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%。     

Preparation and characterization of self-crosslinking fluorinated polyacrylate latexes and their pressure sensitive adhesive applications

Self-crosslinking fluorinated polyacrylate latexes based on butyl acrylate (BA), fluorine monomer octafluoropentyl methacrylate (OFPMA), self-crosslinking functional monomers acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) were synthesized by a monomer-starved seeded semi-continuous emulsion polymerization process. The latexes and their corresponding films were characterized by laser particle size analyser, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results indicated that the particle size of the latexes and the gel content of the films were both independent of the amount of OFPMA employed. On the other hand, the particle size of the latexes decreased and the gel content of the films increased with the incorporation of AA and HEA as expected. Glass transition temperature (T_g) and the thermal stability of the copolymer were both improved gradually as OFPMA content increased. XPS, AFM and water contact angle measurement indicated that the fluoroalkyl groups had a tendency to enrich on the surface of the films. However, this enrichment of fluorine on the film surface was reduced after the introduction of self-crosslinking functional monomers into the system. Finally, the adhesive property of the latexes was evaluated for application as a pressure sensitive adhesive (PSA).     

Preparation and Adhesion Property of a Low Temperature Cross-Linkable Vinyl Acetate-Acrylate Copolymer Latex

The functional acrylate monomer (FAM) containing an amino group was synthesized by using glycidyl methacrylate (GMA) and ammonia. FAM was then copolymerized with Vinyl acetate and other acrylate monomers by emulsion copolymerization. The cross-linkable latex was obtained by adding a set content of glutaraldehyde to the earlier copolymer emulsion. The FT-IR results show that the cross-linking reaction between amino and aldehyde groups is detected during the curing process of copolymer. The glass transition temperature (T_g) of the copolymer can be evidently increased from ?16.2 to ?8.7°C as the FAM alters from 0 to 10%. T-peel strength of the polyethylene-polyethylene (PE-PE) packaging films laminated by products was studied. The results show peel strength dramatically increases with the cross-linking density at room temperature, and still reaches 2.5 N·15 mm^?1 even at 60°C, which can satisfy the application requirement enough.     

环氧共聚物乳液性能的研究

本文研究了以甲基丙烯酸环氧丙酯作为活性单体，采用种子乳液聚合制备四元体系的共聚物乳液，对其稳定性，流变性等性能进行了表征测试，考察了甲基丙烯酸环氧丙酯及其含量对乳液性能的影响．     

Synthesis and thermal self-crosslinking reaction of copolymers from 2,3-epoxypropyl methacrylate and p-substituted phenyl methacrylates

Copolymers of 2,3-expoxypropyl (glycidyl) methacrylate (GMA) with various phenyl methacrylates such as 4-nitrophenyl methacrylate (NPMA), 4-chlorophenyl methacrylate (CPMA), or phenyl methacrylate (PMA), and other monomers such as methyl methacrylate (MMA), ethyl acrylate (EA), or styrene (ST) were synthesized by radical copolymerization, and then thermal self-crosslinking reactions of the obtained copolymers were carried out using various catalysts such as quarternary ammonium salts, tert-amines, or the crown ether/potassium salt systems at 100–150°C. Although the copolymer of GMA–NPMA–MMA does not produce any gel products without catalyst upon heating at 110°C for 5 h, this copolymer gives gel products in 82% yield using 10 mol% of tetrabutylammonium bromide as a catalyst under the same conditions. The rate of gel production of the copolymer of NPMA is faster than those of copolymers of CPMA and PMA. The rate of the gel production of the copolymer of GMA–NPMA–EA is also faster than those of copolymers of MMA and ST. Furthermore, it was found that the rate of gel production of the copolymer was strongly affected by the kind of catalyst, the catalyst concentration, and the reaction temperature.     

Studies on selective adsorption resins. XXI. Preparation and properties of macroreticular chelating ion exchange resins containing phosphoric acid groups

Macroreticular cation exchange resins containing phosphoric acid groups (RGP) were prepared by the reaction of glycidyl methacrylate–divinylbenzene copolymer [or poly(glycidyl methacrylate)]beads (RG) with phosphoric acid or phosphorous oxychloride, and the adsorption behavior of metal ions on the RGP was investigated. The phosphorylation of the polymer beads could be effectively carried out by treatment of the polymer beads with 85% phosphoric acid at 80°C for 3 h. The RGP obtained from glycidyl methacrylate–divinylbenzene (2 mol %) copolymer beads showed high cation exchange capacity, salt splitting capacity, and adsorption capacity for Cu²⁺, Zn²⁺, Cd²⁺, Ca²⁺, and Ag⁺. On the other hand, the RGP obtained from poly(glycidyl methacrylate)beads had high adsorption capacity for Al³⁺, Fe³⁺, and UO₂²⁺. The RGP prepared by treating the RG with phosphoric acid had a higher selective adsorption for Li⁺ than for Na⁺.     

