甲基丙烯酸甲酯反相无皂微乳液聚合

以偶氮二异丁腈(AIBN)为引发剂,对甲基丙烯酸甲酯／丙烯酸(AA)／水构成的反相无皂微乳液体系的聚合进行了研究,结果发现可以得到具有多孔结构的聚合物材料,而且聚合速率(dC／dt)随AIBN和AA用量的变化分别有dC／dt∝[AIBN]^1.0与dC/dt∝[AA]^1.7的动力学关系。     

甲基丙烯酸甲酯/丙烯酸丁酯的无皂乳液共聚

以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为主要原料,过硫酸铵为引发剂,进行无皂乳液聚合.结果表明:在不添加乳化剂的情况下,当MMA/BA=1:1、引发剂用量为0.24%、反应温度为80℃、反应时间8.0h时,所得乳液最稳定,单体转化率为81.84%,此无皂乳液对牛皮纸的粘接性比常规乳液好.     

丙烯酸树脂无皂乳液的研究

用可聚合乳化剂AMPS（2－丙烯酰胺基－2－甲基－丙基磺酸钠），采用种子半连续无皂乳液聚合方法，研制成一种耐水性极好的丙烯酸树脂乳液，并对其性能及影响因素进行了考察和讨论。试验结果表明，聚合工艺及AMPS的用量对乳液的聚合稳定性有较大影响。     

丙烯酰胺反相微乳液体系的制备、聚合及表征

本论文探讨了用Span80,Tween60为复合乳化剂,煤油为分散介质,制备丙烯酰胺的反相微乳液,并研究了所形成微乳兴的微观结构和影响该微乳液体系聚合反应的因素,本文重点研究了复合乳化剂的配比,丙烯酰胺反相微乳液体系的形成机理,并通过紫外分光光度计,旋转粘度计等对微乳液体系可能形成的微观结构和特性进行了分析探讨。其后,采用氧化还原引发剂体系进行了微乳液聚合,并对聚丙烯酰胺的物理性能,化学结构,相对分子质量等进行了测定和表征。     

丙烯酸酯无皂乳液的研究

在甲基丙烯酸甲酯和丙烯酸丁酯的无皂乳液体系中，加入适量的自制聚氨酯型反应性乳化剂(URE)，考察单体配比和有机溶剂对乳胶膜性能的影响，并研究了聚合物乳液的稳定性。结果表明：与传统乳液聚合体系相比，所合成的胶乳耐电解质、耐酸碱、耐有机溶剂的性能均好。     

甲基丙烯酸甲酯/羟甲基丙烯酰胺无皂乳液共聚合的研究

以甲基丙烯酸甲酯为主单体、N-羟甲基丙烯酰胺为功能性单体、K2 S2 O8为引发剂进行了无皂乳液共聚合的研究 ;探讨了固含量、单体配比、反应温度、引发剂含量等对乳液稳定性和粒径大小的影响 ,制备了固含量较高 ( 30 %)、稳定性较好的丙烯酸酯无皂乳液。研究结果表明甲基丙烯酸甲酯 /N-羟甲基丙烯酰胺无皂共聚合的最佳条件为固含量 30 %、功能性单体 2 0 %、引发剂 1 %、反应温度 75℃。     

可聚合乳化剂合成含氟丙烯酸酯无皂乳液及其性能

以甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）、甲基丙烯酸六氟丁酯（HFMA）等为主要原料,采用预乳化种子乳液聚合法合成了含氟丙烯酸酯无皂乳液,考察了可聚合乳化剂烯丙氧基壬基酚聚氧乙烯（10）醚硫酸铵（DNS-86）和HFMA的用量对无皂乳液的电解质稳定性和涂膜耐水性的影响。利用傅里叶红外光谱、差示量热扫描仪及热重分析对氟丙乳液涂膜进行了表征。结果表明：与传统乳液聚合得到的乳液及相应的涂膜相比,无皂乳液的耐电解质性能和涂膜的耐水性都有一定的提高,含氟单体有效地参与了聚合,涂膜的疏水性大大增强,耐热性显著提高。     

微乳液及微乳液聚合

本文综述了微乳液的性质、结构、制备方法，以及国内外正相、反相微乳液聚合的研究概况２。     

丙烯酸铵反相微乳液体系研究

为了制备一个均匀稳定且固含较高的丙烯酸铵反相微乳液体系,通过对微乳液体系电导率、丁达尔现象、稳定性等参数的测定,考察了连续相、乳化剂、HLB值、水相、电解质以及助乳化剂等因素对丙烯酸铵微乳液体系的影响,最终得到了由Isopar M异构烷烃以及Span80/OP-10复配乳化剂构成的丙烯酸铵反相微乳液体系。该体系单体固含达17.65%,均匀稳定,长期放置不分层。     

