Porous acrylonitrile/itaconic acid copolymers prepared by suspended emulsion polymerization

Porous acrylonitrile (AN)/itaconic acid (IA) copolymers were successfully prepared by suspended emulsion polymerization for the first time, with potassium peroxydisulfate (KPS) as an initiator, poly(vinyl alcohol) (PVA) as a dispersant agent, and Span80 as an emulsifier. The effects of the water/monomer mass ratio, agitation conditions, KPS concentration, PVA concentration, Span80 concentration,s and IA concentration on the average particle size and size distribution, particle morphology, and porosity of the AN/IA copolymers were investigated. The results show that the final AN/IA copolymers formed with agglomerates of primary particles had a porous structure, low particle density, and uniform particle size and did not agglomerate easily between the particles. The preparation conditions for the AN/IA copolymers were optimized as follows: (1) the water/monomer mass ratio was 0.3 : 1; (2) the concentrations of KPS, IA, PVA, and Span80 were 0.5, 12.4, 0.1, and 0.5 wt %, respectively, based on the weight of AN separately; (3) the agitation rate was 400 rpm; (4) the polymerization temperature was 70°C; and (5) the reaction time was 3 h. The size of the final AN/IA copolymer particles was in the range 200–400 μm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Surface properties of perfluoroalkylethyl acrylate/n-alkyl acrylate copolymers

Wetting behavior of perfluoroalkylethyl acrylate (FA)/n-alkyl acrylate (AA) copolymers with the various length of side chains of the AAs is discussed from a standpoint of surface molecular mobility. The copolymerization reactivity ratio indicates that these polymers are random copolymers. The surface properties were studied by measuring dynamic contact angle, static contact angle and freeze-dried X-ray photoelectron spectroscopy, and the bulk properties by wide-angle X-ray diffraction and differential scanning calorimetry. The advancing contact angles for water were independent of side-chain length of AAs and were almost constant at 120°. We have attributed this phenomenon to the orientation of perfluoroalkyl groups (R_f groups, C_xF_2x+1) in air, which is independent of side-chain length of AAs. On the contrary, the receding contact angles showed small values of about 45° when n numbers below 8 and increased when n numbers above 12. This can be explained as follows. High wettability during the receding process at the n numbers below 8 results from regression of R_f groups at the water–solid interface caused by minimization of the interface free energy. The low wettability during the receding process at the n numbers above 12 shows that R_f groups cannot regress due to its crystallization. This mechanism is also supported by other measurements. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1741–1749, 1999     

核壳型短链含氟丙烯酸酯乳液的合成及表征

该文研究了核壳型短链含氟丙烯酸酯乳液的合成与表征。以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的共聚体为核,短氟碳链2-(全氟己基)乙基甲基丙烯酸酯(FMA6)和非氟烷基丙烯酸酯的共聚体为壳,采用多步乳液聚合法,合成系列具有核壳结构的含氟丙烯酸酯乳液,研究了壳相中氟单体用量和非氟烷基丙烯酸酯的烷基链长度n(链长n=4、8、12、16、18)对产物疏水疏油性能的影响,并对产物进行表征。结果表明:当采用氟单体用量为总单体质量的8.5%,甲基丙烯酸十六酯(CMA)的共聚体为壳层时,由合成乳液制得的乳胶膜的疏水疏油性最佳,对水接触角为124.67°,对二碘甲烷接触角为112.76°。FTIR、TEM和DSC/TGA表征表明,原料单体均参加了反应;乳液颗粒具有明显的核壳结构;聚合物存在两个玻璃化温度(-18.87℃和32.08℃),热分解温度比不含氟的聚合物提高了近20℃。由此说明,用合成的核壳型短链含氟丙烯酸酯乳液制得的涂膜具有优异的疏水疏油性和耐热性能。     

无机-有机纳米复合乳液的原位聚合及其应用

综述了原位乳液聚合法制备无机．有机纳米复合乳液的技术现状及其形成机理，并运用此技术合成了舍无机纳米粒子的压敏胶用无机-有机纳米复合乳液，分析了纳米粒子在制备过程中的分散性能，从纳米粒子引入方式、乳化剂用量、纳米粒子加入量3方面对压敏胶性能进行考查。     

Preparation and properties of urethane/acrylate composite by emulsion polymerization technique

Aqueous polyurethane–acrylic hybrid emulsions were prepared by semibatch emulsion polymerization of a mixture of acrylic monomers (styrene, butyl acrylate and acrylic acid) in the presence of polyurethane dispersion. Equivalent physical blends were prepared by mixing acrylic emulsion and polyurethane dispersion. The weight ratio between acrylic and polyurethane components was varied to obtain enhanced performance properties and microphase structure of hybrid latexes. The synthesized emulsion hybrids and physical blends were characterized by fourier transform infrared spectroscopy, thermogravimetric analysis. The experimental results indicate better acrylic–polyurethane compatibility in hybrid emulsions than in physical blends, resulting in improved chemical and mechanical properties. The blend ratio 50:50% (w/w) exhibited synergistic effects between the two polymers and revealed remarkable improvement in various coating properties over other blend ratios and the individual resin components.     

