乙基纤维素-艾叶粉溶液微胶囊的制备及缓释性能研究

文章首次以乙摹纤维素为壁材,采用溶剂蒸发法制得艾叶粉水溶液微胶囊.正交实验得出制备微胶囊的最佳工艺条件为:乙基纤维索:芯材:乙酸乙酯:水相=1:2.5:13:130(质量比),搅拌速度:1500 r/min,乳化时间:15 mim,水油两相混合搅拌时间:10 min.通过扫描电镜表征结果显示,所得微胶囊固体颗粒呈球形,分散性好,粒径在20～200 μm范围内.实验制得微胶囊最大载药量为48.07%,具有良好的包覆效果.透析缓释实验表明,微胶囊在37.0℃恒温生理盐水浸泡60 h后,仍有艾叶药理活性成分存在,较好地延长了储藏时间和药物有效作用时限.     

壳聚糖/乙基纤维素微胶囊的制备及特性

In this work a system which consists of chitosan microcores entrapped in ethylcellulose is presented.Vitamin D2 was eficiently entrapped in chitosan microcores with spray-drying method and was microencapsulated by coating of ethylcellulose.The average size of chitosan microspheres was 6.06μm.The morphology and release properties of microcapsules were tested.The results of release in vitro showed that the microcapsule could realize sustained release for 12h in artificial intestinal juice.     

乙基纤维素-艾叶粉溶液微胶囊的制备

文章首次以乙基纡维素为壁材,采用溶剂蒸发法制得艾叶粉水溶液微胶囊。正交实验得出制备微胶囊的最佳工艺条件为：乙基纤维素：芯材：乙酸乙酯：水相=1：25：13：130（质量比）,搅拌速度：1500r／min,乳化时间：15mim,水油两相混合搅拌时间：10min。通过扫描电镜表征结果显示,所得微胶囊固体颗粒呈球形,分散性好,粒径在20-200μm范围内。实验制得微胶囊最大载药量为48．07％,具有良好的包覆效果。透析缓释实验表明,微胶囊在3.0℃恒温生理盐水浸泡60h后,仍有艾叶药理活性成分存在,较好地延长了储藏时间和药物有效作用时限。     

基于乙基纤维素构建缓释型NaCl微胶囊及性能研究

以氯化钠为囊芯材料,乙基纤维素(EC)为微胶囊壁材,通过乳化-溶剂挥发法制备缓释型融雪剂NaCl/EC微胶囊。利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、热分析仪(TG)和电导率仪对NaCl/EC微胶囊的微观形貌、包封效能和缓释性能进行表征,考察微胶囊形成参数(搅拌速度、溶剂挥发温度、NaCl掺量)对缓释性能的影响。结果表明,在搅拌速度400 r/min,溶剂挥发温度30℃,NaCl与EC质量比为2∶1的优化条件下,制得的NaCl/EC微胶囊产物呈规则球形,分散均匀,表面光滑,缓释效果较好。     

微胶囊化红磷阻燃剂的制备

１前言红磷（Ｐｎ）是磷原子聚合体组成的产物，是黄磷在隔绝空气下加热转化而制得的紫红色无定形粉末。无毒无臭，着火点为２４０℃，具有阻燃作用。但在实际应用中，未进行表面处理的红磷用作阻燃剂时存在如下缺点：（１）红磷暴露在空气中，将和空气中的水分作用而发生氧化还原不均化反应，在红磷粒子表面上形成磷的氧化物或酸，同时放出剧毒的磷化氢。由于这种反应伴随放热，在大量储存时，会因内部高热而自燃。（２）红磷对热、摩擦和冲击相当敏感，在树脂或橡胶混炼、模塑等工艺的操作过程中存在着火的危险，且单纯的红磷和基材相容性…     

半胱氨酸盐酸盐-乙基纤维素微胶囊的制备研究

选用半胱氨酸盐酸盐作为芯材,乙基纤维素作为壁材,采用有机溶剂蒸发技术制备微胶囊。通过单因素实验和正交分析得到最佳实验条件:壁材浓度为1%,海藻酸钠保护液浓度为0.5%,乙酸乙酯做溶剂,油水相比为5∶1,搅拌速度为1000 r/min,时间为2 h时得到的微胶囊的包埋率最高,粒径最小,分布最均匀。     

