Studies on Thermally Expandable Microspheres

本论文以丙烯腈和甲基丙烯腈为主要单体，采用常压悬浮聚合法，制备了膨胀倍率达20～30倍的可膨胀小球，通过扫描电子显微镜，热重分析，交联密度测定等手段，研究了交联剂，分散剂，第三单体等对小球制备的影响，确定了各自的最佳种类及用量，具体工作如下： 1.系统研究了五种交联剂（二丙二醇二丙烯酸酯，二缩丙二醇二丙烯酸酯，新戊二醇二丙烯酸酯，三羟甲基丙烷三丙烯酸酯，二乙烯基苯，对应简称DPGDA，TPGDA，NPGDA，TMPTA，DVB）种类和用量对制备的可膨胀小球形态和性能的影响，以DPGDA，TPGDA，NPGDA，TMPTA，DVB为交联剂，发现采用交联剂DPGDA所制备的可膨胀小球具有最光滑和...The thermally expandable microspheres, which used acrylonitrile and methacrylonitrile as the main monomer and magnesium hydroxide as the inorganic dispersant, were prepared with atmospheric suspension polymerization, and the foaming rate reach up to 20～30. This study researched systematically the effect of cross-linking agent, dispersant and the third monomer on the preparation of the thermally ex...学位：工学硕士院系专业：材料学院材料科学与工程系_高分子化学与物理学号：2072008115057

纪念五四宪法颁布暨全国人民代表大会成立五十周年理论研讨会纪要

今年 9月是五四宪法颁布、全国人民代表大会成立五十周年。五四宪法是新中国的第一部宪法 ,为我国的社会主义民主法制奠定了基础 ,具有划时代的意义。坚持和完善人民代表大会制度 ,是新的历史条件下推进政治体制改革和社会主义政治文明建设的重要内容。基于“以学术表达纪念、以纪念促进学术”的目的 ,中国社会科学院法学研究所于 2 0 0 4年 9月 5日举办了“纪念五四宪法颁布暨全国人民代表大会成立五十周年理论研讨会”。来自全国各地的 70余位代表莅临会议 ,研讨了诸多热点和前沿问题

Study on Synthesis and Characterization of UV-cured Modified Epoxidized Soybean Oil Oligomers

通讯作者: [email protected][中文文摘]研究了可作为紫外光固化涂料和油墨等产品的基体树脂的改性环氧大豆油树脂的合成及表征.利用环氧大豆油的环氧环的化学活性,先后与丙烯酸和马来酸酐进行反应,分别合成了油溶性环氧大豆油丙烯酸酯(AESO)和水溶性的马来酸改性环氧大豆油树脂(MAESO).并用红外和核磁对两种产物的结构进行了表征.添加紫外光引发剂后,两种产物在紫外光照射下均可快速固化.合成AESO最佳条件为环氧大豆油:丙烯酸=1.2:1(摩尔比),催化剂三苯基膦的用量为总质量的1%,反应温度为120℃;合成MAESO最佳条件为AESO:马来酸酐=4:1(摩尔比),催化剂钛酸正丁酯用量为1%,反应温度90℃.[英文文摘]In this paper,two kinds of basal resins,the modified epoxidized soybean oil oligomers,for UV-cured coatings and inks were studied.The epoxidized soybean oil(ESO) was modified by acrylic acid(AA) and maleic anhydride(MA).As a result,oil-soluble acrylated epoxidized soybean oil(AESO) and water-soluble maleinated acrylated epoxidized soybean oil(MAESO) were gained respectively.The resulting products were characterized by FTIR and 1H-NMR.With the addition of UV initiator,these two products could be cured in a short time under the UV light. The suitable conditions of the synthesis of these two oligomers have been discussed. For AESO, the best reaction conditions are ESO: AA= 1. 2: 1( by mol. ) , the mount of the catalyst Ph3P is 1%, reaction temperature is 120 ℃; for MAESO the best reaction conditions are AESO: MA= 4: 1( by mol.) ,the mount of the catalyst tetrabutyl titanate is 1%, reaction temperature is 90℃

Rate-accelerating of Boric Oxide for Atom Transfer Radical Polymerization of Styrene

联系人简介: 邹友思, 男, 教授, 博士生导师, 主要从事活性自由基聚合研究. E-mail [email protected][中文文摘]以2-溴丙酸乙酯为引发剂,溴化亚铜为催化剂,N,N,N′,N″,N″-五甲基二乙基三胺为配体,以氧化硼为加速剂,进行了苯乙烯原子转移自由基聚合的加速研究.发现氧化硼与引发剂比例为4时,加速效果最为明显,且对分子量的控制效果较好.在85℃时,添加该比例的氧化硼,苯乙烯在6 h的聚合转化率达到78.5%.在65,75及85℃条件下,加入氧化硼时体系的聚合反应动力学为一级反应,苯乙烯聚合速率分别为空白体系的1.82,1.54和1.5倍;聚合物的分子量可控,分子量分布窄,体系呈现明显的活性聚合特征.通过核磁共振谱对聚合物的结构进行了表征,证明氧化硼在整个聚合过程中只起加速作用,并不影响聚合机理和聚苯乙烯的结构.氧化硼价廉,有利于实现原子转移聚合的工业化.[英文文摘]The polymerization of styrene was mediated by copper(Ⅰ) bromide/pentramethyltriamine(PMDETA) using ethyl 2-bromopropionate(EBP) as an initiator and boric oxide(BO) as a rate-accelerating additive.BO was found to be effective to accelerate ATRP of styrene,and the conversions were improved to 78.5% during 6 h at 85 ℃.An optimal molar ratio of BO/EBP for the polymerization of styrene was 4∶1.First-order kinetics,increase of Mn with respect to conversion,and the relatively narrow polydispersity demonstrate that the polymerization of styrene in the presence of BO proceeds in a living fashion. The apparent rate constant of polymerization was improved by a factor of 1.82, 1.54 and 1.5 at 65,75 and 85℃ respectively NMR spectra study indicates that no influence occurred on the structure of polysty rene when BO w as added as promo ter. BO is likely to solve the slow polymerization rate of ATRP and promote its industrial application

