非离子型水性聚氨酯的制备及其涂膜表面性质研究

采用自乳化方法合成不同聚乙二醇(PEG)含量的非离子型水性聚氨酯乳液(WPU),并用傅里叶变换衰减全反射红外光谱(ATR-FTIR)、原子力显微镜(AFM)、接触角测量仪研究不同PEG含量对WPU涂膜表面性质的影响。结果表明:随着PEG含量的增加,WPU硬段与硬段之间氢键作用减弱,表现出硬软段微相分离程度降低;同时,WPU涂膜表面甲基含量增加,表面粗糙度下降,表现出涂膜表面能下降,水接触角增大。     

超支化聚酯改善聚酯粉末涂料表观性能的研究

采用硬脂酸对商业化的超支化聚酯(Blotorn H20)进行端基改性,提高其玻璃化转变温度(T_g),将其作为增大粉末涂膜表面张力和降低熔体黏度的助剂,以期达到减少涂膜表面缩孔和针孔,改善粉末涂料涂膜的表观性能的目的。运用红外光谱仪(FT-IR)、差式扫描量热分析系统(DSC)、旋转流变仪、接触角测量仪等方法进行了表征,研究表明硬脂酸封端Blotorn H20超支化聚酯(SA-HBP)的T_g升高到70℃,满足粉末涂料的贮存要求;与未加入SA-HBP的粉末涂料相比,加入SA-HBP后熔体黏度降低了20%～50%,表面接触角从100°降到80°,橘皮、针孔和缩孔等表面缺陷减少,同时物理机械性能如硬度、耐冲击性、附着力均有所改善。     

水性UV固化星型聚氨酯丙烯酸酯的性能研究

制备了水性UV固化星型杂臂聚氨酯丙烯酸酯(WSPUA),重点研究了星型聚氨酯分子臂的软段组成(PC-DL1000和PEG400)对其乳液和UV固化涂膜性能的影响。结果表明:乳液粒径、表面张力和革表面接触角随PCDL用量减少而变小;涂膜抗张强度、断裂伸长率、耐溶剂性能随PCDL用量减少而降低,耐水性随PCDL用量减少而提高;涂膜微相分离程度随PCDL用量增加而增加,软段玻璃化温度随PCDL用量增加而降低,热稳定性随PCDL用量增加而提高。     

有机染料对聚甲基丙烯酸甲酯产品着色后性能的影响

依据聚合着色技术,在聚甲基丙烯酸甲酯(PMMA)合成过程中添加有机染料。选择有机染料紫BA,研究了其质量分数的变化对着色PMMA产品的色度、光泽度、分子量及熔体质量流动速率(MFR)的影响,同时探讨了有机染料对PMMA产品的着色机理。结果表明,有机染料紫BA质量分数增加时,着色PMMA产品的分子量增加,MFR降低;从视觉上看,产品色彩的深度增加,表面光泽度降低。     

端羟基聚醚改性环氧树脂研究

合成了不同分子量(450,1200,2000)的端羟基聚醚(mPEG)改性双酚A型环氧树脂,通过DSC、动态热机械分析(DMA)研究了mPEG/EP的固化反应活性及改性环氧树脂酸酐固化体系的热性能与冲击性能进行了研究,并用扫描电子显微镜(SEM)分析了冲击试样断面。结果表明,改性体系的固化反应活性略有降低;在mPEG含量为15%时固化体系的冲击韧性都达到最大值;改性环氧树脂固化体系的玻璃化转变温度(Tg)随mPEG的含量增大有所降低,且相同质量下mPEG分子量越小下降幅度越大。     

环氧树脂及其涂料

<正>201702001一种具有优异疏水性、抗划伤性的UV固化环氧涂层[刊,英]/Sangermano,Marco等//Macromolecular Materials and Engineering.-2016,301(1).-93~98通过将经氟化改性官能化的二氧化硅粒子分散于UV固化环氧涂料中,对UV固化环氧涂膜的表面性能进行了选择性改性,极大地增强了其疏水性和抗划伤性。研究了光聚合过程并对涂膜进行了全面表征。UV固化涂膜上的水接触角测试表明,交联后涂膜的接触角随配方中官能化二氧化硅含量的增加而增加。另外,在渗透     

