Multifunctional silicone rubber/paraffin@PbWO4 phase-change composites for thermoregulation and gamma radiation shielding

A new type of silicone rubber (SR)-based gamma radiation shielding and thermal regulation composite was developed with paraffin (Pn) @lead tungstate (PWO) phase-change microcapsules as functional fillers. These SR/Pn@PWO composites have a PWO component that not only exhibits excellent photon attenuation but also can provide a barrier to the molten phase-change material core. The thermal and mechanical properties of the composites were characterized by differential scanning calorimetry, thermal regulation experiment and mechanical tests. Thermal analysis indicated that the SR/Pn@PWO composites not only reveal reliable energy storage performance which can reach to 52.72 J g⁻¹ enthalpy values but also exhibit good thermal durability. In addition, SR/Pn@PWO composites have enhanced mechanical properties and excellent thermoregulation performance. And the more microcapsules content, the more significant enhancement effect is. A high-purity germanium gamma spectrometer to measure the attenuation coefficient of the composites for gamma radiation showed that the SR/Pn@PWO composites have good γ-ray-shielding property, which increased with the increase of the microcapsules content.     

微胶囊红磷和聚苯醚对高抗冲聚苯乙烯的协同阻燃作用

利用微胶囊红磷(MRP)和聚苯醚(PPO)来提高高抗冲聚苯乙烯(HIPS)的阻燃性能,通过熔融共混法制备了一系列不同组成的MRP-PPO/HIPS复合材料.采用水平燃烧、垂直燃烧、氧指数、锥形量热分析、高温热分解实验等方法研究了复合材料的阻燃性能.研究表明,阻燃剂用量相同时,在HIPS基体中同时加入MRP和PPO得到的复合材料比单独加入MRP或PPO得到的复合材料具有更好的阻燃性能.当MRP-PPO/HIPS的质量比为10∶20∶70时,复合材料的氧指数为23.9％,水平燃烧级别达到FH-1级,垂直燃烧级别达到FV-0级,阻燃性能达到最佳.MRP用量过多时,复合材料的阻燃性能下降.研究认为,PPO和MRP对HIPS具有较强的协同阻燃作用.两者以适当比例并用时能够使复合材料在燃烧时的热释放速率和燃烧热大幅度减小,降低了气相燃烧区的温度,起到气相阻燃作用.同时,复合材料在热分解和燃烧时能够生成连续和致密的炭层,抑制了燃烧过程中的热量传递和物质交换,起到凝聚相阻燃作用.因此,复合材料的阻燃性能显著改善.     

Preparation and thermal properties of microencapsulated phase change material for enhancing fluid flow heat transfer

Microencapsulated phase change material (MEPCM) is formed by packing PCM into a microcapsule with a solid but flexible shell. MEPCM can be used to enhance liquid cooling performance considerably. In this paper, experiments on the preparation of MEPCM with a double‐layered shell have been conducted. An in‐situ polymerization microencapsulation process was used to prepare the MEPCM with melamine resin as the shell material and n‐Docosane (C₂₂H₄₆) as the core material. Interesting parameters like the size of the prepared MEPCM, the core mass fraction in the MEPCM, and the thermal storage capability of the prepared MEPCM have been measured and analyzed. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(1): 28–37, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20138     

水基预涂型锁固密封胶概况

国外从20世纪70年代就开展预涂型锁固密封胶的研究及应用工作,因其可部分代替液态型厌氧胶,提高汽车等机械行业生产自动化水平,国内也从上世纪80年代开展预涂型锁固密封胶的研究,并在东风汽车公司成功应用;预涂型锁固密封胶分溶剂型及水基型两大类,水基型具有安全环保等优势,本文概述了水基预涂型密封胶的国内外技术发展概况,主要对水基型预涂微胶囊厌氧锁固密封胶和单组分水基型预涂密封胶的研究、性能及应用情况作了简要的介绍和展望。     

无腥味鱼肝油软糖的研制

在制作凝胶软糖的过程中加入富含天然维生素A、D的微胶囊化鱼肝油,制成一种新型功能保健糖果——无腥味鱼肝油软糖。     

Effect of packaging conditions and temperature on viability of microencapsulated bifidobacteria during storage

