有机硅-丙烯酸酯共聚物防粘剂

华南理工大学科研者将MMA、BA、丙烯酸羟丙酯、八甲基环四硅氧烷、乙烯基硅氧烷等原料,在过硫酸铵引发下,以种子乳液聚合法合成出以聚硅氧烷为核,聚丙烯酸酯为壳的有机硅-丙烯酸酯共聚物,其可做防粘剂。当聚硅氧烷的质量分数在2 0 %～30 %时,该共聚物剥离及粘附力有较好保持率,且隔离效果好。有机硅-丙烯酸酯共聚物防粘剂@王涛     

烯烃基碳硅氧烷树枝状大分子单体及其应用

概述了烯烃基碳硅氧烷树枝状大分子单体的结构,介绍了层级为1和层级为2的烯烃基碳硅氧烷大分子单体的合成方法及结构表征,以及烯烃基碳硅氧烷树枝状大分子单体在有机聚合物改性及化妆品领域的应用,如:与有机单体溶液共聚制备有机硅改性共聚物、与丙烯酸酯单体乳液共聚制备有机硅改性丙烯酸酯乳液、与长链烷基丙烯酸酯共聚制备化妆品成膜剂、与甘油或木糖醇共改性制备亲水性有机硅交联共聚物等。     

有机硅-丙烯酸酯共聚物乳液的制备及在调湿涂料中的应用

以3-甲基丙烯酰氧丙基三甲氧基硅烷(MPTS)为功能改性单体,丙烯酸酯及少量的丙烯酸为主要共聚单体,采用离子型/非离子型复合乳化剂,过硫酸钾(KPS)为引发剂,制备了有机硅改性的丙烯酸酯共聚物乳液(SAE)。考察了MPTS用量、甲基丙烯酸-β-羟丙酯(HPMA)用量、引发剂用量及聚合温度对乳液稳定性的影响。采用IR、TG对SAE进行了表征。共聚物乳液SAE为成膜物,硅藻土、膨润土等为颜填料,制备了有机硅改性丙烯酸酯共聚物调湿涂料(SAE-C)。在测定共聚物乳液膜、SAE-C涂料基本性能的基础上,进一步测定了涂料SAE-C调湿功能。结果表明,MPTS能提高SAE乳液膜的附着力和涂料的耐水性;SAE乳液与SAE-C涂料均能达到国家内墙涂料和建筑涂料相关标准。同时,具有较好的增/降湿性能,可用作具有调湿功能的内墙涂料。     

有机硅-丙烯酸酯共聚乳液

华南理工大学的柯跃虎等人以甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸、有机硅单体等为原料,采用半连续乳化乳液聚合工艺,合成出核壳结构的有机硅改性共聚乳液。在有机硅单体用量5 %、引发剂用量0 6%、核壳中乳化剂配比1∶2、反应温度80℃的条件下合成的乳液性能最佳。FTIR谱图分析表明,有机硅单体在聚合过程中已接枝成为共聚物的一部分,有机硅单体的引入明显地改善了乳液的诸多性能有机硅-丙烯酸酯共聚乳液     

γ-甲基丙烯酰氧丙基甲基二甲氧基硅烷改性丙烯酸酯乳液的合成及性能研究

通过γ-甲基丙烯酰氧丙基甲基二甲氧基硅烷(KH571)与丙烯酸酯类单体进行聚合反应,采用水解抑制法合成出有机硅改性丙烯酸酯乳液。研究了聚合工艺、软硬单体配比、乳化剂用量和比例,以及有机硅单体、引发剂和水解抑制剂用量等因素对硅丙乳液聚合过程稳定性及产品性能的影响,找出了合成硅丙乳液的最佳工艺参数。同时利用红外光谱对共聚物结构特征进行了分析。     

有机硅改性-丙烯酸酯共聚乳液的制备与性能研究

文章研究了有机硅单体与丙烯酸类单体的乳液聚合反应,制备出高性能的改性丙烯酸酯乳液。主要讨论了乳化剂、引发剂、有机硅加入方式及用量对乳液性能的影响。用有机硅改性丙烯酸酯乳液制成的涂料具有优越的耐水性,其耐洗刷性可达6万次。     

