Thermal stability and surface properties of acrylic PSAs modified by hexafluorobutyl acrylate

The article attempted to prepare special acrylic adhesives with preferable adhesion property and better thermal stability by introducing a fluorinated monomer. The FT-IR result showed that fluorinated monomers and acrylic monomers participated in copolymerization successfully. Furthermore, fluorinated groups performed good compatibility with acrylic resins, based on differential scanning calorimetry curve. According to the TG test under different heating rates, the activation energy of PSAs containing different content of fluorinated monomers was calculated to evaluate the effect of hexafluorobutyl acrylate on heat resistance of PSAs. Then, the findings of contact angle test revealed that the fluorinated PSAs also had rather lower surface energy than ordinary PSAs. Finally, the results of peel strength measurements indicated that the fluorinated PSAs demonstrated excellent adhesion property on various materials, especially low surface energy substrates.     

Synthesis of silicone–acrylic resins and their applications to superweatherable coatings

Silicone–acrylic resins were synthesized to prepare superweatherable paints for building materials. The raw materials used were n‐butyl acrylate, methyl methacrylate, and n‐butyl methacrylate as acrylic monomers and 3‐methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer reactive with the acrylic monomers. Acrylic copolymers were synthesized such that their glass‐transition temperatures were adjusted to 30°C and their MPTS contents were varied to 10, 20, and 30 wt %. As the content of silicone and MPTS increased, average molecular weight and viscosity increased, and thermal stability at high temperatures improved. When we tested the properties of coatings by blending the synthesized silicone–acrylic resins with a white pigment, adhesion was superior with various substrates, and their properties were suitable on the whole. Weatherability was tested by an outdoor exposure test with a weather‐ometer and an accelerated weathering tester, and their results showed that silicone–acrylic resin composed of 30 wt % MPTS was a superweatherable coating. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1614–1623, 2001     

Sensory characterization and identification of odorous constituents in acrylic adhesives

Most products in our surroundings contain adhesives, including acrylic adhesives which are used in many industry sectors. Some of these adhesives contain solvents that produce strong odors, but even adhesives which are produced without solvents can emit intensive or pungent odors. In the latter case, the odor may arise from monomers in the adhesive product, from manufacturing by-products or from degradation products. Here we analyzed several acrylic, methacrylic and benzyl acrylic adhesives to identify representative odorous contaminants. The volatile fraction of the products was extracted and isolated by solvent-assisted flavor evaporation (SAFE), then analyzed via high-resolution gas chromatography olfactometry (HRGC-O), HRGC-mass spectrometry (HRGC-MS/O) and two-dimensional HRGC-MS/O. Aroma extract dilution analysis was carried out to determine the most prominent odorants. Using this targeted odorant-analytical approach, we identified 27 odorous substances representing diverse classes of molecules, including phenols with leather-like, horse stable-like or medicinal odors, acrylates eliciting glue-like, moldy and fruity impressions, and different esters with honey-like or effervescent tablet-like smells. These results show that the odor of acrylic adhesives results from a mixture of different odorants that cannot generally be traced back to the main constituents of the product but are rather likely to stem from impurities and trace side products and other contaminants.     

Molecular parameters and their relation to the adhesive performance of acrylic pressure‐sensitive adhesives

Model acrylic pressure‐sensitive adhesives (PSAs) based on poly(2‐ethyl‐hexyl acrylate‐stat‐acrylic acid) and poly(n‐butyl acrylate‐stat‐acrylic acid) at 97.5/2.5 wt % were synthesized using semicontinuous emulsion and solution polymerizations. Microgels formed in the lattices retained their discrete network morphology in the film. In contrast, acrylic solution was essentially gel free and crosslinking in the film was provided by the reaction of acrylic acid and post added Al Acetyl Acetonate after solvent evaporation, which led to continuous network morphology. The difference in film network morphology caused significantly lower shear holding power for the film from emulsion PSA compared with that of solvent‐borne film. Unlike shear holding power, loop tack and peel of acrylic PSAs were mainly controlled by the same sol/gel molecular parameters, regardless of emulsion or solution PSAs. The important molecular parameters are sol‐to‐gel ratio, entanglement molecular weight, weight average molecular weight, and to a lesser extent, glass transition temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2230–2244, 2001     

The effect of varied monomer composition on adhesive performance and peeling master curves for acrylic pressure‐sensitive adhesives

