石蜡基微胶囊相变材料研究进展北大核心CSCD

本文从微胶囊壁材出发,重点介绍了石蜡基/高分子、无机和高分子-无机杂化壳微胶囊的制备及应用,并总结了上述微胶囊的优势和不足。其中石蜡基/高分子壳微胶囊的壁材包括三聚氰胺-甲醛树脂、脲醛树脂、三聚氰胺-甲醛-尿素树脂、聚氨酯树脂、丙烯酸树脂等,石蜡基/无机壳微胶囊的壁材包括二氧化硅、二氧化钛、碳酸钙、氧化锌等,石蜡基/高分子-无机杂化壳的壁材包括三聚氰胺-甲醛树脂、三聚氰胺-甲醛-尿素树脂、丙烯酸树脂等与二氧化钛、二氧化硅等无机粒子复合。并对石蜡基微胶囊相变材料的未来发展方向和应用前景进行展望,以期为今后研究提供借鉴。     

药用微胶囊的制备

微胶囊技术是21世纪重点研究开发的高新技术之一,用途广泛。本文综述了微胶囊的制备原理及方法,着重阐述了采用超临界二氧化碳技术和溶剂蒸发法制备药物微胶囊的最新研究进展,介绍了超临界流体快速膨胀(RESS)法、超临界流体抗溶剂(SAS)法和气体饱和溶液微粒制备(PGSS)法的特点,总结了溶剂蒸发法制备微胶囊的原理和溶剂蒸发法制备药物微胶囊的工艺研究现状,分析了药物微胶囊的表征方法及性能,并对今后微胶囊技术的发展作了展望。     

微胶囊技术在生物医药中的应用

综述了微胶囊的制备原理,介绍了微胶囊主要制备技术,包括超临界流体技术和溶剂蒸发法在制备药物微胶囊中的应用,并对以后微胶囊技术的发展作了展望.     

高芯材含量聚苯乙烯石蜡微胶囊的制备及性能研究

为解决石蜡在使用过程中的一系列问题,以聚苯乙烯为壁材,58~#石蜡为芯材,采用悬浮聚合法制备了高芯材含量的微胶囊.考察了二己烯基苯(DVB)用量、芯壁比、复合改性时共聚单体种类和用量对微胶囊的影响.采用FT-IR、SEM、DSC、TG表征了微胶囊的结构、形貌、储热性能及热稳定性能.实验结果表明,DVB用量11%、芯壁比3∶1制备的微胶囊大小均匀,无团聚现象;交联改性的同时,加入20%MA单体共聚改性制备的微胶囊形貌好,热稳定性最佳,微胶囊中石蜡含量为91.7%时储热性能最优.     

生物农药微胶囊壁材料研究

用原位聚合法对生物农药阿维菌素进行包囊,然后制备微胶囊制剂,并对用于该制剂的两种高分子囊壁材料-三聚氰胺甲醛树脂和脲醛树脂的性能进行了研究。结果表明,两种树脂皆为较好的生物农药用微胶囊缓释剂型的囊壁材料,其制备工艺简单,具有良好的稳定性、粒径大小与分布、悬浮性、缓释性等,包封率均达80％以上。其中三聚氰胺甲醛树脂悬浮性较脲醛树脂更好,缓释性更持久。     

纳米二氧化硅改性石蜡微胶囊相变储能材料的研究

以石蜡为芯材,甲基丙烯酸甲酯-丙烯酸共聚物为壁材,纳米SiO2为改性剂,采用原位聚合法制备了石蜡微胶囊相变储能材料,系统研究了添加纳米SiO2对石蜡微胶囊相变材料性能的影响;采用傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、示差扫描量热法(DSC)和热重分析(TGA)等对石蜡微胶囊相变材料的化学结构、表面形貌和热性能进行了表征.研究表明,纳米SiO2能够有效提高微胶囊壁材的热稳定性,当丙烯酸酯壁材中添加3％改性纳米SiO2时,微胶囊呈球形且表面光滑,尺寸250 ～ 300 nm,具有良好的储热能力,相变潜热高达134.79 J/g,分解温度比未添加改性纳米SiO2的石蜡微胶囊提高了40 K,经过1000次热循环测试,石蜡渗漏率仅2.96％.     

