Effects of glycidyl methacrylate content and addition sequence on the acrylic latexes with carboxyl groups

Acrylic latexes with epoxy and carboxyl groups have been synthesized via a two-stage emulsion polymerization process. Different contents of glycidyl methacrylate (GMA) were introduced by three addition modes to copolymerize with methyl methacrylate, butyl acrylate, acrylic acid (AA) in the presence of K₂S₂O₈. To obtain stable latexes, NaHCO₃ was employed as a buffer to compensate for the acidity from the thermal dissociation of K₂S₂O₈, and triethylamine was used to neutralize the carboxyl acid from AA. The results showed that the stable latexes with core/shell structure were synthesized by this method, and higher GMA content or addition at earlier stage led to forming the latexes with higher content of coagulum and bigger sized particles. During the formation of films, the polymer epoxy groups underwent the crosslinking reaction with carboxyl acid. When the GMA content increased or GMA was introduced at a later stage, high crosslinking extent was formed in the films. As a result, the crosslinking provided the films with improved water resistance, chemical resistance, tensile strength, hardness, abrasion resistance, and thermal stability.     

叔丙乳液的合成及水性防锈漆的研制

以甲基丙烯酸甲酯、丙烯酸丁酯、叔碳酸乙烯酯为主要单体,甲基丙烯酸、甲基丙烯酸缩水甘油酯、甲基丙烯酰氧基丙基三甲氧基硅烷为交联单体合成了叔丙乳液。研究了乳化剂的种类、用量及配比,交联单体的用量对乳液及涂膜性能的影响。确定复合乳化剂（RE-610/LCN407）的最佳用量为单体总量的2%,RE-610/LCN407的最佳质量比为1∶2。试验发现：当甲基丙烯酸缩水甘油酯与极性单体甲基丙烯酸的官能团比例为1∶1时,二者进行交联,可提高叔丙乳液的交联度。通过加入铁红、三聚磷酸铝、滑石粉、硫酸钡等制备的水性防锈漆,对金属底材具有良好的保护性。     

色粉纸用自交联丙烯酸树脂乳液的合成及性能

根据色粉纸表面固砂的性能要求,以丙烯酸丁酯(BA)、甲基丙烯酸异辛酯(EHMA)为软单体、丙烯酸甲酯(MA)、甲基丙烯酸甲酯(MMA)为硬单体,丙烯酸羟丙酯(HPA)为交联单体,甲基丙烯酸(MAA)、甲基丙烯酸缩水甘油酯(GMA)作为功能单体,采用半连续种子乳液聚合法,制备了具有核壳结构的水性丙烯酸酯树脂乳液(WSAE-G),进一步将其作为色粉纸表面固砂用黏合剂和成膜剂.讨论了GMA用量对乳液粒径、稳定性和黏度等的影响.利用DLS和TEM对乳液乳胶粒子的大小及形貌进行了表征,使用TG、DSC以及万能材料试验机对胶膜的性能进行了测试.对固砂产品表面进行SEM测试.结果表明:GMA用量为1％(以混合单体总质量为基准,下同)时,乳液粒径为142.4 nm,PDI为0.063,乳液分散稳定指数(TSI)为0.162287.TEM显示,乳液具有清晰的核壳结构.胶膜拉伸强度达9.057 MPa.制得的色粉纸层间结合力为244.9 J/m2,所形成的固砂层均匀、磨砂性较好且不易掉砂.     

Effect of oxirane groups on curing behavior and thermal stability of vinyl ester resins