甲基丙烯酸甲酯-甲基丙烯酸三氟乙酯共聚物细乳液的合成及其表征

以甲基丙烯酸甲酯(MMA)和甲基丙烯酸三氟乙酯(TFEMA)为反应单体进行细乳液聚合,制得了MMA-co-TFEMA共聚物乳液。利用FTIR和GPC表征了共聚物的结构和分子量,采用激光光散射法及透射电镜对乳胶粒子的粒径大小及形貌进行了表征,并通过接触角法对共聚物膜的表面性能进行了研究。结果表明,与常规乳液相比,以细乳液方法制得的MMA-co-TFEMA共聚物乳液稳定性好,粒径分布窄,聚合物的分子量分布窄,并且共聚物膜随着氟含量的增加疏水疏油性增强,表面能降低。     

Investigation of the effect of molar mass on coating properties of self-crosslinking latexes based on acrylic microgels

The effect of reducing the molar mass of the shell layer of core–shell latex particles on film-forming and final coating properties of self-crosslinking latexes was investigated. Latex particles were prepared by the semi-continuous non-seeded emulsion polymerization of methyl methacrylate, butyl acrylate and methacrylic acid as main monomers. The particle core was slightly cross-linked (using a constant amount of allyl methacrylate as a comonomer) to prevent the copolymers forming the core phase from migration into the shell phase. For interfacial cross-linking, diacetone acrylamide was copolymerized into the shell layer of latex particles to provide sites for subsequent reaction with adipic acid dihydrazide. The molar mass of copolymers forming the shell layer was systematically varied by isooctyl 3-mercaptopropionate chain transfer agent included in the synthesis of each of the shell layers and the molar mass distribution was determined using size exclusion chromatography coupled with a multi-angle light scattering detection. Fundamental properties of latexes and cast films were systematically compared. These properties included minimum film-forming temperature, pendulum hardness, adhesion, impact resistance, stress–strain properties as well as the characterization of water absorption. The results confirmed theoretical predictions and described empirically the effects of reducing the molar mass of the shell layer copolymer on final properties of coating films.     

Preparation and characterization of acrylonitrile‐ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile‐co‐ethyl methacrylate), P(AN‐EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO₄ salt loaded (PAN‐co‐PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac‐conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Controlled preparation and properties of acrylic acid epoxy-acrylate composite emulsion for self-crosslinking coatings

A stable epoxy-acrylate composite latex was successfully prepared through emulsion polymerization of modified epoxy acrylic (EPAC) oligomer with acrylate monomer. The EPAC oligomer was obtained using active acrylic acid (AA) to react with epoxy resin. And by regulating the reaction degree of the active hydrogen of AA and epoxide group, there is the acquisition of terminal double bond that gives EPAC reactivity, together with the partial retention of the epoxide group that enables self-crosslinking during film formation. The structural conformation of the oligomer was ascertained by Fourier transform infrared (FTIR) spectroscopy. The factors influencing the stability of the epoxy-acrylate composite latex were investigated. The epoxy-acrylate composite latex was the most stable when methyl acrylic acid was 1.5 wt% and modified EPAC oligomer was 15 wt% of the total monomer weight. The morphology and property of the composite latex films were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and temperature-modulated differential scanning calorimetry (TOPEM-DSC). The results confirm that there is successful emulsion copolymerization between modified EPAC oligomer and acrylate monomer. TEM show that the particles of epoxy-acrylate composite have a core-shell structure, and there is no free epoxy resin. The FTIR and TOPEM-DSC results reveal that the copolymer emulsion possesses self-crosslinking ability. During film formation, self-crosslinking reaction occurs between epoxide groups with carboxyl groups, giving exothermal phenomena. The thermal stability as well as the corrosion resistance of the films was analyzed. The results show outstanding thermal stability as well as corrosion resistance attributable to the crosslinking reticulation structure. It is envisaged that the epoxy-acrylate composite latex has great potential in the development of high-performance aqueous coatings.     