不饱和聚酯/苯乙烯无皂乳液共聚合与聚合物微凝胶

以羧基封端的不饱和聚酯（ＵＰ）和苯乙烯（Ｓｔ）为单体进行了无皂乳液共聚合,制备了聚合物微凝胶,提出了ＵＰ－Ｓｔ无皂乳液聚合的成核机理,讨论了ＰＨ值、ＵＰ／Ｓｔ等因素对体系稳定性和微凝胶产率的影响,该聚合物微凝胶能明显提高ＵＰ的冲击强度。     

Microemulsion polymerization of methyl methacrylate initiated with γ ray

Polymerization of methyl methacrylate was studied in an oil and water microemulsion stabilized with styrene 12-butinoyloxy-9-octadecenoic acid. During the polymerization the size change of the monomer-swollen particles with conversion was measured with photon correlation spectroscopy, and the hydrodynamic diameter of the final polymer latex was about 50 nm. The polymerization kinetics in this microemulsion were also investigated. The apparent plateau of the polymerization rate was observed at a low dose rate and high emulsifier content. The mechanism leading to this plateau was discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2621–2626, 1999     

Polymerization of acrylamide in styrene containing inverse microemulsions: polymerization kinetics and polymer product composition studies

The kinetics of free‐radical homopolymerization and copolymerization of acrylamide (AAm) and styrene (S) initiated by water‐soluble ammonium peroxodisulfate, (APS) or by toluene‐soluble dibenzoyl peroxide (DBP) in inverse microemulsion toluene/S/AOT (sodium bis(2‐ethylhexyl)sulfosuccinate)/water/AAm characterized by a low volume fraction of the aqueous phase (Φ_aw ≈ 0.08) as a function of the concentration of S in the oil phase of the inverse microemulsion system have been studied. S strongly decreases the rate of AAm/S (co)polymerization. This is valid for both APS and DBP initiators. Kinetic measurements indicate the important role for cross‐initiation of water soluble AAm growing chains and of oil soluble S analogues activated by the primary free‐radicals generated from APS (or from DBP) in the dispersed water droplets (or in the continuous oil‐phase) of the inverse microemulsion, respectively. With inverse microemulsions containing toluene (70.73 %)/S (2.44 %)/AOT(17.56 %)/water (7.32 %)/AAm (1.95 %), after polymerization (initiator APS, 3.04 × 10⁻² mol dm⁻³ of water) and separation of the polymeric components, the following yields were obtained: AAm/S (co)polymer (89.20 mass%; ie 62.24 mass% of AAm structural units and 26.96 mass% of S structural units), polyacrylamide (9.4 mass%) and polystyrene (1.4 mass%). © 2000 Society of Chemical Industry     

甲基丙烯酸甲酯的RAFT微乳液聚合

该文合成了一种双官能团的RAFT试剂——S,S'-二(α,α'-二甲基-α″-乙酸)三硫代碳酸酯(BDAT)。以其为链转移剂,在微乳液体系中进行了甲基丙烯酸甲酯的RAFT聚合。分别讨论了聚合反应温度和链转移剂浓度对聚合反应的影响,并对相关的聚合反应动力学常数进行了计算。研究结果表明,在微乳液中进行的RAFT聚合具有显著的活性聚合的特征。聚合产物的相对分子质量(简称分子量,下同)随着转化率的提高而线性增加,同时聚合产物具有较窄的分子量分布,聚合过程随着链转移剂浓度的增加而逐渐可控。另外,利用透射电子显微镜对链转移剂浓度对微乳液粒子尺寸的影响也进行了考察,扫描电镜照片表明,微乳液聚合所得乳液粒子呈现单分散性状态,并且粒子尺寸随着链转移剂浓度的增加而逐渐增加。     

Polymerization of methyl methacrylate with metal acetylacetonates and triethylaluminum catalysts

Polymerization of methyl methacrylate (MMA) with metal acetylacetonates, especially vanadium (III) acetylacetonate [V(acac)₃], in combination with AIEt₃ was studied. V(acac)₃–AIEt₃ catalyst could initiate the polymerization of MMA, although other Mt(acac)_xs are also effective. It was found that the polymerization of MMA with V(acac)₃–AIEt₃ catalyst proceeded through a coordination mechanism, from the results of copolymerization with styrene and polymerization in the presence of radical inhibitors. The resulting polymers were found to form stereocomplexes in acetone. Based on these results, it is concluded that multi-active sites in the polymerization of MMA with V(acac)₃–AIEt₃ catalyst were produced.     

