原位聚合法制备石蜡微胶囊相变材料

以尿素、甲醛、三聚氰胺共聚物为壁材,以石蜡为微胶囊芯材,采用原位聚合法制备微胶囊结构的相变控温材料,采用SEM、DSC等分析手段对样品的结构和性能进行表征,从而获得影响微胶囊性能的主要因素,以及优化的制备工艺条件。     

磁性显示微胶囊的同轴双喷头法制备

利用微胶囊技术,以海藻酸钠和明胶为壁材,四氧化三铁的混合溶液为芯材,采用同轴双喷头法制备了磁性显示微胶囊。考察了芯材溶液压强、壁材溶液压强、芯材溶液搅拌速度、喷头高度和喷头角度对微胶囊合格率的影响。结果表明,最佳制备参数为芯材压强175 kPa,壁材压强300 kPa,芯材溶液搅拌速度600 r/min,喷头高度40 cm,喷头角度35°。在最佳条件下制备出的磁性显示微胶囊粒径主要分布在100～250μm,内外表面光滑,囊壁透明,分散性好,形态完整,具有良好磁响应性。     

多彩液晶微胶囊的制备及性能研究

采用手性剂掺杂向列相混合液晶制备出具备类似胆甾相液晶温变显色性能的液晶混合物。通过控制向列相液晶中手性剂的添加量,调节混合液晶的颜色,制备出系列室温下呈颜色转变的液晶混合物。在此基础上,探究3种不同添加剂对混合液晶显色性能的影响,确定具备最佳温变显色性能的液晶混合物配方。以上述液晶混合物为芯材、异佛尔酮二异氰酸酯(IPDI)为壁材,采用界面聚合法在不同反应条件下制备出一系列液晶微胶囊,并确定最佳反应条件。结果表明:最佳反应条件下,制备的液晶微胶囊粒径范围在50～105μm之间,平均粒径在68.06μm左右,囊芯材料含量约占35%。液晶微胶囊呈规则球形,粒径比较均匀,具有良好的温变显色性能,且热稳定性较高,热分解温度达330℃以上。     

可逆示温微胶囊的制备及性能研究

采用油相分离法,以示温变色材料CoCl2·6H2O为芯材料,乙基纤维素、聚乙烯为壳材料,Span80为乳化剂,环己烷(HC)为溶剂,制备了可逆示温微胶囊.利用扫描电子显微镜、光学显微镜和热台偏光显微镜对可逆示温微胶囊进行了结构表征与性能分析,对所制备可逆示温微胶囊材料的耐疲劳性、耐溶剂性以及与高分子材料的相容性进行了研究,并重点就可逆示温微胶囊在油墨中的制备工艺、对油墨性能的影响进行了深入的研究与讨论.结果表明,所制备的微胶囊粒径均匀,平均粒径为4.5 μm.所制备的可逆示温丝网油墨具有优良的性能.     

一步法制备明胶-阿拉伯树胶电子墨水微胶囊

采用硬脂酸对TiO2纳米颗粒进行表面改性处理,以明胶-阿拉伯树胶为壁材,通过 一步复凝聚法制备了白色电子墨水微胶囊.傅立叶变换红外光谱仪及动态光散射仪分析表明,改性后的TiO2在四氯乙烯中具有良好的分散性.对分散体系进行微胶囊化处理后,颗粒能够均匀而稳定地分布在微胶囊内.调节明胶-阿拉伯胶用量、滴酸速度及浓度等,获得了无粘连、囊壁光滑、厚度可控的微胶囊.在10 V/靘的直流电场作用下,胶囊内改性TiO2纳米颗粒表现出良好的电场响应可逆移动特征.     

工艺参数对可逆示温微胶囊性能影响的研究

以乙基纤维素和聚乙烯为壳材料,热敏变色材料氯化钴为芯材料,Span80为乳化剂,采用油相分离法,对热敏变色材料氯化钴进行高分子材料包覆,制备了polyethylene/ethyl cellulose(PE/EC)可逆示温微胶囊.研究了壳材料用量、乳化剂用量、搅拌速率、相分离时间和环己烷用量等工艺参数对微胶囊的形成状态、包裹率等的影响规律,研究结果表明,工艺参数对微胶囊的变色温度影响不显著;随着相分离时间的增加,微胶囊的包裹率增大;随着搅拌速率的增加,微胶囊的包裹率呈先增大再降低的趋势.利用扫描电镜(SEM)和光学显微镜(OM)进行表征.微胶囊化的最佳试验条件为核壳比为1∶1, 相分离时间为3 h～4 h,搅拌速率为900 r/min.所制备的微胶囊极大地提高了可逆示温材料的变色灵敏性、环境适应性与高分子材料的相容性,具有良好的应用前景.     