聚乙二醇功能化程度对纳米金壳夹心二氧化硅载药量及稳定性影响研究

本文系统研究了不同聚乙二醇(PEG)功能化程度对纳米金壳夹心二氧化硅(GSNs)载药量及稳定性的影响.透射电子显微镜(TEM)观察结果表明,GSNs表面经修饰分子量为5 KDa的α-甲氧基-ω-巯基聚乙二醇(mPEG-SH)分子后,PEG分子层平均厚度约为4 nm;随PEG化程度增加,GSNs聚集沉降速度改善,稳定性提高,久置后(35 d)稳定性良好;电感耦合等离子体发射光谱(ICP-OES)测试表明,当PEG与Au反应摩尔比为0.24时,PEG分子层在金壳表面接近饱和;不同PEG化程度对GSNs载药量基本无影响.本研究可为优化无机纳米材料表面PEG修饰过程,发展无机纳米载体材料体内应用提供理论依据.     

烯烃复分解法制备端基官能化液体橡胶研究进展

用烯烃复分解法制备端基官能化液体橡胶具有分子量可控、易于引入多种官能团、反应条件较温和等优势。本文即综述了利用烯烃复分解法制备端羟基、端羧基、端酯基等官能化液体橡胶的研究新进展,并提示了其今后的发展方向。     

PMMA/SiO_2纳米复合膜表面性能的研究

采用有机硅处理剂对纳米SiO2进行化学修饰,得到表面官能团化的纳米SiO2,然后再通过溶液聚合法制备了聚甲基丙烯酸甲酯/二氧化硅(PMMA/SiO2)纳米复合膜.利用傅里叶红外光谱仪(FT-IR)、扫描电镜(SEM)、原子力显微镜(AFM)、水接触角仪(WCA)对其进行表征.结果表明,经有机硅处理剂官能团化的纳米SiO2能很好地分散于PMMA基体中,SiO2有富集到聚甲基丙烯酸甲酯表面的趋势,加入纳米SiO2降低了聚甲基丙烯酸甲酯表面自由能,提高了膜表面的水接触角.经四氢呋喃溶剂刻蚀后,膜表面的水接触角显著提高,得到憎水型PMMA/SiO2纳米复合膜.     

聚乙烯醇基相变储能材料的制备与表征

相变储能材料能够解决能量储存和释放在时间和空间上的矛盾,被广泛应用于储热技术。以聚乙烯醇(PVA)和聚乙二醇单甲醚(mPEG)为原料,制备PVA/mPEG接枝聚合物和PVA+mPEG共混聚合物,并讨论不同相变剂mPEG分子量及添加量对PVA/mPEG接枝聚合物的化学结构及相变储能的影响。利用差示扫描量热仪(DSC)对PVA/mPEG接枝聚合物和PVA+mPEG共混聚合物进行表征。结果表明:随着mPEG含量的增加,PVA/mPEG接枝聚合物的相变焓和相变温度升高。随着mPEG分子量的增加,PVA/mPEG接枝聚合物的熔点和相变焓显著提高。PVA/mPEG接枝聚合物的稳定性优于PVA+mPEG共混聚合物。结合相变材料的力学性能,当mPEG的添加量为PVA的3%、mPEG分子量为1 000时,制备的PVA/mPEG接枝聚合物的性能较优异。     

Enrichment of poly(butyl methacrylate) and its graft copolymer of polybutadiene on the surface of polypropylene blend

The enrichment and diffusion of poly (butyl methacrylate) (PBMA) and its graft copolymer of polybutadiene on the surface of polypropylene (PP) blends were investigated using attenuated total reflection infrared spectroscopy (ATR‐FTIR), contact angle measurements (CDA), and scanning electron microscopy (SEM). It has been found that the selective aggregation of the PBMA and its copolymers on the surface of blends is mainly affected by the content, molecular weight, and the segregated domains. Lower content and higher surface energy die are in favor of the enrichment of additives on the surface of PP. PBMA with higher molecular weight has lower diffusivity and bigger phase domains, which results in its lower enrichment on the surface of PP blend film. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Temperature dependence of surface composition and morphology in polymer blend film

