Methacrylate-functionalized POSS as an efficient adhesion promoter in olefin-based adhesives

This study aims to investigate the effects of methacrylate-functionalized polyhedral oligomeric silsesquioxane (MA-POSS) on polyolefin-based adhesives. The so called adhesive was synthesized by the cooligomerization of 1-decene/9-decene-1-ol monomers using a Ti amine bis-phenolate catalyst, [Ti{2,2′-(OC₆H₂-4,6-^tBu₂)₂NHC₂H₄NH(OⁱPr)₂], which was subsequentlyacrylated via a simple reaction with methacryloyl chloride. Different weight fractions of MA-POSS nanoparticles were solution blended with synthesized adhesive and undergone curing reaction with blue light. Observation of a unique tan δ peak in dynamic mechanical thermal analysis (DMTA) curve was clear evidence that two employed moieties were miscible and only one hybrid polymeric phase was created. Most noticeably, significant increase in mechanical parameters was detected in the lower inclusion compositions, 0.2-1 wt% of MA-POSS, where flexural strength and flexural modulus were increased up to 99 and 110%, respectively. Furthermore, thermal stability of the synthesized nanocomposite enhanced dramatically by increasing MA-POSS weight fraction. Influence of employed nanoparticles on adhesion properties of synthesized nanocomposites was evaluated with tensile shear bond strength and pull off analysis. According to the adhesion results, the MA-POSS causes an adhesion promotion on the fabricated adhesive/POSS nanocomposites.     

Metallo‐supramolecular materials based on terpyridine‐functionalized polyhedral silsesquioxane

In this study, novel metallo‐supramolecular materials based on terpyridine‐functionalized polyhedral silsesquioxane were synthesized from 4′‐chloro‐2,2′:6′,2″‐terpyridine and amino‐group‐functionalized polyhedral oligomeric silsesquioxane. The obtained terpyridine‐functionalized polyhedral silsesquioxanes were converted to metallo‐supramolecular hybrid materials by coordination polycondensation reaction with Co(II) or Cu(II) ions. The supramolecular polymers created were characterized by means of structure, morphology and stimuli‐responsive performance employing scanning electron microscopy, amperometric techniques and UV–visible and Fourier transform IR spectroscopy. UV?visible and cyclic voltammetry studies showed that both the optical and electrochemical properties of metallo‐supramolecular materials are affected by the substituent at the pyridine periphery. The supramolecular polymers obtained exhibited electrochromism during the oxidation processes of cyclic voltammogram studies. As a result, these terpyridine‐functionalized polyhedral silsesquioxanes are good candidates for electronic, opto‐electronic and photovoltaic applications as smart stimuli‐responsive materials. © 2013 Society of Chemical Industry     

Improved interfacial adhesion with the help of functional polyhedral oligomeric silsesquioxanes in silicone rubber/rayon fiber composites: Physical,mechanical, thermal,and morphological properties

The aim of this article is to improve the interfacial adhesion between silicone rubber (SR) and Rayon fiber by the help of functional hybrid POSS nanoparticles. Two POSS types were compared, octavinyl-POSS (O-POSS) and methacryl-POSS (M-POSS), having reactive  CC double bonds that can impart in peroxide crosslinking. O-POSS is nonpolar, whereas M-POSS is polar and is able to make H-bond with Rayon fibers. POSS type and their concentrations were examined as the experimental parameters. H-adhesion tests indicated that both POSS types enhanced the adhesion of SR composites to Rayon fibers compared with control recipe. Specifically, slightly higher values were obtained with the use of M-POSS. It was observed that both O-POSS and M-POSS slowed down the curing rate but increased the degree of crosslinking. The cure extent of O-POSS containing composites was found to be higher than that of M-POSS containing ones. Thermal gravimetric analyses revealed that thermal stability of SR composites was significantly improved by the addition of POSS particles. Higher char yield and degradation temperatures were obtained with O-POSS at higher loadings with respect to M-POSS. The POSS distribution at lower loading levels was found to be homogenous for both POSS types as observed from scanning electron microscope and transmission electron microscope.     