助焊剂活性物质的制备与研究

通过润湿角和铺展性表征对16种有机活性剂进行了性能测试,用热失重法测试其热解过程,对所选活性剂进行复配处理完成表面包覆并制得活性物质。结果表明:柠檬酸和苹果酸复配符合要求,三乙醇胺可以很好地调节助焊剂的酸度,丙烯酸树脂可作为活性物质微胶囊的囊壁材料。微胶囊化后的复配活性物质易溶于有机溶剂,pH值接近6。以其制备的助焊剂的助焊效果良好,IMC层薄而明晰。     

微胶囊相变材料制备条件的优化

考察了乳化剂用量和搅拌速度对微胶囊相变材料制备的影响,通过测试证明：当乳化剂用量为9.4~9.8mL,搅拌速度为300r/min时,在三聚氰胺：甲醛=1：2.5,石蜡为10g,温度为80℃的条件下,制备得到的微胶囊相变材料包膜性能和分散性能较好。     

石蜡微胶囊化及其红外伪装隐身性能研究

用石蜡和脲醛树脂制备微胶囊相变材料,测试了微胶囊的各种性能,并对其在红外伪装隐身上的应用进行了研究．结果表明微胶囊相变材料既能够有效地模拟真目标的红外热特征,也能有效地遮蔽目标的红外热特征,具有红外隐真—示假的双重功能．     

明胶-阿拉伯树胶电子墨水微胶囊显示性能优化

以明胶-阿拉伯树胶为壁材,四氯乙烯为分散介质,硬脂酸改性的TiO2为显示颗粒,采用复合凝聚法制备了红白显示的电子墨水微胶囊。详细讨论了TiO2用量对反射性能的影响,讨论了Span80用量对分散体系稳定性的影响。结果表明:随着电荷控制剂Span80用量的增加,颗粒的Zeta电势和电泳淌度随之增加,使得分散体系的稳定性增加。当Span80浓度为3.0%时,分散体系长时间放置,无沉降发生。制备的微胶囊涂膜后,器件的对比度及分辨率均得到了良好改善。同时,驱动电压可达2.5 V/μm,响应时间降低到150ms。     

Autonomous Self‐Healing of Epoxy Thermosets with Thiol‐Isocyanate Chemistry

Thiol‐isocyanate chemistry, combined with a dual capsule strategy, is used for the development of extrinsic self‐healing epoxy materials. It is shown that the amine groups present in the matrix both serve as a catalyst for the addition reaction between a thiol and an isocyanate and as a way to covalently link the healed network structure to the surrounding resin. The tapered double cantilever beam (TDCB) geometry is used for evaluating the recovery of the fracture toughness at room temperature after different healing times. Using manual injection of the healing agents into the crack, a healing efficiency up to 130% is obtained for the EPIKOTE 828/DETA epoxy material. On the other hand, when two types of microcapsules, one containing a tetrathiol reagent and the other a low toxic isocyanate reagent, are incorporated into this epoxy thermoset (20 wt%), a recovery of more than 50% is reached. The influence of parameters such as the amount and core content of the microcapsules on the healing efficiency is investigated. Furthermore, the thiol‐isocyanate chemistry is also tested for an industrial cold‐curing epoxy resin (RIM 135/RIMH 137).     

Self‐Healing Properties of Protein Resin with Soy Protein Isolate‐Loaded Poly(d,l‐lactide‐co‐glycolide) Microcapsules

Self‐healing soy protein isolate (SPI)‐based “green” thermoset resin is developed using poly(d,l ‐lactide‐co‐glycolide)(PLGA) microcapsules containing SPI, as crack healant. The SPI–PLGA microcapsules with an average diameter of 778 nm that contain sub‐capsules are prepared using a water‐in‐oil‐in‐water double‐emulsion solvent evaporation technique. The encapsulation efficiency is found to be high, up to 89%. Thermoset green SPI resin containing the SPI–PLGA microcapsules successfully arrests and retards the microcracks. The healing efficiency is investigated using mode I fracture toughness test for resins containing different concentrations of microcapsules from 5 to 20 wt% and glutaraldehyde as a crosslinker at 9 or 12 wt%. The SPI resin containing 12 wt% glutaraldehyde and 15 wt% microcapsules shows self‐healing efficiency of up to 48%. It is observed that the SPI released from SPI–PLGA microcapsules can react with the excess glutaraldehyde present in the resin when the two come in contact within the microcracks and bridge the two fracture surfaces. The results of this study show for the first time that SPI–PLGA microcapsules can self‐heal protein‐based green resins. The same method can be extended to self‐heal other proteins as well as protein‐based green composites resulting in higher fracture toughness and longer useful life.     