Colloidal and polymer properties difference of fluorinated acrylate latex prepared with different fluorinated monomers

Fluorinated acrylate latex was prepared by copolymerizing fluorinated monomer, butyl acrylate, and methyl methacrylate, which was initiated by potassium persulfate in the water. The resultant fluorinated latex and its film were characterized with contact angle determinator, dynamic light scattering detector, and differential scanning calorimetry, respectively. Influence of type of fluorinated monomers on colloidal and polymer properties of fluorinated acrylate latex was studied. Results show that the coagulation rate, particle size, contact angle, glass transition temperature, and chemical resistance are increased with the increase of the number of fluorine atom in the fluorinated monomer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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。     

自交联含氟丙烯酸酯共聚物乳液的制备

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等为主要单体,甲基丙烯酸六氟丁酯(HFMA)为含氟单体,N-羟甲基丙烯酰胺(NMA)为交联单体,采用种子乳液聚合法制备了自交联含氟丙烯酸酯共聚物乳液。研究了HFMA、NMA、复合乳化剂(SDS OP-10)、引发剂(KPS)用量、聚合温度、聚合时间和搅拌速度等因素对聚合反应最终转化率和乳液稳定性的影响,结果表明在m(MMA)∶m(BA)=1∶1及搅拌速率210 r/min条件下,HFMA、NMA、SDS OP-10和KPS加入量分别为总单体量的7%、3%、3%和0.5%(均为质量分数),以及聚合温度75℃、反应时间4 h时,制备得到的乳液单体总转化率高,乳液凝聚率低,聚合反应稳定,涂膜的综合性能优良。此外,含氟乳胶膜的FT-IR及TG-DSC分析结果表明,HFMA有效地参与了共聚反应,提高了涂膜的耐热性。     

Copolymerizations of macromonomer prepared by addition-fragmentation chain transfer polymerization of methyl acrylate trimer

Summary An oligomer of the methyl acrylate unsaturated trimer bearing 2-carbomethoxy-2-propenyl ω-end group (M _n = 1300, M _w/M _n = 1.7, and functionality > 0.7) was copolymerized as a macromonomer (0.02 mol/L) with styrene (1.0 mol/L) in benzene at 60 °C. The amounts of monomer and macromonomer in the feed simultaneously decreased with increasing time to indicate copolymer formation, and the macromonomer was found to be as reactive as styrene toward poly(styrene) radicals. The M _ns of the copolymers were 13900–22000 depending on conversion. No resonance due to the unsaturated <ω-end group bound to the poly(styrene) chain was detected by ¹H-NMR spectroscopy, indicating that no fragmentation of adduct radical of the end group to expel the poly(methyl acrylate trimer) radical. Polymerization of ethyl methacrylate (1.0 mol/L) in the presence of the macromonomer (0.02 mol/L) resulted in a mixture of the unreacted macromonomer and homopolymer of ethyl methacrylate. No end group bound to the poly(ethyl methacrylate) was detected by ¹H-NMR spectroscopy, excluding the possibility of addition fragmentation chain transfer to the macromonomer to expel an oligomer radical of the methyl acrylate trimer. Addition of the poly(methacrylate) radical to the macromonomer is extremely slow under the present conditions of copolymerization. Received: 27 March 2003/Revised version: 30 April 2003/ Accepted: 30 April 2003 Correspondence to Bunichiro Yamada     

m‐Chloroaniline emulsion polymerization,macromolecular chain structure and electrochemical properties