The effects of oxirane groups in vinyl ester (VE) resin and reactive diluent on curing characteristics and thermal behavior of cured resins are described. Stoichiometric (0.5:1, sample A) as well as nonstoichiometric (0.5:0.85, sample B) ratios of the diglycidyl ether of bisphenol-A (DGEBA) and methacrylic acid (MA) were used for the synthesis of VE resins. Resin sample B had more residual epoxy groups because of the stoichiometric imbalance of the reactants. VE resins thus obtained were diluted with methyl methacrylate (MMA; 1:1, w/w), and controlled quantities of epoxy groups were introduced by partial replacement of MMA with glycidyl methacrylate (GMA), keeping the overall ratio of resin and reactive diluent constant. Increase of GMA content in resin A or B resulted in a decrease in gel time, indicating that the curing reaction is facilitated by the presence of epoxy groups. An increase in initiator content also reduced the gel time. In the differential scanning calorimetry (DSC) scans, a sharp curing exotherm was observed in the temperature range 107 ± 3–150 ± 1 °C. The onset temperature (T_onset) and peak exotherm temperature (T_exo) decreased with increase in GMA content. Heat of curing (ΔH) also increased with increase in GMA content. A broad exotherm was observed after the initial sharp exotherm that was attributed to the etherification reaction. Cured VE resins were stable up to 250–260 °C, and started losing weight above this temperature. Rapid decomposition was observed in the temperature range 400–500 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 416–423, 2001     

无皂苯丙防锈乳液的合成研究

以苯乙烯(St)、丙烯酸丁酯(BA)为主要单体,甲基丙烯酸(MAA)、甲基丙烯酸缩水甘油酯(GMA)、乙烯基三乙氧基硅烷(A-151)为交联单体合成了无皂苯丙乳液。研究了反应型乳化剂的种类及用量、交联单体的用量对乳液及涂膜性能的影响。确定反应型乳化剂的最佳用量为单体总量的3%。试验发现:当甲基丙烯酸缩水甘油酯与甲基丙烯酸的用量分别为单体总量的3%和3%时,二者可进行交联,能提高苯丙乳液的交联度和致密性。通过加入缓蚀剂PD-star-102,解决了苯丙乳液初期的闪锈问题,同时对涂膜的耐盐水性能有所提高。     

Polymerization of glycidyl methacrylate,methacrylic acid,acrylamide and their mixtures with cotton fabric using fe2+-thioureadioxide-H2O2 redox system

Polymerization of glycidyl methacrylate (GMA), methacrylic acid (MAA), acrylamide (Aam) and their binary mixtures with cotton cellulose fabrics using Fe²⁺-thioureadioxide-H₂O₂ redox system was investigated under a variety of conditions. While temperatures of 50, 80, 65, and 95°C constituted the optimal polymerization temperature for GMA, MAA, Aam and GMA/MAA (8:2), respectively, maximum polymerization of GMA/MAA (2:8), Aam/MAA (8:2) and Aam/MAA (2:8) occurred at 75°C. The polymerization reaction proceeded initially very fast then levelled off irrespective of the monomer or monomer mixtures used. However, the magnitude of the polymer add-on at levelling off of polymerization followed the order GMA > GMA/MAA (2:8) ≥ GMA/MAA (8:2) > Aam/MAA (2:8) ≥ MAA ≥ Aam/MAA (8:2) > Aam. The polymer add-on enhanced by increasing the H₂O₂ concentration up to a certain limit and then decreased. The same situation was encountered with respect to thioureadioxide concentration. The involvement of the epoxy ring of GMA with MAA during polymerization of their mixture with cellulose occurred only at a higher ratio of GMA in the mixture. Also a significant contribution of Aam in the polymer add-on obtained with a Aam/MAA mixture could only be achieved at a higher ratio of Aam in this mixture.     

自交联反应性丙烯酸酯类微凝胶乳液及其涂膜的性能

采用半连续种子乳液聚合法,以三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)为交联剂、甲基丙烯酸缩水甘油酯(GMA)和甲基丙烯酸(MAA)为功能单体,合成了具有球形结构的自交联反应性丙烯酸酯类微凝胶乳液,并对其结构、性能以及涂膜的性能进行了研究.结果表明,合成的产物是带有悬吊双键及环氧基团的球形自交联反应性丙烯酸酯类微凝胶乳液,其粒径在40～50 nm,呈假塑性;当TMPTMA的质量分数为3%～6%、MAA的质量分数为3.00%～5.00%时,热处理后涂膜的耐水性和力学性能最佳.     

