三油酸甘油酯的合成研究

详细论述了催化酯化合成三油酸甘油酯的方法，此合成分两步完成，避免了酯化反应的可逆性，高质量的产品符合医药用标准。     

共聚物水凝胶接触镜材料与牛血清蛋白亲和性的影响因素

为了评价蛋白质在自行制备的共聚物水凝胶角膜接触镜材料上的沉积行为。将水凝胶膜样品置于牛血清蛋白(BSA)水溶液中,沉积一定时间后,采用染料染色结合分光光度法分析沉积前后牛血清蛋白浓度的变化,计算沉积量。实验发现,随沉积温度升高,牛血清蛋白的沉积量增大;沉积时间超过5天,仍然没有达到饱和沉积;牛血清蛋白的浓度越高,沉积量越大。共聚物水凝胶材料中,N-乙烯吡咯烷酮(NVP)组分的含量越大,沉积量越大;而甲基丙烯酸酯组分则导致牛血清蛋白的沉积量减小,以甲基丙烯酸甲酯(MMA)最为明显。     

三油酸甘油酯与甲醇酯交换反应热力学分析

为了揭示酯交换反应的热力学特性,并为动力学研究和生物柴油的工业化生产提供基础数据,采用Benson基团贡献法和其他经验公式计算了三油酸甘油酯与甲醇之间发生的3步连续可逆酯交换反应的焓变、Gibbs自由能变及平衡常数的值,以及在303—338K各值随温度的变化关系。结果表明,在该温度范围内,反应焓接近于0,Gibbs自由能为正值,平衡常数接近于1。说明三油酸甘油酯与甲醇酯交换反应体系的反应热较小,温度对平衡的影响不大。     

共聚物水凝胶角膜接触镜材料的初期脱水行为

以N-乙烯基吡咯烷酮、甲基丙烯酸羟乙酯以及甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯为原料,制备共聚物水凝胶角膜接触镜材料,建立了膜状水凝胶材料的脱水模型,采用重量法和热失重法研究了该材料的初期脱水行为.结果表明,水凝胶膜的初期脱水速度与其交联密度的平方成反比;共聚物水凝胶中N-乙烯基吡咯烷酮的含量越大,脱水速率越大;甲基丙烯酸甲酯、甲基丙烯酸乙酯以及甲基丙烯酸丁酯的含量越大,脱水速率越低,以甲基丙烯酸乙酯最明显;在初期脱水阶段,水凝胶膜的脱水行为可用一级动力学描述.     

非水相酶促不可逆转酯反应合成阿魏酸三油酸甘油酯

在有机相甲苯中通过阿魏酸乙烯酯(VF)和三油酸甘油酯(TO)的酶促转酯反应合成油脂抗氧化剂阿魏酸三油酸甘油酯。用阿魏酸乙烯酯作为底物可使转酯反应不可逆,这有利于产物产率的提高并缩短反应时间。通过核磁共振波谱和质谱对阿魏酸乙烯酯的结构进行了表征,并考察了底物摩尔比、反应时间、反应温度、酶用量、水活度对产物产率的影响。结果表明,以甲苯为溶剂,当底物n(VF)∶n(TO)=1∶3,反应时间62 h,反应温度55℃、酶用量20 g/L,水活度(aw)为0.07时,产物的产率最大,达96.73%。     

水凝胶角膜接触镜材料的研究进展

分析了角膜接触镜对所需高分子材料性能的要求;介绍了角膜接触镜材料的研发历程,特别介绍了仿生材料水凝胶、互穿网络水凝胶、NVP-CS-HEMA半互穿网络水凝胶等新型角膜接触材料及其性能;在材料制备方面,重点讨论了化学引发和光引发技术;最后对本领域的发展进行了展望。     

油酸甘油酯的合成及其改善柴油润滑性研究

以对甲苯磺酸为催化剂,甲苯为携水剂,油酸和甘油为原料合成了二油酸甘油酯与三油酸甘油酯的混合物。实验考察了物质的量比、反应时间、反应温度和对甲苯磺酸(催化剂)用量对酯化率的影响,并通过红外光谱对产品结构进行表征。结果表明,适宜的反应条件是:n(丙三醇)∶n(油酸)=0.7∶1;反应温度155~160℃;反应时间9h;催化剂用量5%;甲苯(携水剂)用量20%,在此条件下油酸的酯化率达99.4%,产物的酸值(mg·KOH/g)2。用HFRR法评定产物抗磨性能,结果表明:在低硫柴油中添加300mg/kg时,磨斑直径从830μm降至386.6μm,且不影响低硫柴油的其他理化性质。     

水凝胶接触镜材料进展

采用水凝胶材料制造的角膜接触镜具有含水量高、配载舒适，透氧率高等特点，本文综述了各种水凝胶角膜接触镜材料的特点，并综述了水凝胶角膜接触镜材料的透氧机理、制备方法以及成型技术。     

水凝胶角膜接触镜材料及其应用

简要叙述了制造角膜接触镜的水凝胶类材料，并综述了水凝胶角膜接触镜成型技术以及水凝胶材料角膜接触镜的应用。     

Poly(HEMA-co-AAm)水凝胶对氯霉素的缓释作用

采用本体共聚法制备poly(HEMA-co-AAm)（甲基丙烯酸羟乙酯与丙烯酰胺共聚物）水凝胶,采用恒温释放方法研究了poly(HEMA-co-AAm)水凝胶对氯霉素的缓释作用。结果表明,随水凝胶中AAm组分的含量增大,水凝胶对氯霉素的吸收量增大,氯霉素的释放速率也相应增大;随缓释介质的pH值下降,氯霉素的释放速率增大;在初始释放阶段,氯霉素的迁移速率随水凝胶中AAm组分的含量增大而增大,但随后并无明显影响。     

