季铵化壳聚糖包覆腐殖酸微胶囊的制备及性能

以季铵化壳聚糖(QCTS)为壁材、腐殖酸(HA)为芯材,制备了季铵化壳聚糖包覆腐殖酸(QCTS/HA)微胶囊。采用傅里叶变换红外光谱(FTIR)、偏光显微镜(POM)、扫描电子显微镜(SEM)对微胶囊的性能进行了表征。以芯壁比[m(HA)∶m(QCTS)]、固化剂硫酸钠的用量和搅拌速度作为单因素,探讨了微胶囊的最佳制备条件。并且对最佳制备条件下的微胶囊进行了形貌观测以及吸水性和保水性测试。结果表明,QCTS/HA微胶囊的最佳制备条件为:m(HA)∶m(QCTS)=3∶1,硫酸钠用量为QCTS/HA总质量的1.0%,搅拌速度为500 r/min;与相同制备条件得到的未改性微胶囊CTS/HA相比,改性后的QCTS/HA微胶囊包覆层表面孔隙结构比较完善,分布均匀,孔洞较多,具有更加优异的吸水性和保水性,其12 h的吸水率和保水率分别高达348%和208%。     

壳聚糖包覆腐殖酸微胶囊的制备及其保水性能研究

以壳聚糖(CTS)为壁材,腐殖酸(HA)为芯材,制备了壳聚糖包覆腐殖酸(CTS/HA)微胶囊保水材料。通过傅里叶红外光谱(FTIR)、偏光显微镜(POM)和场发射扫描电镜(SEM)分别表征和观察CTS/HA微胶囊的结构和表面形貌,探讨了不同芯壁比〔m(CTS)∶m(HA)〕、固化剂用量和搅拌速度对微胶囊表面形态的影响,并测试了CTS/HA的保水性能。结果表明,CTS/HA呈现包覆微胶囊结构,当m(CTS)∶m(HA)=1∶3、固化剂用量为CTS/HA总质量的1%、搅拌速度为500 r/min时,微胶囊具有较好的表面形态,且具有较好的吸水和保水性能,其12 h的吸水率和保水率分别高达248%和158%。     

复凝聚法制备石蜡相变储能微胶囊及其性能研究

以壳聚糖和阿拉伯胶为壁材,石蜡为芯材,采用复凝聚法制备相变储能微胶囊。通过单因素实验,探究pH、复凝聚反应时间、芯壳比、交联剂用量等对微胶囊包覆率及包覆效率的影响。使用扫描电子显微镜、傅里叶红外光谱仪、差示扫描量热仪和热重分析仪对微胶囊的形貌、化学组成及热性能进行研究。结果表明,在最优工艺条件下(pH=4.5,复凝聚反应时间20 min,芯壳比1.5∶1,交联剂用量2 m L)制备出的微胶囊粒径20~30μm之间,包覆率为52.84%,包覆效率为56.27%。壳聚糖/阿拉伯胶壁材对石蜡起到保护作用,使其耐热性提高。     

PVA/活性炭微胶囊复合膜的制备与性能研究

以壳聚糖为壁材、活性炭为芯材,采用乳化-固化法制备了壳聚糖包覆的活性炭微胶囊,并将其与聚乙烯醇(PVA)复合,得到PVA/活性炭微胶囊复合膜。利用光学显微镜、扫描电镜、红外光谱等手段确定了制备微胶囊的最佳工艺参数,并考察了微胶囊用量对PVA复合膜性能的影响。结果表明:当壳聚糖用量为1.5%,乳化剂用量为1.5%,油/水相比为5:1,交联剂用量为1.0 ml,芯壁比为1:2时,可制备出成球效果较好的壳聚糖包覆的活性炭微胶囊;活性炭经壳聚糖包覆后可提高其与PVA的相容性,少量微胶囊的添加即可有效改善PVA复合膜的力学、阻隔等性能。     

制备工艺条件对固化剂微胶囊性能的影响

以改性胺1618固化剂为囊芯、以脲醛树脂为壁材单体,采用界面聚合技术,成功制备了一种新型聚脲改性胺微胶囊固化剂。考察了芯壁质量比、反应体系p H及搅拌速率对微胶囊包覆率、分散性及分布情况的影响,确定最佳制备工艺条件。采用傅里叶变换红外光谱、扫描电镜及热重分析仪对微胶囊的化学结构及性能进行表征。结果表明,当芯壁质量比为0.8、反应体系p H为2~3、搅拌速率为0.5 kr/min,该条件下制备的微胶囊包覆率为66.7%,分散性及表面致密性好,其热稳定温度达到216℃。     

