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.     

新型功能性倍半硅氧烷的合成与表征

以三氯丙基三甲氧基硅烷、苯基三甲氧基硅烷为原料,在一定条件下合成了笼形八聚(三氯丙基)倍半硅氧烷和双层倍半硅氧烷。进一步与叠氮钠、冠醚等通过取代反应、点击反应等方法来合成多种功能性的倍半硅氧烷,它们在复合材料等领域将有很好的应用前景。利用1-核磁共振光谱、13-核磁共振光谱、29-Si核磁共振光谱、基质辅助激光解吸电离飞行时间质谱等手段,对它们的结构分别进行了表征。     

桥联聚倍半硅氧烷纳米带的制备

依照文献以L-丙氨酸为手性源合成了一阴离子型两亲小分子化合物,利用圆二色谱研究了该化合物在水中的自组装行为,同时通过溶胶-凝胶复制法,以该手性阴离子型两亲小分子化合物的自组装体作为模板,以(3-胺丙基)三甲氧基硅为结构助剂,以倍半硅氧烷为硅源制备了桥联聚倍半硅氧烷纳米带,并利用扫描电镜、透射电镜和圆二色谱方法研究了该纳米带结构。透射电镜和圆二色谱表征结果表明,1,4-亚苯基桥联聚倍半硅氧烷和4,4′-亚联苯基桥联聚倍半硅氧烷的结构为中间有间隙的双层纳米带,且在纳米和埃的尺度下具有手性。     

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.     

聚苯基倍半硅氧烷研究进展

分别介绍了梯型、笼形聚苯基倍半硅氧烷及其共聚物的结构、性质和合成方法,重点综述了苯基倍半硅氧烷共聚物研究进展,并对苯基倍半硅氧烷材料的发展趋势进行了展望。     

梯形聚苯基倍半硅氧烷的新型制备方法

以苯基三氯硅烷为原料,利用经过改良的热平衡缩合法,得到产物梯形聚苯基倍半硅氧烷(Ph-T)。借助傅立叶红外、X射线衍射和核磁共振硅谱等方法,确定了产物具有规整的梯形分子结构;以热重分析测定了其耐热性,在空气中失重5%时温度为530℃,具有优良的耐热性能。     

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...     

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.     

取代基对聚倍半硅氧烷结构和表面特性的影响

采用酸性条件下有机三烷氧基硅烷的水解缩合制备聚倍半硅氧烷.通过富里叶红外光谱(FTIR)、29Si核磁共振谱(29Si NMR)、X射线衍射谱(XRD)、原子力显微镜(AFM)、光学接触角(OCA)等手段对样品的结构和表面进行了测试和表征,研究结果表明随着有机三烷氧基硅烷中取代基的碳原子数目的增加,其相应聚倍半硅氧烷的笼状网状结构比增加,缩合程度降低,涂层的表面粗糙度和水接触角增大.     

CO_2增稠剂聚醋酸乙烯酯-甲基倍半硅氧烷的合成

以过氧化苯甲酰为链引发剂,采用接枝聚合的方法在聚甲基倍半硅氧烷的支链上修饰聚醋酸乙烯酯,制得甲基倍半硅氧烷与醋酸乙烯酯的接枝共聚物。产物的红外光谱中同时出现了羰基的1747 cm-1、甲基的1377 cm-1以及Si-O-Si的1027 cm-1和1121 cm-1等特征吸收峰,表明该产物中同时含有醋酸乙烯酯和聚甲基倍...     

聚碳酸酯与硅倍半氧烷复合物气相热裂解和凝聚相产物对比

采用实验室自制的笼型八苯基硅倍半氧烷(OPS)和一种新型阻燃剂含磷笼型低聚硅倍半氧烷(DOPO-POSS),通过双螺杆挤出机加工的方式与聚碳酸酯(PC)共混制得质量分数4%DOPO-POSS和6%OPS的阻燃复合物。利用裂解-气相色谱/质谱联用仪(Py-GC/MS)对复合物的裂解产物进行了分析;通过傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜-X射线能谱仪(SEM-EDS)分别对残炭的凝聚相结构与元素组分进行分析。Py-GC/MS分析结果表明,总的质谱图显示PC/DOPO-POSS和PC/OPS复合物在热解过程中释放出大量小分子气体产物,有效地促进了炭层的膨胀;OPS在气相裂解中释放出大量的苯和气态Si O2,并有少量CO2气体释放;DOPO-POSS裂解过程中释放出多种小分子气体,其中DOPO含量最高,达到26%。FT-IR对凝聚相炭层结构测试表明,PC/OPS和PC/DOPO-POSS复合物的内部炭层结构相似,由无机炭结构组成;在外部炭层结构中,PC/OPS复合物含有大量-O-Si-O-结构,并伴随有少量的芳香烃炭结构和Si-C结构;PC/DOPO-POSS复合物主要由-P(=O)-O-Si-结构和少量Si-O结构组成。SEM-EDS测试结果表明,PC/DOPO-POSS复合物炭层成分中C元素含量最高,O元素含量次之,Si和P元素含量最少;PC/OPS复合物炭层成分中,Si和O元素含量最大,占到92.5%,C元素含量最低。     

Synthesis and characterization of functional ladder-like polysilsesquioxane and their hybrid films with polyimide