高性能改性丙烯酸酯乳液的制备

研究了有机硅单体与丙烯酸类单体的乳液聚合反应,制备出高性能的改性丙烯酸酯乳液。主要研究了乳化剂、引发剂、有机硅加入方式及用量对乳液性能的影响,用有机硅改性丙烯酸酯乳液制成的涂料具有优越的耐水性,其耐洗刷性达4万次。     

有机硅改性丙烯酸酯微乳液的合成与表征

采用种子乳液聚合法,以有机硅微乳液为种子乳液,在其表面进行壳聚合,合成了核壳型有机硅改性丙烯酸酯微乳液。研究了交联单体以及有机硅种子乳液用量对硅丙微乳液性能的影响,并通过红外、核磁共振及差热分析等表征了共聚物的结构。结果表明:当引发剂用量为乳液总质量的0.4%、双丙酮丙烯酰胺为交联单体且用量为乳液总质量的3%、有机硅种子乳液用量为25%时,硅丙微乳液的单体转化率达95.53%,凝胶率小,乳胶粒粒径81.2 nm;与纯丙乳液相比,成膜性更好,玻璃化转变温度低3.7℃。     

高性能改性丙烯酸酯乳液及其涂料的研制

研究了有机硅单体与丙烯酸类单体的乳液聚合反应，制备出高性能的改性丙烯酸酯乳液。主要讨论了乳化剂、引发剂、有机硅加入方式及用量对乳液性能的影响。用有机硅改性丙烯酸酯乳液制成的涂料具有优越的耐水性，其耐洗刷性达60000次。     

有机硅—丙烯酸酯共聚乳液的合成

本文详细地讨论了有机硅──丙烯酸酯乳液共聚物的合成工艺条件，以及改变这些工艺条件对于聚合过程及产物性能的影响。并用红外光谱和动态力学谱证明了共聚结构的存在。结果表明：有机硅—丙烯酸酯共聚物的耐热、耐寒及耐水性均有一定程度的提高。     

Drug-releasing kinetics of MPEG/PLLA block copolymer micelles with different PLLA block lengths

Copolymers of poly(L -lactic acid) and methoxy end-capped poly(ethylene glycol) were synthesized, and their structure and physical properties were characterized. Micellar structures were formed in aqueous media because of the amphiphilic nature of the copolymers, and their sizes were measured with both dynamic light scattering equipment and scanning electron microscopy. Indomethacin was loaded into the copolymer micelles, and its releasing behavior was monitored. The drug-releasing mechanism was determined from an investigation of the biodegradation kinetics of the copolymer micelles. The releasing mechanism was governed by diffusion rather than a biodegradation process. We adapted a model based on Fick's diffusion theory to describe the overall releasing behavior with the extraction of the diffusion coefficient. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2599–2605, 2001     

Nano-container assembled thin films with time-programmed release of hydrophobic dyes

We introduce an all nano-container assembled multilayer thin films for controlling the release of hydrophobic functional materials. Two complementary charged block copolymer micelles were used as a nano-container for layer-by-layer assembly of thin films. Block copolymer micelles were composed of positively charged hairy polystyrene-block-poly(4-vinylpyridine) and negatively charged hairy (long corona region relative to the hydrophobic core part) or crew-cut (huge hydrophobic core chains, compared with the hydrophilic corona region) polystyrene-block-poly(acrylic acid) micelles. Two different fluorescent dye-incorporated block copolymer micelles multilayer films deconstructed when rehydrated in physiological condition, phosphate buffer saline solutions, releasing block copolymer micelles as a hydrophobic material carrier, suggesting that the detachment behavior of block copolymer micelles integrated into the multilayer films differs according to layer-by-layer assembled block copolymer micelle combinations. These results indicate the suitability of thin films for applications including the controlled release of hydrophobic materials. Atomic force microscope analysis suggested the successful preparation of block copolymer micelles. Film growth and release of fluorescence dyes were monitored by UV-Vis spectra.     