Poly(m‐chloroaniline) (PmClAn) was synthesized by emulsion polymerization. The influences of reaction temperature and initiator concentration on polymerizations were studied. It was found that PmClAn with number‐average molecular weight of 1.85 × 10³ g mol^?1 was obtained by the following conditions: 80 °C, [monomer] = 0.187 × 10^?3 mol l^?1, [sodium lauryl sulfate] = 4.8 × 10^?2 mol l^?1, [potassium peroxydisulfate] = 5.6 × 10^?2 mol l^?1, reaction period = 2.0 h. ¹H NMR, FTIR, and transmission and scanning microscopy were used for structural characterization of PmClAn. It was shown that the ratio of benzoid to quinoid units in the macromolecular chain was respectively 3:2, and that PmClAn has a typical crystalline monoclinic form. A PmClAn molecular chain configuration was also proposed on the basis of crystallographic data. Cyclic voltammetry experiments revealed the PmClAn membrane electrode electroactivity. This electroactivity increased when the polymer was proton‐doped. When Pt particles were electrodeposited onto the polymer membrane electrode, they presented a preferred orientation. Isopropanol oxidation intensities with platinized PmClAn modified electrodes were larger than with a platinized Pt electrode. We also found that oxidation occurred mainly on the Pt particles deposited on the polymer, and that the anodic peak potential changed with polymer and its doping level. These results indicated that the Pt particles interacted with the polymer and that catalytic properties could be observed. © 2002 Society of Chemical Industry     

Thermomechanical properties of styrene‐butyl acrylate/organo‐silica nanocomposite films prepared by seed emulsion polymerization

Organo‐silica nanoparticles were prepared by sol–gel technique of triethoxyvinylsilane (VTES) in aqueous solution. The vinyl groups located on the surface of organo‐silica were used to induce the polymerization process and the encapsulation into styrene‐butyl acrylate copolymer emulsion. The prepared latex samples were characterized using FTIR, ¹HNMR, UV–visible, thermal analysis, field emission‐SEM and TEM. Results of TGA revealed that nanosilica has retarded the decomposition of nanocomposite polymers with at least 10°C higher than that of pure emulsions. DSC has shown an increase in the nanosilica ratio up to 5% which leads to a dramatic decrease in the glass transition (T _g) of nanocomposite polymer due to the formation of silica nanoparticles homopolymer. DMTA results indicated that the storage modulus of pure polymer is less than nanocomposite, which proves the reinforcing role of nanosilica in the matrix of polymer. Water resistance and UV‐blocking ability have improved by introducing the nanosilica into the matrix of prepared polymer. POLYM. COMPOS., 38:61–67, 2017. © 2015 Society of Plastics Engineers     

氧化还原引发剂对丙烯酸酯乳液性能及聚合机制的影响

以过硫酸钾(KPS)和亚硫酸氢钠(NaHSO3)为自由基聚合体系的氧化-还原型引发剂,以十二烷基硫酸钠(SDS)和脂肪醇聚氧乙烯醚硫酸钠(AES)为阴/非离子型复合乳化剂,制备甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和甲基丙烯酸(MAA)共聚物乳液。研究了引发剂种类及用量对该乳液性能及聚合过程等影响,探讨并提出了酸性条件下丙烯酸酯乳液体系的新型引发机制。结果表明:在其他条件保持不变的前提下,当m(KPS):m(NaHSO3)=1.00:0.45、w(KPS+NaHSO3)=0.6%时,乳液的单体转化率(98%)和黏度(5.900 Pa.s)相对最高,反应时间(2.0 h)相对较短且初始聚合温度(60℃)相对最低,此时乳液质量最稳定。     

Ionomer synthesis by emulsion polymerization of styrene and sodium acrylate

The emulsion copolymerization of styrene and sodium acrylate is reported using either a water-soluble initiator (potassium persulfate, or KPS), or an oil-soluble one [2,2-azoisobutyronitrile (AIBN)]. Reaction rates are fast with both KPS and AIBN. With KPS, conversions >90% are achieved in 50 min, with AIBN, conversions reach 85% in 100 min. Particle size, measured by quasielectric light scattering (QLS), increases with conversion. Particle size in final latices is ∼ 70–80 nm. Copolymer formation is confirmed by infrared (IR) spectroscopy, plasma emission spectroscopy (PES), and scanning electron microscopy (SEM). IR and PES indicate that mainly sodium acrylate reacts at the beginning of the reaction and then styrene is incorporated in the copolymer backbone. The copolymer produced with KPS contains more sodium acrylate than the one made with AIBN. These differences can be explained in terms of the reactivities and partitioning (local concentrations) of the monomers and of the type of initiator used. Thermomechanical analysis (TMA) of the copolymers reveals two transitions: one at ∼ 100°C, which is due to the glass transition temperature (T_g) of polystyrene blocky segments in the copolymer, and another one at higher temperatures, which is associated to the T_g of segments composed of alternated sodium acrylate and styrene units. The higher-temperature transition shifts to lower values as the reaction proceeds because these segments become richer in styrene. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 879–889, 1997     

