Styrene–acrylic acid copolymers as new stabilizers of dispersion RAFT polymerization of butyl acrylate

The RAFT-based copolymers of acrylic acid and styrene may be successfully used as stabilizers of dispersion polymerization of butyl acrylate by providing the formation of stable block copolymer dispersion.     

Unprecedented Sequence Control and Sequence-Driven Properties in a Series of AB-Alternating Copolymers Consisting Solely of Acrylamide Units

Herein, we report a method to synthesize a series of alternating copolymers that consist exclusively of acrylamide units. Crucial to realizing this polymer synthesis is the design of a divinyl monomer that contains acrylate and acrylamide moieties connected by two activated ester bonds. This design, which is based on the reactivity ratio of the embedded vinyl groups, allows a “selective” cyclopolymerization, wherein the intramolecular and intermolecular propagation are repeated alternately under dilute conditions. The addition of an amine to the resulting cyclopolymers afforded two different acryl amide units, i.e., an amine-substituted acryl amide and a 2-hydroxy-ethyl-substituted acryl amide in alternating sequence. Using this method, we could furnish ten types of alternating copolymers; some of these exhibit unique properties in solution and in the bulk, which are different from those of the corresponding random copolymers, and we attributed the differences to the alternating sequence.     

Unprecedented Sequence Control and Sequence‐Driven Properties in a Series of AB‐Alternating Copolymers Consisting Solely of Acrylamide Units

Herein, we report a method to synthesize a series of alternating copolymers that consist exclusively of acrylamide units. Crucial to realizing this polymer synthesis is the design of a divinyl monomer that contains acrylate and acrylamide moieties connected by two activated ester bonds. This design, which is based on the reactivity ratio of the embedded vinyl groups, allows a “selective” cyclopolymerization, wherein the intramolecular and intermolecular propagation are repeated alternately under dilute conditions. The addition of an amine to the resulting cyclopolymers afforded two different acryl amide units, i.e., an amine‐substituted acryl amide and a 2‐hydroxy‐ethyl‐substituted acryl amide in alternating sequence. Using this method, we could furnish ten types of alternating copolymers; some of these exhibit unique properties in solution and in the bulk, which are different from those of the corresponding random copolymers, and we attributed the differences to the alternating sequence.     

Atom transfer radical polymerization of acrylates in an ionic liquid: Synthesis of block copolymers

Atom transfer radical polymerization (ATRP) of acrylates in ionic liquid, 1‐butyl‐3‐methylimidazolium hexaflurophospate, with the CuBr/CuBr₂/amine catalytic system was investigated. Sequential polymerization was performed by synthesizing AB block copolymers. Polymerization of butyl acrylate (monomer that is only partly soluble in an ionic liquid forming a two‐phase system) proceeded to practically quantitative conversion. If the second monomer (methyl acrylate) is added at this stage, polymerization proceeds, and block copolymer formed is essentially free of homopolymer according to size exclusion chromatographic analysis. The number‐average molecular weight of the copolymer is slightly higher than calculated, but the molecular weight distribution is low (M_w/M_n = 1.12). If, however, methyl acrylate (monomer that is soluble in an ionic liquid) is polymerized at the first stage, then butyl acrylate in the second‐stage situation is different. Block copolymer free of homopolymer of the first block (with M_w/M_n = 1.13) may be obtained only if the conversion of methyl acrylate at the stage when second monomer is added is not higher than 70%. Matrix‐assisted laser desorption/ionization time‐of‐flight analysis confirmed that irreversible deactivation of growing macromolecules is significant for methyl acrylate polymerization at a monomer conversion above 70%, whereas it is still not significant for butyl acrylate even at practically quantitative conversion. These results show that ATRP of butyl acrylate in ionic liquid followed by addition of a second acrylate monomer allows the clean synthesis of block copolymers by one‐pot sequential polymerization even if the first stage is carried out to complete conversion of butyl acrylate. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2799–2809, 2002     