溶剂蒸发法制备改性胺固化剂微胶囊的研究

以改性胺固化剂(1618)为囊芯、聚醚酰亚胺(PEI)为囊壁,采用溶剂蒸发法制备了EP(环氧树脂)固化用PEI包覆1618微胶囊。研究结果表明:固化剂芯材已被微胶囊PEI壁材成功包覆,其热稳定温度为130℃;以明胶作为分散剂时,制得的固化剂微胶囊表面光滑,分散性较好;随着芯壁比的增加,固化剂微胶囊的表面变得光滑、致密,并且其平均粒径减小(当芯壁比从1.0∶2.0增至1.5∶1.0时,平均粒径由45.8μm减至24.7μm)。     

复凝聚法制备石蜡相变储能微胶囊及其性能研究

以壳聚糖和阿拉伯胶为壁材,石蜡为芯材,采用复凝聚法制备相变储能微胶囊。通过单因素实验,探究pH、复凝聚反应时间、芯壳比、交联剂用量等对微胶囊包覆率及包覆效率的影响。使用扫描电子显微镜、傅里叶红外光谱仪、差示扫描量热仪和热重分析仪对微胶囊的形貌、化学组成及热性能进行研究。结果表明,在最优工艺条件下(pH=4.5,复凝聚反应时间20 min,芯壳比1.5∶1,交联剂用量2 m L)制备出的微胶囊粒径20³0μm之间,包覆率为52.84%,包覆效率为56.27%。壳聚糖/阿拉伯胶壁材对石蜡起到保护作用,使其耐热性提高。     

明胶/阿拉伯胶复合凝聚法制备DCOIT微胶囊

以羟乙基纤维素(HEC)为乳化剂、明胶和阿拉伯胶为壁材、4,5-二氯-2-正辛基-4-异噻唑啉-3-酮(DCOIT)芯材、甲醛为固化剂、冰醋酸(HAc)和氢氧化钠(NaOH)为pH值调节剂,采用复合凝聚法制备了DCOIT微胶囊。通过单因素试验法探讨了壁材浓度、壁芯比、反应时间、pH值、搅拌速率和乳化剂类型等对微胶囊的粒径、稳定性和包埋率等影响。结果表明:当w(壁材)=3%、壁芯比=m(壳层单体)/m(核层单体)=3、反应时间为2 h、pH≤4.5和搅拌速率为1 000 r/min时,相应DCOIT微胶囊的性能相对最佳。     

溶剂挥发法制备聚砜包覆桐油自修复微胶囊

以聚砜为壁材,桐油为芯材,采用溶剂挥发法制备了聚砜（PSF）包覆桐油自修复微胶囊。考查了不同种类的分散剂、搅拌速度、芯壁比（芯材与壁材的质量比）等工艺参数对微胶囊性能的影响,通过扫描电子显微镜、光学显微镜和热重分析仪等对微胶囊的表观形貌、粒径、壁厚、包覆率和热稳定性能等进行表征。采用所合成的微胶囊制备了环氧树脂基防腐蚀涂层,并对其防腐蚀性能进行了评价。结果表明,30 ℃时,以明胶/聚乙烯醇复配体系作为分散剂,芯材与壁材质量比为1.3:1,搅拌速度为700 r/min时制备出的微胶囊表面光滑致密,粒径在130 μm左右,热稳定温度为350 ℃;盐雾实验结果表明,所制备的微胶囊自修复涂层具有良好的防腐蚀性能。     

脲醛树脂包覆环氧树脂微胶囊的制备及性能研究

制备了脲醛树脂包覆环氧树脂(EP-UF)微胶囊,探讨了芯材与壁材的质量比、工艺条件对微胶囊的性能影响,以及微胶囊对EP基体的修复过程与修复能力。结果表明,当脲甲醛预聚体的合成温度为70℃、EP和苯甲醇的质量比为10:3、芯材与壁材的质量比为0.8、乳化剂用量为5%-7%、分散搅拌速度为500r/min、pH=3时,所制得的EP-UF微胶囊的平均粒径约为55μm,囊壁的密闭性好、强度高,芯材的包覆率高、流动性好,微胶囊填充EP基体材料的拉伸强度、修复率较高。     

