Synthesis,Morphology, and Viscoelastic Properties of Polyhedral Oligomeric Silsesquioxane Nanocomposites with Epoxy and Cyanate Ester Matrices

Octaaminophenyl(T₈)POSS [1, (C₆H₄NH₂)₈(SiO_1.5)₈] and dodecaaminophenyl(T₁₂)POSS [2, (C₆H₄NH₂)₁₂(SiO_1.5)₁₂] were synthesized, characterized and then incorporated into two types of thermoset resins: (1) the bisphenol-F-based cyanate ester resin, PT-15, and (2) epoxy (Epon 828, Shell Chemical Corp.)/4,4′-diaminodiphenylmethane (DDM) resin, respectively, to make two series of nanocomposites. The sum of amino groups in both DDM and POSS were held in a 1:1 mole ratio to the epoxy groups. EPON-828/1/DDM and EPON-828/2/DDM composites (78.63/0/21.37, 77.48/5/17.52, 76.34/10/13.66, 74.05/20/5.95 and 72.28/27.72/0 wt/wt/wt compositions for both series) were prepared. PT-15/1 and PT-15/2 composites (99/1, 97/3 and 95/5 wt/wt compositions for both types) were also prepared. These nanocomposites were characterized by transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), solvent extraction and FT-IR. In all systems, POSS 1 and 2 were chemically bound into the resin matrix and phase-separated POSS particle domains were not observed. Incorporation of both 1 and 2 can dramatically elevate the high temperature bending storage moduli, E′, of epoxy resins.     

氰酸酯树脂/八(γ-氯丙基)多面体低聚倍半硅氧烷复合材料

采用八(γ-氯丙基)多面体低聚倍半硅氧烷(T8)改性氰酸酯树脂(CE)制备了系列CE/T8复合材料。研究了复合材料的冲击性能、动态热力学性能、热稳定性能以及断面形貌。结果表明:T8的加入能明显提高复合材料的冲击性能,当加入10%的T8时,复合材料的冲击强度较纯CE提高了12.29 kJ/m2;复合材料在高温阶段(大于500℃)的热稳定性与纯CE相比有一定提高,有助于改善CE的阻燃性能;T8的加入使复合材料的玻璃化转变温度和储能模量均有所降低。     

Polyhedral Oligomeric Silsesquioxane (POSS)-Styrene Macromers

Four polyhedral oligomeric silsesquioxane (POSS) macromers, R₇Si₈O₁₂styrene (R=isobutyl, cyclopentyl, cyclohexyl, or phenyl), containing a single polymerizable styrene unit were synthesized from the POSS-trisilanols R₇Si₇O₉(OH)₃ in a high yield and purity. The base-assisted reaction to produce these macromers appears to be general for POSS-trisilanols of this type. However, in some cases it may be necessary to control the rate at which the base is introduced during reaction to prevent unwanted side reactions that decompose the trisilanol. Cyclohexyl-, cyclopentyl-, and isobutyl-substituted POSS-stryenes (at 30 wt% or approximately 4 mol% loadings) undergo free radical bulk polymerizations with styrene to produce polymers that show variation in the modulus above the glass transition temperature. The phenylPOSS derivative is too insoluble in styrene to undergo this polymerization. The effect on the modulus is more pronounced for the copolymers containing 30 wt% cycloalkylPOSS than that seen with isobutylPOSS, which is similar to that for bulk polymerized polystyrene. The effect of the group at the POSS cage on bulk polymer properties has been noted before and is presumed to arise from differences in polymer microstructure.     

Morphology and Thermomechanical Properties of Melt‐Mixed Polyoxymethylene/Polyhedral Oligomeric Silsesquioxane Nanocomposites

The influence of the functionalization of fully condensed POSS cages on the properties of POM‐based nanocomposites is studied. POSS with different organic substituents [glycidylethyl, aminopropylisobutyl, and poly(ethylene glycol)] are taken into account and melt mixed with POM. Good dispersion was achieved upon the addition of amino functionalized POSS, leading to an increase on the thermal decomposition temperature under nitrogen atmosphere up to 50 °C. However, µm‐size aggregates were observed for other nanocomposites. There is no significant change in other thermal properties of the nanocomposites. The relationships among these effects and the morphological characteristics of the systems were analyzed.