Preparation and Properties of Submicrometer Particle Methyl Methacrylate-Butyl Acrylate Polymers with Multilayer Morphology

Abstract

Multilayer submicrometer particles having a core and 'a shell consisting of poly(methyl methacrylate) and an interlayer of a crosslinked copolymer of poly(butyl acrylate) were prepared by seeded emulsion polymerization. The interlayer encapsulates the core and hinders the encapsulated polymer from being dissolved. On dispersion stirring of the melt of a multilayer polymer, the encapsulation is disrupted and the amount of insoluble polymer corresponds to the mass of the middle layer of poly-(butyl acrylate). The impact resistance of films prepared from slightly crosslinked polymer samples increases markedly. Provided that the density of the interlayer network is high, the stirring causes the impact resistance of the polymer to be gradually reduced so that for highly crosslinked polymer material it becomes lower than for untreated polymer.     

芳香PET树脂母粒的研制

通过丙烯酸和丙烯酸正丁酯溶液共聚合，得到丙烯酸－丙烯酸正丁酯共聚物，该树脂与环氧氯丙烷反应后再与PET树脂切片继续反应，可使PET树脂切片表面形成聚丙烯酸酯自膨润型吸油网络结构，将表面具有聚丙烯酸酯自身膨润型吸油网络结构的PET树脂切片（简称为留香剂）在油溶性香精中浸泡，香精就被吸附在留香剂表面，即得到芳香PET树脂母粒。用SEM观察了母粒的表面结构形态。     

Synthesis and characterization of graft copolymers of poly(vinyl chloride) with styrene and (meth)acrylates by atom transfer radical polymerization

Graft copolymers of poly(vinyl chloride) with styrene and (meth)acrylates were prepared by atom transfer radical polymerization. Poly(vinyl chloride) containing small amount of pendent chloroacetate units was used as a macroinitiator. The formation of the graft copolymer was confirmed with size exclusion chromatography (SEC), ¹H NMR and IR spectroscopy. The graft copolymers with increasing incorporation of butyl acrylate result in an increase of molecular weight. One glass transition temperature (T_g) was observed for all copolymers. T_g of the copolymer with butyl acrylate decreases with increasing content of butyl acrylate.     

壳多糖与丙烯酸丁酯的乳液接枝共聚研究

以十二烷基苯磺酸钠为乳化剂，过硫酸钾－亚硫酸氢钠为引发剂，研究了壳多糖与丙烯酸丁醋的乳液共聚合，结果表明当［Ｋ２Ｓ２Ｏ８］＝［ＮａＨＳＯ３］＝２．５７×１０－３ｍｏｌ·１－１，［ＢＡ］＝０．６８ｍｏｌ．１－１，［Ｃｈｉｔｏｓａｎ］＝１９．２ｇ·ｌ－１，在７０℃下反应５小时，共聚反应的接技率和接枝效率均较高．用红外光谱，差热分析，Ｘ射线衍射，扫描电镜对接技共聚物进行了表征，此外测试了共聚物胶乳成膜的机械性能，表明用丙烯酸丁酯对壳多糖进行接枝改性，可提高壳多糖的韧性，扩大其应用范围．     

含氟丙烯酸酯共聚物防粘剂的制备及其表面性能研究

以甲基异丁基甲酮为溶剂,偶氮二异丁腈为引发剂,全氟烷基乙基丙烯酸酯、丙烯酸十八酯、丙烯酸丁酯和甲基丙烯酸羟乙酯为原料,溶液聚合制得了均一的含氟丙烯酸酯共聚物防粘剂,并研究了其表面性能。结果表明:全氟烷基乙基丙烯酸酯单体的加入显著降低了共聚物的表面能,提高了共聚物膜的硬度、耐水、耐碱、耐溶剂等性能。当加入ω(氟单体)为30%时,表面能降低至14.7 mN/m,低于有机硅类防粘剂的表面能,含氟丙烯酸酯共聚物膜与压敏胶的的剥离力较低,剩余粘附率为93.2%,该共聚物膜的防粘等综合性能最好。     

