POSS改性聚亚苯基硅氧烷的合成与表征

以α,ω-二羟基聚（四甲基对硅亚苯基）硅氧烷为起始原料,分别与1,4-双（甲基氯硅基）苯和甲基二氯硅烷反应,合成了两种带硅氢基的聚亚苯基硅氧烷P1和P2;然后,再与烯丙基七戊基低聚倍半硅氧烷（烯丙基七戊基POSS）进行硅氢加成反应,引入POSS侧基,合成了POSS-P1和POSS-P2。经^1H NMR和^29Si NMR分析证实得到了目标产物;GPC分析表明,两种聚合物经POSS改性后摩尔质量均增大,摩尔质量分布变宽;DSC和TGA分析表明,两种聚合物经POSS改性后熔点分别提高8.4℃和10.6℃,热质量损失率达到5%时的温度分别提高197℃和162℃,且均在400℃以上。     

单官能化倍半硅氧烷的合成与表征

以异丁基三甲氧基硅烷为原料,通过部分水解缩合反应合成了七聚(异丁基)倍半硅氧烷三硅醇(T7);T7继续与乙烯基三氯硅烷、三氯氢硅、四氯化硅、3-氯丙基三氯硅烷反应封角后,得到单官能度的倍半硅氧烷(T8);T8再转化为其它官能团的倍半硅氧烷(POSS),合成了一系列单官能度的POSS:乙烯基POSS、活性氢基POSS、氯基POSS、羟基POSS、二甲基氢硅氧基POSS、氯丙基POSS、叠氮丙基POSS。利用1H核磁共振光谱、13C核磁共振光谱、29Si核磁共振光谱对它们的结构进行了详细的表征。     

笼型单乙烯基倍半硅氧烷的合成及表征

用环戊基三氯硅烷合成不完全缩合三羟基硅氧烷［(C₅H₉)₇Si₇O₉(OH)₃］,再以乙烯基三氯硅烷和不完全缩合三羟基硅氧烷为原料,以四氢呋喃和三乙胺为混合溶剂,通过“顶角-戴帽”反应合成了笼型单乙烯基倍半硅氧烷,即1,3,5,7,9,11,13-七环戊基-15-乙烯基笼型倍半硅氧烷(VinylPOSS)。利用FTIR、¹H NMR、²⁹Si NMR、¹³C NMR、元素分析、WAXD和TGA表征了VinylPOSS的结构及热稳定性。研究结果表明VinylPOSS的产率随着反应时间的增加而提高,当反应时间为10 h时,产率高达90%;其在弱极性溶剂中具有较好的溶解性,5%失重温度为283℃,800℃残留率为56%,具有较高的热稳定性。研究了VinylPOSS和高含氢硅油(HHSF)的反应性,结果表明VinylPOSS能与含氢硅油发生α、β加成反应, 且以β加成为主。     

聚醚硅氧烷/ 聚倍半硅氧烷双重改性蓖麻油基水性聚氨酯

以蓖麻油与聚醚硅氧烷（PEPSO）互混作为多元醇原料制备出植物油基水性聚氨酯。在预聚体合成过程中,加入不同含量的四羟基八苯基双层笼型倍半硅氧烷,通过醇羟基与异氰酸酯基的反应,将聚倍半硅氧烷（POSS）引入到植物油聚氨酯基体中,制备出聚氨酯纳米复合材料,并探讨纳米粒子-聚倍半硅氧烷对聚氨酯材料热稳定性,表面疏水性及力学性能的影响。热重分析（TGA）结果表明,复合材料的初始降解温度 T5% 和最终稳定温度 Tf 都会提高;静态接触角测试结果表明随 POSS 含量的增加,材料表面的疏水性随之增大。同时从扫描电镜图中可以看到,随着 POSS 含量的增加,断面的不平整度增大,粒子间的团聚愈发严重;拉伸测试结果表明 POSS 的引入能在一定程度上提高材料的拉伸强度。     