A group of pressure‐sensitive adhesives were prepared with constant glass transition temperature, using emulsion polymerization. The monomers chosen were butyl acrylate, 2‐ethylhexyl acrylate, and methyl methacrylate, along with a small amount of acrylic acid. The proportion of acrylic acid monomer was held constant for each polymer preparation but acrylic ester monomer levels were varied. The glass transition temperatures of the acrylate copolymers were measured by using differential scanning calorimetry. Drying and weighing the tetrahydrofuran‐insoluble polymer fractions were used to determine the polymer gel fractions. Films of constant coating thickness were applied to poly(ethylene terephthalate) film and adhesive properties (tack and shear) were examined. Peel was examined through the construction of master curves derived from peel tests conducted over a range of temperatures and peel rates. As the 2‐ethylhexyl acrylate content increased, the latex gel fractions were found to increase. With increasing EHA and gel fraction, peel shear was found to increase. When peel force master curves were compared, divergence in peel master curves occurred as peel rates increased where polymers with higher butyl acrylate contents reached greater peel stress values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2909–2917, 2004     

Solventless UV crosslinkable acrylic pressure sensitive adhesives

The synthesis and characterization of solventless acrylic UV crosslinkable pressure sensitive adhesives are presented. Different prepolymers were synthesized using bulk polymerization procedure. The reaction mixture consisted of acrylic monomers (2-ethylhexyl acrylate, acrylic acid and t-butyl acrylate), azobisisobutyronitrile initiator, chain transfer agent n-dodecylmercaptan and unsaturated UV photoinitiator 4-acryloyloxybezophenone, which was copolymerized into polymer backbone. Different formulations were tested and the prepolymer was characterized by viscosity measurements and final monomer conversions. The prepolymers were coated onto PET foil and crosslinked by application of UV light source. Peel adhesion at 180° on glass plate was measured. Gel phase was determined using the Soxhlet extraction and copolymer glass transition temperatures (T_g) were analyzed by differential scanning calorimetry (DSC). Results showed that the final monomer conversions in highly exothermic bulk polymerization reached a level between 75% and 90%. Prepolymer viscosity was highly influenced by change in polymer molecular weight and by addition of acrylic acid as a comonomer. On the other hand, the viscosity remained at the low level when t-butyl acrylate was used. The amount of gel phase for all adhesives was above 60 wt.%. Peel strength measurements showed decrease in peel strength with decreasing polymer molecular weight and increase of peel, when acrylic acid was used as a comonomer. All adhesive coatings with t-butyl acrylate comonomer showed cohesive failure.     

可聚合乳化剂对苯丙乳液胶粘剂性能的影响

采用可聚合乳化剂烯丙氧基壬基酚聚氧乙烯(10)醚硫酸铵(DNS-86),通过半连续法合成了苯丙乳液胶粘剂,探讨了可聚合乳化剂用量的变化对所制备的苯丙乳液胶粘剂性能的影响。结果表明:与常规乳化剂相比,用可聚合乳化剂合成苯丙乳液胶粘剂时,单体转化率提高;初粘力增加较大;随可聚合乳化剂用量增加,乳胶粒平均粒径减小,且皆呈单分散性。当可聚合乳化剂用量为单体总量的2．0％时,制得的苯丙乳液胶粘剂耐水性和粘接性最好,综合性能优异。     

Aromatic–Aliphatic acrylic monomers and polymers: Synthesis and characterization

Two new ester‐type monomers were synthesized by the condensation of acrylic acid with the products of the hydroxyethylation of 4‐nonylphenol or 4‐tert‐butylphenol. The hydroxyethylation reaction was performed with 1,3‐dioxolan‐2‐ona in the presence of alkalies. By hydroxyethylation, the phenols were changed into alcoholic derivatives able to react with acrylic acid to give acrylic esters. The insertion of the aryl–alkyl groups into the structure of the acrylic esters, and implicitly of the corresponding polymers, was carried out with the intention of increasing their thermostability and improving their behavior as pressure‐sensitive adhesives on the whole. The monomers and the polymers were characterized by elemental and thermogravimetric analyses, IR and ¹H‐NMR spectroscopy, and other special methods. The results of these investigations confirmed the formulated suppositions. The inherent viscosities of the resulting polymers were in the range of 47–64 mL/g, and their thermal stability was up to 315–320°C, far higher than that of the polyacrylates used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 802–814, 2002     

