乳化剂对含氟丙烯酸酯共混膜结构和性能的影响

用阴离子、非离子和阳离子乳化剂制备了聚甲基丙烯酸甲酯-丙烯酸丁酯乳液,非离子乳化剂制备了聚甲基丙烯酸六氟丁酯乳液。将含氟乳液与不含氟乳液共混,并室温成膜。采用AFM、SEM-EDS、接触角仪比较了上述3种共混膜的结构和性能。结果表明不含氟乳液乳化剂为阴离子或非离子时,更有利于形成两面异性,具备优异的性能。     

含氟乳化剂丙烯酸酯乳液的制备及性能

以丙烯酸丁酯、甲基丙烯酸甲酯、丙烯酸、十二烷基硫酸钠为主要成份分别制备了含氟乳化剂FC80、FC91 1、FC90 8、4 FC氟醇的丙烯酸酯共聚物乳液 ,测定了它们的表面张力、粘度、PH值、固含量等性能 ,重点讨论了 FC80含量对乳液性能的影响。实验发现在 FC80含量为 0 .0 5%时丙烯酸酯共聚物乳液性能变化明显     

含氟乳化剂FC80含量对丙烯酸酯乳液共聚物性能的影响

研究了含氟乳化剂 FC80含量对丙酸酯乳液共聚物性能的影响。结果表明随 FC80含量从0 .0 1 %增加到 0 .3% ,丙烯酸酯乳液共聚物的表面张力和粘度下降 ;耐酸性增强 ,p H值稳定范围增宽 ;乳液粒子直径下降 ;稀释和贮存稳定性好 ;耐电解质稳定性呈现抛物线变化。 FC80含氟乳化剂的最佳用量以 0 .0 5 %到 0 .1 %为宜。     

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。     

细乳液聚合法制备含氟丙烯酸酯共聚物乳液的研究

通过细乳液聚合法制备含氟丙烯酸酯共聚物（FPA）乳液,采用红外光谱（ FT-IR）、透射电镜（TEM）、原子力显微镜（AFM）、热重分析仪（ TG）、扫描电镜和表面能谱（ SEM-EDS）等对聚合物进行表征,并考察了乳化剂与助乳化剂的物质的量比,氟单体用量和超声时间对乳液粒径的影响。结果表明,甲基丙烯酸六氟丁酯（ 6FA）、丙烯酸丁酯（ BA）、苯乙烯（ St）3种单体成功聚合,乳化剂与助乳化剂的物质的量比为 1.5∶1,超声时间为 60 min,氟单体用量为 10%时,乳液粒径最小且分布较窄,表面张力从 45.028 mN/m降至 33.399 mN/m,且乳胶膜粗糙度增加,热稳定性提高。     

丙烯酸酯乳液膜表面乳化剂形态研究

讨论了丙烯酸酯乳液中乳化剂在成膜及热处理过程中的存在形式及其对乳液膜性能的影响。研究表明,在乳液干燥成膜过程中,乳化剂与其他聚合物之间的相容性问题导致其在膜表面富集,在热处理过程中,富集分布发生变化,从而使乳液膜的各项性能发生变化。     

含氟乳化剂回收技术研究进展

介绍了氟树脂生产过程中废气与废水中含氟乳化剂的各种回收方法。认为废气回收技术中主要以碱液吸收为主;废液回收技术中,沉淀法容易形成二次污染;真空浓缩法易起泡、能耗大;离子交换法交换容量大、体系效率高,但交换树脂再生耗料大,形成二次污染;泡沫分离与纳滤结合法、反渗透膜处理法、全膜法避免了二次污染,但泡沫分离与纳滤结合法工艺过程设计复杂,不易连续操作。分析表明,含氟乳化剂排放将会成为技术壁垒,回收技术在氟树脂制备行业将会有迫切的需求,全膜法自动化程度高、能耗低、具有较好的工业利用价值,有望被大幅推广应用。     

浅谈含氟丙烯酸酯共聚乳液研究进展

介绍了含氟丙烯酸酯的性能和用途,对含氟丙烯酸酯共聚乳液常规乳液聚合以及最新共聚方法进行了简单的介绍,总结出几种改进含氟丙烯酸酯体系表面性能的方法,并展望氟丙烯酸酯发展。     