四元共聚物的热裂解色谱-质谱分析

报道了2－丁烯、甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸辛酯四元共聚物在不同裂解温度下的热裂解行为。用热裂解色谱－质谱分析方法，研究了裂解温度对裂解产物的影响，并讨论了四元共聚物的热裂解规律。     

胆甾醇丙烯酸酯／甲基丙烯酸丁酯无规共聚物的研究

胆甾醇丙烯酸酯／甲基丙烯酸丁酯无规共聚物的研究李安东，宋襄玉，周恩乐（中国科学院长春应用化学研究所高分子物理开放研究实验室，长春，１３００２２）关键词胆甾醇丙烯酸酯，甲基丙烯酸丁酯，高分子液晶，相态转变近来场致显示受到极大重视［１，２］，但对含有胆甾...     

Tunable cross-linked copolymer networks for improvement of physical performance

The ability to tune the physical properties of polymeric materials through the different compositions in copolymer networks is suitable for the strategy of materials accompanied by combined high mechanical strength and stretchability simultaneously. Here, we developed a practical and straightforward strategy of a copolymer network structure via controlling the compositions of the acrylic-based urethane copolymers of diurethane acrylate (DUA) and diurethane cyclic acrylate (DUCA) with hydrogen-bonds through photo-polymerization. The copolymer networks led to the development of a physically cross-linked structure between the amide groups of DUA and/or DUCA and the hydroxyl groups of pentaerythritol ethoxylate (PEEL) by hydrogen-bonds. Based on the rheological analysis, the composition of the copolymer networks had a significant effect on the control of physical properties and development of cross-linked structure and thus led to the tunable comprehensive properties including high elastic modulus, high chain mobility and high recovery performance with a higher proportion of DUCA in the copolymer networks. Consequently, the tunable copolymer networks based on the developed physically cross-linked structure can improve the elastic properties, recovery performance, and healing ability simultaneously, providing significant progress in the fields of coating and adhesive.     

Amphiphilic Triblock Copolymers Based on Acrylic Acid and Alkyl Acrylates Synthesized via RAFT Polymerization-Induced Self-Assembly and RAFT Miniemulsion Polymerization

The aim of this research is to reveal the advantages and limitations of different heterophase polymerization methods, such as dispersion, emulsifier-free emulsion and miniemulsion polymerization, for the obtaining of in situ self-assembled amphiphilic triblock copolymer core-shell particles. In the present research, we addressed the problems of the controlled synthesis of two- and three-component amphiphilic ABA triblock copolymers based on acrylic acid, fluoroalkyl acrylates and butyl acrylate via polymerizationinduced self-assembly and reversible addition fragmentation chain transfer polymerization (RAFT) miniemulsion polymerization using symmetrical trithiocarbonates.     

Determination of the molecular-weight characteristics of polyacrylic acid and its copolymer with butyl acrylate

A new procedure was suggested for pretreatment of polyacrylic acid and its copolymer with butyl acrylate with the aim of examining the molecular-weight distribution: chemical modification by esterification with benzyl alcohol. Conditions were chosen for turbidimetric titration of the resulting polymers. The results confirmed the efficiency of isopropanol as chain-transfer agent in copolymerization of acrylic acid with butyl acrylate. The molecular-weight characteristics of polyacrylic acid prepared by radical polymerization in water in the presence of Cu(II) ions were determined.     

A new procedure for preparing butyl acrylate-vinyl n-butyl ether copolymer as effective thickening additive to oils

The possibility of preparing copolymers by radical copolymerization on adding an active monomer, butyl acrylate, to refluxing inactive vinyl n-butyl ether was examined. The copolymer composition was studied by IR and NMR spectroscopy and by gravimetric analysis. The molecular weight and polydispersity coefficient of the copolymer were determined.     