     

笼型聚倍半硅氧烷(POSS)改性聚氨酯的研究进展

介绍了笼型聚倍半硅氧烷(POSS)的结构特征及性能特点,利用其与聚合物间良好的相容性,可以将带有一个或多个反应性基团的P OSS经物理混合或化学键合等方式,在聚氨酯体系内形成侧链型、线型和星型结构,从纳米尺寸上实现对材料的设计及改性,以改善聚氨酯材料本身在耐热性、耐水性和耐候性等方面的不足.最后对P OSS在聚氨酯材料...     

LED封装用新型聚倍半硅氧烷材料的设计、合成与表征

以乙烯基三乙氧基硅烷为原料,通过水解缩合反应制成八乙烯基倍半硅氧烷(Vi-POSS),然后与七甲基三硅氧烷进行硅氢加成反应,获得一种无色透明POSS衍生物,并用FTIR、1H NMR、GPC、XRD和TGA对Vi-POSS及其衍生物的结构和性能进行表征。结果表明,七甲基三硅氧烷基成功连接到Vi-POSS中,该基团的引入使其初始分解温度从238.47℃升至486.52℃,显著提高了Vi-POSS的热稳定性;同时也有效地改善了与液体硅橡胶的相容性,可以获得一种无色透明的光学材料,有望在大功率LED封装材料中发挥重要作用。     

苯胺甲基笼型倍半硅氧烷改性环氧树脂的性能

研究了苯胺甲基笼型倍半硅氧烷(PAM-POSS)/环氧树脂(E-44)/MeTHPA/TEA体系的固化反应及其热性能,并考察了固化杂化树脂的力学性能。结果表明:随着PAM-POSS含量的增加,杂化树脂的冲击强度和弯曲强度呈先增大后下降的趋势,当PAM-POSS质量分数为10%时,冲击强度和弯曲强度达到最大值。     

八叠氮基聚倍半硅氧烷的合成及表征

以对羟基苯甲酸、八（二甲基硅氧基）聚倍半硅氧烷、叠氮化钠为原料,经酯化、醚化、水解、硅氢加成等反应制备了八叠氮基的六面体聚倍半硅氧烷[POSS-（N3）8],通过1H NMR、13C NMR、FT-IR对其进行了表征;并探讨了叠氮化反应温度对POSS-（N3）8产率的影响。结果表明,随着叠氮化反应温度的降低,POSS-（N3）8的产率逐渐增加;当叠氮化反应温度为70℃时,POSS-（N3）8的产率达到60%。     

Phenolic Resin/Octa(aminophenyl)-T<Subscript>8</Subscript>-Polyhedral Oligomeric Silsesquioxane (POSS) Hybrid Nanocomposites: Synthesis,Morphology, Thermal and Mechanical Properties

