Material encapsulation in poly(methyl methacrylate) shell: A review

Material encapsulation is a relatively new technique for coating a micro/nanosize particle or droplet with polymeric or inorganic shell. Encapsulation technology has many applications in various fields including drug delivery, cosmetic, agriculture, thermal energy storage, textile, and self-healing polymers. Poly(methyl methacrylate) (PMMA) is widely used as shell material in encapsulation due to its high chemical stability, biocompatibility, nontoxicity, and good mechanical properties. The main approach for micro/nanoencapsulation of materials using PMMA as shell comprises emulsion-based techniques such as emulsion polymerization and solvent evaporation from oil-in-water emulsion. In the present review, we first focus on the encapsulation techniques of liquid materials with PMMA shell by analyzing the effective processing parameters influencing the preparation of PMMA micro/nanocapsules. We then describe the morphology of PMMA capsules in emulsion systems according to thermodynamic relations. The techniques to investigation of mechanical properties of capsule shell and the release mechanisms of core material from PMMA capsules were also investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48039.     

人工颅骨用复合材料中微量甲基丙烯酸甲酯的气相色谱法测定

采用氢气焰离子化检测器(FID),以正丁醇为外标物,PEG-20M为固定相,甲醇作为溶剂,气相色谱法测定复合材料人工颅骨中微量MMA的含量。其相对标准偏差<0.022,平均回收率(n=4)为98.0％～99.1％。此方法操作简便,用于实际样品分析可得到满意的结果。     

Study of the effect of BDMA catalyst in the epoxy novolac curing process by isothermal DSC

Epoxy novolac/anhydride cure kinetics has been studied by differential scanning calorimetry under isothermal conditions. The system used in this study was an epoxy novolac resin (DEN431), with nadic methyl anhydride as hardener and benzyldimethylamine as accelerator. Kinetic parameters including the reaction order, activation energy and kinetic rate constants, were investigated. The cure reaction was described with the catalyst concentration, and a normalized kinetic model developed for it. It is shown that the cure reaction is dependent on the cure temperature and catalyst concentration, and that it proceeds through an autocatalytic kinetic mechanism. The curing kinetic constants and the cure activation energies were obtained using the Arrhenius kinetic model. A suggested kinetic model with a diffusion term was successfully used to describe and predict the cure kinetics of epoxy novolac resin compositions as a function of the catalyst content and temperature. Copyright © 2003 Society of Chemical Industry     

纳米钛硅分子筛TS-1催化甲乙酮氨氧化合成甲乙酮肟

以纳米钛硅分子筛TS-1为催化剂，采用三口玻璃反应器研究了甲乙酮（MEK）氨氧化的反应性能。采用SEM、TEM和XRD等分析手段表征了TS-1的晶粒尺寸。考察了TS-1的晶粒尺寸、反应物的加料方式、溶剂、催化剂用量、反应温度和反应物料配比对甲乙酮氨氧化反应性能的影响。结果表明，甲乙酮氨氧化反应的最佳反应条件为：75℃，n（NH3）：n（H2O2）：n（MEK）=4．0：1．5：1．0，TS-1用量21．6g（以1mol MEK计）；H2O2和氨水连续进料，最佳溶剂为叔丁醇或叔丁醇和水的混和液。在最佳反应条件下，甲乙酮的转化率和甲乙酮肟的选择性可分别达到99．4％和99．8％。     

涂料用纯丙乳液的性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和甲基丙烯酸(MA)为主要原料,利用半连续乳液聚合工艺,制备了一种涂料用纯丙乳液基料;考察了乳化剂、引发剂用量及pH值对产物性能的影响。结果表明,当w(乳化剂)=3%,w(引发剂)=0.35%,pH在8~9左右时,涂膜的吸水率达到7.9%,残余单体量<0.5%,水稀释稳定性,钙离子稳定性,冻融稳定性均通过测试,纯丙乳液具有较好的综合性能。     

催化裂化装置生产异戊烯的模拟计算研究

应用HYSIM模拟软件,对催化裂化(FCC)装置获取碳五馏分的各种方案进行了研究,并对各方案的优缺点进行了评述。仅有一套FCC装置的炼油厂或者同时拥有几套FCC装置但各装置稳定汽油辛烷值接近的炼油厂,推荐采用塔底方案。炼油化工型企业可考虑塔顶方案或侧线方案。     

LaZSM5-Al-Mg催化剂上乙烯与甲苯烷基化制对甲基乙苯

以LaZSM5沸石为基质,添加铝和镁的氧化物所制得的择形催化剂,可大大提高乙烯与甲苯烷基化制甲基乙苯中对甲基乙苯选择性。考察了稀释气和反应产物的添加对烷基化反应的影响。失活后的催化剂可烧炭再生。     

甲醇气相羰化合成醋酸甲酯的产物分析

以热导池为检测器,分别采用8/100间苯二甲酸+GDX-103、Porapak-Q分析甲醇气相羰化的液相产物和气相产物,确定了气相色谱分析的操作条件,测定了各组分的校正因子,并应用于甲醇绿色羰化合成醋酸甲酯的催化剂评选,得到了满意的结果。     

MnCl_2/活性炭催化合成正丁基氨基甲酸甲酯

通过对不同活性组分的筛选,开发出活性炭负载氯化锰(M nC l2/AC)催化剂,用于碳酸二甲酯(DMC)和正丁胺甲氧羰基化反应合成正丁基氨基甲酸甲酯(MBC)。考察了M nC l2负载量对M nC l2/AC催化剂催化性能的影响及反应温度、反应时间、催化剂用量和原料配比对反应的影响。实验结果表明,适宜的M nC l2负载量为0.2mm ol/g;适宜的反应条件为:n(DMC)∶n(正丁胺)=3,催化剂的质量分数为5%,反应温度80℃,反应时间7h。在此条件下,正丁胺能完全转化,MBC的收率达到96.5%。探讨了不同载体负载的M nC l2催化剂的催化性能,发现中性载体有利于甲氧羰基化反应。     

N-油酰基肌氨酸钠对除盐水缓蚀性能的探讨

对N-油酰基肌氨酸钠单体的缓蚀性能以及与常用除盐水缓蚀剂的协同作用作了探讨,发现在一定浓度下,单体对经过加氨调节后的高温除盐水(氨后除盐水)有良好的缓蚀作用,且与大多数除盐水缓蚀剂有良好的协同效应。在此基础上研制了一种复合药剂,并对其缓蚀、阻蚀性能作了研究。动电位极化曲线扫描图谱表明,该复合药剂属于抑制阳极腐蚀的阳极型缓蚀剂,其适用的水质条件为[Cl~-+SO_4~(2-)]不超过50 mg／L,pH不低于8.0；与阻垢剂复配,可以适用于含Ca~(2+)不超过45 mg／L的水质条件。