甲基丙烯酸缩水甘油酯的合成研究

采用二步法合成了甲基丙烯酸缩水甘油酯,研究了第一步反应过程4种溶剂对甲基丙烯酸钠盐形成的影响,探讨了第二步反应过程不同相转移催化剂、反应温度及所合成钠盐中碱过量比率与产物收率的关系,对最后产物进行了分析和表征。结果表明,合成反应第一步可使用水为溶剂,碱过量10%,第二步反应中,使用三乙基苄基氯化铵为催化剂,控制反应温度105℃～110℃,反应3.0h,可使GMA收率达到80.5%。     

水性环氧丙烯酸乳液的合成研究

以甲基丙烯酸甲酯、苯乙烯为硬单体,丙烯酸丁酯为软单体,甲基丙烯酸、丙烯酸羟乙酯和双丙酮丙烯酰胺为功能单体,环氧树脂为改性剂,水为分散介质,通过乳液共聚合制备环氧-丙烯酸乳液,讨论了聚合工艺、引发剂用量、反应温度、环氧树脂种类和用量以及软硬单体配比对乳液聚合反应及涂膜性能的影响。     

Covalent attachment of chromophores to chlorinated copolymers for optical waveguides: Synthesis and optical characterization

Polymeric optical devices are attracting increasing interest in the field of photonics because of the very appealing performances as structures for both propagating and modulating light signals according to the properties of the employed organic materials. This paper reports the preparation and characterization of low-loss polymer waveguides fabricated from chlorinated copolymers by photochemical crosslinking. A novel monomer derived from reaction between glycidyl methacrylate (GMA) and the chromophore Disperse Red 19 (DR19) was prepared and successfully copolymerized with GMA and chlorostyrene (CS) to obtain the dye-modified copolymer. The latter was crosslinked by photoinitiated polymerization of the pendant epoxy groups, to obtain stable polymeric waveguides. It was found that the major product of the reaction between GMA and DR19 was formed through transesterification of the methacrylate with elimination of glycidol, while traces of products deriving from the epoxy ring-opening reaction were detected. The presence of the nitro substituent on DR19 favoured chain-transfer reactions during the polymerization reaction, leading to a decrease in the polymerization degree. It was also observed that the presence of grafted DR19 negatively affected the crosslinking reaction, as a lower epoxy group conversion was observed for the modified copolymer. Thermal analysis showed increased thermal stability for the copolymer containing DR19. m-line spectroscopy was used to measure the refractive index at 632.8 nm. The experimental results confirm that the new class of chlorine-based polymeric materials represent a very attractive proposal in the panorama of materials employed in the fabrication of electro-optical devices for telecommunication applications.     

Synthesis and characterization of porous glycidylmethacrylate–divinylbenzene monoliths using the high internal phase emulsion approach

Highly porous monoliths were synthesised using glycidyl methacrylate (GMA) and divinylbenzene in the presence of a porogen, and emulsion templating as the preparation technique (polyHIPEs). Two surfactants were used as the emulsion stabiliser. It turned out that the choice of the surfactant was essential for the successful synthesis of polyHIPEs containing large amount of the functional monomer GMA, and characterised by a well-defined morphology. Sorbitan monooleate (SPAN 80) showed poor performances in stabilising emulsions with a content of GMA > 40% v/v. On the contrary, polyglycerol of a fatty acid (PGE 080/D) exhibited superior performances allowing to stabilise emulsion with a GMA content up to 80% v/v. The ensuing polyHIPEs presented a well-defined morphology and surface areas very close to those of the corresponding resins of the same composition. This proved that emulsion destabilising phenomenon such as Ostwald ripening was effectively inhibited by PGE.An important part of the research work was dedicated to investigate whether the epoxy group retained its integrity during synthesis and purification. It turned out that the percentage of the exposed epoxy groups that underwent hydrolysis depended on the size of the pores. Pores below a threshold size were not wetted by water and the epoxy groups present inside them were left unchanged. On the contrary, the epoxy groups within pores characterised by a diameter above this threshold underwent hydrolysis.     