Study on One Part Blocked Polyurethane-Ag Conductive Adhesive

通讯作者: [email protected][中文文摘]以封闭型聚氨酯为基体、三羟甲基丙烷(TMP)为固化剂,制备了单组份银粉导电胶,并研究其性能.该聚氨酯基体由2,4-甲苯二异氰酸酯(TDI)、TMP和少量聚乙二醇进行缩聚,并与己内酰胺反应而得.在基体中添加TMP固化剂、银粉和二氧化硅并充分搅拌后制得单组份导电胶.通过红外光谱、剪切强度和电阻率的测定对产物进行了表征,结果表明,70℃下TMP、TDI的加成反应需要时间为4~4.5 h,与己内酰胺的封闭反应时间为3~4 h;银粉的质量分数为75%时产物性能最好;加入少量二氧化硅能够提高导电胶的剪切强度,但电阻率会随之升高.[英文文摘]The preparation and properties of one-component Ag powder conductive adhesive which consisted of TMP-TDI adduct as matrix and TMP as hardener were studied.TMP-TDI adduct was synthesized by TMP,TDI and PEG.Then the prepolymer was blocked by caprolactam to get blocked polyurethane.Hardener,Ag powder and fumed silica were added to the polyurethane to prepare one-component conductive adhesive through agitating well.The products were characterized by FTIR,moreover,their shear strength and electrical resistivity were measured respectively. The results demonstrated that the addition reaction of TMP and TDI needed 4~4.5 h, while the blocked reaction needed 3~ 4 h. The optimum mass fraction of Ag powder was 75%. Employing fumed silica to the conductive adhesive reinforced the shear strength and elect rical resistivity

Rate-accelerating of Boric Oxide for Atom Transfer Radical Polymerization of Styrene

The polymerization of styrene was mediated by copper (I) bromide/pentramethyltriamine (PMDETA) using ethyl 2-bromopropionale(EBP) as an initiator and boric oxide(BO) as a rate-accelerating additive. BO was found to be effective to accelerate ATRP of styrene, and the conversions were improved to 78.5% during 6 h at 85 degrees C. An optimal molar ratio of BO/EBP for the Polymerization of styrene was 4:1. First-order kinetics, increase of M,, with respect to conversion, and the relatively narrow polydispersity demonstrate that the polymerization of styrene in the presence of BO proceeds in a living fashion. The apparent rate constant of polymerization was improved by a factor of 1.82, 1.54 and 1.5 at 65, 75 and 85 degrees C respectively. NMR spectra study indicates that no influence occurred on the structure of polystyrene when BO was added as promoter. BO is likely to solve the slow polymerization rate of ATRP and promote its industrial application

The Effect of Cross-Linking Agent on the Preparation of the Thermally Expandable Microspheres

以丙烯腈为主要单体,以氢氧化镁为无机分散剂,采用常压聚合法,制备了膨胀倍率达到20-30倍的可膨胀小球。系统研究了二丙二醇二丙烯酸酯(dPgdA)、三缩丙二醇二丙烯酸酯(TPgdA)、新戊二醇二丙烯酸酯(nPgdA)、三羟甲基丙烷三丙烯酸酯(TMPTA)和二乙烯基苯(dVb)等5种交联单体对可膨胀小球制备的影响。通过扫描电子显微镜、热重分析、交联密度测定等手段研究了可膨胀小球的形貌、粒径、发泡剂的含量、交联密度、发泡倍率。确定dPgdA为最佳的交联剂种类,用量为1.7%。采用dPgdA作为交联剂的小球既具有较完好的球状形貌,又有较小的粒径,较高的发泡剂含量和较高的交联度,膨胀倍率可达30倍。The thermally expandable microspheres,using acrylonitrile as the main monomer and magnesium hydroxide as the inorganic dispersant,were prepared with atmospheric suspension polymerization.This study systematically researched the effect of cross-linking agent such as dipropylene glycol diacrylate(DPGDA),tripropylene glycol diacrylate(TPGDA),trimethylolpropane trimethacrylate(TMPTA), noe ponlyl glycol di acrylate(NPGDA)and divinylbenzene(DVB)on the preparation of the thermally expandable microspheres.By using scanning electron microscope,thermogravimetric analysis and determination of cross-linking density,the morphology,particle size,foaming agent content,cross-linking density and foaming ratio of thermally expandable microspheres were studied.As a result,DPGDA is found to be the most suitable cross-linking agent because the microspheres prepared with it have the perfect surface morphology,small particle size,high blowing agent content and high cross-linking degree and the dosage is 1.7%

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势,重大成果频出,具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈,如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中,有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外,值得一提的是,长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果"水稻高产优质性状形成的分子机理及品种设计"荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理,旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态,与广大读者共同分享我国科学家所取得的辉煌成就

2019年中国植物科学若干领域重要研究进展

2019年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量大幅增加,在光生物学、植物抗逆和分子进化等若干领域取得了重要成果。其中,硅藻光合膜蛋白超分子结构和功能研究入选2019年度中国科学十大进展和中国生命科学十大进展;植物抗病小体的结构与功能研究入选2019年度中国生命科学十大进展。该文评述了2019年中国科学家在植物科学若干领域取得的重要研究进展,以期追踪和报道当前中国植物科学领域发展的前沿和热点及展示中国科学家所取得的辉煌成果