Thermal/pH-sensitive core-shell copolymer latex and its potential for targeting drug carrier application

In this work, the synthesis, properties of a thermal/pH-sensitive core-shell copolymer latex were studied and its potential application as a targeting drug carrier was also investigated, where the crosslinked copolymer of N-isopropylacrylamide (NIPAAm) and chitosan was synthesized by soapless dispersion polymerization as the core, and the copolymer of methacrylic acid (MAA) and methyl methacrylate (MMA) was prepared as the shell. The weight ratio of chitosan/NIPAAm and the concentration of crosslinking agent in feed had been changed to investigate their effects on the particle size, reaction rate, zeta potential, surface functional groups, and specific surface area of latex particles. The swelling and thermo-sensitive behavior of the film made from these core-shell latexes were also studied under different pH values of buffer solution. The model drug (caffeine) could be loaded inside the copolymer particles and protected from releasing through the transport process effectively. And the thermo-responsive property of these copolymer particles significantly enhanced the protein conjugation that showed the potential of the latex being applied on the targeting drug carrier.     

Nanomechanical and surface frictional characteristics of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene

Surface mechanical and tribological properties of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene were evaluated using nanoprobe investigation techniques and compared to the properties obtained at the macroscale. These copolymers are commonly referred to as self-reinforced polymers (SRPs) because of their intrinsic high strength and modulus without addition of a reinforcing agent. Specimens were prepared by spin casting, solvent casting, and compression molding. Surface mechanical properties and film thickness were measured by nanoindentation and scratching techniques. Friction properties were found using lateral force microscopy (LFM), and surface topography was imaged by tapping mode atomic force microscopy (AFM). Macroscale friction testing revealed a kinetic coefficient of friction of 0.08 for SRP, approaching that of Teflon. Similarly low relative friction coefficients were obtained in nanoprobe measurements. Nanoindentation of SRP, polycarbonate (PC), and polyetherimide (PEI) demonstrated superior surface hardness and modulus of SRP copolymer thin films.     

Effect of modifier characteristics on toughness of poly(vinyl chloride)

The effects of the mechanical properties of an acrylic graft copolymer and a silicone/acrylic composite rubber graft copolymer on the toughening of poly(vinyl chloride) (PVC) are examined. In the experiment for improvement of impact resistance of PVC, toughness of the blend polymer of a silicone/acrylic composite rubber graft copolymer is improved remarkably. The effect is attributed to the suppression of stress concentration below the fibril strength of the polymer alloy effectively by releasing the constraint of strain resulting from easy void formation at low stress. © 1996 John Wiley & Sons, Inc.     

SBS改性胶粘剂的合成及其性能研究

在交联单体丙烯酸（AA）存在下,研究了SBS／MMA－BA四元接枝共聚合及其产物的性能。讨论了AA用量、混合单体用量、SBS起始浓度、混合单体配比及反应温度对接枝共聚物性能的影响。获得适宜的合成工艺条件。通过大量测试表明,用SBS改性的接枝共聚物配制的胶粘剂,具有粘结力大、剥离强度高、使用方便等特点。     

Development of polymer‐molding‐releasing metal mold surfaces with perfluorinated‐group‐containing polymer plating

The polymer‐molding‐releasing properties of metal molds were found to be related to the following factors: (1) interfacial chemical bonding between the surfaces of polymers and metal molds and (2) a friction force or friction coefficient between polar substances and/or low‐molecular‐weight components in the polymers and physical factors on mold surfaces. We theoretically and experimentally confirmed that metal molds with good polymer‐molding‐releasing properties had very small surface free energies. We also proved that the surface free energies in the resulting polymer moldings were lower than before shaping. The molding releasing properties improved with decreasing friction force and friction coefficient between the surface of polymers and metal molds and with decreasing surface free energy. To obtain metal molds with lower surface free energies, we developed a polymer plating method with perfluorinated‐group‐containing triazine dithiol. The Metal mold treated by polymer plating had lower critical surface tension (7.5 mJ/m²) than Teflon (18 mJ/m²), indicating that the surface consisted of CF₃ ? groups. The treated mold showed excellent durability in its releasing properties, which was better than that of the untreated mold. This technique was developed for the production of molds for the Fθ lens and the naturally bright focusing screen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2549–2556, 2003     