Ladder-like polyphenylsilsesquioxane has been synthesized by a convenient two-step approach and then modified to ladder-like poly(nitrophenyl)silsesquioxane (LPNPSQ) and poly(aminophenyl)silsesquioxane (LPAPSQ) by nitration and reduction reaction. These ladder-like polysilsesquioxanes (LPSQs) were characterized by Fourier transform infrared, nuclear magnetic resonance and X-ray diffraction (XRD). The results confirm the ladder-like structures of LPSQs and suggest the decrease of regularity after the chemical modification. Then high performance polyimide/ladder-like polysilsesquioxane (PI/LPSQ) hybrid films have been prepared by incorporating synthetic LPSQs with different functional groups into PI matrix, respectively, using conventional techniques. The interfacial interactions between PI matrix and LPSQ were investigated with XRD and scanning electron microscopy. Then the thermal and mechanical properties of the hybrid films were studied using dynamic mechanical analysis and tensile tests. The results indicate that different functional groups in LPSQs have great effects on the interfacial interactions and the properties of the hybrids. Both LPNPSQ and LPAPSQ can be dispersed uniformly in PI matrix because of the physical or chemical interaction between functional groups and PI. With these strong interfacial interactions, PI/LPNPSQ and PI/LPAPSQ hybrid films show higher glass transition temperatures and better mechanical properties.     

Controllable preparation of thio-functionalized composite polysilsesquioxane microspheres in a microreaction system

Controllable preparation of monodispersed composite polysilsesquioxane microspheres (CPSQs) with scalability is required but difficult to realize in a conventional stirred batch reactor because of the reactors’ poor mixing performance and scaling-up effects. A new semi-continuous microreaction system integrating a microreactor with a stirred batch reactor was developed for the synthesis of monodispersed thio-functionalized CPSQs by employing a two-step sol–gel method. Methyltrimethoxysilane and (3-mercaptopropyl)trimethoxysilane were used as silicon sources. The effects of the synthesis variables were systematically studied. The particle size could be adjusted between several hundreds of nanometers and several micrometers with a narrow size distribution (the coefficient of variation was <10%), and the sulfhydryl group (SH) concentration reached 14.13 at.%. Compared with the batch reactor, the semi-continuous microreaction system showed higher synthesis reproducibility and higher potential for the large-scale production of CPSQs.     

Biodegradable Polysilsesquioxane Nanoparticles as Efficient Contrast Agents for Magnetic Resonance Imaging

Polysilsesquioxane (PSQ) nanoparticles are crosslinked homopolymers formed by condensation of functionalized trialkoxysilanes, and provide an interesting platform for developing biologically and biomedically relevant nanomaterials. In this work, the design and synthesis of biodegradable PSQ particles with extremely high payloads of paramagnetic Gd(III) centers is explored, for use as efficient contrast agents for magnetic resonance imaging (MRI). Two new bis(trialkoxysilyl) derivatives of Gd(III) diethylenetriamine pentaacetate (Gd‐DTPA) containing disulfide linkages are synthesized and used to form biodegradable Gd‐PSQ particles by base‐catalyzed condensation reactions in reverse microemulsions. The Gd‐PSQ particles, PSQ‐ 1 and PSQ‐ 2 , carry 53.8 wt% and 49.3 wt% of Gd‐DTPA derivatives, respectively. In addition, the surface carboxy groups on the PSQ‐ 2 particles can be modified with polyethylene glycol (PEG) and the anisamide (AA) ligand to enhance biocompatibility and cell uptake, respectively. The Gd‐PSQ particles are readily degradable to release the constituent Gd(III) chelates in the presence of endogenous reducing agents such as cysteine and glutathione. The MR relaxivities of the Gd‐PSQ particles are determined using a 3T MR scanner, with r₁ values ranging from 5.9 to 17.8 mMs^?1 on a per‐Gd basis. Finally, the high sensitivity of the Gd‐PSQ particles as T₁‐weighted MR contrast agents is demonstrated with in vitro MR imaging of human lung and pancreatic cancer cells. The enhanced efficiency of the anisamide‐functionalized PSQ‐ 2 particles as a contrast agent is corroborated by both confocal laser scanning microscopy imaging and ICP‐MS analysis of Gd content in vitro.     

不同有机官能团聚硅氧烷微球的制备与表征

以乳液聚合法制备粒径分布均匀、球形度良好的聚甲基硅氧烷微球(MPSQ)、聚乙烯基硅氧烷微球(VPSQ)、聚巯丙基硅氧烷微球(MPPSQ),采用SEM、DLS、FT-IR、XRD、TGA、接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。研究结果表明,有机基团对微球的耐热性与疏水性有重要影响,MPSQ和VPSQ的耐热性优于MPPSQ,疏水性从高到低依次为:MPSQ>VPSQ>MPPSQ。聚硅氧烷微球的形成过程可能是单体首先在催化剂的作用下,水解生成硅醇,硅醇开始缩聚形成核,之后通过吸取溶液的硅醇,不断成长,最终形成微球,其中同时存在核生成和核生长,两过程相互竞争,哪个过程占优势取决于反应条件。提高反应温度,使得核生成占优势,最终生成的微球粒径变小,单分散性变差。     

Fabrication of conductive silver micropatterns on an organic-inorganic hybrid film by laser direct writing

This paper describes fabrication of silver (Ag) micropatterns on a double-decker-shaped polysilsesquioxane (DDPSQ) hybrid film by laser-induced pyrolysis (LIP) of a film prepared from liquid-dispersed Ag nanoparticles. The line width of Ag micropatterns fabricated by LIP can be controlled flexibly by changing the numerical aperture (NA) value of an objective lens and the focusing point. By changing NA value of an objective lens, line widths of Ag micropatterns can be varied flexibly from 75 μm to 5 μm. The Ag micropatterns show an excellent adherence to DDPSQ surface as evaluated by adhesive tape test. The resistivity of the Ag micropattern is determined to be 4.3 × 10^− 6 Ω cm, which is comparable to that of bulk Ag (1.6 × 10^− 6 Ω cm).     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.