含氟丙烯酸酯橡胶的合成及性能

以丙烯酸乙酯、丙烯酸丁酯、含氟丙烯酸酯为单体,采用半连续乳液聚合法合成了含氟丙烯酸酯橡胶(ACM),用傅里叶变换红外光谱表征了其微观结构,考察了含氟单体种类及用量对含氟ACM亲水性、玻璃化转变温度及硫化特性的影响,以及交联剂二乙烯基苯(DVB)用量对含氟ACM硫化胶拉伸性能的影响。结果表明,丙烯酸六氟丁酯或丙烯酸十二氟庚酯(简称G 05)的转化率均超过90%;随着含氟单体用量的增加,ACM乳液涂膜的接触角逐渐增大,当加入质量分数为5%的G 05时,涂膜变为疏水性表面;含氟ACM只有1个玻璃化转变温度,且随着含氟单体用量的增加而逐渐下降;含氟ACM的操作安全性高,在硫化初期具有良好的流动性能;当DVB质量分数为3%时,含氟ACM的拉伸强度达到11.2 MPa。     

可聚合非离子乳化剂对丙烯酸酯乳胶性能的影响

合成了可聚合非离子乳化剂烯丙基脂肪醇聚氧乙烯醚(al-AEO₁₂),并用其制备了丙烯酸酯乳胶,考察了乳化剂用量对乳胶固含量、凝胶率、粒径分布、乳胶膜吸水率等性能的影响。结果表明：随着乳化剂用量的增加,乳胶固含量提高,凝胶率降低,平均粒径减小,乳胶膜吸水率降低,乳胶性能提高。将al-AEO₁₂与阴离子乳化剂SDS复配使用,且两者质量比为2∶1时乳胶性能最优,乳胶膜吸水率最低,此时乳胶粒径分布较窄,在透射电镜下可以观察到明显的核壳结构。     

Synthesis and characterization of fluorinated polyacrylate latex emulsified with novel surfactants

The fluorinated polyacrylate latex were successfully prepared with semi- continuous seeded emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) and hexafluorobutyl methacrylate (HFMA) which was initiated with potassium persulfate (KPS) initiator and emulsified with the novel mixed surfactants of sodium lauryl glutamate (SLG) and alkylphenol ethoxylates (OP-10). The structure of the resultant latex was confirmed by Fourier transform infrared spectroscopy (FTIR). The particle size of the latex was measured by Zetatrac dynamic light scattering detector. The film of latex was tested by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle (CA). The optimum conditions of preparing the novel fluorinated polyacrylate latex are optimized and the results are as follows: the amount of emulsifiers is 4.0%; mass ratio of SLG to OP-10 is 1:1, the amount of the initiator is 0.6%. The mass ratio of MMA to BA is 1:1 and the amount of HFMA is 7.0%. In this case, the conversion is high and the polymerization stability is good. In addition, the water resistance and thermal properties of the latex films were improved significantly in comparison with the film of the latex prepared without the fluorinated monomer.     

Adhesion of latex films; influence of surfactants

The aim of the work presented in this article was to investigate the role of surfactants on adhesion properties of latex films. Several polymer/surfactant/support systems were used. Polymers were poly(2-ethyl hexyl methacrylate) or a methyl methacrylate/ethyl acrylate copolymer partially grafted onto a hydrophilic polyester. Surfactants were sodium dodecyl sulfate (SDS), hexadecyl pyridinium chloride (HPCI), or ethoxylated nonyl phenol containing 10 or 30 segments of ethylene oxide (NP10 or NP30). Supports were glass plates or poly(ethylene terephthalate) films. Adhesion was measured by a peel test at 180°. Loci of failure were determined by multitechnique analysis of the surfaces revealed after peeling. At medium and high peel rates, the peel energy versus surfactant concentration curves show either a maximum or a minimum, depending on the surfactant. When the peel rate is decreased, these maxima and minima flatten out and, at zero peel rate (extrapolated values), the peel energy becomes independent of the surfactant concentration. Surfaces analyses revealed that the surfactant is always present at the locus of failure. Rupture takes place in a thick (above 10 nm) (SDS), in a thin (a few nanometers) (NP30), or at the top of a surfactant layer (HPCI). The locus of failure is independent of the peel rate and of the surfactant concentration. The conclusion is that the surfactant strongly influences adhesion properties of latex films but several points remain unexplained.     

Viscoelastic properties of latex paint films in tension: Influence of the inorganic phase and surfactants

The tensile properties of latex coatings were investigated with a set of custom formulated artist-type paints at an age of 1 year. All films in the study contained a poly(methyl methacrylate-cobutyl acrylate) binder exhibiting a glass-transition at approximately 10 °C. The viscoelastic behaviour of the latex matrix is first highlighted through a series of experiments involving different strain histories and temperatures. Influence of the inorganic particle concentration and geometry is then illustrated using TiO₂ and calcined kaolin for the secondary phase. Experimental data from a wide range of conditions are summarised through master curves of secant modulus and failure strains using time–temperature superposition. The results indicate that the latex films behave in a rheologically simple manner and it is possible to predict the response outside of the experimental time-scale. An analysis by similar methods is also given for TiO₂ pigmented films with/without surfactant removed by immersion in water. Differential scanning calorimetry and atomic force microscopy were also used in conjunction with mechanical tests. The combined findings suggest that a fraction of surfactant migrates to the TiO₂ interface during film formation, where it interferes with adhesion of the acrylic matrix.     