Self‐Healing of an Epoxy Resin Using Scandium(III) Triflate as a Catalytic Curing Agent

A novel Lewis acid‐catalysed self‐healing system is investigated for implementation into epoxy‐based fibre reinforced polymer (FRP) composite materials. The catalyst, scandium(III) triflate, is selected using a qualitative approach and subsequently embedded with pre‐synthesised epoxy‐solvent loaded microcapsules, into an epoxy resin. Healing is initiated when microcapsules are ruptured at the onset of crack propagation. The epoxy monomer healing agent contained within actively undergoes ring‐opening polymerisation (ROP) on contact with the locally dispersed catalyst, forming a new polymer to bridge the two fractured crack planes. Self‐healing performance is quantified using a tapered double cantilever beam (TDCB) test specimen and the effects of microcapsule content and healing temperature and time are all independently considered. As an initial ‘proof of concept’ study, results show that a material recovery value of greater than 80% fracture strength is achieved for this novel Lewis acid‐catalysed self‐healing epoxy resin.     

含磷酚醛树脂的合成和在环保型FR-4覆铜板中的应用

文章简要介绍了含磷酚醛树脂的合成、应用及性能,并利用其对环氧树脂的阻燃进行改性,在环保型FR-4层压板中进行应用,取得了较好的效果。     

环氧树脂灌封材料的增韧研究

抗冲击精密电子元器件用灌封材料往往需要具有好的韧性.在综合考虑灌封材料力学性能与灌封工艺性的基础上,采用自制带液晶基团聚酯型环氧树脂对环氧树脂E-51进行了增韧改性研究.结果表明,优化配方的增韧型环氧树脂灌封材料在保持自身较高压缩强度的同时,抗冲击强度提高了4.1倍,且具有良好的灌封工艺性,其在25℃条件下的适用期(凝...     

Novel All‐Natural Microcapsules from Gelatin and Shellac for Biorelated Applications

The generation of novel all‐natural biopolymeric microcapsules fabricated using natural biopolymers, protein (gelatin) and resin (shellac), is reported. These novel microcapsules are generated using a simple extrusion method wherein the gelatin‐shellac mixture is dropped in an acidic medium resulting in an instantaneous solidification of aqueous drops into solid spherical microcapsules that retain their shape on air‐drying. The formation of the microcapsules is basically due to the strong interactions between two oppositely charged polymers (as confirmed from isothermal titration calorimetry and infrared spectroscopy) and the instant precipitation of acid‐resistant shellac. These novel microcapsules prepared without the help of any cross‐linkers or harsh solvent are extensively characterized and several biorelated applications for pharmaceuticals (encapsulation and release of bioactive molecules), foods (loading of colorants and flavors), sensors (encapsulation of pH sensitive dye), and biotechnology (enzyme immobilization) fields are further demonstrated.     

石墨/环氧树脂/BaTiO3基PTC复合材料的研究

利用环氧树脂将PTC陶瓷材料与石墨进行复合,探讨了石墨和环氧树脂的含量及两者比例对PTC复合材料性能的影响。在保证该材料具有一定升阻比的前提下,有效地降低了PTC材料的室温电阻率。在大量实验的基础上应用相关理论探讨了其低阻化的机理。     

X荧光筛选法在树脂等材料卤素含量分析中的应用

采用X荧光筛选法可快速分析电子产品中卤素元素氯、溴元素的含量。选用岛津EDX-LE能量色散型X荧光光谱仪,EDX-LE具有较好的灵敏度和精确度,在大气氛围下进行氯和溴含量的测试,该方法可用于树脂材料等电子产品中的卤素筛选分析。     

集成电路封装用树脂材料的发展动向

封装技术是IC产业中非常重要的一环,多种新型封装形式对封装材料提出了更高的要求。简要介绍了用于IC封装的树脂材料的发展动向。     

环氧树脂–银粉复合导电银浆的制备

导电油墨(导电银浆等)是以全印制电子技术制作印制电路板的关键材料。研究了以环氧树脂为连结剂、自制超细银粉为填料、聚乙二醇等材料为添加剂的复合导电银浆配方及制备方法。研究获得的最佳配方为:w(银粉)为70%～80%,其他各组分之间的质量比ζ(环氧树脂∶四氢呋喃∶固化剂∶聚乙二醇)=1.00∶(2.00～3.00)∶(0.20～0.30)∶(0.05～0.10)。在最佳配方范围内,复合导电银浆室温固化后电阻率小于100Ω/cm,有机物挥发少,对环境友好,符合实际应用要求。