多室结构微胶囊的制备及应用研究进展

多室结构微胶囊是近年发展起来的一种新型多功能材料,它拓展了单室结构微胶囊的功能,推动了药物靶向传递、微反应器、细胞治疗、复杂传感器等领域的研究与发展。本文综述了近年来多室结构微胶囊的研究进展,重点讨论了其制备方法,主要包括层层自组装法、复合流体电喷法及微流体双乳化法,分析了不同制备方法的特点;介绍了多室结构微胶囊在智能药物运输、微容器、基因及细胞治疗等领域的应用,指出了该领域研究存在的问题及今后的发展方向。     

脲醛树脂微胶囊的改性

为了提高脲醛树脂微胶囊的稳定性,选择化学结构不同的聚乙烯醇、苯酚、三聚氰胺对脲醛树脂进行了改性.通过优化反应条件,得到了具有良好耐热、耐水性的脲醛树脂微胶囊.采用光学显微镜观测了微胶囊的形貌;用FT-IR表征了微胶囊的化学结构;用TGA分析了微胶囊的热性能.研究结果表明:3种改性后的微胶囊的热稳定性均有所提高,其中苯酚改性的微胶囊热稳定性最好;聚乙烯醇改性微胶囊的疏水性下降,苯酚和三聚氰胺改性的微胶囊的疏水性都有所增强.     

原位聚合法制备厌氧胶固化引发剂微胶囊

采用原位聚合法制备了以脲醛树脂为壁材、过氧化苯甲酰为芯材的厌氧胶固化引发剂微胶囊。研究了乳化剂聚丙烯酸钠、十二烷基苯磺酸钠、阿拉伯树胶、苯乙烯-马来酸酐共聚物的单独使用及阿拉伯树胶与苯乙烯-马来酸酐共聚物的复配组合和其它工艺条件对微胶囊制备的影响;运用FT-IR、TG和SEM等测试技术对微胶囊进行了表征。结果表明,以苯乙烯-马来酸酐共聚物和阿拉伯树胶作为复合乳化剂,反应终点pH值为1.5左右,反应温度70℃,反应时间4 h,搅拌速率1 000 r/m in,可制得分散适中、形貌较好、粒径约为100μm的微胶囊。以实验制备的微胶囊配制成可预涂厌氧胶胶液,性能可以达到国外公司同类产品的技术指标。     

电泳显示微胶囊的制备和性能

以有机颜料联苯胺黄为显色粒子, 四氯乙烯和甲苯混合溶液为分散介质, 油溶性蓝N为吸光染料, 用超分散剂CH-2C分散颜料粒子, 脲醛树脂为壁材, 通过一步原位聚合法制备了电泳显示微胶囊. 通过显微镜检查微胶囊的表面形貌及粒径, 并对微胶囊内颜料粒子的电场响应特性和显示性能进行考察. 结果表明, 所得微胶囊表面光滑, 囊壁透明, 囊内颜料粒子对电场变化能够快速可逆地响应, 并具有双稳显示特性.     

蓄热调温石蜡相变微胶囊的制备及性能

采用界面聚合法,以甲苯2,4-二异氰酸酯和哌嗪为反应单体、30号相变石蜡为芯材,制得了一种智能纺织品用蓄热调温相变微胶囊。通过红外光谱、扫描电镜、差示扫描量热仪对微胶囊的化学组成、形貌和蓄热性能进行了表征,测试了其耐热和耐溶剂性。结果表明:所得微胶囊主要为球形,表面光滑,平均粒径为10.6μm,对w=0.40的NaOH溶液、w=0.60的H2SO4溶液、无水乙醇、丙酮稳定,能被甲苯、二甲基甲酰胺、乙醚破坏。相变潜热为118 J/g,石蜡在微胶囊中的质量分数为84%。     

Preparation,characterization, and thermal properties of microPCMs containing <Emphasis Type="Italic">n</Emphasis>-dodecanol by using different types of styrene-maleic anhydride as emulsifier