Adhesive properties of heat-sealed EVAc/PE films in dependence on recipe,processing, and sealing parameters

The investigated peel system in this study consists of a polyolefine-based, coextruded, three-layer film having ethylene-vinyl acetate (EVAc) copolymer at the interface, heat sealed against a biaxial-oriented polyethylene terephthalate film. This system can primarily be found in the packaging industry offering a residue-free and non-destructive peel behavior. The peel force required to separate the joint depends on the mass fraction of vinyl acetate (VAc) in the EVAc copolymer, the processing conditions in the blowing process of the PE/PEVAc film, and on the sealing parameters. In dependence on the processing conditions and sealing parameters, the standard peel system with EVAc copolymer containing 18 wt.% VAc was investigated. The processing parameters were varied among the processing line of the blown film and their influence on the peel properties were studied. As processing parameters the screw speed within the extruder and the resulting layer thickness, the cooling behavior of the film bubble and the blow-up ratio (BUR) of the film bubble were investigated. The effect of pretreatment conditions was also investigated. The investigations revealed a significant dependence of the peel force on the pretreatment conditions. Processing conditions and the VAc content have a minor impact on the peel properties.     

氟碳化合物FC-77在Pluronic嵌段共聚物胶束中包封与缓释

采用乙醇注入法制备FC-77的载药纳米胶束,通过动态光散射、透射电子显微镜表征了载药纳米胶束的粒径和形貌;通过紫外可见光谱研究了FC-77在嵌段共聚物P123中的包封率和释放曲线。结果表明,含1%P123的FC-77载药纳米胶束粒径为270 nm,呈球形分布,包封率为50%6,00 min时的释放量为92.2%。进一步地,通过调节嵌段共聚物的组成、浓度等可以改变载药纳米胶束的粒径和包封率。结果证明,嵌段共聚物胶束体系能作为FC-77载药制剂的载体,并且通过调整嵌段共聚物胶束体系配方,可以得到理想的FC-77药物载体。     

Effect of high molecular weight acrylic copolymers on the viscoelastic properties of engineering resins

In this work, the viscoelastic properties of acrylic‐based copolymer blends with poly(methyl methacrylate) (PMMA) and polycarbonate were investigated in the molten and solid states. High molecular weight copolymers of methyl methacrylate with butyl acrylate (MMA‐co‐BA) having varying molecular weight and composition were used to enhance the rheological properties in shear and extension. Blends containing up to 15 wt% of copolymer were prepared at 200°C and 150 rpm by using a DSM micro‐compounder. The samples were characterized by size exclusion chromatography (SEC), dynamic mechanical analysis (DMA), and rheology. The rheological properties were determined by using small amplitude oscillatory measurements (SAOM) in shear and a Rheotens? device for melt strength determination. For PMMA, the effects of high molecular weight PMMA copolymer on the matrix were related to the molecular weight, the tacticity of the copolymer, and the individual components. The rheological properties in shear showed enhanced storage and loss moduli at low frequency, while no change was observed at high frequency. In addition, extensional viscosity measurements made by using the filament stretching technique showed a significant increase in melt strength compared to that of the base PMMA with the blend containing the highest molecular weight copolymer showing the maximum force and a reduced drawdown ratio. For polycarbonate, its blends with acrylic copolymer were found to be immiscible. Similar enhancement in the moduli at low frequencies was observed, but a significant increase in the viscosity was obtained as well, resulting from the response of the two‐phase system. This change in the rheological properties was further increased at 15 wt% loading. Owing to the formation of a phase‐separated morphology, the melt strength was found to increase only slightly. J. VINYL. ADDIT. TECHNOL., 12:143–150, 2006. © 2006 Society of Plastics Engineers