Synthesis and characterization of butyl acrylate/methyl methacrylate/glycidyl methacrylate latexes

The butyl acrylate (BA)/methyl methacrylate (MMA), and glycidyl methacrylate (GMA) composite copolymer latex was synthesized by seeded emulsion polymerization technique taking poly(methyl methacrylate) (PMMA) latex as the seed. Four series of experiments were carried out by varying the ratio of BA : MMA (w/w) (i.e. 3.1 : 1, 2.3 : 1, 1.8 : 1, and 1.5 : 1) and in each series GMA content was varied from 1 to 5% (w/w). The structural properties of the copolymer were analyzed by FTIR, ¹H‐, and ¹³C‐NMR. Morphological characterization was carried out using transmission electron microscopy (TEM). In all the experiments, monomer conversion was ～99% and final copolymer composition was similar to that of feed composition. The incorporation of GMA into the copolymer chain was confirmed by ¹³C‐NMR. The glass transition temperature (T_g) of the copolymer latex obtained from the differential scanning calorimetry (DSC) curve was comparable to the values calculated theoretically. With increase in GMA content, particles having core‐shell morphology were obtained, and there was a decrease in the particle size as we go from 2–5% (w/w) of GMA. The adhesive strength of the latexes was found to be dependent on the monomer composition. With increase in BA : MMA ratio, the tackiness of the film increased while with its decrease the hardness of the film increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Contribution of Ungrafted Segments in Core-Shell Impact Modifier in the Toughening of PBT Resins by Epoxy Functionalized Poly(Butadiene-graft-Styrene)

A series of poly(butadiene-graft-styrene) core-shell impact modifiers and glycidyl methacrylate functionalized PB-g-PS (PB-g-PSG) with different glycidyl methacrylate content were synthesized by seeds emulsion polymerization. The modifiers were used to toughen poly(butylene terephthalate) resins. The results showed that poly(butylene terephthalate) was efficiently toughened by functionalized PB-g-PSG but not by poly(butadiene-graft-styrene). The introduction of glycidyl methacrylate improved the miscibility and properties. The effects of the ungrafted segments in modifiers on the properties of blends were investigated. The miscibility and properties dropped after the ungrafted segments in modifiers were separated. Results indicated that ungrafted PS segments showed positive effect on toughening of poly(butylene terephthalate).     

水性丙烯酸酯共聚物EVA表面处理剂的合成

采用乳液聚合法合成丙烯酸酯EVA表面处理剂,研究丙烯酸、丙烯酸丁酯、醋酸乙烯酯、丙烯腈和甲基丙烯酸缩水甘油酯等单体对丙烯酸酯EVA表面处理剂乳液性能的影响。所制备的丙烯酸酯EVA表面处理剂对交联程度低的EVA发泡鞋底具有良好的处理效果。     

Elucidation of the nanoparticle effect on the grafting of vinyl monomers onto cotton fabric

The grafting emulsion polymerization of vinyl monomers onto cotton was carried out in the presence of double‐modified montmorillonite clay. The obtained results show that grafting with glycidyl methacrylate/montmorillonite gave a higher rate of grafting than grafting with methyl methacrylate/montmorillonite in all clay percentages, and also, the grafting yield of glycidyl methacrylate monomer onto cotton in the presence of montmorillonite clay had a higher value than that in the absence of the clay for all factors studied. Cotton grafted with glycidyl methacrylate/montmorillonite with a graft yield of about 50% was prepared according to the emulsion polymerization technique and was treated with different concentrations of dibutylamine solutions ranging from 1 to 4%. The obtained samples were characterized according to nitrogen content, thermal stability, scanning electron microscopy, mechanical properties, water absorption, and color strength according to acid, basic, and reactive dyes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

叔胺型丙烯酸酯共聚物乳液室温可见光交联研究

本研究以甲基丙烯酸甲酯、丙烯酸丁酯、N -羟甲基丙烯酰胺、甲基丙烯酸二甲氨基乙酯为共聚单体进行乳液聚合制备叔胺基丙烯酸酯共聚物乳液 ,然后在该共聚物乳液中加入光敏性乙烯基不饱和单体和可见光下分解的光敏引发剂 ,共混物涂膜于自然光下室温固化交联。考察了光敏引发剂用量、交联单体种类和用量、交联时间对乳胶膜交联程度的影响。结果表明 ,以异丙基硫杂蒽酮为光引发剂 ,分别以甲基丙烯酸缩水甘油酯、三丙二醇二丙烯酸酯及三羟甲基丙烷三丙烯酸酯为交联单体时 ,乳胶膜交联度在 0 5～ 1h内 >70 % ,2h内 >80 %。     

