沸石、硅藻土孔结构及调湿性能的研究

调湿材料是能自动调节室内湿度的一种新型多功能材料,本文对两种多孔无机矿物:沸石和硅藻土孔径分布、比表面积以及吸湿、放湿性能进行了实验研究,作出其吸湿及放湿曲线,并分析微观形貌与其调湿性能差异的关系.     

硅藻土的孔结构特性对吸湿和放湿性能的影响

通过对临江硅藻精土、酸浸硅藻土和硅藻土助滤剂的孔结构特性以及吸湿、放湿性能进行研究,得出了硅藻土孔结构特性与其调湿性能关系及其影响规律.结果表明:相同材料的吸湿量大于其放湿量,酸浸硅藻土的平衡吸湿量较高,在湿度70％环境下的平衡吸湿量随其比表面积、孔体积的增大而增加,随平均孔径的增大而降低;平衡放湿量随比表面积、孔体积和平均孔径的增大均表现为先增大后减小的趋势.     

氧化石墨烯/SiO_2复合材料改性水性聚氨酯的制备及性能研究

将自制杂化材料SiO_2-GO加入水性聚氨酯(WPUA)中,制备了SiO_2-GO/WPUA复合乳液,研究了该复合乳液及其胶膜的结构及性能。改性后GO与SiO_2表面活性基团之间存在相互作用,SiO_2更好地阻隔了GO的团聚,实现GO有效地剥离。随着SiO_2-GO填料的增加,SiO_2-GO/WPUA复合乳液的粒径逐渐增大。由热失重、拉伸测试可知,SiO_2-GO杂化填料的加入,可提高SiO_2-GO/WPUA的力学性能和热稳定性。当SiO_2-GO填料质量分数为0.7%时,复合胶膜的拉伸强度为50.14MPa。TG测试结果表明,在热分解率为30%、50%时,SiO_2-GO/WPUA膜比WPUA的分解温度分别提高了28、46℃。SiO_2-GO/WPUA胶膜耐热性优于WPUA胶膜。     

沸石复合型调湿涂料调湿性能的研究

南方夏雨秋燥,保持室内恒定湿度对人体健康状况和物品存放很有帮助。选用氯化钙组装多孔沸石和硅藻土制成沸石复合型调湿乳胶涂料,该涂料具有良好吸湿和放湿能力,吸湿能力达到10%,放湿能力达到9%。     

偶联剂KH550改性氧化石墨烯/聚苯乙烯磺酸钠 及其与丁苯橡胶的复合材料性能研究

在界面剂聚苯乙烯磺酸钠(PSS)的物理改性作用下,以硅烷偶联剂KH550(简称KH550)对氧化石墨烯(GO)进行化学改性,制得KH550改性GO(KH550-GO)/PSS,采用乳液法制备KH550-GO/PSS/丁苯橡胶(SBR)复合材料,并对其结构和性能进行研究。结果表明:通过PSS的加入,使KH550-GO在SBR中的分散性得到改善;与不加KH550-GO/PSS的复合材料相比,KH550-GO/PSS/SBR复合材料的物理性能和气密性能显著提高。     

壳聚糖/明胶复合微球的制备及吸附性能研究

以壳聚糖和明胶为原料,span 80为乳化剂,戊二醛为交联剂,采用乳化交联法制备了壳聚糖/明胶复合微球并用于Cr(Ⅵ)的吸附。考察了复合微球的各制备因素对微球形貌的影响,通过单因素分析研究了壳聚糖与明胶的比例、乳化剂用量、乳化时间对复合微球吸附性能的影响。结果表明,壳聚糖与明胶的比例为1∶2、span80用量为6mL、乳化时间为50min时,制备的复合微球对Cr(Ⅵ)的吸附性能良好,吸附量较大,Cr(Ⅵ)的去除率可达95.3%。     

