共振技术测定共聚物组成,用Ｍａｙｏ－Ｌｅｗｉｓ共聚物组成方程拟合实验数据计算竞聚率。得到的丙烯腈／醋酸乙烯酯（ＡＮ／ＶＡｃ）本体共聚的竞聚率数据用于分析间歇聚合反应试验,理论计算与试验数据吻合。并研究了丙烯腈／醋酸乙烯酯／甲基丙烯磺酸钠（ＡＮ／ＶＡｃ／ＳＭＡＳ）三元水相共聚反应体系的特征,测定了该三元共聚体系表观竞聚率     

苯乙烯/丙烯酸丁酯微乳液聚合竞聚率及共聚物链段分布的研究

以苯乙烯/丙烯酸丁酯(St/BA)为共聚单体进行了微乳液聚合反应,测定了共聚物组成和共聚单体的竞聚率。由竞聚率计算了共聚物分子的链段分布,分析了共聚物分子的微观结构。     

苯乙烯/丙烯酸丁酯微乳液共聚物链段分布的研究

以苯乙烯/丙烯酸丁酯(St/BA)为共聚单体,进行了微乳液聚合反应,测定了共聚物组成和共聚单体的竞聚率。由竞聚率计算了共聚物分子的链段分布,分析了共聚物分子的微观结构。     

氯乙烯/丙烯腈共聚物组成和溶解性及影响因素

以十二烷基硫酸钠(SDS)为乳化剂,过硫酸钾(KPS)和亚硫酸氢钠(SBS)为氧化还原引发体系,通过乳液聚合方法制备了氯乙烯(VC)/丙烯腈(AN)共聚物.采用氧瓶燃烧法测定了共聚物的氯含量,并计算了共聚组成,通过抽提测定了共聚物在丙酮中的溶解性.考察了一步法聚合过程中共聚物组成及溶解性随聚合时间的变化,研究了初始单体投料比、引发剂用量、聚合温度等工艺条件对共聚物组成及溶解性的影响.结果表明,由于AN活性高,VC/AN共聚组成和溶解性随聚合时间变化较大;共聚物在丙酮中的溶解性与共聚组成相关,受初始单体投料比影响最大,在VC/AN投料物质的量比为7.6:1时可以获得在丙酮中全部溶解的共聚物.     

纳米氧化镁对甲基丙烯酸-丙烯腈共聚体系竞聚率的影响

以偶氮二异丁腈(AIBN)为引发剂,引发甲基丙烯酸(MAA)和丙烯腈(AN)本体聚合。采用滴定法和称重法测定了在低转化率(小于10%)下不同单体配比的共聚物组成,并采用Fineman-Ross法及Kelen-Tudos法计算、作图得到两种单体的竞聚率,它们的最大差值为0.09,说明滴定法和称重法具有一定的可信度。用上述方法测定了反应体系在纳米MgO存在下共聚单体竞聚率的变化,结果表明:加入纳米MgO,MAA和AN的竞聚率均下降。     

丙烯腈/衣康酸在DMSO/H2O中的共聚物结构模拟

采用丙烯腈(AN)与衣康酸(IA)在DMSO/H2O中共聚,计算了两种反应单体的竞聚率:rAN=0.405,rIA=2.946。采用计算机模拟,进一步研究了聚(丙烯腈 co 衣康酸)共聚物的分子结构与转化率的关系。给定自由基共聚反应的初始条件,还模拟了丙烯腈与衣康酸二元共聚物序列分布。随着转化率不同,共聚物中衣康酸的组成相差较大,反应初期大多数的IA共聚单体参加反应,特别是在少量衣康酸作共聚单体时,随着衣康酸的加入,丙烯腈的平均序列长度快速降低。     

丙烯腈/丙烯酸甲酯/衣康酸三元共聚物序列结构的Monte Carlo模拟

以丙烯腈(AN)、丙烯酸甲酯(MA)、衣康酸(IA)为共聚单体,合成碳纤维用聚丙烯腈原丝的三元共聚物,利用Monte Carlo法模拟了AN／MA／IA三元共聚物的组成和序列结构,讨论了共聚单体对共聚物分子链序列结构的影响,探讨了增加序列结构均匀性的方案。结果表明:Monte Carlo法可以较为准确的模拟该共聚物的序列结构;AN／MA／IA以98／0.7／1.3的单体配比可以得到序列结构比较理想的共聚物;采取分批加入IA的方法,使共聚物的序列结构均匀性得到提高。     

