接枝法制备聚苯乙烯/笼型倍半硅氧烷复合材料

以工业级的3-氯丙基三氯硅烷和七聚(苯基)倍半硅氧烷三硅醇钠为原料,通过顶端封角法合成了含有一个3-氯丙基、七个苯基的单官能团POSS(3-氯丙基POSS),并以其作为聚苯乙烯的添加剂,采用化学接枝的方法制备POSS/PS复合材料.利用傅立叶转变红外光谱(FT-IR)、核磁共振(1H-NMR、29Si-NMR)和X-射...     

巯基-苯基聚倍半硅氧烷的合成

以巯丙基三甲氧基硅烷和苯基三甲氧基硅烷为原料,在甲醇作溶剂、浓HCl作催化剂的条件下水解缩合制备了巯基聚倍半硅氧烷和巯基-苯基聚倍半硅氧烷,并利用FTIR和GPC对合成产物进行了表征。结果表明:当苯基单体添加量为20%时,所制备的巯基-苯基聚倍半硅氧烷中均含有一定量的巯基和苯基,在引入部分苯环增加折光率的同时也保持了产物拥有进一步反应的活性巯基,且相对分子质量较大,分子量分布较窄。     

3,3,3-三氟丙基三甲氧基硅烷的合成研究

以3,3,3-三氟丙基三氯硅烷和甲醇为原料,采用溶剂法合成3,3,3-三氟丙基三甲氧基硅烷,讨论了氮气流速、反应温度、原料配比、溶剂种类、滴加方式等因素对产物收率的影响.并用GC-MS对产物进行了分析.通过实验得出该反应较优的反应条件为:用正己烷作溶剂,N2流速为100mL/min,3,3,3-三氟丙基三氯硅烷和甲醇的摩尔比为1∶3.1,反应温度在70℃左右,3,3,3-三氟丙基三甲氧基硅的产率可达89.4%.     

八氯丙基多面体低聚倍半硅氧烷的合成与表征

以工业化的γ-氯丙基三甲氧基硅烷为原料,在浓盐酸为催化剂的条件下制备了八氯丙基多面体低聚倍半硅氧烷(OCPS).研究了反应温度、反应物的投料比对产物收率的影响.得到了最佳合成产物的条件:在40℃的反应温度下,水解缩合20天,γ-氯丙基三甲氧基硅烷、浓盐酸、甲醇的体积比为5:4:100时产率最高,达到28.5%,并对产物结构进行了1HNMR、13CNMR、29SiNMR、FT-IR、GPC表征.     

溶剂法醇解合成3,3,3-三氟丙基三甲氧基硅烷的研究

以3,3,3-三氟丙基三氯硅烷和甲醇为原料,采用溶剂法醇解合成3,3,3-三氟丙基三甲氧基硅烷,研究了原料配比、N2流量、滴加速度、反应温度及反应时间等因素对合成的影响,运用GC-MS、FT-IR等手段对反应过程和结果进行了综合分析,提出了最佳合成条件.     

梯形聚甲基/苯基倍半硅氧烷的合成及其热稳定性研究

选用甲基三氯硅烷和苯基三氯硅烷为主要原料合成了梯形聚甲基倍半硅氧烷(有机硅树脂Ⅰ)和梯形聚苯基倍半硅氧烷(有机硅树脂Ⅱ).并进行了红外光谱和差热分析.     

紫外光固化丙烯酸改性聚有机硅氧烷的性能研究

利用γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)、正硅酸乙酯(Si-28)、六甲基二硅氧烷(MM)的受控水解反应制备了含有丙烯酰氧基团的聚硅氧烷预聚体,对合成的预聚物进行红外光谱、核磁共振氢谱表征。结果表明:所得预聚物分子中含有大量的活性基团(羟基与不饱和双键基团),可进行紫外光引发固化。同时考察了反应原料用量对硅氧烷预聚体及其固化后性能的影响,结果显示,随着六甲基二硅氧烷用量的增加其热稳定性逐渐降低。     

聚二甲基硅氧烷-梯形苯基倍半硅氧烷共聚物的制备

探讨了用羟基硅油(PDMS)和苯基三甲氧基硅烷(PTMS)合成聚二甲基硅氧烷-梯形苯基倍半硅氧烷共聚物的反应条件,通过IR、1H-NMR确定了目标产物的结构.     

催化合成三氟丙基三氯硅烷的研究

以3,3,3-三氟丙烯与三氯硅烷为原料在铂催化剂作用下合成3,3,3-三氟丙基三氯硅烷,考察了催化剂活化温度、反应温度、催化剂用量等对反应的影响.确立了最佳的反应条件.     