Octa(aminophenyl)-T₈-polyhedral silsesquioxane, 1, can serve as a cross-linking agent for organic polymeric resins. Amino functional groups of 1 can form chemical bonds or hydrogen-bonds to appropriate matrix polymers or resins. Various resole phenolic resin/1 nanocomposites (0, 1, 3, 6, and 12 wt% 1) were prepared. Hydrogen bonding between phenolic hydroxyls and the amino groups of 1 in these nanocomposites were investigated by FT-IR. The aggregation morphologies of 1 within these samples were examined using SEM, TEM, and Wide Angle X-ray Diffraction (WAXD) studies. Small quasispherical nanometer-sized POSS particles which were further aggregated into clusters, like individual grapes in a bunch, formed into phase-separated domains as large as 400 nm in diameter as the loading of 1 increased. These particles exhibited a broad 2θ = 5.8° WAXD peak indicating the presence of some crystalline order within the nanoparticles of 1 making up the aggregates. This corresponds to an average crystalline plane lattice distance of 17.5 Å. However, extraction of the finely powdered nanocomposites by refluxing THF failed to remove 1 indicating the vast majority of 1 must be chemically bound. Thus, the aggregates must have resin within their structure. The storage modulus (E') in both the glassy and rubbery regions, thermal stability, and glass transition temperature of the composites were improved by 1 wt% 1. However, at high loadings of 1, these properties gradually decreased. Surface extractions by THF removed only a portion of the 1 in the surface regions based on X-EDS analyses for Si, suggesting that a portion of 1 might chemically bond into the phenolic resin matrix during the cure. As the loading of 1 increased, the content of 1 at specific surface locations gradually tends to increase and confirmed excellent dispersion of 1 in the micron size-scale at all locations.     

Thermo-Sensitive Shape Memory Polymer Nanocomposite Based on Polyhedral Oligomeric Silsesquioxane (POSS) Filled Polyolefins

Shape memory polymer nanocomposite of EOC-EPDM blend has been prepared by the incertion of two different types of POSS nanoclay namely octaisobutyl POSS and trisilanolIsobutyl POSS. Compared to TSIB POSS, OIB POSS shows significant impact upon the shape memory behaviour of the blend. With increasing amount of POSS nanoclay, reduction in percentage shape fixity is lower for the nanocomposite containing OIB POSS rather than the TSIB POSS containing nanocomposite. On the other side, presence of closed cage like structure also results higher shape recovery ratio and lower shape recovery induction time for OIB POSS containing nanocomposite.     

多面体低聚倍半硅氧烷对环氧树脂热性能影响分析

选用有机-无机纳米杂化材料乙烯环氧基多面体低聚倍半硅氧烷(EOVS)和环氧醚基多面体低聚倍半硅氧烷(GPOSS)为改性剂,与4,4′-二氨基二苯甲烷环氧树脂共混制得不同改性剂质量分数(树脂与改性剂总质量的百分数)的EOVS或GPOSS改性环氧树脂,考察了改性树脂的固化反应程度、玻璃化转变温度(Tg)和热稳定性.结果表明...     

笼形倍半硅氧烷/硅橡胶复合材料的性能研究

以加成型液体硅橡胶(LSiR)和笼形倍半硅氧烷(POSS)为原料制备POSS/LSiR复合材料,并对其耐热性能和微观结构进行研究。结果表明:POSS分子与LSiR发生加成反应;POSS用量为10和15份的POSS/LSiR复合材料耐热性能和抗烧蚀性能提高。     

笼形氨丙基聚倍半硅氧烷/聚乳酸杂化材料的制备与性能

用溶液共混的方法,制备了不同质量分数的笼形氨丙基聚倍半硅氧烷(OAPS)与聚乳酸(PLLA)杂化材料。用傅立叶红外光谱(FTIR)、差示扫描量热法(DSC)、动态热机械分析(DMA)、热失重分析(TGA)等手段对该体系进行了考察。结果表明,OAPS质量分数为5时,PLLA的羰基伸缩振动峰由1758cm-1红移至1748cm-1,OAPS氨基伸缩振动峰由3362cm-1红移至3296cm-1,说明PLLA羰基与OAPS氨基之间形成了氢键;随着OAPS质量分数由0增至5,OAPS/PLLA杂化材料的玻璃化转变温度(Tg)由47℃升高至56℃,熔融温度(Tm)由141℃升高至146℃,储能模量由1100MPa增至1250MPa;OAPS的加入没有改变PLLA的热分解温度。     

A Polyhedral Oligomeric Silsesquioxane (POSS) Doped with Cerium(III) / Fe(II) and its Application as an Electrochemical Sensor for L-dopamine

Silicon - A Polyhedral oligomeric silsesquioxane (POSS) doped with cerium (III) was synthesized and reacted with potassium hexacyanoferrate (SCeH). The vibrational, structural, morphological and...     