焙烧处理对硅藻土吸/放湿性能的影响

为阐明焙烧过程对硅藻土调湿性能的影响、解析硅藻土孔结构与调湿性能之间的关系,本研究采用静态吸附法测试了硅藻原土及不同温度制度焙烧硅藻土的吸/放湿能力,结果表明,500～700℃焙烧后硅藻土的放湿率高于硅藻原土,吸湿率则低于硅藻原土;焙烧温度提高或时间延长,样品的吸/放湿率均呈下降趋势,800℃长时间焙烧后的降幅尤为明显.扫描电镜(SEM)与X射线衍射(XRD)分析表明,焙烧过程不会显著改变硅藻壳的微观形貌和物相结构;孔结构表征(氮吸附法)发现,500～700℃焙烧处理导致硅藻土的微孔含量降低、中孔含量提高;硅藻土的中孔含量与放湿率之间存在良好的一致性关系,说明中孔的存在是决定硅藻土调湿性能的关键因素.     

层层自主装法制备GO杂化多壁微胶囊及其稳定性的影响探究

氧化石墨烯(GO)纳米粒子片层结构可用作Pickering乳液分散剂,芯材离子液体的稳定分散是制备微胶囊的关键,以GO作为Pickering乳液分散剂,并设计以GO为单一壁材制备了自润滑微胶囊,考虑到GO具有优异的耐摩擦性能和良好的热稳定性,再通过层层自主装法,使得壁层之间可以通过静电吸附和氢键作用连接,从而合成多层GO壁自润滑微胶囊。重点研究pH值、油水比、GO的质量浓度对GO的Pickering乳液的影响及GO杂化多壁微胶囊制备的最佳稳定条件。实验证明在pH值为2,油水质量比为5%,GO质量浓度为0.1 mg/L的实验条件下制备的微胶囊最佳。     

新型保温建筑涂料用微胶囊乳液的制备

以三聚氰胺为壁材,空气(或二氧化碳气体)为芯材,采用锐孔法和乳化缩聚技术制备涂料用微胶囊乳液。以微胶囊的外形、粒径大小,微胶囊乳液稳定性、导热系数为评价指标,对涂料用微胶囊乳液制备方法、工艺条件进行了研究。结果表明:方法可行,工艺简便,经济;涂料用微胶囊乳液保温性能较佳。     

氧化石墨烯改性十二醇/PMMA相变微胶囊的制备及其对涂层隔热性能的影响

以十二醇为芯材,甲基丙烯酸甲酯(MMA)为壁材单体,偶氮二异丁腈为引发剂,二乙烯基苯为交联剂,十二烷基硫酸钠和十六烷为乳化体系,制备了氧化石墨烯(GO)改性十二醇/PMMA相变微胶囊。采用扫描电镜和红外光谱仪表征了它们的形貌和分子结构。尽管随着GO含量增加,导热系数提高,热稳定性增强,但是GO含量过多会影响微胶囊的形成,导致其相变焓下降。当GO占油相质量的0.1%时,微胶囊的相变焓为95.9 J/g,导热系数为0.186 9 W/(m·K)(与未加入GO的微胶囊相比增强了28%)。以10%微胶囊与苯丙乳液制成的涂层具有一定的调温性能。     

Adsorptive removal kinetics of anionic dye onto chitosan films doped with graphene oxide: An in situ fluorescence monitoring

The aqueous adsorption of a fluorescent dye (pyranine) onto crosslinked chitosan-graphene oxide composite films was studied. In situ fluorescence monitoring technique is introduced as easy and fast experimental technique to select optimal adsorbent conditions. The effect of ionic crosslinker on adsorption was studied with sodium tripolyphosphate, trisodium citrate, and sodium sulfate, respectively. Among the crosslinkers, it was realized that sodium sulfate crosslinked films showed a greater adsorption rate for pyranine than the other two types of crosslinked films. Recently, graphene oxide is of interest as a filler compound for many biopolymer applications due to its favorable thermal, mechanical and surficial properties. In the present study, graphene oxide incorporation increased adsorption rate of the dye and the mechanical strength of ionically crosslinked chitosan films. The adsorption behavior of the adsorbent was explained by a kinetic model. Samples were characterized using scanning electron microscopy, thermogravimetric analysis, swelling experiments and tensile testing method.     