负离子聚合法合成笼型聚倍半硅氧烷双端基官能化聚苯乙烯及其表征

采用氯丙基七异丁基多面体低聚倍半硅氧烷为封端剂,通过负离子聚合法合成了笼型聚倍半硅氧烷(POSS)双端基官能化聚苯乙烯(POSS-PS-POSS)。采用核磁共振波谱和液相凝胶渗透色谱对POSS-PS-POSS的结构和相对分子质量及其分布进行了表征,证明了POSS与聚苯环乙烯基锂发生了封端反应生成POSS-PS-POSS。同时考察了调节剂和封端剂的用量、封端温度和时间、聚苯乙烯的数均分子量对封端效率的影响。结果表明,当四氢呋喃与双丁基锂的摩尔比为5.0/1.0、封端剂与双丁基锂的摩尔比为1.1/1.0、反应温度为60℃、反应时间为50 min时,封端效率最高。     

多面体低聚硅倍半氧烷的研究进展

综述了多面体低聚硅倍半氧烷（POSS）的结构特性和合成方法，重点介绍了同取代基、单官能度、双官能度、多官能度四类POSS的合成方法，比较了各种合成方法的优劣，展望了POKS合成研究的发展方向。     

硅醇基POSS改性有机硅树脂的热性能

以甲基苯基有机硅树脂作为基体,硅醇基笼形倍半硅氧烷(POSS)作为改性剂,研究了不同POSS加入量和不同POSS加入方式对有机硅树脂热性能的影响,并对不同结构硅醇基POSS改性的有机硅树脂的热性能进行了综合评价。结果表明,采用三硅醇苯基POSS作为改性剂且其质量分数为5%时,通过加热反应方式制备的改性甲基苯基有机硅树脂起始热分解温度和900℃热失重率分别为448.3℃和15.45%。与未改性的甲基苯基有机硅树脂相比,起始热分解温度提高了48.9℃,900℃热失重率降低了6.37%。     

官能化POSS的制备及其在聚合物改性中的应用进展

介绍了单官能和多官能多面体低聚倍半硅氧烷(POSS)的制备方法:顶端-封角法、三官能团硅烷RSi X3的水解缩合法、官能团衍生法、聚有机倍半硅氧烷的热分解;然后从物理改性和化学改性两方面阐述了POSS改性聚合物的方法;最后总结了官能化POSS在聚合物改性中的应用进展并对其今后的发展方向进行了展望。     

官能化POSS的制备及其在聚合物改性中的应用进展

介绍了单官能和多官能多面体低聚倍半硅氧烷(POSS)的制备方法:顶端-封角法、三官能团硅烷RSi X3的水解缩合法、官能团衍生法、聚有机倍半硅氧烷的热分解;然后从物理改性和化学改性两方面阐述了POSS改性聚合物的方法;最后总结了官能化POSS在聚合物改性中的应用进展并对其今后的发展方向进行了展望。     

含POSS聚芴亚胺酮的合成、表征与性能研究

以9,9-双（4-氨基苯基）芴、4,4＇-二溴二苯甲酮及八氨基苯基笼型聚倍半硅氧烷（POSS）为反应单体,通过Buchwald-Hartwig交叉偶联反应,制得了一系列不同POSS含量的POSS基聚芴亚胺酮（PIKF）。通过红外、核磁共振、电子能谱、X射线衍射等对其结构进行了表征,采用热失重分析、紫外/可见光谱及荧光光谱测试了其性能。结果表明,随着POSS含量的提高,聚合物的起始热分解温度逐步升高（从497.62℃升高到508℃和541.61℃）;POSS的引入可有效降低聚集现象的发生,从而使其最大吸收波长红移（从385 nm移至412 nm）;而非共轭大体积POSS基的引入打断了链内共轭,使聚合物的最大发射波长蓝移（从518 nm至490 nm）。     

Characterization of poly(vinyl pyrrolidone‐co‐isobutylstyryl polyhedral oligomeric silsesquioxane) nanocomposites

Poly(vinyl pyrrolidone‐co‐isobutyl styryl polyhedral oligomeric silsesquioxane)s (PVP–POSS) were synthesized by one‐step polymerization and characterized using FTIR, high‐resolution ¹H‐NMR, solid‐state ¹³C‐NMR, ²⁹Si‐NMR, GPC, and DSC. The POSS content can be controlled by varying the POSS feed ratio. The T_g of the PVP–POSS hybrid is influenced by three main factors: (1) a diluent role of the POSS in reducing the self‐association of the PVP; (2) a strong interaction between the POSS siloxane and the PVP carbonyl, and (3) physical aggregation of nanosized POSS. At a relatively low POSS content, the role as diluent dominates, resulting in a decrease in T_g. At a relatively high POSS content, the last two factors dominate and result in T_g increase of the PVP–POSS hybrid. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2208–2215, 2004     