Synthesis of Aromatic Polyhedral Oligomeric SilSesquioxane (POSS) Dianilines for Use in High-Temperature Polyimides

A series of novel aromatic Polyhedral Oligomeric SilSesquioxane (POSS) dianiline molecules has been synthesized for use in the preparation of high temperature aromatic polyimides. A general synthetic strategy was devised to improve the structure, yield, and utility of POSS dianilines over those currently available. Peripheral aromatic functionality was specifically incorporated in order to improve thermal properties and to increase compatibility with aromatic polymers. Silyloxy and/or aromatic functional groups were used to link the aniline groups to the POSS cage in order to ensure that this linkage was not a thermal weak point. Additionally, the stereochemistry of the aniline functionality has been varied to produce both meta- and para- isomers. The new dianiline monomers can be used to produce high molecular weight polyimide polymers. These dianilines have been incorporated both as pendants to the polymer backbone, and in a ??bead-on-a-string?? fashion by insertion into the polymer main-chain. In addition to producing POSS polyimides with superior thermal stability, these new monomers will allow full characterization and comparison of POSS-polyimides with differing structures in order to delineate the structure-property relationships of POSS and polymer architectures.     

多乙氧基POSS的合成及在RTV硅橡胶中的应用

以乙烯基三甲氧基硅烷为原料,制备了八乙烯基笼型倍半硅氧烷（OvPOSS）;再与γ-巯丙基三乙氧基硅烷（KH580）进行巯基-烯点击反应,合成八聚（三乙氧基硅丙巯基二亚甲基）笼型倍半硅氧烷（POSS—TEOST）;将POSS—TEOST加入室温硫化（RTV）硅橡胶中,考察了其用量对RTV硅橡胶性能的影响。采用^1H／^13C／^29Si NMR、FT-IR等对POSS—TEOST进行了表征,并研究了POSS—TEOST用量对RTV硅橡胶热性能、力学性能、硬度的影响。结果表明,在OvPOSS与KH580的量之比为1：8时,OvPOSS上8个乙烯基全部与巯基进行了反应;随着POSS—TEOST用量的增加,硅橡胶的热性能大幅度提升,氮气氛围中最大分解温度提高了75℃,在空气氛围中最大分解温度提高了124℃;此外,硅橡胶的拉伸强度和硬度分别提高了78％和55％。     

八氨基倍半硅氧烷改性聚酰胺酰亚胺基润滑涂层的性能研究

为开发苛刻服役环境下高性能、长寿命的有机润滑涂层,以氨基丙基三乙氧基硅烷（KH550）为原料制备了八氨基倍半硅氧烷（ NH₂-POSS）,并将其添加到聚酰胺酰亚胺基涂层（ HM-1100A）中,研究了改性前后涂层的结构、力学性能和摩擦性能。结果表明：经 NH2-POSS改性后的 HM-1100A涂层相比原始涂层具有更高的硬度、内聚强度及较低的表面能,并且涂层的摩擦性能有显著提高。通过对比 HM-1100A、KH550改性 HM-1100A及 NH₂-POSS改性 HM-1100A 3种涂层的热重、硬度、表面能和摩擦性能,研究了其作用机理,分析发现 NH₂-POSS独特的中空笼形结构和八官能团的引入有效提高了涂层的物理机械性能和摩擦性能。     

八乙烯基笼形倍半硅氧烷(OvPOSS)的合成、表征

本实验以乙烯基三氯硅烷和乙烯基三甲氧基硅烷作为前驱体,利用直接水解法合成了八乙烯基笼形倍半硅氧烷(Ov POSS),并计算了产品的收率,表征了产品的结构。两种前驱体制备的目标产物的收率分别为26.90%和12.46%,通过29Si NMR、XRD和FT-IR表征均证实产物为Ov POSS。