Preparation and water sorption properties of novel SiO2-LiBr microcapsules for water-retaining pavement

Novel SiO_2-LiBr microcapsules for water-retaining pavement were prepared and firstly characterized by scanning electron microscope(SEM), particle size analysis, and Fourier transform infrared spectroscopy(FT-IR). The water vapor sorption and desorption of the formulated microcapsules was then experimentally studied using dynamic vapor sorption(DVS), with the results fitted to three kinds of adsorption kinetics models. In addition, the specific surface area(SSA) was also calculated based on BET theory;and the thermal performance was investigated by laser flash analysis(LFA). Experimental results show a change of 103% in mass of the microcapsule sample under 90% relative humidity(RH) at 30 ℃ after water vapor sorption. The fitting of results indicates that the adsorption process is mainly governed by the intra-particle diffusion mechanism, followed by the pseudo-first-order adsorption process. In comparison with most conventional pavement materials, it is found that the SSA of the formulated microcapsules is much larger while the thermal conductivity is lower. The unique properties of the formulated SiO_2-LiBr microcapsules have significant potential to take the edge off the urban heat island effect and reduce rutting when applied to water-retaining pavement materials.     

季铵化壳聚糖包覆腐殖酸微胶囊的制备与性能研究

以季铵化壳聚糖（QCTS）为壁材、腐殖酸(HA)为芯材,制备季铵化壳聚糖包覆腐殖酸(QCTS/HA)微胶囊。采用傅里叶红外光谱(FTIR)、偏光显微镜(POM)、扫描电子显微镜(SEM)对微胶囊的性能进行表征。以芯壁比〔m(HA):m(QCTS)〕、固化剂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和保水性能测试。结果表明,QCTS/HA微胶囊的最佳工艺参数为：m(HA):m(QCTS)=3:1,固化剂用量为总质量的1%,搅拌速度为500r/min;与相同条件下未改性的微胶囊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和保水性能,其12h的吸水率和保水率分别高达348%和208%。 关键词：季铵化壳聚糖;腐殖酸;核壳结构;微胶囊;吸水性能,保水性能     

壳聚糖包裹广藿香精油微胶囊的制备及表征

采用复合凝聚法,以广藿香精油为芯材,壳聚糖（CTS）和阿拉伯胶（GA）为壁材,制备了广藿香精油微胶囊。采用扫描电子显微镜（SEM）、激光粒度仪、傅里叶红外光谱（FT-IR）等对微胶囊进行表征。结果表明,当乳化剂用量为质量分数1%,芯壁质量比为1∶2,乳化转速为2 500r/min,复凝pH为5,固化剂用量为1.5g时,微胶囊包封率和载药量最佳,微胶囊球形规则、分散性好,平均粒径为10.5μm。     

羧甲基纤维素-壳聚糖LbL空腔微胶囊的制备

微胶囊技术现已广泛应用于生物医药,环境保护,日用化工,农业科学及航空航天等领域,随着应用范围扩大,开发新技术与新方法制备微胶囊,使其具有更精确可控的结构已成为微胶囊技术发展的重大课题之一。选择两种生物相容性较好的天然聚电解质—羧甲基纤维素(CMC)和壳聚糖(CS),作为制备新型微胶囊的原料,利用聚阴离子羧甲基纤维素和聚阳离子壳聚糖之间的静电结合,成功制备出一种具有新结构的中空聚电解质微胶囊并初步研究了其形貌能基本性能。     

