溶胶-凝胶法制备PEW/SiO2杂化材料及表征

通过熔融接枝反应将乙烯基三甲氧基硅烷（VTMS）接枝到聚乙烯蜡（PEW）分子链上,接枝物红外光谱（FTIR）的1090、1030、960 cm^-1等处出现了—Si—O—CH3的特征吸收峰。以正硅酸乙酯（TEOS）为前驱体,混入接枝PEW中,通过溶胶-凝胶法（sol-gel）制备了PEW/SiO₂杂化材料。使用透射电镜（TEM）和热重分析（TG）研究了杂化材料的形态及性能,结果表明,通过sol-gel可以制备SiO₂含量为0. 98%～4. 12%的杂化材料,SiO₂颗粒与PEW接枝物分子间具有良好的相容性,纳米SiO2的存在提高了PEW的耐热性能,当SiO₂含量为3. 75%时,PEW的分解温度提高了21. 34℃。     

Study on the preparation and properties of styrene–butyl acrylate–silicone copolymer latices

Copolymer latices of styrene–butyl acrylate–silicone were prepared using a semicontinuous addition process and batch and monomer emulsion addition processes. The results showed that a stable latex with narrow particle size dispersion and a high monomer conversion can be obtained only by the semicontinuous addition process. The simultaneous free‐radical and ionic copolymerization mechanisms were discussed. 3‐Methacryloyloxypropyl trimethoxysilane in this work was used as a coupling agent to form a chemical bond between vinyl polymer and polysiloxane. It was found that the copolymerization reaction and the properties of latex and latex film were obviously influenced by silicone content. When the silicone content was less than 25 wt %, copolymerization proceeded readily and a stable latex could be prepared. With increasing silicone content, monomer conversion, latex stability, film hardness, and tensile strength decreased, whereas the water resistance and impact strength increased. Results of Soxhlet extraction, silicon analysis, and dynamic mechanical properties of latex polymer confirmed the occurrence of copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3194–3200, 2001     

Fabrication of a New Polyimide/Titania (TiO2) Nanocomposite Thin Film by the Sol-Gel Route

Polyimide/titania nanocomposite (PI/TiO₂ NC) was successfully fabricated through the in situ formation of TiO₂ within a PI matrix by the sol-gel process. FT-IR and XRD results confirmed the formations of the TiO₂ in the PI matrix. Transmission electron microscopy of the NC10% showed that the TiO₂ phase was well dispersed in the polymer matrix. The mechanical properties of the NC films were increased and elongation at break decreased with increasing TiO₂ content. Thermogravimetric analysis results revealed that the decomposition temperature of hybrid materials was increased with an increase in the content of TiO₂ nanoparticles within the NC films.     

3-氯丙基三甲氧基硅烷合成新方法的研究

为提高产率、降低成本,以3-氯丙烯和三甲氧基硅烷为原料、水合三氯化钌为催化剂进行3-氯丙基三甲氧基硅烷的一步合成反应,研究了反应温度、催化剂浓度、原料的加料方式、反应时间、原料的配比对产物收率的影响.结果表明,最佳的反应条件为反应温度80℃、钌催化剂质量分数63 μg/g、3-氯丙烯向三甲氧基硅烷中滴加方式、三甲氧基硅...     

甲氧基聚氧化乙烯丙基三甲氧基硅烷的合成与表征

以甲氧基聚氧化乙烯单烯丙基醚和三甲氧基硅烷为原料进行硅氢加成反应,实验分别从反应时间、温度、催化剂用量、反应物物质的量比、甲氧基聚氧化乙烯单烯丙基醚分子量对甲氧基聚氧化乙烯单烯丙基醚的硅氢加成反应转化率的影响进行了研究。结果表明,当甲氧基聚氧化乙烯单烯丙基醚与三甲氧基硅烷的物质的量比为1∶1.2,反应温度85℃,时间8...     

γ-（2，3-环氧丙氧）丙基三甲氧基硅烷的合成研究

以三甲氧基氢硅与烯丙基缩水甘油醚为原料,在氯铂酸-N,N-二甲基苯胺一异丙醇溶液为催化剂下硅氢加成反应得γ-（2,3-环氧丙氧）丙基三甲氧基硅烷,讨论了影响硅氢加成反应的主要因素,并得出了最佳合成工艺条件：催化剂用量为4×10^-6、反应温度95℃～105℃、反应时间为1．5h、原料配比三甲氧基氢硅／烯丙基缩水甘油醚摩尔比为1．05,在此条件下γ-（2,3-环氧丙氧）丙基三甲氧基硅烷的收率达89．3％。     