Grafting sites of acrylic mixed monomers onto unsaturated fatty acids: Part 2

Acrylic groups were grafted onto alkyds via free radical chemistry. The alkyd comprised soybean oil, glycerol, phthalic anhydride, and tetrahydrophthalic anhydride. To closely model acrylated-alkyds, a mixture of four acrylic monomers were copolymerized with the alkyd including: methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), and vinyltrimethyoxysilane (VTMS). Two different initiator systems were used, benzoyl peroxide (BPO) and 2,2′-azobisisobutyronitrile (AIBN), for comparison. To elucidate the grafting sites, 1D NMR spectroscopy and 2D NMR spectroscopy were used. Gradient heteronuclear multiple quantum correlation (gHMQC) was needed to assign the chemical shifts of the 1D carbon and proton NMR spectra. The gHMQC spectra provided evidence of acrylic–alkyd grafted structures formed at doubly allylic hydrogens located on the fatty acid chains. As a side reaction, acrylic groups were grafted into the polyester backbone of the alkyd via hydrogen abstraction of the glycerol. The gHMQC spectra show no evidence of grafting across double bonds on either the fatty acid side chains or the THPA backbone. It was also determined that choice of initiator has no effect on graft location. However, the system initiated with BPO provided spectral evidence of the formation of benzoic acid, which shows that the peroxide initiator can directly abstract the doubly allylic hydrogen. The side product, isobutyronitrile did not appear in the spectra obtained from the AIBN initiated system.     

水性丙烯酸树脂的制备及其水溶性研究

以甲基丙烯酸甲酯、丙烯酸丁酯为主要单体,以过氧化苯甲酰为引发剂,通过引入亲水性基团羧基和羟基,制备了水性丙烯酸树脂。讨论了亲水单体含量、中和度等对丙烯酸树脂水溶性的影响。     

Preparation and comparative evaluation of well-defined fluorinated acrylic copolymer latex and solution for ancient stone protection

In this work the well-defined fluorinated acrylic copolymer latex and solution were prepared by the radical initiated seed emulsion polymerization and solution polymerization, respectively, using the same monomers of dodecafluoroheptyl methacrylate (DFHM), butyl acrylate (BA) and methyl methylacrylate (MMA). The copolymer latex BA/MMA/DFHM was designed as core–shell structure and the copolymer solution poly(BA–MMA–DFHM) was structured with low molecular weight. The chemical and morphology structures as well as the film properties obtained from latex and solution were analyzed and compared by spectroscopic techniques (FT-IR and NMR), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), scanning electron microscopy coupled with energy-dispersive X-ray detector (SEM–EDX) and static contact angles (CAs) instrument. Moreover, the BA/MMA/DFHM latex and poly(BA–MMA–DFHM) solution (with 29 wt% of DFHM) were applied onto two kinds of sandstone samples by capillary absorption, and their preliminary protecting efficiency was evaluated. It is demonstrated that the comprehensive performances of BA/MMA/DFHM latex films were quite comparable to those of poly(BA–MMA–DFHM) solution cast films, the latter exhibited a better protective performance.     

水性丙烯酸树脂的合成研究

以甲基丙烯酸甲酯、丙烯酸丁酯为主要单体,以过氧化苯甲酰为引发剂,通过引入亲水性基团羧基和羟基,制备了水性丙烯酸树脂。确定了最佳反应条件,讨论了水性基团的用量对树脂性能的影响,并用红外光谱(FT-IR)和差示扫描量热分析(DSC)对所合成树脂的结构进行了分析和表征。     

Electropolymerised acrylic coatings for polymer-metal adhesion enhancement

Electrochemical polymerisation (ECP) of acrylic monomers produces thin coatings on metal substrates and is a potentially useful method for forming adhesion promoting tie-layers at a polymer-metal interface. Uniform, passive films of poly (methyl methacrylate) and poly (glycidyl acrylate) have been formed via a cathodic free radical mechanism on stainless steel electrodes from aqueous electrolytes. The thickness of these films was found to increase with electrolysis time and the passive nature has been demonstrated by cyclic voltammetry studies. Adhesion tests were performed to compare the adhesion strength and failure mechanisms of various adhesives to coated and uncoated stainless steel substrates. The results indicate that ECP tie-layers can significantly increase the adhesive bond strength and alter the failure mechanisms observed. Electropolymerised acrylic coatings on metal substrates are thus seen as a promising approach for pretreatment of metals for adhesion enhancement.     

不同单体对SGA耐冷热冲击性能的影响

考查了不同单体及用量对丙烯酸酯结构胶耐冷热冲击性能的影响,制备了一种耐冷热冲击性能优异的丙烯酸酯结构胶：甲基丙烯酸羟丙酯的最佳用量为15％,常温剪切强度）4／30．1MPa,冷热冲击老化后剪切强度为23．23MPa,粘接强度衰减率为23％。     

Diffusion coefficients of acrylic monomers in poly(methyl methacrylate)

The average diffusion coefficients (D_avg) of three acrylic monomers methyl methacrylate (MMA), butyl methacrylate (BtMA) and cyclohexyl methacrylate (ChMA) in poly(methyl methacrylate) (PMMA) were measured by the thermogravimetric (TGA) technique. The measured D_avg values were in the range of (0.2∼105.7) × 10⁻⁷ for a PMMA solid content of 10∼50% and a temperature range of 323∼353 K. It was found that the solid content of PMMA, the molar volume of the acrylic monomer and the temperature significantly affected the D_avg values. A large decrease in the D_avg value was found at the 50% PMMA solid content for all three acrylic monomers. The order of the D_avg value for MMA, BtMA, and ChMA was MMA > BtMA > ChMA due to an increasing molar volume. The D_avg value was significantly increased with an increasing temperature, especially at a low PMMA solid content. The measured D_avg value can be used for predicting the refractive index distribution of gradient-index polymer optical fibers.     

