EFFECT OF 2—HYDROXYETHYL METHACRYLATE ON SEMIBATCH EMULSIFIER—FREE EMULSION COPOLYMERIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

The semibatch emulsifier-free emulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate(BA) in the presence of 2-hydroxyethyl methacrylate(HEMA) initiated by K2S2O8(PSP) was studied.The latex particles can maintain an appreciable stability during the emulsifier-free emulsion copolymerization of MMA and BA in the presence of HEMA.The average particle diameter increase with an increase of total solids content,HEMA content,PSP content,ionic strength of the system and monomer feed rate,and decrease with the monomer feed ration from 3/1 (MMA/BA:molar ration).to 1/3.The stability of this reaction system is improved by adding HEMA as nonionic comonomer,High solids content (50%) latex with monodisperse particle can be obtained using this process.     

EFFECT OF 2-HYDROXYETHYL METHACRYLATE ON SEMIBATCH EMULSIFIER-FREE EMULSION COPOLYMERIZATION OF METHYLMETHACRYLATE AND BUTYL ACRYLATE

IINTRODUCTIONSemibatchemulsionpolymerizationisanimportalmethodfortheproductionofpolymersforthecoatingsandadhesivesindustries.Thetraditionallatexproductsaregenerallystabilizedbyemulsifiers.However,theemulsifiersremaininginthelatexproductcanhaveanegativeeffectontheapplicationpropertiessuchasadhesiontosubstratesandfilmformationandwaterresistanceofthecoatingmaterials,becausethesmallandmobileemulsifiermoleculestendtomigratetothesurfacelayerofthepolymericfilm.Withtheemulsifier-freeemulsionpolym…     

Influence of hydrophobic monomers on secondary nucleation of hydroxyl‐functionalized latexes

The influence of butyl acrylate (BA) and methyl methacrylate (MMA) on hydroxyl functionalized latexes was investigated. The hydrophobicity of the monomer feed was varied via the BA/MMA ratio. In addition to monitoring the effect of hydrophobic monomer feed on secondary nucleation, the polymerization kinetics and final latex properties were also obtained for comparison. Five different BA to MMA molar ratios were combined with five 2‐hydroxyethyl methacrylate (HEMA) concentrations (0, 10, 20, 30 and 40 mol% in monomer composition). All latexes were synthesized through seeded semibatch emulsion polymerization process. Particle size distributions and average particle sizes of the latexes were determined by dynamic light scattering (DLS) and qualitatively compared with transmission electron microscope (TEM) images. The BA to MMA ratio significantly influences the boundary HEMA concentration at which homogeneous secondary nucleation occurs. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2190–2202     

甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率

甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率邹友思郭金全戴李宗潘容华（厦门大学化工系，厦门，３６１００５）基团转移聚合是制备极性单体的嵌段或无规共聚物的有效方法。如用甲基丙烯酸甲酯（ＭＭＡ）和丙烯酸丁酯（ＢＡ）进行嵌段共聚，可制得热塑性弹性体［１...     

Copolymers of 2-hydroxyethyl methacrylate and alkyl acrylates: Studies of molecular weight distribution and thermal behavior

Several copolymers of 2-hydroxyethyl methacrylate (HEMA) with methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA), and methyl methacrylate (MMA) were prepared at 70°C in nitrogen atmosphere using 0.2% (w/v) benzoyl peroxide as initiator. The copolymer composition was evaluated by estimation of hydroxyl group in the copolymers. Intrinsic viscosity of HEMA–EA, HEMA–BA, and HEMA–MMA copolymers was determined at 35°C in dimethyl formamide. Molecular weight distribution of copolymer samples was evaluated by gel permeation chromatography. Thermal behavior of the copolymers was investigated by dynamic thermogravimetry. Thermal stability decreased on increasing HEMA content in MA, EA, and BA copolymers. However, a reverse trend was observed in HEMA–MMA copolymers.     

A Transformable and Bulky Methacrylate Monomer That Enables the Synthesis of an MMA-nBA Alternating Copolymer: Sequence-Dependent Self-Healing Properties

In this study, we designed a methacrylate molecule with an alkyl-substituted trichloro salicylic acid pendant as a transformable bulky monomer to enable the synthesis of an alternating copolymer of methyl methacrylate (MMA) and n-butyl acrylate (nBA). The adamantyl-substituted methacrylate monomer ( 1-Ad ) showed very low homopolymerization propensity in radical polymerizations, but afforded the alternating copolymer with nBA via copolymerization. The 1-Ad units in the resultant copolymer were quantitatively and selectively transformed into MMA via transesterification with methanol to yield the alternating copolymer of MMA and nBA. Its alternating sequence was clearly demonstrated by a structural analysis via ¹³C NMR spectroscopy as well as the low reactivity ratios for the 1-Ad and nBA pair. Finally, we verified the superior self-healing ability of the alternating copolymer compared to that of the corresponding 1 : 1 statistical copolymer.     