采用悬浮聚合法批量制备相变储能材料微胶囊

采用悬浮聚合法,利用自己设计的相变材料微胶囊(Micro PCMs)批量制备的生产设备合成了以正十八烷为囊芯,以苯乙烯马来酸酐-甲基丙烯酸甲酯共聚物P(MMA-co-SMA)为囊壁的相变储能微胶囊,熔融热焓值最高可达到150.12 J/g,结晶热焓值可达151.05 J/g,并通过扫描电子显微镜,差示扫描量热仪等对其性能进行了分析。讨论了乳化速度和乳化时间对批量制备相变储能微胶囊的热焓值和产量的影响。     

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。     

石墨烯-13X/LiCl复合吸附剂开式吸附-解吸性能

利用不同质量分数的石墨烯（MLG）与13X/LiCl合成新型复合吸附剂。通过扫描电镜（SEM）和N₂吸附表征复合吸附剂的微观形貌和孔隙特性,测试了复合吸附剂开式环境下的水蒸气吸附及解吸性能,并探究复合吸附剂中石墨烯质量分数对吸附解吸性能的影响。通过80%相对湿度（RH）的高湿工况进一步筛选出盐的质量分数为18.4%的13X/LiCl为最佳盐含量的吸附剂（MZ）作为合成复合吸附剂的基质。实验结果表明：石墨烯增加了复合吸附剂的结构性参数（比表面积,孔体积及孔径）,其中比表面积由未添加石墨烯的MZ [(262±3)g/m²],最大可提升至12G-MZ [(304±4)g/m²];复合吸附剂表现出优异的水蒸气吸附性能,所有复合吸附剂的相对吸附量均高于MZ（0.554g/g）,3G-MZ吸附性能最佳,水蒸气吸附量高达0.587g/g,是13X的2.7倍;除12G-MZ外,随着吸附剂中石墨烯质量分数的增加,水蒸气解吸率随之增加,其中9G-MZ的解吸率接近90%,较MZ（81.8%）提升了9.7%。该研究可为复合吸附剂应用于吸附空气取水提供基础研究数据。     

Microencapsulation of capsanthin by soybean protein isolate‐chitosan coacervation and microcapsule stability evaluation

Although capsanthin possesses excellent coloring performance and healthcare functions, its application in the food industry is limited due to its susceptibility to humidity, heat, and light. The purpose of this research was to microencapsulate capsanthin by soybean protein isolate (SPI)‐chitosan coacervation and evaluate whether the microencapsulation improved the stability of capsanthin against the adverse conditions mentioned above. The results indicated that the optimum conditions for capsanthin microencapsulation were emulsification speed 10,000 rpm, emulsification temperature 45°C, wall concentration 15 g/L and core to wall ratio 1:2 (w/w). Under these conditions, the droplets in the emulsion were even in size distribution without agglomeration and the microencapsulation efficiency and microencapsulation yield reached 90.46% and 86.69%, respectively. Microencapsulation increased the stability of capsanthin against low/medium moisture, heat, and especially light, but was less effective in protecting capsanthin microcapsules in high moisture. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39671.     

Two-beam-laser interference mediated reduction,patterning and nanostructuring of graphene oxide for the production of a flexible humidity sensing device

Two-beam-laser interference was used for the simultaneous reduction, patterning and nanostructuring of graphene oxide on flexible polyethylene terephthalate substrates for the production of a high performance humidity sensing device. Hierarchical graphene nanostructures were formed after laser interference treatment of graphene oxide, which holds great promise for gaseous molecular adsorption, and thereby significantly increases their sensing performance. By tuning the laser power, the content of oxygen functional groups, could be changed within a certain range, which contributes not only controllable conductivity but also tunable response/recovery time of the humidity sensor due to the interaction between water molecules and oxygen functional groups on the graphene oxide sheets. The laser interference processing of graphene oxide films is a mask-free, surfactant-free and large-area approach to the production of hierarchical graphene micro-nanostructures, and thus shows great potential for fabrication of future graphene-based microdevices.