甲基丙烯酸甲酯-丙烯酸乙酯乳液共聚动力学研究

为了合成适于药物包衣用的甲基丙烯酸甲酯-丙烯酸乙酯(MMA-EA)共聚物胶乳,对以非离子型乳化剂OP-10为乳化剂、过硫酸钾为引发剂的MMA-EA乳液共聚动力学进行了研究。发现初期共聚速率随着乳化剂浓度、引发剂浓度和聚合温度的增加而增大,这是由于共聚物乳胶粒子平均粒径随着乳化剂、引发剂浓度和聚合温度的增加而减小,乳胶粒子数目增加所致。通过调节乳化剂、引发剂以及反应温度可以达到合适的聚合反应速率,最终合成出转化率大于95%的MMA-EA共聚乳液。     

Poly(methyl acrylate-co-methyl methacrylate)/montmorillonite nanocomposites fabricated by soap-free emulsion polymerization

The exfoliated poly(methyl acrylate-co-methyl methacrylate)/montmorillonite (MMT) nanocomposite latex solutions fabricated by soap-free emulsion polymerization were able to cast into a film. The films were transparent and ductile unless more than 5 wt% of MMT was incorporated. With the MMT content higher than 5 wt%, the inflammable residuals of nanocomposites after combustion could preserve their original film profile acting like an inflammable scaffold. Moreover, as 20 wt% MMT was incorporated, the yield strength of the films was increased up to 20 times and Young’s modulus up to 2,000 times. However, the water vapor permeability coefficient of the films was only decreased down to its half value. This unexpected behavior of permeability was associated with the decrease of T _g as the content of MMT was increased, owing to the large difference of the reactivity ratios between methyl acrylate and methyl methacrylate monomers and their differential absorption to the MMT during copolymerization.     

Novel excimer fluorescence method for monitoring polymerization: 1. Polymerization of methyl methacrylate

An excimer is formed by the association of an excited molecule with another molecule in its ground state. Such an excimer is characterized by a broad structureless fluorescence which is shifted to longer wavelengths compared to the fluorescence spectrum of the isolated molecule. Intramolecular excimer fluorescence has been observed in solutions of pyrene-labelled alkanes such as 1,3-bis-(1-pyrene)propane and 1,10-bis-(1-pyrene)decane.We have measured the solvent-viscosity dependence of the intensity ratio $\text{F}{}_{\mathrm{<mtext>M</mtext>}}\text{F}{}_{\mathrm{<mtext>D</mtext>}}$ for solutions of these pyrene-labelled alkanes in mixed solvents made of ethyl acetate and glycerol tripropionate. Here F_M and F_D are, respectively, the fluorescence intensity of the unassociated pyrene groups and that of the intramolecularly formed pyrene excimers. We have found that for each of the two pyrene-labelled alkanes, the ratio $\text{F}{}_{\mathrm{<mtext>M</mtext>}}\text{F}{}_{\mathrm{<mtext>D</mtext>}}$ increases with the increase in solvent viscosity. Further, we have shown that by adding a trace amount of 1,3-bis-(1-pyrene)propane or 1,10-bis-(1-pyrene)decanee to a polymerizing system, we can measure the ratio $\text{F}{}_{\mathrm{<mtext>M</mtext>}}\text{F}{}_{\mathrm{<mtext>D</mtext>}}$ to monitor in situ the polymerization reaction. polymerization;     

Polymerization of methyl methacrylate at high temperature with 1‐butanethiol as chain transfer agent

The free‐radical polymerization of methyl methacrylate (MMA) at high temperature (120 to 180°C) has been studied in the presence of di‐tertiobutyle peroxide as an initiator and 1‐butanethiol as a chain transfer agent. No solvent was used, and the polymerization was run to high monomer conversion. Based on the experimental data collected with a dilatometric reactor, the features of the reaction have been pointed out. Working at high temperature with a chain transfer agent proved efficient to reduce the intensity of the gel effect and control the molecular weight obtained. At a temperature up to 170°C, however, the burn‐out of the initiator limits the final conversion, and the increase of the polymerization rate during the gel effect has been more difficult to detect and quantify. An empirical expression of the termination rate constant has been adopted to describe the autoacceleration and predict the conversion versus time curves and the average molecular weight of the polymer obtained. The mathematical model includes two adjustable parameters that have been determined as a function of the temperature and the initial concentration of the chain transfer agent. The agreement between the predicted and experimental data on conversion and molecular weight was good, while the polydispersity index was often underestimated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1589–1599, 1999     

Kinetics of methyl methacrylate grafting polymerization onto flaky aluminum powder

With ammonium persulfate (APS) as the initiator, the kinetics of methyl methacrylate (MMA) grafting polymerization onto flaky aluminum powder (Al) was studied. It was found that the experimental apparent grafting polymerization rate, R_g = KC × C × C, was basically consistent with the theoretical result based on the theory of stable polymerization and equivalent activity, R_g = KC × C × C_MMA. The activation energy of grafting, homogenous, and total polymerization rate was calculated as 65.1, 35.4, and 37.5 kJ mol^?1, respectively. It could be validated that the relationship among these activation energies accorded with the theoretical result of parallel reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010