In Situ Semibatch Emulsion Polymerization of 2‐Ethyl Hexyl Acrylate/n‐Butyl Acrylate/Methyl Methacrylate/Cellulose Nanocrystal Nanocomposites for Adhesive Applications

Cellulose nanocrystals (CNCs) are safe, “green,” hydrophilic nanoparticles. CNCs are added in situ during a semibatch 2‐ethyl hexyl acrylate (EHA)/n‐butyl acrylate (BA)/methyl methacrylate (MMA) emulsion polymerization. As EHA is a more hydrophobic monomer, manipulation of the monomer feed composition allows for the evaluation of the effect of hydrophobicity on CNC distribution in the nanocomposite and ultimately on adhesive properties. The adhesive properties (loop tack, peel strength, and shear strength) of three different EHA/BA/MMA latex formulations are shown to simultaneously improve with increasing CNC loading. However, the hydrophobicity of the EHA leads to a nonuniform distribution of CNCs in the latex films. Comparison of the in situ polymerized nanocomposites to their blended counterparts is also made.     

甲基丙烯酸正丁酯/甲基丙烯酸β羟乙酯共聚吸附功能纤维的制备及表征

以过氧化苯甲酰(BPO)为引发剂, 合成了甲基丙烯酸正丁酯/甲基丙烯酸羟乙酯(BMA/HEMA)二元共聚树脂, 采用冻胶纺丝技术制备了低分子量有机液体吸附功能纤维, 利用傅里叶变换红外光谱(FTIR)和13C核磁共振波谱(NMR)、广角X射线衍射仪(WAXD)和综合热分析仪以及环境扫描电子显微镜(SEM)研究了共聚物的交联结构、纤维的结晶性能以及纤维的表面形貌, 同时研究了共聚合阶段HEMA与BMA投料比对纤维饱和吸附量的影响. 研究结果表明, 树脂大分子间不存在化学交联结构, 大分子内和大分子间存在氢键作用, 有利于物理交联结构的形成; 纤维结晶性能随着HEMA质量分数增加而减弱, 且HEMA质量分数对纤维表面形貌有较大影响; 纤维对甲苯和三氯乙烯的饱和吸附量随着HEMA质量分数增加而增大, HEMA质量分数相同时所得纤维对三氯乙烯的吸附量明显高于对甲苯的吸附量.     

Copolymerization of 2-hydroxyethyl methacrylate with alkyl acrylates

Copolymerization of 2-hydroxyethyl methacrylate (HEMA) with methylacrylate (MA), ethylacrylate (EA), n-butylacrylate (BA) and methylmethacrylate (MMA) were studied in bulk at 60° using benzoyl peroxide as initiator. The monomer reactivity ratios were determined using several methods and are briefly discussed.     

The Effect of Nano-SiO2 Colloid on Soap-free Emulsion Polymerization of Methyl Methacrylate and Hydroxyethyl Methacrylate

Soap-free emulsion polymerization of methyl methacrylate (MMA) and hydroxyethyl methacrylate (HEMA) was carried out in the presence of colloidal nano-SiO₂ particles. The effect of nano-SiO₂ level on the monomer conversion, polymerization rate (Rp), and emulsion stability was investigated. The viscosity, particle size distribution of the emulsions, surface tension, and ionic conductivity of these systems were determined. Upon the introduction of the nano-SiO₂ particles into this system, the Rp and monomer conversion increased and the average particle size of the P(MMA-HEMA) emulsion decreased in comparison to emulsions formed in the absence of nano-SiO₂. However, the particle size distribution became broader to some degree. Scanning electron microscope observations demonstrated that the shape of these latex particles were uniformly spherical. The surface tension and ionic conductivity of the system increased significantly after polymerization, but the presence of nano-SiO₂ resulted in an increase in surface tension and a decrease in ionic conductivity in comparison to the particle–free system.     