Synthesis, characterization, and properties of chain terminated polyhedral oligomeric silsesquioxane-functionalized perfluorocyclobutyl aryl ether copolymers

A new class of perfluorocyclobutyl (PFCB) polymers covalently functionalized with polyhedral oligomeric silsesquioxane (POSS) is presented. Three discreetly functionalized POSS monomers possessing thermally reactive trifluorovinyl aryl ether (TFVE) were prepared in good yields. The POSS TFVE monomers were prepared by initial corner-capping of cyclopentyl (-C₅H₉), iso-butyl (-CH₂CH(CH₃)₂), or trifluoropropyl (-CH₂CH₂CF₃) functionalized POSS trisilanols with acetoxyethyltrichlorosilane followed by sequential acid-catalyzed deprotection and coupling with 4-(trifluorovinyloxy)benzoic acid. TFVE-functionalized POSS monomers were thermally polymerized with 4,4′-bis(4-trifluorovinyloxy)biphenyl or 2,2-bis(4-trifluorovinyloxybiphenyl)-1,1,1,3,3,3-hexafluoropropane monomers via a condensate-free, [2 + 2] step-growth polymerization. The polymerization afforded solution processable PFCB polymers with POSS macromer installed on the polymer chain ends. POSS monomers and their corresponding copolymers were characterized by ¹H, ¹³C, ¹⁹F, and ²⁹Si NMR, GPC, ATR-FTIR, and elemental combustion analysis. GPC trace analysis showed agreeable number-average molecular weight for various weight percent of cyclopentyl or iso-butyl and trifluoropropyl chain terminated POSS PFCB copolymers. DSC analysis showed the introduction of increasing POSS weight percent in the endcapped PFCB copolymers lowers the glass transition temperatures as high as 31 °C. On the other hand, the trifluoropropyl POSS endcapped PFCB polymer glass transition temperature was unaffected when copolymerized with the more fluorinated 2,2-bis(4-trifluorovinyloxybiphenyl)-1,1,1,3,3,3-hexafluoropropane monomer. TGA analysis of POSS PFCB copolymers showed step-wise decomposition of copolymers resulting from the initial degradation of the POSS cages at 297-355 °C in nitrogen and air which was confirmed by pyrolysis coupled with GC-MS. This initial weight loss was proportional to the weight percent of POSS incorporated into the polymer. The balance of decomposition was observed at 450-563 °C in nitrogen and air which is higher than the PFCB homopolymers in most cases. Polymer surface characterization was performed on spin cast transparent, flexible films. These composite films exhibited good POSS dispersion within the matrix PFCB polymer as was shown by TEM analysis.     

Development of Siloxane Based Tetraglycidyl Epoxy Nanocomposites for High Performance Applications—Study of the Mechanical,Thermal, Water Absorption and Flame Retardant Behaviour

A study was made in the present investigation on siloxane containing tetraglycidyl epoxy nanocomposites in order to determine their suitability for use in high performance applications. The synthesis of the siloxane tetraglycidyl epoxy resin denoted as ‘E’ was done and it was characterized by Fourier Transform Infrared (FT-IR) spectra and ¹H, ¹³C Nuclear Magnetic Resonance (NMR) spectra. Nanoclay and polyhedral oligomeric silsesquioxanes (POSS)-amine nanoreinforcements denoted as N1 and N2 were incorporated into the synthesized epoxy resin. Curing was done with diaminodiphenylmethane (DDM) and bis (3-aminophenyl) phenylphosphine oxide (BAPPO) curing agents denoted as X and Y respectively. The mechanical, thermal, flame retardant and water absorption behaviour of the epoxy nanocomposites were studied and the results are discussed.     

Thermally initiated cationic polymerization and properties of epoxy siloxane

Difunctional epoxy siloxane monomers containing disiloxane, trisiloxane, and tetrasiloxane were prepared by hydrosilylation of an α,ω‐difunctional Si? H‐terminated siloxane with a vinyl‐functional epoxide. Cationic polymerization of these monomers using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantimonate and their reactivities were examined. The reactivity order was disiloxane > trisiloxane > tetrasiloxane. Thermal discoloration of these polymers increased with catalyst concentration and also with the length of dimethyl siloxane. UV discoloration was also accelerated by catalyst. From the thermo gravimetric analysis, it was found that the thermal stabilities of polymers increased with increasing the length of dimethyl siloxane chain. Mechanical properties of polymers were also tested by thermal mechanical analysis and dynamic mechanical analysis, and it was found that the flexibility of polymers was increased with increasing siloxane chain length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2010–2019, 2006     