氢氧化铝微胶囊化红磷的制备及其性能研究

红磷作为一种阻燃剂,由于其具有含磷量大,来源丰富等优点而被广泛的使用,但由于其不稳定,颜色较深等缺点限制了它的使用范围。利用氢氧化铝作为囊材对红磷进行微胶囊化处理,并对其微胶囊化条件通过正交实验进行了优化。氢氧化铝包覆红磷的最佳包覆条件为:pH=5.5,分散剂含量为0.234g,OP-10/十二烷基硫酸钠的比例为1∶3,包覆时间为2h,包覆温度65℃,Al2(SO4)3含量为15%。     

红磷阻燃剂微胶囊化研究进展

综述了微胶囊红磷阻燃剂的研究进展情况,讨论了其目前所存在的问题,指出了微胶囊红磷阻燃剂的发展趋势。     

微胶囊红磷膨胀型阻燃剂的制备及应用

制备了微胶囊红磷/季戊四醇/三聚氰胺膨胀型阻燃剂(IFR)。采用吸湿性、抗氧化性、SEM、TG等测试方法对阻燃剂进行了表征。结果表明:微胶囊红磷的吸湿性减小、抗氧化性增强;TG分析显示,微胶囊红磷在385~422℃、470~553℃有两个失重阶段;600℃时,未包覆红磷残重仅为6%,而微胶囊包覆红磷的残重为12%;微胶囊红磷膨胀型阻燃剂的最佳组成为:微胶囊红磷:季戊四醇:三聚氰胺=4.00:0.75:2.00(摩尔比);500℃下,IFR残重高达65.06%;当IFR添加量为30%时,阻燃环氧树脂的氧指数从未添加IFR时的19.0%提高到26.3%。     

乙基纤维素包覆活性炭微粒的制备与表征

对兼具吸附和催化剂载体功能的多孔结构活性炭,以乙基纤维素为材料用相分离进行包覆。利用扫描电镜、热重分析仪、静吸附仪以及自动物理吸附仪对乙基纤维素包覆活性炭前后的表面形貌特征、比表面积和静吸附性能等进行了评价。结果表明,包覆后活性炭对低浓度苯蒸气静吸附性能基本无影响,比表面积和总孔容降低甚微。     

Interaction between iodine and ethyl cellulose

Interaction between iodine and ethyl cellulose was investigated by immersing ethyl cellulose membranes in aqueous iodine–iodide solution (iodine doping) and incorporating iodine in the solution from which the membrane was cast. Oxygen and nitrogen permeabilities in iodine‐doped ethyl cellulose decrease with an increase in the concentration of iodine in the dopant solution up to 0.003 mol L⁻¹ and increase sharply at higher iodine concentrations, and ultraviolet–visible and far‐infrared spectra indicate formation of a charge transfer complex. Differential scanning calorimetry of both types of membrane shows changes in the characteristic phase transitions of ethyl cellulose after iodine treatment, including the crystal–liquid crystal transition that has been reported to occur in ethyl cellulose. Further evidence for liquid crystal phases has been found from circular dichroism. X‐ray photoelectron spectroscopy of iodine‐doped ethyl cellulose films indicates that the iodine is present in two different chemical states, probably l and l₂. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1303–1314, 1999     

NaCl-EC微胶囊的制备及缓释性能研究

以乙基纤维素(EC)为壁材,NaCl为芯材,聚乙烯(PE)为添加剂,采用油相分离法制备了NaCl-EC微胶囊。最佳条件为:选用乙基含量为48%~49.5%,黏度为200cP的EC,浓度为2.4%,NaCl与EC的用量比为1∶5,PE用量为0.45%,搅拌速率为450r.min-1,采用水浴缓慢降温方式。筛选出最佳工艺条件下制备的粒径在80~120目的微胶囊,研究了其在25℃下的释放性能。囊芯释放百分率以2.03%~56.47%之间,按零级动力学方程进行,64h后累计释放量为70.45%。     

脲醛树脂微胶囊包覆红磷阻燃剂制备工艺的研究——Ⅱ．包覆工艺研究

研究了脲醛树脂的预聚物通过原位聚合对红磷进行包覆的一些影响因素。实验表明,影响包覆条件的主要因素是预聚物与水的质量比、包覆温度、pH值和包覆时间。通过正交实验得到了进行微胶囊包覆的最佳条件为：红磷与水的质量比为1∶30,反应温度为75℃,pH值为3．5,反应时间为2h。颜色为白色,吸湿量为4．01％,用微胶囊红磷去阻燃聚氯乙烯,当含量为9．0％时,在500℃下残余物为14．45％。     