甲基丙烯酸甲酯-丙烯酸丁酯共聚物微观结构研究

用１３Ｃ ＮＭＲ研究了由基团转移共聚得到的甲基丙烯酸甲酯 丙烯酸丁酯共聚物的微观结构，共聚物中单体链节的三元组含量从季碳和羰碳的共振信号测得，实验测得的三元组分数与通过竞聚率和单体组成比按末端基效应模式的计算值相符．丙烯酸丁酯由于具有大得多的竞聚率值而呈现较强的均聚倾向．     

Thermal and mechanical properties of polylactide toughened with a butyl acrylate-ethyl acrylate-glycidyl methacrylate copolymer

In this work, a specific polylactide (PLA) 4032D was melt-mixed with a new toughener: butyl acrylate (BA), ethyl acrylate (EA) and glycidyl methacrylate (GMA) copolymer (BA-EA-GMA). DMA tests showed that PLA/BA-EA-GMA blends were partially miscible. The degree of crystallinity of PLA increased while the cold crystallization temperature shifted to higher temperatures with increasing BA-EA-GMA content. The SEM micrographs showed that PLA/BA-EA-GMA blends had a good dispersion and this phenomenon was in good agreement with their higher impact strength. The result showed that the adding of BA-EA-GMA has enhanced the flexibility of PLA/BA-EA-GMA blends as compared with pure PLA. The impact strength was changed from 3.4 kJ/m² for pure PLA to 29.6 kJ/m² for 80/20 PLA/BA-EA-GMA blend.     

超声无皂乳液聚合制备BA/St/AM三元共聚物乳胶粒及其聚合机理研究

将超声技术引入到无皂乳液聚合方法中,在不加入任何引发剂和乳化剂的情况下,制备了丙烯酸丁酯(BA)/苯乙烯(St)/丙烯酰胺(AM)三元共聚纳米乳胶粒.研究了不同超声时间对单体转化率、乳胶粒粒径以及乳液粘度的影响.同时还探讨了超声无皂乳液聚合机理,认为AM在聚合过程中起到了引发和稳定的作用.TEM照片表明,乳胶粒直径大约在80nm左右,FTIR及DSC分析表明产物为三元共聚物,而不是共混物.     

Free-Radical copolymerization of N-vinylsuccinimide with butyl acrylate in the presence of zinc chloride and aluminum chloride

The free-radical copolymerization of N-vinylsuccinimide with butyl acrylate performed in dimethyl sulfoxide and benzyl alcohol in the presence of zinc chloride and aluminum chloride as complexing agents is studied. Under the given conditions, the reactivity ratios are determined. It is shown that zinc chloride influences the electron-density distribution only in butyl acrylate molecules. It is found that benzyl alcohol retards the total rate of polymerization. The character of the monomer-unit distribution in copolymer macromolecules is described.     

Inverse microemulsion polymerization of oil-soluble monomers in the presence of hydrophilic polyacrylamide nanoparticles

A new method for preparation of modified polymer particles in two steps was proposed. Free radical polymerization of an oil soluble vinyl monomer like butyl acrylate in inverse microemulsion containing polyacrylamide particles led to the formation of modified, partly hydrophobized, polyacrylamide particles. For the first step of the process (preparation of polyacrylamide particles in inverse microemulsion) is typical a very high polymerization rate while for the second step (polymerization of an oil soluble monomer (methyl acrylate, ethyl acrylate, butyl acrylate 2-ethylhexyl acrylate, methyl methacrylate, styrene) in the presence of polyacrylamide particles in inverse microemulsion, the reverse is true. The polymerization of an oil soluble monomer in some instances leads to the formation of 2-phase or even 3-phase disperse systems. The polymeric products obtained after precipitation of the polymer particles from the inverse microemulsions by ethanol were extracted by water and/or toluene and analyzed for acrylamide content. The separated polymer product contained high content of acrylamide, AAm/oil soluble monomer (butyl acrylate BA, or styrene, S) copolymer (85% of AAm/BA, ≈ 99% of AAm/S) besides relatively small amounts of homopolymers of oil soluble monomers (15% of BA, ≈ 1% of S homopolymers).