Surfactant concentration and morphology at the surfaces of acrylic latex films

The final outcome of surfactants during latex film formation is a topic of ongoing concern and interest. In this study of an acrylic latex containing an anionic surfactant, two notable phenomena are observed. (1) A higher surfactant concentration is present at the air surface of the latex films, regardless of the film-forming temperature and time. In some cases, surfactant is not visible in an atomic force microscope (AFM) image as a separate phase, but compositional profiles obtained with Rutherford backscattering spectrometry (RBS) reveal an enhanced concentration of surfactant over a depth from the surface that is comparable to the latex particle diameter. (2) The surfactant features that are imaged with the AFM evolve from a thin uniform layer, to a ‘finger-like' morphology, to small flat droplets, and finally to larger, hemispherical ‘blobs.' We suggest that surfactant is first deposited from the air/water interface onto the latex surface during the drying process. During this progression in the morphology of the surfactant, the ratio of the surface area-to-volume decreases. We speculate that this phenomenon is driven by a reduction in surface energy.     

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 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.     

含氟聚（甲基）丙烯酸酯乳液的研究进展

含氟聚(甲基)丙烯酸酯乳液具有合成简便和性能易调等优点,所得涂膜表面能低、耐污性能好、化学稳定性优异,因而在水性氟碳涂料领域受到广泛关注。含氟聚(甲基)丙烯酸酯单体的化学组成对乳液和涂膜性能影响很大。该文分类总结了含氟核心单体包括含氟烷基(甲基)丙烯酸酯、含氟杂原子(甲基)丙烯酸酯、含氟芳香(甲基)丙烯酸酯、含氟(甲基)丙烯酰胺和含氟磺酰胺(甲基)丙烯酸酯等的结构与乳液和涂膜性能的关系,然后对含氟聚(甲基)丙烯酸酯单体和乳液的合成方法进行归纳,最后简要介绍含氟聚(甲基)丙烯酸酯乳液的应用,并对乳液研究存在的问题和未来的发展方向进行展望。     

Effect of acrylic acid on water-whitening resistance of polyacrylate latex films and its mechanism

Two groups of polyacrylate latexes with higher (21 ~ 35 °C) or lower (−33 ~ −43 °C) glass transition temperatures (T_g) were prepared by adjusting the monomer ratio of butyl acrylate (BA) and styrene (St), and the effect of acrylic acid (AA) on water-whitening resistance of these latex films was investigated. It was found that the water-whitening resistance of the two groups of latex films was different. With the increase of AA content, the water whitening resistance of the latex films with higher T_g continued to improve, while that of the latex films with lower T_g increased first and then decreased. A series of characterizations, such as light transmittance, water whitening, water absorption, static water contact angle, surface morphology, and optical microscope test of the latex film, and so forth, showed that the reason for this difference was that under higher AA content (≥5%), compared with the polyacrylate latex films with lower T_g, the latex films with higher T_g could reach the saturation state of water absorption quickly, and water in these latex films exhibited continuous and large area distribution, rather than formation of many so-called micro- or nano-scale water sacs that can scatter light as found in the latex films with lower T_g.     

Surfactants in latex films; interactions with latex components and quantitative analysis using ATR and step-scan PAS FT-IR spectroscopy

This paper focuses on the behavior of low-molecular-weight surfactant molecules in latex films and how their distribution may influence coalescence and other film properties. Using recently developed spectroscopic non-destructive analytical tools, quantitative assessments concerning surfactant distribution and their interactions with latex components will be presented. Particular efforts will be given to recent developments in quantitative analysis using attenuated total reflectance (ATR) and step-scan photoacoustic (S²-PAS) Fourier transform infrared (FT-IR) spectroscopy.     

Studies on the damping performance of polystyrene/polyacrylate latex IPN

Polystyrene/polyacrylate latex IPN (PS/PA LIPN) was synthesized using two-stage emulsion polymerization. The effects of various polymerization parameters on the damping performance were investigated systematically. The results show that the multicomponent copolymerization favours broadening of the damping temperature range. Changing the sequence of adding raw materials and the amount of crosslinker used enables a great improvement in the compatibility of the two networks. Adding inorganic fillers is an important way of increasing and broadening the damping value. Transmission electron micrographs of PS/PA LIPN show the microscopic morphology of LIPN consistent with the above results.