氧化铝的表面改性及其在导热有机硅灌封胶中的应用

比较了3种硅烷偶联剂对氧化铝的表面改性效果。相对于未改性氧化铝,十六烷基三甲氧基硅烷、γ-氨丙基三乙氧基硅烷和乙烯基三(β-甲氧基乙氧基)硅烷改性氧化铝的吸油值分别降低了56.8%、32.5%、35%,而对应的硅橡胶胶料的黏度分别降低了74.3%、48.6%和45.4%,分散性提高,颗粒无明显团聚,改性效果突出;十六烷基三甲氧基硅烷的改性效果最优,其最佳用量为氧化铝粉体质量的1.5%。将十六烷基三甲氧基硅烷改性氧化铝填充至有机硅灌封胶中,考察了填充量对硅橡胶导热性能、黏度和力学性能的影响。结果表明,当改性氧化铝的填充量为900份时(相对于100份乙烯基硅油),胶料的黏度仅11 800 mPa.s,硫化硅橡胶的热导率高达2.47 W/m.K,拉伸强度1.6 MPa,拉断伸长率35%。     

Adhesion of Injection Molded PVC to Steel Substrates

Interactions occurring at the interface between injection-molded poly (vinyl chloride) (PVC) and steel substrates that were coated with thin films of aminosilanes were investigated by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). The silane films were formed by adsorption of γ-aminopropyltriethoxysilane (γ-APS) or N-(2-aminoethyl-3-aminopropyl)trimethoxysilane (γ-AEAPS) from 2% aqueous solutions onto polished steel substrates. PVC was injection molded onto the silane-primed steel substrates and annealed at temperatures up to 170°C for times as long as 30 min. PVC was peeled off of the primed steel substrates using a 90° peel test and the substrate failure surfaces were thoroughly rinsed with tetrahydrofuran (THF) and distilled water to remove PVC and other compounds that were not strongly bonded to the substrates. The PVC failure surfaces were characterized by attenuated total reflection infrared spectroscopy (ATR) and PVC rinsed off of the substrate failure surfaces was characterized by transmission infrared spectroscopy. The resulting transmission and ATR spectra showed an absorption band near 1650 cm^-1 that was attributed to unsaturation in PVC. The substrate failure surfaces were characterized by XPS; curve-fitting of N(1s) and Cl(2p) high-resolution spectra showed the formation of amine hydrochloride complexes by protonation of amino groups of the silanes with HCl that was liberated from PVC during the onset of thermal dehydrochlorination. Furthermore, quaternization or nucleophilic substitution of labile pendent allylic chloride groups by amino groups on the silanes took place, thus grafting PVC onto the aminosilanes. It was determined that PVC that had β-chloroallyl groupings along its chains showed better adhesion with steel primed with aminosilanes and that generation of allylic chloride groups in PVC chains was the rate-limiting step in the reaction between PVC and aminosilane. Moreover, the effect of crosslinking of silane films on adhesion between PVC and aminosilane primed steel was investigated and it was concluded that interdiffusion of the polymer phase and the silane phase was also critical in obtaining good adhesion.     

双溶剂法合成三甲氧基硅烷

采用双溶剂法,以三氯氢硅和甲醇为原料合成三甲氧基硅烷。考察了溶剂种类、原料配比、反应温度、甲醇的滴加速度、氮气鼓泡量等因素的影响,最佳合成条件为:以二甲苯和石油醚(30～60℃)为双溶剂体系,n (三氯氢硅):n(甲醇)=1:2．8,反应温度35～45℃,甲醇的滴加速率6．2～7．2 mL/min,氮气鼓泡量约0．15 m~3/h,产物收率大于90%。     

巯基功能化活性炭对汞离子的吸附性能研究及机理初探

以活性炭为基体,利用γ-巯丙基三甲氧基硅烷(TMMPS)为改性剂对其进行巯基改性,获得了新型除汞材料巯基功能化活性炭(SFAC).采用SEM-EDS、FT-IR对材料进行表征,结果表明-SH成功被引入到活性炭表面.吸附等温线研究表明改性后活性炭(SFAC)的吸附容量高达472 mg/g,较原活性炭(AC)提高了近1倍.针对高酸性的PVC含汞废水环境,模拟考察了溶液酸度对材料吸附性能的影响,结果表明SFAC在高酸[w(HCl)=31％]下,材料仍能稳定存在,并保持一定的吸附能力,表明材料有很强的耐酸性.同时开展材料对汞离子的吸附动力学研究,初步探讨Hg2+在SFAC上的吸附机理.