碱溶性核/壳型丙烯酸酯胶粘剂乳液的合成研究

以反应型阴/非离子乳化剂(DNS-86/ANPEO-10)为复配乳化剂、丙烯酸(AA)和甲基丙烯酸(MAA)为混合羧基单体、丙烯酸异辛酯(EHA)和甲基丙烯酸缩水甘油酯(GMA)为混合交联单体等,采用半连续种子乳液聚合法合成了核/壳型碱溶性丙烯酸酯乳液。讨论了反应型乳化剂、羧基单体及交联单体等对丙烯酸酯乳液胶粘剂性能的影响。结果表明:各种功能单体、反应型乳化剂均参与了共聚反应,并且相应基团的红外光谱(FT-IR)特征吸收峰比较明显;当w(DNS-86+ANPEO-10)=2.5%且m(DNS-86)∶m(ANPEO-10)=1.0∶(1.0～1.5)、w(AA+MAA)=8%且m(AA)∶m(MAA)=2∶3、m(HEA)∶m(GMA)=1.5∶1且w(HEA+GMA)=4%～5%时,采用核/壳聚合工艺制备的乳液胶粘剂,其耐水性及碱溶性良好,并且其综合性能相对最佳。     

Preirradiation‐induced emulsion graft polymerization of glycidyl methacrylate onto poly(vinylidene fluoride) powder

An epoxy‐group‐containing monomer, glycidyl methacrylate (GMA), was grafted onto poly(vinylidene fluoride) powder via preirradiation‐induced emulsion graft polymerization. The existence of graft chains was proven by chemical structure characterization with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy analysis. The degree of grafting was calculated by means of fluorine content analysis. A kinetic study indicated that, with the emulsion graft polymerization system, the GMA conversion rate was high, exceeding 80%. The variation in the molecular weight of the grafted polymer was measured by gel permeation chromatography, and its crystallinity was investigated with differential scanning calorimetry. The epoxy groups in graft chains were found to be suitable for further chemical modification. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

聚丙烯酸酯-聚甲基丙烯酸缩水甘油酯自交联共聚物乳液的结构及性能表征

以过硫酸钾为引发剂,聚乙烯醇为高分子分散剂,甲基丙烯酸缩水甘油酯(GMA)为交联剂,采用种子无皂乳液聚合方法制备了丙烯酰胺(AM)、丙烯酸(AA)、丙烯腈(AN)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)共聚的自交联聚丙烯酸酯-聚甲基丙烯酸缩水甘油酯共聚物。用TEM、FTIR、XRD、DSC对共聚合物乳液的粒子形态及聚合物的结构进行了表征,通过SEM观察了纸张表面及断面的微观结构。结果表明,用GMA作交联剂,可制备稳定的自交联聚丙烯酸酯-聚甲基丙烯酸缩水甘油酯共聚物乳液;该聚合物属于非晶态聚合物,且经GMA交联后形成的网络聚合物强度大大增加;当w(GMA)=0.7%,w(PVA)=4%时,可使纸张干强度指标:环压指数、耐破度、抗张指数相对空白原纸分别提高约32%、95%、25%。     

Environmentally benign precipitation copolymerization of methacrylate ester and styrene to make polymeric microspheres in supercritical carbon dioxide

The polymeric microspheres were synthesized by the precipitation copolymerization of glycidyl methacrylate (GMA) with methacrylic acid(MAA) or 2‐hydoxyethyl methacrylate (2‐HEMA) containing styrene (ST) in SC‐CO₂. Scanning electron microscopy (SEM) showed that the products were spherical microparticles, with the addition of MAA and/or 2‐HEMA as the monomer, with diameter of 0.2–2 μm. The effects of copolymerization pressure, temperature, and ratios of GMA/MAA, ST, and/or GMA/2‐HEMA, on the particle size and morphology were investigated in detail. A new experiment setup is proposed for the large amount of production, based on the rule of lower monomer concentration, more stable system, and better use of the present polymerization apparatus. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2425–2431, 2007     

The xanthate method of grafting. XII. Effect of operating conditions on the grafting of vinyl monomers onto wood pulp

The present paper examines the influence of various reaction parameters (e.g., pH, type, and concentration of peroxide, reaction time, oxygen as well as reaction medium) on the graft copolymerization of methacrylic acid, butyl methacrylate, epoxypropyl acrylate, and epoxypropyl methacrylate onto chemithermomechanical pulps, initiated by the xanthate method. The optimum concentration of H₂O₂ changes with the monomer used. Among the peroxides investigated, H₂O₂ offered the best performance. Oxygen and organic solvents, e.g., acetone and vegetable oil, inhabited grafting reaction. In addition, epoxy monomers showed better results compared to other monomers; this may be due to the participation of epoxy groups in the polymerization reaction     