聚甲基丙烯酸缩水甘油酯疏水纳凝胶的制备与表征

采用乳液聚合法制备了聚甲基丙烯酸缩水甘油酯疏水纳凝胶。通过透射电子显微镜、傅里叶红外光谱和动态激光光散射等测试对其结构和形貌进行了表征,对疏水纳凝胶形成过程规律和对温度、pH和时间稳定性进行了考察,并探究了单体浓度、交联剂含量和乳化剂浓度对纳凝胶粒径的影响规律。结果表明：所得疏水纳凝胶具有粒径均一、分散稳定和溶胀性能好等优点。疏水纳凝胶粒径在一定温度和pH范围内无变化,在30天内粒径从76nm增至116nm,zeta电位随温度升高而增加,其值稳定在-90~-30mV之间,说明是一种较为稳定的凝胶体系。在实验范围内,纳凝胶粒径随单体甲基丙烯酸缩水甘油酯和交联剂二甲基丙烯酸乙二醇酯浓度的增加从80nm增至250nm,随乳化剂浓度增加从230nm降至60nm。     

丙烯酸乳液胶粘剂的研究

采用半连续乳液聚合工艺,以MMA、BA、AA等为主要单体,加入乳化剂、引发剂、交联剂,经共聚反应,合成自交联型丙烯酸酯乳液胶粘剂。讨论了聚合机理,考查了固含量、离子稳定性、离心稳定性、剥离强度、拉伸强度、粒径、黏度等多项性能;根据综合的性能测试,分析了单体种类及配比、共聚物的玻璃化温度、丙烯酸用量、乳化剂用量及配比、引发剂用量、温度等因素对乳液型胶粘剂性能的影响,得出了最适宜的反应条件和胶粘剂最佳配方。通过性能对比,表明自交联型丙烯酸酯乳液胶黏剂性能更为优异。     

交联型阳离子聚乙烯醇接枝丙烯酸酯共聚物的制备及其对纸张增干强性能的影响

采用无皂聚合工艺合成了交联型阳离子聚乙烯醇接枝丙烯酸酯共聚物乳液,作为纸张增强剂可显著提高纸张的抗张指数、撕裂度、耐破度等。对阳离子基单体和交联性单体的比例、合成工艺条件等对纸张增强效果的影响进行了探讨。当m(环氧丙基三甲基氯化铵):m(甲基丙烯酰氧乙基三甲基氯化铵):m(甲基丙烯酸缩水甘油酯)=1:6:1,w(乳液)=0.8%时,纸张的抗张强度,撕裂度,耐破度等性能指数均有35%以上的提高。     

Synthesis and photopolymerization of acrylic acrylate copolymers

Acrylate‐functionalized copolymers were synthesized by the modification of poly(butyl acrylate‐co‐glycidyl methacrylate) (BA/GMA) and poly(butyl acrylate‐co‐methyl methacrylate‐co‐glycidyl methacrylate). ¹³C‐NMR analyses showed that no glycidyl methacrylate block longer than three monomer units was formed in the BA/GMA copolymer if the glycidyl methacrylate concentration was kept below 20 mol %. We chemically modified the copolymers by reacting the epoxy group with acrylic acid to yield polymers with various glass‐transition temperatures and functionalities. We studied the crosslinking reactions of these copolymers by differential scanning calorimetry to point out the effect of chain functionality on double‐bond reactivity. Films formed from acrylic acrylate copolymer precursors were finally cured under ultraviolet radiation. Network heterogeneities such as pendant chains and highly crosslinked microgel‐like regions greatly influenced the network structure and, therefore, its viscoelastic properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 753–763, 2002     

Water-based radiation-curable latexes

Film-forming polystyrene/poly(n-butyl acrylate-co-glycidyl methacrylate) [PS/P(BA-co-GMA)] core–shell latex particles were prepared via a two-stage emulsion polymerization procedure using a polystyrene latex seed. Delayed addition of GMA was used in order to locate functional epoxy groups close to the particle surfaces. It was found that a temperature of 25°C at the second-stage polymerization, in combination with a redox initiator system, was essential for the formation of a uniform shell of BA–GMA copolymer around the PS core. The latex particle morphology was investigated by transmission electron microscopy (TEM). Reactive double bonds were introduced into the particle shells in order to produce a film-forming latex system that could be cured by ultraviolet (UV)-radiation without any need to use reactive multifunctional monomers or oligomers as crosslinkers. The surface-bound epoxy groups were used as grafting sites for amine or carboxyl functional unsaturated monomers, respectively. The grafting was demonstrated by Fourier transform infrared (FTIR) spectroscopy. Films prepared from modified and unmodified latexes were exposed to UV radiation in the presence of a photoinitiator. Crosslinking was tested by thermal mechanical analysis (TMA) and by determination of swelling and gel content of exposed films. It was demonstrated that films from the modified latexes after irradiation had significantly higher stiffness and gel content and showed lower swelling than unmodified ones. © 1996 John Wiley & Sons, Inc.