乙基纤维素与聚苯乙烯共混体系的相溶性研究

用紫外光谱、X射线衍射和DSC、偏光显微锐、相差显微镜和电镜等方法研究了乙基纤维素-聚苯乙烯共混体系的相溶性。结果表明该体系为部分相溶体系。     

MQ硅树脂微胶囊红磷阻燃剂的制备工艺研究

采用原位聚合法制备了MQ硅树脂微胶囊红磷阻燃剂,并用差示扫描量热仪(DSC)对产品的热分解温度进行表征。探讨了相关工艺条件对产品热分解温度的影响,所得优惠工艺条件:M/Q值为0.6,水用量为8倍的六甲基二硅氧烷(MM)和正硅酸乙酯(TEOS)物质的量之和,无水乙醇与六甲基二硅氧烷的质量比为0.9,盐酸用量占总物料质量的1%,反应温度为65℃,反应时间为4.0 h。在优惠工艺条件下所得产品的热分解温度为257.6℃。     

Mechanical and thermal properties of EVA blended with biodegradable ethyl cellulose

In this study, biodegradable blend of Poly (Ethylene‐co‐Vinyl Acetate) (EVA) and Ethyl Cellulose (EC) were prepared. Ethylene vinyl alcohol (EVOH) copolymer was used as an interfacial compatibilizer to enhance adhesion between EVA and EC. The melt blended compatibilized biocomposites were examined for mechanical and thermal properties as per the ASTM standards. It has been found that the EC has a reinforcing effect on EVA leading to enhanced tensile strength and also impart biodegradability. Thus, a high loading of 50% EC could be added without compromising much on the mechanical properties. Analysis of the tensile data using predictive theories showed an enhanced interaction of the dispersed phase (EC) and the matrix (EVA). The compatibilizing effects of EVOH on these blends were confirmed by the significant improvement in the mechanical properties comparable with neat EVA as also observed by SEM microscopy. The TGA thermograms exhibits two‐stage degradation and as EC content increases, the onset temperature for thermal degradation reduces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

脱铝超稳Y沸石负载Cu催化纤维素醇解合成乙酰丙酸乙酯

以非缓冲体系下柠檬酸脱铝改性的USY分子筛为载体,铜为金属活性组分,采用浸渍法制备脱铝超稳Y沸石负载Cu。考察了该催化剂对纤维素醇解制备乙酰丙酸乙酯（EL）的催化活性。在反应温度为200℃、反应时间为3 h的条件下,催化纤维素转化生成EL的产率为48.2%。通过XRD、FT-IR、BET、NH₃-TPD、Py-IR和TG-DTA对催化剂进行表征,结果表明,Cu-DUSY催化剂热稳定性好,晶体结构稳定。Cu-DUSY回收利用4次EL产率仍可保持40%以上,具有较好的催化活性。     

Effect of solvent on morphology of electrospinning ethyl cellulose fibers

The influence of the composition of a multicomponent solvent on the surface morphology and diameter distribution of ethyl cellulose fibers produced by electrospinning technology was investigated. The results showed that the average diameter of the fibers using the multicomponent solvent was thinner than when using either of the two components and the diameter distribution of the fibers became narrower. Tiny tubercles formed on the fiber surface, which may improve the specific surface area and broaden the applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1292–1297, 2005     

脲醛树脂微胶囊包覆红磷阻燃剂制备工艺的研究 Ⅰ.预聚物合成工艺研究

研究了脲醛树脂的预聚物通过原位聚合对红磷进行包覆的一些影响因素。实验表明影响预聚物质量的主要因素是第一阶段尿醛比(F/U)1,第二阶段尿醛比(F/U)2,反应温度和pH值。制备预聚物的最佳条件为:第一阶段尿醛比为2.3∶1(摩尔比),第二阶段尿醛比为1.3∶1(摩尔比),pH值为5.1,反应温度为75℃。制备的预聚物来包覆红磷,颜色为白色;用微胶囊红磷阻燃聚乙烯,当含量为9%时,在500℃下残余物为4.85%。