Microcapsules containing polar phase change material (PCM) n-dodecanol were synthesized by in situ polymerization using melamine-formaldehyde resin as shell and styrene-maleic anhydride copolymer (SMA) as emulsifier. The effects of polarity of PCM and types and amounts of SMA emulsifier on the properties of microencapsulated PCMs (microPCMs) were studied and characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and laser particle diameter analyzer. The results show that thermal properties of microPCMs are affected greatly by the types and amounts of SMA. Anionic SMA emulsifier is suitable for the encapsulation of n-dodecanol. The polarity of PCM leads to the higher adding amount of SMA emulsifier. When mass ratio of emulsifier to n-dodecanol is 4.8%, the phase change latent heat and encapsulation efficiency reach to the maximum value of 187.5 J/g and 93.1%, respectively. Irregular spherical microPCMs with mean diameter of 30.6 μm and phase change temperature of 21.5 °C are obtained and can be used for energy storage.     

Thermal performance evaluation of a solar air heater with and without thermal energy storage

This communication presents the experimental study and performance analysis of a solar air heater with and without phase change material (PCM) viz. paraffin wax and hytherm oil. There are three different arrangements viz. without PCM, with PCM and with hytherm oil to study the comparative performance of this experimental system. Inlet, outlet temperatures and radiation with respect to time have been recorded and found that the output temperature in case with thermal energy storage (TES) is higher than that of without TES, besides, the outlet temperature with paraffin wax is slightly greater than that of with hytherm oil. Also there is no energy gain in the evening in case of without TES but in case of with TES there is a heat gain for around 4 h in the evening which gives the backup for hot air for around four more hours which is the main advantage of this systems with TES. Based on the data, the efficiency of the system has been calculated and it is noted that the efficiency in the case of heat storage is higher than that of without TES, besides the efficiency in the case of the paraffin wax is slightly higher than that of the hytherm oil case.     

石蜡/碱改性硅藻土/膨胀石墨复合相变储热材料的制备及性能

通过碱处理,优化了硅藻土(DIA)的孔隙结构,提高了孔隙率,增加了石蜡(paraffin)负载量。通过直接浸渍法制备了新型性状稳定的石蜡/碱改性DIA/膨胀石墨(EG-alDIAP)复合材料,并研究了其结构与性能的关系。结果表明,复合相变材料的石蜡负载量从47.4%提高到了61.1%,进而提高了复合材料的储热性能;向改性DIA中添加膨胀石墨(EG)提高了复合材料的传热能力,添加质量分数10%EG时导热系数提高了113%(从0.276 W·m^-1·K^-1提高到了0.589 W·m^-1·K^-1)。随着EG含量的升高,复合相变材料的相变潜热有所增加,但化学相容性、稳定性等无明显变化。含10%EG的石蜡/碱改性DIA复合材料具有可靠的储能性能、良好的温度调节性能和蓄放热能力。     

石蜡/碱改性硅藻土/膨胀石墨复合相变储热材料的制备及性能

通过碱处理,优化了硅藻土(DIA)的孔隙结构,提高了孔隙率,增加了石蜡(paraffin)负载量。通过直接浸渍法制备了新型性状稳定的石蜡/碱改性DIA/膨胀石墨(EG-alDIAP)复合材料,并研究了其结构与性能的关系。结果表明,复合相变材料的石蜡负载量从47.4%提高到了61.1%,进而提高了复合材料的储热性能;向改性DIA中添加膨胀石墨(EG)提高了复合材料的传热能力,添加质量分数10%EG时导热系数提高了113%(从0.276 W·m^-1·K^-1提高到了0.589 W·m^-1·K^-1)。随着EG含量的升高,复合相变材料的相变潜热有所增加,但化学相容性、稳定性等无明显变化。含 10%EG的石蜡/碱改性 DIA复合材料具有可靠的储能性能、良好的温度调节性能和蓄放热能力。     

Detection of joint capsule changes by differential scanning calorimetry (DSC) in different types of hip disorders to evaluate surgical techniques (a preliminary report)