新型有机硅改性丙烯酸酯乳液的制备及性能

为了解决常规有机硅单体在乳液聚合反应中易水解的问题,通过γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)和三甲基氯硅烷间的取代反应合成了一种难水解的新型有机硅单体γ-甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷,再以其和丙烯酸酯类单体为原料,采用种子乳液共聚法合成了高硅含量有机硅-丙烯酸酯复合共聚乳液。采用傅里叶红外光谱(FTIR)、核磁共振(NMR)对新型有机硅单体进行了结构表征,利用红外光谱、表面接触角测试、热失重分析、拉伸测试等表征了乳液及乳胶膜性能。结果表明:新型有机硅改性丙烯酸酯乳胶膜比纯丙烯酸酯乳胶膜在耐水性、耐热性及力学性能等方面均有显著提高。     

Ammonolysis of (3-chloropropyl)trimethoxysilane

Technological parameters of the ammonolysis of (3-chloropropyl)trimethoxysilane to (3-aminopropyl)trimethoxysilane have been determined. Influence of temperature, reaction time and the molar ratio of ammonia to (3-chloropropyl)trimethoxysilane has been examined. Influence of the parameters has been described using the following factors describing the process: the degree of conversion of (3-chloropropyl)trimethoxysilane and the selectivity of transformation to (3-aminopropyl)trimethoxysilane in relation to consumed (3-chloropropyl)trimethoxysilane.     

POSS/PS复合材料的制备及其热性能

单官能团3-氯丙基笼形倍半硅氧烷(POSS)与官能化的聚苯乙烯(PS)进行缩合反应,得到POSS/PS复合材料,其热性能得到明显改善。单官能团3-氯丙基POSS由顶端封角法制备;PS经过3步处理以引入醇钠基团：Friedel-Crafts酰基化反应将羰基引入到PS的苯基上,羰基被硼氢化钠还原为羟基,金属钠与羟基反应生成醇钠基团;单官能团3-氯丙基 POSS分子上的C—Cl与PS上的醇钠基团缩合从而制备POSS接枝的POSS/PS复合材料。利用1H NMR和FTIR技术表征中间产物和POSS/PS复合材料,结果表明POSS笼上的C—Cl与官能化后PS链上的醇钠官能团之间的缩合反应效率很高。XRD测试表明POSS具有良好的分散性。TGA、DSC分析结果表明,由于POSS的引入,POSS/PS复合材料比纯PS的初始分解温度提高69℃,玻璃化转变温度提高16℃。     

Pore structure control factors of polyamine-bridged polysilsesquioxanes by sol–gel method and their structure-adsorption properties for Au(III)

A series of bridged polysilsesquioxane (BPS) materials was synthesized by the sol–gel method from 3-chloropropyl trimethoxysilane, diethylenetriamine (DETA) or ethylenediamine. Tetraethyl orthosilicate (TEOS) and/or one of the two templates, hexadecyl trimethyl ammonium bromide (CTAB) or P123, were used in the co-condensation process to construct some of the porous adsorbents. The adsorption of Au(III) was the highest for samples without TEOS, especially for the DETA series with CTAB template. This study elucidates the synthesis and applications of BPS materials.     

原子转移自由基聚合制备PMMA/POSS杂化材料

以八(γ-氯丙基)倍半硅氧烷(OCP-POSS)为引发剂,通过原子转移自由基聚合(ATRP)制备了PMMA/OCP-POSS有机/无机杂化材料.采用GPC、DSC和TGA对杂化材料的结构与性能进行了表征.结果表明,在DMF、异丙醇、甲苯等3种不同溶剂中均可合成分子量分布较窄的PMMA杂化材料.以DMF为溶剂,所得PMMA/OCP-POSS杂化材料的分子量分布系数可达到1.18.与分子量相当的线形PMMA相比,含OCP-POSS的PMMA杂化材料具有更高的玻璃化转变温度和热稳定性.     

单分散球形MoS2超细粉体材料的制备

采用液相沉淀-高温氢还原两步合成新方法制备单分散球形MoS2超细粉体材料,利用透射能谱、X射线衍射仪(XRD)、冷场扫描电子显微镜(SEM)和马尔文激光粒度仪等研究了反应条件对产物化学组成、晶型的影响以及酸浓度、熟化时间和反应温度对前驱体MoS3平均粒径的影响.研究结果表明:反应条件对 前驱体MoS3的晶型没有影响;M...     

多铁材料BiFeO3的制备与表征

以硝酸铁和硝酸铋为反应物,柠檬酸为络合剂,硝酸为催化剂,采用柠檬酸溶胶–凝胶法制备粒径分布均匀的多铁性材料BiFeO3纳米粉体,通过TG-DSC、XRD、FT-IR、SEM及AFM等手段对样品的结构、形貌及纯净度进行表征.研究结果表明,在溶胶过程中前驱液的pH值以及干凝胶的煅烧温度等合成条件对BiFeO3纳米粉体的制备和纯净程度都有一定的影响,最佳的合成条件是前驱溶液的pH=7～8,干凝胶的煅烧温度为600℃.在该条件下得到的BiFeO3纳米粉体中无杂相Bi25FeO40和Bi2Fe4O9等,纳米颗粒尺寸在100 nm左右,分散性良好,饱和磁化强度Ms=1.08 A·m2/kg,剩余磁化强度Mr=0.13 A·m2/kg,矫顽力Hc=15.76 kA/m.     