AN-VAc-AMPS三元共聚合研究

介绍了丙烯腈 ( A N) -醋酸乙烯 ( VAc) (或丙烯酸甲酯 ( MA ) -2 -丙烯酰胺基 -2 -甲基丙磺酸 (英文缩写 AMPS)三元共聚合体系各组分竞聚率的测定方法 ,并比较三元共聚体系和二元共聚体系的AN /VAc竞聚率 ,对三元连续共聚进行了试验 ,讨论 A MPS含量与染色性的关系 ,聚合工艺条件与转化率关系。对聚合物溶液的流变性能及纺丝工艺 ,纤维的性能作了简单介绍。聚合及纺丝试验结果证明 ,以 AMPS为第三单体的三元共聚体系可纺性良好 ,所得纤维的物理性能、染色性能、吸水性和抗静电性均优于一般腈纶     

偏氯乙烯—氯乙烯悬浮共聚竞聚率和共聚物组成

在不同温度下测定了偏氯乙烯-氯乙烯悬浮共聚的竞聚率,剖析了共聚物组成随转化率的变化规律,根据45℃下测得的竞聚率,应用单体组成-转化率的普适积分式和简化积分式计算了共聚物平均组成,与实验值吻合。在适当转化率下终止聚合反应,可望获得组成分布不宽的共聚物。     

丙烯腈和烯丙基磺酸钠在硫氰酸钠浓水溶液中共聚合的研究

本文研究了丙烯腈(AN)和烯西基磺酸钠(SAS)在硫氰酸钠浓水溶液中于pH5和70℃下的共聚合。反应混合液中硫氰酸钠的浓度为40％。测得AN和SAS的单体竞聚率分别为r_1=1.88,r_2=0.17。据此计算出SAS的Q和e值,分别为0.089和0.13。共聚反应速率随配料中SAS含量的增加而急速下降。讨论了溶液性质对SAS竞聚率的影响。指出AN与SAS共聚以及AN与甲基烯丙基磺酸钠共聚在反应工艺过程中配料控制上的不同之处。     

Investigations of the copolymerization of acrylonitrile with vinyl acetate and sodium methallylsulfonate

The bulk copolymerizations of acrylonitrile (AN) with vinyl acetate (VAc) initiated by azobisisobutyronitrile (AIBN) and the suspension copolymerization of AN with VAc and sodium methallylsulfonate (SMAS) in water with a Na₂S₂O₅–Na₂ClO₃ redox initiator system at 65°C, were investigated. The copolymer compositions were determined by ¹H-NMR. The reactivity ratios (γs) for the two copolymerization systems were determined analytically, based on Mayo–Lewis equation, by fitting the calculated curves with the experimental data. The γs for the AN and VAc bulk copolymerization were found to be γ₁₂ = 2.85 and γ₂₁ = 0.11. The values of the apparent γs for the suspension copolymerization of AN, VAc, and SMAS were as follows: γ₁₂ = 3.58, γ₂₁ = 0.39, γ₁₃ = 1.45, γ₃₁ = 0, γ₂₃ = 0.92, and the rate constant ratio R₃ = k₃₁/k₃₂ = 0.04. A simulated result produced with the obtained γs agreed fairly well with experimental data of bulk copolymerization in a batch reactor. The apparent γs obtained were also successfully used to analyze the results of suspension polymerization in a continuous pilot reactor.© 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 854–860, 2001     

Study on monomer reactivity ratios of acrylonitrile/itaconic acid in aqueous deposited copolymerization system initiated by ammonium persulfate