In this study, paraffin-/ultrasonic-treated diatomite was characterized for use as phase change material (PCM) for thermal energy storage in buildings. The diatomite was treated with ultrasound at various periods of time. The diatomite treated with ultrasound for 60 min (DA-60) was the optimum condition providing the highest surface area without structural degradation. The melting point and latent heat of the paraffin/DA-60 composite PCM were 59 °C and 45.90 J g^?1, respectively. The obtained form-stable PCM had good thermal reliability after 500 cycles of thermal cycling test. The thermal performance of PCM was tested by incorporating the paraffin/DA-60 composite PCM into gypsum board. The results showed that the gypsum board containing the paraffin/DA-60 composite PCM had better thermal energy absorption and release characteristics than those of the control sample. The incorporation of paraffin/DA-60 composite PCM into suitable building materials could thus considerably reduce the energy consumption of cooling system in buildings.     

正十六烷聚脲微胶囊化相变材料

用界面聚合法，合成了直径大约2.5 μm可用于热能储存含相变材料的聚脲包覆微胶囊.在含乳化剂的水溶液中，将溶有芯材正十六烷的有机相乳化成微米级油性液滴，随后加入的水溶性单体二胺与甲苯2,4-二异氰酸酯在胶束界面相互反应形成囊壁.分别用乙烯二胺，1,6-己二胺和它们的混合物作为水溶性单体进行了研究.并用红外光谱和热分析分别考察了不同胺类对微胶囊化学结构和热性质的影响.红外谱图显示合成了聚脲微胶囊，热重曲线表明含正十六烷的聚脲微胶囊能够耐受大约300 ℃高温，差示扫描量热测试表明所有样品均具有合适的相转变热，冷热循环实验揭示微胶囊能够维持储热容量不衰减.研究表明微胶囊化的正十六烷作为相变储热材料具有良好的应用前景.     

Thermodynamics and performance evaluation of encapsulated PCM-based energy storage systems for heating application in building

This communication presents the comparative study of two different types of thermal management systems for room’s heating applications using calcium chloride hexahydrate as the thermal energy storage material encapsulated in panels and balls. During the daytime, TMS was outside the test room to store the solar heat in TMS. The solar heat made available to charge the PCM from solid to liquid and to warm the test room throughout the observation period during night time. As the room temperature drops significantly during the night time, so as the level of comfort. Both the thermal management systems have been used to heat the test room during night time and the temperature of the test room has been maintained at thermal comfort level without any conventional source of energy, i.e. using passive system. Also the experimental values were compared with those of the theoretical values and are found in good agreement with each other. Thus, it can be concluded that the experimental study carried out for both the thermal management systems have been validated by theoretical approach or vice versa and hence found to be satisfactory towards the successful operation of these systems.     

换热器与相变材料的兼容性研究进展

相变材料是一类以潜热实现能量存储释放的储能材料,由于其在相变温度附近具有很大的储热密度,相变材料可以被用于建筑控温、太阳能热发电和高温传热蓄热等应用中。 换热器是相变储能设备的重要组成部分,可以将热量在供需两端进行传递和转移,保障需求一方的使用,随着相变材料研究的不断深入及其工程应用的广泛普及,换热器已在众多相变储能项目中发挥了重要的枢纽作用。 为了保证换热器的使用性能,需要对换热器在相变材料中的防腐蚀性进行全面的分析。 本文总结了大量国内外的文献,分析不同成分的相变材料对换热器材料的腐蚀性,为换热器材料的选择提供了参考。     

水合盐相变储能材料的研究进展

无机水合盐相变储能材料具有相变潜热大、相变温度适中、价格低廉等优点,在太阳能高效利用、跨季节储热采暖、工业余废热利用、轻纺行业等方面具有广阔的应用前景。但过冷、相分离、导热系数低等问题限制了其实际应用。本文介绍了水合盐相变储能材料近年来的研究进展,分析了水合盐相变存在的过冷及相分离现象的原因。通过成核剂法、多孔基体吸附法、微胶囊法等方法可以降低其过冷度;通过增稠剂法、晶形改变剂法等方法可以改善其相分离问题;通过与高导热性的纳米粒子、多孔的高导热基体相复合,可以提高其导热性能。最后,指出了今后水合盐相变储能材料的重点研究方向,可以从与计算化学相结合、寻找合适的无机壳材料以及探究共晶体系等方面继续深入研究。