半连续乳液聚合法制备高支化聚甲基丙烯酸甲酯

以甲基丙烯酸甲酯(MMA)为单体、二乙烯基苯(DVB)为支化剂和十二硫醇(C12SH)为链转移剂,采用半连续乳液聚合法制备了一系列低凝聚率高支化的PMMA(聚甲基丙烯酸甲酯)。着重探讨了不同单体配比对该乳液的稳定性、支化度(DB)、玻璃化转变温度(Tg)、相对分子质量及其分布等影响。结果表明:高支化PMMA乳液的粒径较小、粒径分布较窄;当n(DVB):n(C12SH)=1:2时,DVB和C12SH总用量越多[或当n(MMA):n(DVB)=100:10时,C12SH用量越多],聚合物的DB越高、相对分子质量越小、相对分子质量分布越窄且Tg越低。     

Synthesis and properties of acrylate‐acrylic acid‐acrylate triblock copolymers with gemini structure by RAFT polymerization

A class of gemini structure block copolymers with a trithiocarbonate ester spacer group had been synthesized with S, S′‐bis (R, R′‐dimethylacetic acid) trithiocarbonate as reversible addition fragmentation chain transfer agents and acrylic acid as the second monomer. These triblock copolymers were characterized by ¹H NMR spectroscopy, gel permeation chromatography in terms of their compositions, molecular weights and behaviour at the air–water interface. The results showed that the weight‐average molecular weight was larger than theoretical molecular as the acrylate side chain increased. The polymer neutralized by sodium hydroxide solution had low critical micelle concentration which was <10^?2 mol L^?1 in water. TEM and DLS showed that it formed a special micelle structure with large pore structure which might lead to low surface tension and critical micelle concentration in water. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43017.     

用可聚合乳化剂制备氟化丙烯酸酯无皂乳液

以丙烯酸丁酯、甲基丙烯酸甲酯、甲基丙烯酸三氟乙酯为基本原料,用可聚合乳化剂,通过连续滴定方法制备氟化丙烯酸酯无皂乳液。讨论了不同乳化剂和用量以及乳液预乳化稳定性等对转化率的影响。结果表明,在相同的乳液聚合体系中,采用可聚合乳化剂制得的无皂乳液,其胶膜表面能比使用一般乳化剂体系的为低。     

Configurational statistics of copolymers prepared by complex-radical polymerization

Radical copolymerization is considered theoretically taking into account the effect of complexing on the configurational statistics of macromolecules formed. Akinetic model has been developed that considers, apart from the ordinary addition of single monomer units to a propagating chain, the possible addition of monomer unit pairs along with a complexing agent in the form of a ternary complex. Within the framework of this model, the problem of calculating the probabilities of formation of any sequences of monomer units (taking into account their microtacticity) in a macromolecule has been rigorously solved as well as the problem of finding the composition distribution of the copolymer formed. It has been shown that this distribution is described by a conventional Gauss law and the appropriate parameters are given. Possible generalizations of the suggested approach are indicated.     

Characterization of molecular structure of acrylic copolymers prepared via emulsion polymerization using A4F‐MALS technique

The study is primarily focused on the possibility to utilize organic asymmetric flow field‐flow fractionation (A4F) coupled to a multi‐angle light scattering (MALS) detector for the characterization of copolymers of methyl methacrylate with various acrylates prepared by emulsion polymerization. The effects of acrylate monomer type and content on the molar mass distribution and degree of branching of acrylic copolymers have been studied by A4F‐MALS using tetrahydrofuran as a carrier solvent. It has been found that the growing amount of acrylate results in the increase of molar mass, polydispersity, and branching degree as a result of chain transfer to polymer. Highly branched compact macromolecules with ultra‐high molar mass were identified in all copolymers containing a high level of acrylate. In contrast to size traditionally used exclusion chromatography, organic A4F‐MALS has been proved as a very efficient technique for the characterization of high molar mass acrylic emulsion copolymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40995.     

淀粉-丙烯酰胺反相乳液聚合

采用反相乳液聚合,以淀粉、丙烯酰胺为原料,过硫酸铵为引发剂制备了淀粉丙烯酰胺聚合物。实验表明,最佳反应条件为：引发剂加量为单体总量的0.1%,油水体积比为1∶1,反应温度为60℃,反应时间为4 h。淀粉丙烯酰胺聚合物的除浊率可达89%,吸水率达350%。