In this study, Bifidobacterium longum B6 and B infantis CCRC 14633 were microencapsulated in various wall materials, including skim milk, gum arabic, gelatin and soluble starch. The stability of these microencapsulated bifidobacteria held at 25 or 4 °C in glass or polyester bottles with or without deoxidant and desiccant was determined. Microencapsulated cells of B longum B6 were generally more stable than the corresponding microencapsulated cells of B infantis CCRC 14633 under the various storage conditions tested. The presence of deoxidant and desiccant, especially at 25 °C, increased the survival of microencapsulated cells. Furthermore, the survival of bifidobacteria was enhanced when they were stored at 4 °C in glass bottles. It was also found that the wall material affected the survival of microencapsulated bifidobacteria. The viability of B longum B6 and B infantis CCRC 14633 was best when they were encapsulated in skim milk and held at 4 °C in glass bottles. Skim milk‐encapsulated B longum B6 cells showed a relatively low viability reduction of only 0.15–0.20 log (colony‐forming units (cfu g^?1)) after 42 days of storage at 4 °C in glass bottles, regardless of the presence of deoxidant and desiccant. A reduction of 0.38–0.76 log (cfu g^?1) was noted for skim milk‐encapsulated cells of B infantis CCRC 14633 under similar storage conditions. Copyright © 2004 Society of Chemical Industry     

粉末亚麻油的制备研究

以多孔淀粉为载体,玉米醇溶蛋白为壁材,采用旋转锅喷雾包埋法制备粉末亚麻油。结果表明,多孔淀粉吸附亚麻油颗粒与壁材10%玉米醇溶蛋白液的重量比为1.0∶1.5,增塑剂油酸用量3%(以10%玉米醇溶蛋白液为基准),并分次逐渐喷入包埋剂,在70~80℃条件下热风干燥,制得的粉末亚麻油包埋率为95%,产品具有抗氧化、无异味、耐储存、使用方便等优点。     

微胶囊相变材料PCM在织物上的应用

相变材料微胶囊PCM采用浸轧法对纯棉和涤纶织物进行整理,用DSC法和织物透气仪测试调温织物的储热和透气性能。最优整理工艺为：采用两次一浸一轧的方式、相变材料微胶囊的用量为250 g/L、烘干温度为110 ℃,烘干时间为120 s。DSC热分析表明：调温织物的升温和降温速率较普通织物显著减缓,具有智能调温功能,且调温织物的透气性有所增加。通过此方法可以制备得到具有调温功能的织物,具备一定的耐洗性能,且在涤纶织物上效果略佳。     

相变微胶囊整理棉织物的结构与性能

为研制具有蓄热调温功能的织物,将微胶囊相变材料(MPCMs)整理到棉织物上,通过SEM、FT-IR、DSC及织物强力仪等测试手段测定整理前后棉织物的结构与性能。结果表明:MPCMs可被均匀地整理到棉织物表面,MPCMs整理对棉织物的微细结构不产生影响;经MPCMs整理后棉织物可以吸收一定的热量,整理后棉织物的热分解温度和熔融热焓值均较整理前提高;织物升温曲线表明经MPCMs整理后,织物具有优异的调温性能;整理后的棉织物经、纬向断裂强度均提高,透气性能有一定程度的下降。     

维生素E微胶囊的理化性质表征

采用超声波辅助β-环糊精(β-CD)对维生素E进行包埋,而后再加入乳清浓缩蛋白(WPC)对其进行二次包埋来制备维生素E微胶囊.通过扫描电镜(SEM)发现微胶囊产品与物理混合物的微观形态存在较大差异;在微胶囊产品的差示热扫描(DSC)图谱中出现了一个新的吸热峰;傅里叶变换红外光谱(FT-IR)显示,在微胶囊产品中没有发现维生素E的特征峰并且存在较强的氢键效应;微胶囊产品的X-射线衍射图谱与物理混合物以及β-环糊精的图谱大不相同,在多处变化明显;以上的实验结果证实了维生素E已经被β-环糊精和乳清浓缩蛋白包埋,并且维生素E与β-环糊精之间发生氢键作用形成包合物.