单体极性对甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸钠无皂乳液共聚合的影响

研究了少量甲基丙烯酸钠（ＮａＭＡ）存在下单体极性对甲基丙烯酸甲酯（ＭＭＡ）／丙烯酸丁酯（ＢＡ）无皂乳液共聚合的影响．单体极性降低，使粒径减小、聚合速率提高、乳液表面张力和粘度降低、粒子表面电荷密度增大、聚合物分子量提高．ＭＭＡ／ＮａＭＡ无皂乳液聚合物只呈现一个玻璃化温度Ｔｇ，ＢＡ／ＮａＭＡ无皂乳液聚合物呈现两个Ｔｇ，ＭＭＡ／ＢＡ比为２∶１～１∶２的ＭＭＡ／ＢＡ／ＮａＭＡ无皂乳液聚合物呈现四个Ｔｇ，这是由于粒子外面相对富含ＯＳＯ－３和ＣＯＯ－基聚合物的亚层溶解了较多的水，使ＢＡ向粒子中心扩散，ＭＭＡ向外扩散，造成组成差异和相分离而引起的．     

Synthesis and radical copolymerization of new type pyridinum monomer and redox behavior of its polymers

A new type pyridinium salt monomer, 1-vinyl-4-carbamidopyridinium perchlorate, was prepared, and then homopolymerized and copolymerized with methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), styrene, and acrylonitrile. Redox potentials of these pyridinium salt monomer and polymers were more positive than that of the model compound (1-methyl-4-carbamidopyridinium salt). The copolymer with MMA showed an interesting redox behavior.     

Determination of chain transfer constant to dodecanethiol in styrene/methyl methacrylate and butyl acrylate/methyl methacrylate copolymerization and effect of chain length on composition and stereochemical configuration of copolymers

Free radical copolymerization of styrene/methyl methacrylate (S/MMA) and butyl acrylate/methyl methacrylate (BA/MMA) in the presence of n-dodecanthiol (DDT) has been studied at 60°C in a 3 mol/L benzene solution using 2,2′-azobis(isobutyronitrile) (AIBN) as initiator. Overall chain transfer constant to DDT has been determined for both copolymerization systems, as a function of monomer feed composition using complete molecular weight distribution and the Mayo method. Overall transfer coefficients have values which are dependent on both monomer feed composition and individual comonomer transfer values. Composition, sequence distribution, and stereoregularity of copolymers obtained are, in our experimental conditions, independent of copolymer molecular weight. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2913–2925, 1998     

Di-block copolymer stabilized methyl methacrylate based polyHIPEs: Influence of hydrophilic and hydrophobic co-monomers on morphology,wettability and thermal properties

Due to intermediate hydrophobicity of methyl methacrylate (MMA) monomer in water, it is difficult to prepare its stable water in oil high internal phase emulsion (HIPE). Moreover, the addition of fully hydrophilic co-monomer such as 2-hydroxyethyl methacrylate (HEMA) in MMA monomer makes it further troublesome to stabilize these emulsions. This paper addresses the preparation of such type of difficult to prepare emulsions via addition of an amphiphilic fluorinated di-block copolymer (FDB), poly(2-dimethylamino)ethylmethacrylate-b-poly(trifluoroethyl methacrylate) (PDMAEMA-b-PTFEMA) as stabilizer. Interestingly, HEMA and/or HFBA (hexa fluorobutyl acrylate) as co-monomers were successfully added to impart some special properties such as thermodynamic stability, desired amphiphilicity to the final polyHIPEs. Fluorinated blocks in FDB anchored well at oil/water interface of HIPE, offering enough hydrophobicity to the comparatively hydrophilic monomers and in turn providing resistance against coalescence. MMA polyHIPEs were found to be fully hydrophobic just by replacing HEMA co-monomer with HFBA. Due to superb inherent hydrophobic nature of fluorine atoms, MMA-HFBA polyHIPEs showed remarkable water contact angle of 139°. Furthermore, the addition of fluorinated co-monomer in MMA based HIPEs significantly improved thermal stabilities of these materials with improvement in degradation temperature from 305 °C to 360 °C.     

甲基丙烯酸磺酸基己酯钠盐的共聚合、聚合及其均聚物的抗凝血性能

研究了甲基丙烯酸6-磺酸基己酯钠盐与甲基丙烯酸甲酯、甲基丙烯酸β-羟乙酯及甲基丙烯酸正己酯的共聚合,并测定了它在水及二甲亚砜中的聚合速度关系式。聚甲基丙烯酸6-磺酸基己酯钠盐的抗凝血性能在一定分子量范围内相差不多。     

Polymerization of Methyl Methacrylate and Isobutyl Methacrylate in Ternary-Component Emulsions and Microemulsions: Effect of Surfactant Concentration

Abstract

The similarities and differences in the polymerization of MMA (methyl methacrylate) and iBMA (isobutyl methacrylate) in a ternarycomponent system have been investigated from a turbid emulsion to a transparent microemulsion by increasing the surfactant concentration. In spite of the difference in the solubilities of these two monomers in the aqueous phase, the rate dependencies on the surfactant concentration of both monomers were found to be about 0.30 for the emulsion polymerization and about 0.60 for the microemulsion polymerization with monomer concentrations higher than 5 wt%. However, at a low monomer concentration (3 wt%), different negative rate dependencies of ?0.93 and ?1.20 were obtained for microemulsion polymerization of MMA and iBMA, respectively. The results are discussed in terms of particle nucleation mechanisms.     