农药2,4-D微胶囊悬浮剂的研制

以脲醛树脂为壁材,采用原位聚合法制备2,4-D微胶囊悬浮剂。在固定合成脲醛树脂反应条件的基础上,通过改变成囊过程中囊心与囊壁比、固化剂种类及用量、搅拌速度、固化时间、固化温度、加酸时间、终点pH等的不同,进一步研究上述不同条件对微胶囊粒径大小、粒径分布范围、微胶囊包囊率的影响,从而筛选最优的成囊反应条件。实验结果显示该微胶囊能够满足实际需要。     

癸酸相变微胶囊的制备及热性能

以尿素、甲醛及癸酸为原料,利用原位聚合法制备了脲醛树脂包覆癸酸的相变微胶囊。以芯壁质量比、乳化剂用量、乳化转速及固化剂含量为变量设计正交实验,采用ESEM、FTIR和DSC分别表征癸酸微胶囊的微观形貌、化学结构及热性能,利用渗漏率实验测试癸酸微胶囊的防渗性能。结果表明,m(OP-10)∶m(Span-80)=4∶1的复合乳化剂有利于改善癸酸微胶囊颗粒特性。癸酸微胶囊P(芯壁质量比3∶2、乳化剂用量占芯材质量5%、乳化转速1400 r/min、固化剂间苯二酚用量占尿素质量12%)在微观形貌上分散良好且大小均一,相变潜热为123.91 J/g,渗漏率和包覆率分别为6.95%和69.7%,与癸酸微胶囊S(芯壁质量比1∶1、乳化剂用量占芯材质量6%、乳化转速1100 r/min、固化剂用量占尿素质量10%)相比,癸酸微胶囊P的渗漏率降低了57.2%,包覆率反而提高了132.3%,具有良好的热性能。     

Optimal preparation and characterization of poly(urea–formaldehyde) microcapsules

Microcapsules with epoxy curing agent were successfully prepared by an in‐situ polymerization route with epoxy resin and poly‐(urea–formaldehyde) as core and shell materials, respectively. The synthetic conditions were optimized by a comprehensive investigation on raw materials consumption, size distribution, and surface morphology. Preparation of microcapsules with high wrap ratio was also demonstrated. The as‐synthesized microcapsules were studied using various characterizations techniques, including optical microscope, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and contact angle meter. Spherical microcapsules (size: ～ 60 μm) with smooth surface were obtained when the stirring rate was 400 rpm and the amount of core materials is 76 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

微胶囊自修复砂浆的试验研究

为了解决混凝土开裂提高建筑物的使用寿命以及耐久性能,本文以脲醛树脂作为微胶囊囊壁、环氧树脂E-44作为微胶囊囊芯,采用原位复合法分两步合成微胶囊.本实验探究通过控制囊芯与囊壁质量比为3:10、尿素和甲醛的摩尔比为4:1、温度85 ℃、搅拌时间为3 h等因素,配制出结构完整致密的微胶囊.双掺固化剂和微胶囊制备不同微胶囊掺量的自修复砂浆,探究固化剂和微胶囊掺量对自修复砂浆强度的影响,并对自修复砂浆试件施加不同比例的预压力和空白试验做对照以探究自修复砂浆强度的影响因素以及修复率高低.研究表明,当微胶囊掺量为6%、预压力为50%时自修复砂浆的修复率最高.     

Preparation and curing behavior of latent 2-PhIm-PS microcapsule curing agent for epoxy resin

A core–shell microcapsule latent epoxy curing agent (2-PhIm-PS) is obtained by solvent evaporation method with 2-phenyl imidazole (2-PhIm) as the core material and polystyrene (PS) as the wall material. The microcapsule parameters, morphology, structure, curing behavior, and the mechanic properties of cured epoxy resin with this microcapsule latent curing agent were characterized through comparing with 2-PhIm. The particle size distribution of the microcapsule is narrow, the average particle size is about 10.56 μm, and the core material content is 23%. The prepared 2-PhIm-PS microcapsule curing agent has excellent latent curing properties. It can completely cure epoxy resin E-51 within 10 min at 130°C, and its latent period can be more than 40 days at room temperature. In addition, the curing kinetics of one-component epoxy resin curing system (E-51/2-PhIm-PS) composed of 2-PhIm-PS microcapsules and epoxy resin E-51 is also studied by using Kissinger equation, Flynn–Wall–Ozawa and Crane formula. The results provide an outline for the evaluation on the applicability of the microcapsule curing agent of 2-PhIm-PS for epoxy resin.     