Preparation and Properties of Macroporous Silicon Nitride Ceramics by Gelcasting and Carbonthermal Reaction

1. IntroductionIn recent years, porous Si3N4 ceramics have re-ceived increasing attention for their extensive applicationin many high-tech areas such as bio ceramics[1], cata-lyst supports[2], hot gases filter[3], liquid purification[4],sensors[5], and membrane reactors[6]. Their appeal ismainly because of their unique and inherent proper-ties. Si3N4 ceramics are materials with excellent me-chanical properties, good corrosion resistance and oxida-tion resistance[7]. Since better performance …     

Synthesis and Characterization of High Performance Polymeric Hybrid Siliconized Epoxy Composites for Aerospace Applications

Two different types of hybridized siliconized epoxy matrix systems have been developed using two commercially available (CIBA-GEIGY) epoxy resins with hydroxyl terminated polydimethyl siloxane. The percentage siloxane content in the epoxy systems have been optimized based on the physico-chemical, electrical, mechanical and thermal properties. The matrix resins are cured using aliphatic amine (HY951), aromatic amine (HT972) and polyamidoamine (HY840) from CIBA-GEIGY and γ-aminopropyltriethoxysilane (A-186, Union Carbide). The optimized siliconized epoxy materials are filled with additives like fillers (SiO₂, BaSO₄ and TiO₂), plasticizer (dioctylphthalate), flame retardant (tris (2-chloropropyl) phosphate) and reinforced with E-glass fiber and Kevlar-49 and their effect on electrical and mechanical properties are studied. Introduction of siloxane units (silicone) in to the epoxy systems enhances dielectric properties with little loss of mechanical properties. Additives alter the electrical and mechanical characteristics based on their nature and concentration. Reinforcements enhanced the electrical and mechanical behavior to an appreciable extent. Data resulted from the studies reveal that the siliconized epoxy matrix systems reinforced with E-glass fiber and Kevlar-49 can be used in the filament wound liquid pressure vessels in the field of aerospace and other high performance engineering applications.     

联苯型三芳胺空穴传输材料的新合成工艺研究

三芳胺是一种优良的空穴传输材料,在有机电致发光和有机光导领域有着重要应用.目前的合成方法是在氯化亚铜和邻菲哆啉的催化下,以4,4'-二-碘联苯和二芳基胺反应制备.研究了以4,4'-二溴联苯与二苯胺为原料,研究了在醋酸钯、三叔丁基膦的催化作用下合成N,N,N’,N’-四苯基-1,1'-联苯-4,4’-二胺(TPD)的反应.考察了原料配比、反应时间、催化剂用量以及反应温度对产品收率的影响,得到优化工艺条件为二苯胺与4,4 '-二溴联苯的摩尔比为2.5∶1,醋酸钯用量为0.05mmol,在145℃回流反应6h,产品收率为78.89％.在此条件下,用4,4’-二溴联苯分别与3-甲基二苯胺、4-甲基二苯胺反应合成了N,N'N'-二苯基-N,N '-二(3-甲基苯基)-1,1'-联苯-4,4’-二胺(m-TPD)、N,N’-二苯基-N,N’-二(4-甲基苯基)-1,1’-联苯-4,4’-二胺(p-TPD),产品收率分别为75.59％和69.96％.通过比较,新工艺有效地降低了工艺物料平衡图(PFD)类空穴传输材料的合成成本.     

Effects of cold metal transfer mode on the reaction layer of wire and arc additive-manufactured Ti-6Al-4V/Al-6.25Cu dissimilar alloys

Components of Ti and Al dissimilar alloys were obtained by wire and arc additive manufacturing using two cold metal transfer (CMT) modes.Direct current CMT (DC-CMT) mode was used for Ti alloy deposition,and DC-CMT or CMT plus pulse (CMT + P) mode was used for the Al alloy deposition.During deposition of the first Al alloy layer,little and a significant amount of Ti alloy were melted using DC-CMT and CMT +P mode,respectively.TiAl3 formed in the reaction layer when DC-CMT mode was used,while TiAl3,TiAl,and Ti3Al formed in the reaction layer when CMT + P mode was used.Compared to using DC-CMT mode,more cracks occurred when using CMT + P.The nanohardness of the reaction layer was between that of the Al and Ti alloys,irrespective of the CMT modes.The average tensile strengths of the samples us ingDC-CMT and CMT + P mode were 108 MPa and 24 MPa,respectively.DC-CMT mode was more suitable for the wire and arc additive manufacturing of Ti/Al dissimilar alloys.