水分散体系中苯乙烯和甲基丙烯酸甲酯梯度共聚物的合成与表征

以2-溴代异丁酸乙酯(EBiB)为引发剂,CuBr/CuBr₂/1,10-邻二氮菲(phen)为复合催化剂,十二烷基磺酸钠(SLS)为乳化剂,考察了水分散体系中苯乙烯(St)和甲基丙烯酸甲酯(MMA)的原子转移自由基共聚合的可控性和相对反应活性.在此基础上,通过反应进料法在水分散体系中进行了St和MMA的梯度共聚合,反应表现出“活性”聚合的特征,即所得共聚物的数均分子量随着单体转化率的增加而增大,分子量分布较窄(M_w/M_n<1.50).用¹HNMR跟踪分析了聚合反应过程中共聚物微观组成的变化规律,结果表明,共聚物链中MMA链节的累积含量和瞬时含量都随着共聚物相对链长的增加而增加,即随着聚合物相对链长的增加共聚物的微观组成从St链节占主导地位逐渐变化为以MMA链节占主导地位,表明确实形成了St和MMA的梯度或渐变共聚物.     

Ambient Temperature Photocopolymerization of Tetrahydrofurfuryl Methacrylate and Isobornyl Methacrylate: Reactivity Ratios and Thermal Studies

Photocopolymerization of heterocyclic monomer namely, tetrahydrofurfuryl methacrylate with bulky bicyclic monomer, isobornyl methacrylate with different feed ratios was carried out in bulk with low concentration of an α-hydroxyl ketone based photoinitiator. The ambient temperature photocopolymerization was carried out by using a UV-Visible lamp with fixed low intensity of 0.4 mW cm^?2 for a period of 6 min. The residual monomer remained in the polymerization process were determined by using gas chromatography. The reactivity ratio values for the two monomers were calculated from the copolymer composition data by using Fineman-Ross, Kelen-Tudos, Extended Kelen-Tudos and Mao-Huglin methods. Individually, as well as the average of all the methods revealed that the monomer reactivity ratios of tetrahydrofurfuryl methacrylate were higher than isobornyl methacrylate. The dyad sequence distribution and dyad sequence lengths were calculated using the Igarashi and Pyun method and the sequence length distribution for tetrahydrofurfuryl methacrylate was observed to be higher with an increase in its feed content. This supports the reactivity ratio studies that a higher monomer reactivity ratio value for tetrahydrofurfuryl methacrylate was observed as compared to its comonomer. The thermal studies showed that the glass transition temperatures of the copolymers increased with an increase in isobornyl methacrylate content.     

丙烯酸酯和甲基丙烯酸酯基团转移共聚研究

研究了三种丙烯酸酯分别和四种甲基丙烯酸酯的基团转移共聚，用１Ｈ ＮＭＲ法测定共聚物组成，扩展的Ｋｅｌｅｎ Ｔｕｄｏｓ法测定竞聚率，结果为γＭＡ＝９２３、γＭＭＡ＝００６；γＥＡ＝１４１５、γＭＭＡ＝００１；γＢＡ＝７５１、γＭＭＡ＝００２；γＭＡ＝１４４１、γＥＭＡ＝００１；γＭＡ＝１３９６、γＢＭＡ＝０２３；γＭＡ＝８６６、γｉ ＢＭＡ＝００８，表明基团转移聚合同阴离子聚合有明显的相似之处．     

Copolymerization and Copolymers of 2,4,5-Tribromostyrene with Methyl Acrylate and Methyl Methacrylate

Abstract

2,4,5-Tribromostyrene (TBSt) was copolymerized with methyl acrylate (MA) or methyl methacrylate (MMA) in a toluene solution using 2,2′-azobisisobutyronitrile as free radical initiator. The copolymerization reactivity ratios were found to be for the system TBSt / MA r₁= 7.4 ± 1.2 (TBSt) and r₂= 0.1 ± 1.4 (MA) and for the system TBSt / MMA r₁ = 1.8 ± 0.2 (TBSt) and r₂ = 0.1 ± 0.2 (MMA). The e and Q values were also calculated. The initial rate of copolymerization, as well as molecular weight of the obtained copolymers for both system linearly increase as the content of TBSt in the monomer mixture increases. Similar behavior has also been established for the course of the copolymerization reactions to high conversions. The resulting copolymers rapidly decompose at temperatures 20–800°C above the decomposition of corresponding (metha)crylate hompolymers. However, the glass transition temperature increases markedly with increasing TBS content.