成囊工艺对环氧树脂微胶囊形成状态影响

研究了分散、乳化条件及成囊工艺对以苯乙烯为壁材,采用原位聚合法制备苯乙烯微胶囊状态的影响。讨论了不同乳化剂及其配比,不同乳化分散时间、搅拌速度和固化温度对微胶囊的包覆率、粒径的大小及分布情况的影响,最终确定以阿拉伯树胶和DBS按1∶3的比例混合作为乳化剂,1500 r/min搅拌,分散乳化60 min,85℃固化3 h作为制备环氧树脂微胶囊的优化工艺条件。在此条件下得到平均粒径为15μm左右,粒度分布均匀的球形微胶囊,包覆率在80%以上。     

水泥基用相变微胶囊的颗粒特征与热力学性能

以石蜡、癸酸为芯材,脲醛树脂为壁材,间苯二酚为固化剂,采用原位聚合法制备相变微胶囊,采用ESEM、DSC、TGA来研究相变微胶囊颗粒形貌、粒径分布、热力学性能,以及相变微胶囊掺入水泥基体中的微观形貌.结果表明:微胶囊表面光滑,结构紧致;石蜡微胶囊的相变温度和相变焓分别是54.6℃和61.43 J/g,而癸酸微胶囊的相.变温度和相变焓分别是29.7℃和90.73 J/g;加入固化剂使得微胶囊产率从50％提升到78％以上;30次温度循环石蜡微胶囊相变晗无损失,癸酸微胶囊相变焓损失了31％;微胶囊在水泥基中分布均匀,形貌保存良好.     

Preparation and characterization of controlled-release microencapsulated acids for deep acidizing of carbonate reservoirs

Based on the deficiency of traditional acidification or acid pressure technology in the development of carbonate oil and gas resources, a microcapsule which wraps hydrochloric acid and can be released through temperature control was prepared by using microcapsule technology. The microcapsules were prepared with polyurethane prepolymer (PUA) and 1,6-hexadiol diacrylate (HDDA) polymer as wall material and hydrochloric acid as core material by two emulsification and photocatalysis methods. Its parcel rate is 61.9%. Fourier transform infrared spectroscopy characterization confirmed the successful photopolymerization of PUA prepolymer and HDDA in a strong acid environment. The microscopic morphology analysis of electron microscope showed that the microcapsule was regular and uniform spherical with smooth and dense surface. The particle size analysis showed that the microcapsules were mainly distributed between 40 and 300 μm, and the average particle size was 114.02 μm.The glass temperature of microcapsule wall material was 97°C by DSC method. The release rate of microcapsules was accelerated with the increase of release temperature. The cumulative release rate of acid solution of microcapsules for 3 h reached 28.4%, and the final release rate of microcapsules for 12 h reached 90.7% under 100°C. In addition, the release of microcapsules is less affected by the formation salinity. At 90°C, the maximum release rate of 7.5 g/L CaCL₂ was 49.1%, lower than that of 59.4% in pure water, showing the good salt resistance of the wall materials of microcapsules.     

Preparation of hydroxyapatite/Ca‐alginate composite microspheres via inverse suspension crosslinked method

Composite microspheres were prepared with hydroxyapatite (HA) and Na‐alginate (ALG) via inverse suspension crosslinked method (ISCM). Chloroform/hexane (1 : 2 (volume)) was used as continuous phase, ethyl cellulose (EC) as disperser, mixture of HA powder and ALG solution as dispersed phase, and calcium chloride as crosslinking agent. Morphology of the composite microspheres and HA distribution state were observed by optical microscope. According to the compositions studied, the sample with 0.2 g of EC gives the best continuous phase. The sample with 25 mL/min of adding speed and 120 r/min of stirring speed gives the best adding and stirring conditions. Two kind of the composite microspheres of 50/50 and 70/30 HA/ALG were prepared via ISCM. They are with specific gravity of 1.06 and 1.15, and water content of 88 and 81%, respectively. The size of the dried microspheres is mainly in the range of 125–425 μm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2034–2038, 2007