Diffusive contribution to permeation of hydrogel contact lenses: theoretical model and experimental evaluation by nuclear magnetic resonance techniques

The biocompatibility of contact lenses is closely related to their oxygen permeability. In hydrogel lenses, this characteristic can be attributed to the water permeability resulting from a combination of viscous and diffusive fluxes. Hydrogel lenses were studied by means of nuclear magnetic resonance (NMR) relaxation times, resulting in a mathematical model which evaluated the water self-diffusion coefficient as a quantification of the diffusive contribution to permeation. Comparing the results obtained with the data of permeability to oxygen as measured by other techniques, a reasonable agreement was shown for lenses with a higher water content (WC) with respect to lenses with a lower WC: this difference was accounted for by considering the different contribution to permeation.     

A comparison of water binding and mobility in contact lens hydrogels from NMR measurements of the water self-diffusion coefficient

Measurements of the water self-diffusion coefficient were made for a set of nine commercially available contact lens hydrogels, both at equilibrium water content (EWC) and as a function of reduced water content, using the pulsed field gradient NMR method. The data were shown to lie approximately on a universal curve, suggesting that water content (WC) itself was the predominant factor in determining the water diffusion coefficient. However, fitting of the data to a specific binding model suggested that subtle differences in the diffusional behaviour existed between the materials. These differences were measured in terms of the proportion of specifically bound water (p_wb). It was shown that the calculated proportions could be correlated with the EWC, and that they agreed reasonably well with the proportion of non-freezing water measured for similar materials using DSC.     

Multifractal characterization of unworn hydrogel contact lens surfaces

Purpose: The aim of this work was to estimate the multifractal spectra of 3D surface roughness for unworn hydrogel contact lenses (CL), obtained with atomic force microscopy (AFM) analysis. Materials and methods: Contact lenses made from vifilcon A (Focus® Monthly Toric Visitint® model, CIBA Vision Corp.) were investigated. CL surface roughness was studied by AFM in tapping‐mode™, in an aqueous environment, on square areas ranging from 1 to 4 μm². A detailed methodology for CL surface multifractal characterization, which may be applied for AFM data, was presented. Results: The CL surface roughness revealed multifractal geometry at various magnifications. The generalized dimension D_q and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of CL surface geometry at nanometer scale. Conclusions: Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters. POLYM. ENG. SCI., 54:1066–1080, 2014. © 2013 Society of Plastics Engineers     

Lipase-catalyzed transesterification of ethyl ferulate with triolein in solvent-free medium

The lipase-catalyzed transesterification of ethyl ferulate with triolein in a solvent-free medium was investigated. Transesterification was catalyzed by immobilized lipase from Candida antarctica (Novozym 435), to form ferulyl oleins, a mixture of ferulyl diolein and ferulyl monoolein. These ferulated esters can be widely used as natural antioxidant in both lipid containing food and cosmetic applications. External mass transfer limitations were lowest, when the agitation speed was higher than 180 rpm. A linear relationship between the initial reaction rate and enzyme load up to 10% demonstrated that the internal diffusion limitations could be minimized. The effects of various parameters on yields and rates of reaction were studied in the absence of mass transfer limitations. The initial reaction rate increased when the reaction temperature was raised in the range of 45-65 °C, further increase to 70 °C decreased the final yield to 48.9%. The value of activation energy was calculated as 65.04 kJ/mol based on the Arrhenius law. Under the most favorable conditions, a kinetic model based on the ping-pong bi-bi mechanism with triolein inhibition was found to fit the initial reaction rate data very well and the kinetic parameters were evaluated by non-linear regression analysis.     

硅水凝胶隐形眼镜材料的合成与性能研究

以甲基丙烯酸羟乙酯（HEMA）、N-乙烯基毗咯烷酮（NVP）和γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH-570）为单体,以偶氮二异丁腈（AIBN）为引发剂,通过本体聚合反应合成新型硅水凝胶角膜接触镜.考察了各单体配比、反应温度等对聚合的影响.结果表明,当反应温度为90℃,反应时间为2h,V（HEMA）：V（NVP）：V（KH-570） =8∶ 1∶1时,合成的隐形眼镜透氧量（DK/t）达到64.0×10-9（cm3O2·cm）/（cm2·s·mmHg）,含水量38％,透光率95.5％以上.     

智能水凝胶应用研究进展

智能水凝胶是指在外界环境（如温度、pH、电场、溶剂性质、光强度和光波长、压力、离子强度等）发生变化时,性质随之发生相应变化的水凝胶,即具有环境响应性。作者详细介绍了智能水凝胶在药物控制释放、组织工程、物质分离、酶的固载及调光材料5个方面的应用研究情况。并对智能水凝胶未来的研究方向及应用前景进行了展望。     

智能水凝胶的研究进展

智能水凝胶是指在外界环境(如温度、pH值、电场等)发生变化时,性质随之发生相应改变的水凝胶,即具有环境响应性。水凝胶尤其是智能水凝胶由于其迷人的性质及潜在的应用引起广大科技工作者的研究兴趣。根据智能水凝胶对环境的响应情况,作者详细介绍了pH敏感性水凝胶、温度敏感性水凝胶、光敏感性水凝胶、电场敏感性水凝胶、磁敏感性水凝胶、盐敏感性水凝胶、化学物质敏感性水凝胶以及多重敏感性水凝胶的研究情况,同时对智能水凝胶的研究方向和应用前景进行了展望。