单组分自乳化水性环氧树脂的合成及其涂膜性能研究

用有机硅、甲基丙烯酸及其酯类单体接枝改性环氧树脂,合成了具有自乳化性能的水性环氧树脂乳液。用激光粒度分析仪测定乳液的粒径及其分布,用傅里叶红外、热重分析仪对聚合产物作了结构表征和热分析。考察了温度、引发剂用量对接枝率及接枝率对乳液成膜性能的影响;甲基丙烯酸、有机硅及单体总量对乳液稳定性、成膜物耐水性和耐盐水性的影响。结果表明:当配方选用引发剂、有机硅用量分别为单体总质量的5.5%、2.5%,m(单体总量)∶m(环氧树脂)=1∶2,丙烯酸及其酯类单体的玻璃化温度Tg为30℃,体系酸值为35 mgKOH/g,接枝温度为110℃时,制得的水性环氧树脂乳液具有良好的稳定性、耐水性及耐盐水性。     

Phase state of polyelectrolyte complexes based on blends of acrylic copolymers

The phase state of polyelectrolyte blends based on acrylic copolymers was investigated with differential scanning calorimetry, transmission electron microscopy (TEM), and wedge microinterferometry as a function of the blend composition and ionization of polymer functional groups. A copolymer of N,N‐dimethylaminoethyl methacrylate with methyl methacrylate and butyl methacrylate was used as a polybase, a copolymer of methacrylic acid and ethyl acrylate was employed as a polyacid, and the optional plasticizer was triethyl citrate. A correlation was established between an earlier described mechanism of molecular interaction and the behavior of the glass‐transition temperature (T_g) of the polymer blends. The T_g values of the polyelectrolyte complexes in the gel phase were always higher than T_g in the sol phase. This fact implies that intermolecular cohesion dominated the free volume in the stoichiometric polyelectrolyte complexes formed in the gel phase, whereas nonstoichiometric complexes formed in the sol phase were characterized with the predominant contribution of free volume. TEM and interferograms of polyelectrolyte blends showed the signs of anisotropic ordered supramolecular structure formation. A phase‐state diagram of the polyelectrolyte blends was constructed. The stoichiometric polyelectrolyte complex was immiscible with parent polymers, forming a separate phase that became melted at elevation of temperature because of complex dissociation. Polyelectrolyte miscibility was supposed to result rather from the chemical reaction of the complex formation than from interdiffusion of the polymer components along the gradient of their concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of hydrogel beads from crosslinked poly(methyl methacrylate) microspheres by alkaline hydrolysis

Poly(methyl methacrylate)/(PMMA) microspheres crosslinked with various concentrations of ethylene glycol dimethacrylate (EGDM) were prepared by a suspension polymerization procedure. They were subjected to alkaline hydrolysis in ethylene glycol at high temperature (> 175°C), resulting in the rapid conversion of methacrylate ester functions to methacrylic acid, while retaining the spherical shape of the microspheres intact. The method provides a novel approach to obtain smooth, nearly perfect spherical, mechanically strong, high water-absorbing hydrogel beads from crosslinked PMMA. The reaction has been found to be considerably faster than many of the hydrolysis procedures reported previously. The effect of concentration of alkali, particle size, crosslinking density, and reaction time on the extent of hydrolysis has been investigated to a limited extent.     

甲基丙烯酸缩水甘油酯对大豆蛋白塑料改性作用研究

用模压的方法制备了甲基丙烯酸缩水甘油酯(GMA)改性大豆分离蛋白质(SPI)塑料。表征了GMA改性SPI塑料的力学性能、耐水性,并分析了GMA与SPI之间的相互作用。结果表明GMA在模压过程中,环氧基与蛋白质分子间发生接枝和交联反应,同时自聚,在GMA含量较低时可以同时对SPI塑料起到增强和增塑作用,但是随着GMA含量增加,交联作用增强,塑料的断裂伸长率下降。