Synthesis of eugenol‐based polybenzoxazine–POSS nanocomposites for low dielectric applications

Nanocomposites of eugenol‐based polybenzoxazines/amine containing polyhedral oligomeric silsesquioxane (POSS) have been prepared through copolymerization of allyl‐containing benzoxazine compounds and amine containing POSS. Their structures, curing behaviour, and thermomechanical properties were characterized by Fourier transform infrared, ¹H‐NMR, ¹³C‐NMR, X‐ray diffraction, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The nanoscale dispersion of POSS cores in the nanocomposites was verified by scanning electron microscopy, atomic force microscopy, and transmission electron microscopy studies. The results from DMA and TGA show that the thermal stability, crosslink density and flame retardance of the nanocomposites increased when small amounts of POSS cores (5 wt%) were incorporated into the system. Further the POSS incorporation reduces the dielectric constant of the benzoxazines to about 1.32. Hence, the prepared nanocomposites could be used as ultra‐low‐k materials for advanced microelectronics. POLYM. COMPOS., 36:1973–1982, 2015. © 2014 Society of Plastics Engineer     

Preparation and thermal property of hybrid nanocomposites by free radical copolymerization of styrene with octavinyl polyhedral oligomeric silsesquioxane

The poly(styrene‐co‐octavinyl‐polyhedral oligomeric silsesquioxane) (PS–POSS) organic–inorganic hybrid nanocomposites containing various percent of POSS were prepared via one‐step free radical polymerization and characterized by FTIR, high‐resolution ¹H NMR, ²⁹Si NMR, GPC, DSC, and TGA technologies. The POSS contents in these nanocomposites were determined using FTIR calibration curve. The result shows that the POSS contents in nanocomposites can be tailored by varying the POSS feed ratios. On the basis of the POSS contents in the nanocomposites and the ¹H NMR spectra, the number of reacted vinyl groups of each octavinyl‐POSS macromonomer were calculated to be 6–8. DSC and TGA measurements indicate that the incorporation of POSS into PS homopolymer can apparently improve the thermal properties of the polymeric materials. The dramatic T_g and T_dec increases are mainly due to the formation of star and low cross‐linking structure of the nanocomposites, where POSS cores behave as the joint points and hinder the motion and degradation of the polymeric chains. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

2-溴芴酮的合成

以煤焦油分离产品芴为原料,通过溴代、氧化反应制得2-溴芴酮,对氧化过程中不同溶剂及用量、碱的用量、反应时间对产率的影响进行了优化选择。较佳的反应条件为:四氢呋喃作溶剂,m(2-溴芴)∶m(四氢呋喃)=1∶5.5,n(2-溴芴)∶n(氢氧化钾)=10∶1,室温反应5h,2-溴芴酮的产率大于98.0%,质量分数高于98.0%。产物的结构通过红外和核磁共振波谱进行了表征。     

Synthesis,structure, and properties of high‐impact polystyrene/octavinyl polyhedral oligomeric silsesquioxane nanocomposites

The organic–inorganic hybrid nanocomposites from high‐impact polystyrene/octavinyl polyhedral oligomeric silsesquioxane (HIPS/POSS) containing various percentages of POSS were prepared by free radical polymerization and characterized by Fourier transform infrared spectroscopy (FTIR), ¹H‐NMR, thermal gravity analysis (TGA), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The octavinyl POSS has formed covalent bond connected PS‐POSS hybrid with polystyrene. POSS can well disperse in the composites at the composition of 0.5 and 1 wt%. The mechanical properties and thermostability of HIPS/POSS nanocomposites were significantly improved. The tensile strength, the izod impact strength, and the elongation at break of the nanocomposite containing 1 wt% of POSS was increased, respectively, by 15.73%, 75.62%, and 72.71% in comparison with pristine HIPS. The thermal decomposition temperature of HIPS/POSS (1 wt% of POSS) was 33°C higher than that of pristine HIPS. The HIPS/POSS nanocomposites showed great potential for applications in many fields, such as electric appliance and automotive trim. POLYM. COMPOS. 37:1049–1055, 2016. © 2014 Society of Plastics Engineers