A single water-soluble initiator-ammonium persulfate (APS), not containing alkali metal ions, was first utilized to initiate copolymerization of acrylonitrile (AN)/itaconic acid (IA) in aqueous deposited copolymerization system. Monomer reactivity ratios of this polymerization system were investigated using element analysis method and Q–e schemes. It was found that the monomer reactivity ratios of AN/IA calculated from Q–e schemes are 0.505 (r _AN) and 1.928 (r _IA), while the monomer reactivity ratios of AN/IA in aqueous deposited copolymerization system at 60 °C are 0.64 (r _AN) and 1.37 (r _IA) calculated from Kelen–Tüdõs method, 0.61 (r _AN) and 1.47 (r _IA) from Fineman–Ross method. The three pairs of monomer reactivity ratios are in good agreement. With the increase of the polymerization temperature, the monomer reactivity ratios of AN and IA approach to unity, indicating that the aqueous deposited copolymerization of AN/IA has a tendency to ideal copolymerization. At lower polymerization conversion, the monomer reactivity ratios of AN and IA have hardly any changes. When the polymerization conversion is more than 5%, the monomer reactivity ratio of AN increases, while that of IA decreases.     

Monomer reactivity ratios for acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate

Monomer reactivity ratios of acrylonitrile/ammonium itaconate during aqueous‐deposited copolymerization initiated by ammonium persulfate were investigated. Kelen–Tudos method was used to examine the reactivity ratios. It was shown that the reactivity ratios were influenced by the conversions and temperatures of copolymerization. The reactivity ratios in aqueous‐deposited copolymerization system were similar to those in the solution polymerization system at polymerization conversions of less than 5% [reactivity ratio of acrylonitrile (r₁) 0.842 ± 0.02, reactivity ratio of ammonium itaconate (r₂) = 3.624 ± 0.02]. The reactivity ratio of AN rises and that of (NH₄)₂IA decreases, when the polymerization conversion increases till 13%. Aqueous‐deposited copolymerization initiated by AIBN was also studied. It was found that some polymers were formed in water phase and the monomers had different reactivity ratios by comparison with those initiated by ammonium persulfate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4645–4648, 2006     

Reactivity ratios during radiation‐induced grafting of comonomer mixtures onto polyester fabrics

Radiation‐induced grafting of binary mixtures of acrylonitrile (AN)/styrene (S) and acrylamide (AAm)/styrene (S) onto polyester fabric (PET) has been investigated. Synergism during radiation grafting was investigated by determining the graft yield fraction for each monomer in the final graft copolymer. Moreover, by knowing the mole fraction of each monomer in the grafting solution, the reactivity ratio of the individual monomers in the comonomer mixture during graft copolymerization could be determined: in the case of AN/S comonomer mixture, the calculated reactivity ratios for AN and S are 0.04 and 0.05, respectively; the calculated reactivity ratios of AAm and S in their comonomer mixture are 1.82 and 0.41, respectively. © 2001 Society of Chemical Industry     

Preparation and characterization of P(AN/VAC)/clay based nanocomposites

In this article, P(AN/VAC)/clay nanocomposites were prepared by an in situ polymerization and characterized by transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. The results show that the P(AN/VAC)/clay exhibit a multilayered structure. The montmorillonite layers are totally exfoliated and distributed uniformly in the P(AN/VAC) matrix. The dimension stability and heat resistance property of P(AN/VAC)/clay are superior to those of P(AN/VAC) alone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 703–706, 2006     

Copolymerization kinetics of acrylonitrile with amino ethyl‐2‐methyl propenoate in H2O/DMSO mixture

Amino ethyl‐2‐methyl propenoate (AEMP) was used successfully to copolymerize with acrylonitrile (AN). This was achieved by using azobisisobutyronitrile as the initiator. Kinetics of copolymerization of AN with AEMP was investigated in H₂O/dimethylsulfoxide (DMSO) mixture between 50 and 70 °C under N₂ atmosphere. The rate of copolymerization was measured. The kinetic equation of copolymerization system was obtained and the overall activation energy for the copolymerization system was determined. Values of monomer apparent reactivity ratios were calculated using Kelen–Tudos method. It has been found that the apparent reactivity ratios in aqueous suspension polymerization system are similar to those in solution polymerization system at polymerization conversion less than 25%. At conversion beyond 45%, the changes of monomer apparent reactivity ratios become less prominent. In water‐rich reaction medium (H₂O/DMSO > 70/30), monomer apparent reactivity ratios are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 70/30), apparent reactivity ratios are similar to those in solution polymerization system. With an increase of polarity of solvent, values of apparent reaction ratios both decrease. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2095–2100, 2006