Polymeric coatings based on acrylic resin latexes from miniemulsion polymerization using hydrocarbon resins as osmotic agents

Waterborne acrylic resins with a solid content higher than 40 wt % were obtained by miniemulsion polymerization of methyl methacrylate, butyl acrylate, and acrylic acid using a hydrocarbon coumarone–indene resin (HCR) as osmotic agent. HCR is a cheap polymer widely used for coatings and pressure‐sensitive adhesives. The resin leads to a higher hydrophobicity for the acrylic latex film and acts as osmotic agent in miniemulsion polymerization preventing Ostwald ripening, leading to latexes with particle sizes, size distributions, and stability comparable to those obtained using n‐hexadecane as osmotic agent. However, the monomer conversion and molecular weight were lower, indicating the occurrence of a chain‐transfer reaction. Atomic force microscopy analysis demonstrated that a smooth film surface with phase‐separated morphology was formed when using HCR. Faster film hardness development was achieved with HCR comparing with hexadecane. Compared with market standard in a paint formulation, a similar performance was achieved. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40569.     

Emulsion and miniemulsion copolymerization of acrylic monomers in the presence of alkyd resin

Emulsion and miniemulsion copolymerizations were carried out with acrylic monomers (methyl methacrylate, butyl acrylate, and acrylic acid) in the presence of an alkyd resin. Poly(methyl methacrylate) was used as a hydrophobe or cosurfactant in the miniemulsion reactions. The results demonstrate that miniemulsion polymerization is the preferred process, probably because of mass transport limitations of the alkyd in the conventional emulsion polymerization reactions. The monomer emulsions prepared for the miniemulsion reactions were much more stable and the polymerizations were free of coagulum. Reaction rates, particle size characteristics, grafting efficiencies, and some film properties were measured. © 1996 John Wiley & Sons, Inc.     

水性羟基丙烯酸树脂的制备与研究

以甲基丙烯酸甲酯(MMA)、苯乙烯(St)和丙烯酸丁酯(BA)等为主要单体,引入丙烯酸(AA)、丙烯酸羟基乙酯(HEA)与甲基丙烯酸异冰片酯(IBOMA)等作为功能单体,通过半连续溶液聚合工艺,最后加水分散制得水性羟基丙烯酸树脂。利用FT-IR、透光度、粘度分析研究了单体配比、引发剂(BPO)用量、温度、链转移剂(DDM)用量、功能单体用量等因素对树脂性能的影响。结果表明,当AA、HEA、IBOMA、BPO和DDM的质量分数分别为3%、12%、10%、3%和2%,聚合反应温度100℃时可获得粘度为5 Pa.s,固含量约45%的水性羟基丙烯酸树脂。     

Synthesis and characterization of three-component thermosetting acrylic polymer light conduits

In this study, new thermosetting acrylic polymer light conduits (PLCs) with the composition of A_xB_yC_z were prepared and characterized. The A and B components were methyl methacrylate and butyl acrylate, respectively. Tri-funcational acrylic monomers were used for the C component. The thermal properties and optical properties of the prepared PLCs are presented and compared with a commercially available PLC, S1. The prepared PLCs also have high numerical apertures and large diameters for illumination applications. The peak intensity and position can be tuned from their molecular structures. The peak position in the optical loss spectrum is in a satisfactory agreement with the theoretical calculation from the FTIR spectra, which results from the high harmonics of the C-H stretching vibration band. The peak intensity of the optical loss spectrum is proportional to the C-H bond density of the polymer core. The prepared PLCs have better thermal stability than S1.     

苯丙乳液的性能研究

以苯乙烯、丙烯酸丁酯、甲基丙烯酸甲酯、丙烯酸为反应单体,过硫酸铵为引发剂,聚乙二醇辛基苯基醚和十二烷基磺酸钠为复合乳化剂,通过连续滴加的乳液聚合工艺制备苯丙乳液。结果表明,当软硬单体配比为1∶1(质量比),SDS∶OP-10=1∶1(质量比),引发剂含量为单体总量的0.3%,可制得较好的乳液。