Thin films of poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN) blend can phase separate upon heating to above its critical temperature. Temperature dependence of the surface composition and morphology in the blend thin film upon thermal treatment was studied using in situ X-ray photoelectron spectroscopy (XPS) and in situ atomic force microscopy (AFM). It was found that in addition to phase separation, the blend component preferentially diffused to and aggregated at the surface of the blend film, leading to the variation of surface composition with temperature. At 185 °C, above the critical temperature, the amounts of PMMA and SAN phases were comparable. At lower temperatures PMMA migrated to the surface, leading to a much higher PMMA surface content than in the bulk. The migration and preferential segregation of a blend component in thin films demonstrated here are responsible for the great difference between in situ and ex situ experimental (not real quenching or annealing) results of polymer blend films, and help explain the slow kinetics of surface phase separation at early stage for blend thin films reported in literature. This is significant for the control of surface properties of polymer materials.     

Surface modification of polymethyl methacrylate by graft copolymers

Summary Graft copolymers composed of poly(methyl methacrylate) branches and different backbones of poly(fluoroalkyl acrylate(FA)-co-methyl methacrylate(MMA)), poly (hydroxyethyl methacrylate(HEMA)-co-MMA), and poly(FA-co-HEMA) were prepared by macromonomer technique to study their application as a surface modifier for PMMA films. Contact angle of water droplet on PMMA film specimens containing various amounts of these graft copolymers cast on glass slides from THF solution was found to change considerably with the graft copolymer concentration, depending on their backbone component. And there was considerable difference in contact angle between air and glass side of the film surfaces. These results were considered in terms of the surface accumulation of graft copolymers during the solvent evaporation.     

Fabrication of super-hydrophobic film from PMMA with intrinsic water contact angle below 90°

Super-hydrophobic film is commonly prepared from hydrophobic materials. Poly(methyl methacrylate) (PMMA) is considered as a hydrophilic polymer (intrinsic contact angle below 90°) with the water contact angle (CA) of 68°. However, a super-hydrophobic PMMA film with CA of 154° was obtained by treating polystyrene (PS) and PMMA blended film in a warm selective solvent, cyclohexane. The surface was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (FT-IR). The results show that the conversion from the hydrophilic surface to a super-hydrophobic one is due to the cooperation of the micro-, nano-structure and the side group reorientation in the PMMA chains at the topmost.     

The molecular weight ratio of monomethoxypolyethylene glycol (mPEG) to protein determines the immunotolerogenicity of mPEG proteins

Immunotolerogenic activity of monomethoxypolyethylene glycol-(mPEG) conjugated proteins is a beneficial property in proteinpharmaceutics. However, procedures for the preparation of tolerogenicmPEG proteins have not yet been defined. We prepared mPEG proteinswith different mPEG contents using three proteins, hen egg lysozyme,ovalbumin and bovine gamma globulin, and their tolerogenicitiesto antigen-specific T and B cell responses were examined. Wefound the most appropriate ratio of tolerance induction to be1.5–2.0, which is the molecular weight ratio of conjugatedtotal mPEGs to protein. This value may assist in the preparationof tolerogenic mPEG proteins.     

Effects of drug and polymer molecular weight on drug release from PLGA‐mPEG microspheres

This study investigated the effects of drug and polymer molecular weight on release kinetics from poly (g ‐co‐glycolic acid)‐methoxypoly(ethyleneglycol) (PLGA‐mPEG) microspheres. Bovine serum albumin (BSA, 66 kDa), lysozyme (LZ, 13.4 kDa), and vancomycin (VM, 1.45 kDa) were employed as the model drugs, and encapsulated in PLGA‐mPEG microspheres of different molecular weight. Release of macromolecular BSA was mainly dependent on diffusion of drug at/ near the surface of the matrix initially and dependent on degradation of matrix at later stages, while, the small drug of vancomycin seemed to depend totally on diffusion for the duration of the release study. The release behavior of lysozyme was similar to bovine serum albumin, except a shorter lag period. PLGA‐mPEG molecular weight also affected the release behavior of bovine serum albumin and lysozyme, but not obviously. PLGA‐mPEG microspheres in smaller molecular weight seemed to degrade more quickly to obtain a mass lose and matrix erosion, and thus, an accelerated release rate of bovine serum albumin and lysozyme. Vancomycin released much faster than bovine serum albumin and lysozyme, and exhibited no lag period, as it is thought to be diffusion‐controlled. Besides, vancomycin showed no difference in release behavior as PLGA‐mPEG molecular weight change. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41431.     

Synthesis, Characterization and Surface Properties of Cross-linked Polyurethane Dispersions Modified by Organosiloxane

A series of cross-linked polyether-polyester polyurethane dispersions modified with organosiloxane were prepared based on hydroxyl-terminated polydimethylsiloxane (HTPS) as hydrophobic component and 3-aminopropyl-triethoxysilane (APTS) as cross-linker as well as a bridge between polyurethane (PU) and polysiloxane (PSIL). It was discovered that polydimethylsiloxane segments were incorporated into PU chains chemically and organosiloxane was preferentially oriented toward the surface layer of the film by making a comparison of attenuated total reflection (ATR) spectra between the copolymer and the blend of PU and PSIL, which was further confirmed by investigation of electron spectroscopy for chemical analysis (ESCA). The relationships between surface properties of the film formed from polyurethane dispersion and organosiloxane content were also studied. The results showed that water contact angle of the film increased with the increase of organosiloxane content. Interestingly, it was also found that water contact angle of PUS film increased firstly and then decreased when film-forming temperature varied from 25℃ to 55℃.     

Synthesis and characterization of functionalized carbon nanotubes with different wetting behaviors and their influence on the wetting properties of carbon nanotubes/polymethylmethacrylate coatings

The synthesis and characterization of hydrophobic functionalized multi-wall carbon nanotubes (MWCNTs) were investigated and their influence on the wetting properties of organic coatings and composites was studied. Functionalization was performed using oxidation, 1,3-dipolar cycloaddition, and silanization. Silanization was conducted using three hydrophobic silane precursors: 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, and triethoxyoctylsilane. Functionalization was directly confirmed and characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, and scanning electron microscopy. The water contact angle of the functionalized MWCNTs was 40–142° for different surface functionalities and the functionalized MWCNTs were incorporated into an acidic solution of polymethylmethacrylate. The effect of surface functionality and the concentration of the functionalized MWCNTs on the wetting properties of these composites were studied by measuring the water contact angle. Under optimum conditions, composite surfaces with water contact angles greater than 110° were obtained. Atomic force microscopy was used to determine the topography of the surface and energy dispersion spectroscopy was used to determine the distribution of the functionalized MWCNTs in the composite film. It was shown that the hydrophobic functionalized MWCNTs migrated to the surface; this was more pronounced for the more hydrophobic MWCNTs.     

Surface functionalization of polypropylene by entrapment of polypropylene‐grafted‐poly(ethylene glycol)

A surface functionalization polypropylene was prepared by entrapment a copolymer of polypropylene‐grafted‐poly(ethylene glycol) into polypropylene. The effects of structure of copolymer, contact dies, and content of modifiers were studied. The results of attenuated total reflection infrared spectroscopy(ATR‐FTIR) and contact angle measurements indicated that PP‐g‐PEG could preferably diffuse onto the surface and effectively increase the hydrophilicity of PP. PPw‐g‐PEG with lower PEG contents, lower molecular weight of PPw and PEG had better selective enrichment on the surface of PP blend film. By grafting of PEG‐OH onto the MPP, PP macromolecular surface modifier with better solvent‐resistance than that of PEG can be achieved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009