Polybutadiene/polyhedral oligomeric silsesquioxane nanohybrid: investigation of various reactants in polyesterification reaction

Nano‐sized polyhedral oligomeric silsesquioxane (POSS) diol or ethylene glycol (EG) as diol monomer was incorporated into hydroxyl‐terminated polybutadiene (HTPBD) chain in the presence of fumaryl or thionyl chloride as extenders. Using these polyesterification reactions, two fumarate‐based polyesters and two polyester sulfites were synthesized. Each couple of polyesters and polyester sulfites includes a linear (diol:EG) and a nanohybrid macromer (diol:POSS). Full structural characterization was performed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopies. Gel permeation chromatography was undertaken to study polyesterification mechanisms by deconvolution of the obtained traces. Finally, differential scanning calorimetry, thermogravimetric analysis and cell culture were performed to evaluate the structure–property relationship for the synthesized macromers in comparison with unreacted HTPBD. © 2016 Society of Chemical Industry     

A facile synthesis of mixed soft‐segmented poly(urethane‐imide)–polyhedral oligomeric silsesquioxone hybrid nanocomposites and study of their structure–transport properties

The structure–transport properties of mixed soft‐segmented poly(urethane‐imide) (MSPUI) membranes and their microstructures were investigated. Polypropylene glycol, polycaprolactone diol and bis(3‐aminopropyl)‐terminated polydimethylsiloxane were used as the soft segments in the membrane synthesis via a three‐step polymerization reaction. The chemical structures of the MSPUI membranes were characterized using attenuated total reflectance Fourier transform infrared spectroscopy. Morphology and surface properties of the membranes were studied using scanning electron and atomic force microscopy techniques. Surface energy measurements indicated the enrichment of the hydrophobic soft segment in the membranes. The amorphous nature of the polymers was analysed using wide‐angle X‐ray diffraction. The effect of morphology on the permeability and selectivity of the membranes is discussed. Finally, membrane structure–transport property relationships were correlated. © 2013 Society of Chemical Industry     

Epoxy‐functionalized polyhedral oligomeric silsesquioxane/cyanate ester resin organic–inorganic hybrids with enhanced mechanical and thermal properties

A series of cyanate ester resin (CE) based organic–inorganic hybrids containing different contents (0, 5, 10, 15 and 20 wt%) of epoxy‐functionalized polyhedral oligomeric silsesquioxane (POSS‐Ep) were prepared by casting and curing. The hybrid resin systems were studied by the gel time test to evaluate the effect of POSS‐Ep on the curing reactivity of CE. The impact and flexural strengths of the hybrids were investigated. The micromorphological, dynamic mechanical and thermal properties of the hybrids were studied by SEM, dynamic mechanical analysis (DMA) and TGA, respectively. Results showed that POSS‐Ep prolonged the gel time of CE. CE10 containing 10 wt% POSS‐Ep displayed not only the optimum impact strength but the optimum flexural strength. SEM results revealed that the improvement of mechanical properties was attributed to the large amount of tough whirls and fiber‐like pull‐outs observed on the fracture surfaces of CE10. DMA results indicated that POSS‐CE tended to decrease E′ of the hybrids in the glassy state but to increase E′ of the hybrids in the rubbery state. TGA results showed that CE10 also possesses the best thermal stability. The initial temperature of decomposition (T_i) of CE10 is 426 °C, 44 °C higher than that of pristine CE. © 2013 Society of Chemical Industry     

笼型倍半硅氧烷(POSS)的研究新进展

介绍了倍半硅氧烷(POSS)的结构特点,并综述了POSS的研究进展。概述了国内外的合成方法及其应用。     

聚酰亚胺/SiO_2纳米复合抗原子氧气凝胶的合成与性能

以3,3′,4,4′-联苯四酸二酐(sBPDA)和2,2′-二甲基-4,4′-二氨基联苯胺(DMBZ)为聚合单体,八(氨基苯基)聚倍半硅氧烷(OAPS)为交联剂,SiO2纳米粒子为填料,采用超临界二氧化碳干燥工艺制备了一系列聚酰亚胺(PI)/SiO2纳米复合气凝胶(CPIA-SiO2-0~CPIA-SiO2-7)。研究表明:SiO2纳米粒子的引入对PI气凝胶的耐热性能未产生显著的影响。然而,随着SiO2纳米粒子含量的增加,PI气凝胶的孔隙率从89.6%逐渐降低至79.4%,BET表面积也随之从425.5m2/g降低至380.2m2/g,纳米泡孔孔径分布呈现出变宽的趋势。SiO2的引入显著提高了PI气凝胶的抗原子氧侵蚀能力,含量为7%(质量分数,下同)的PI/SiO2复合气凝胶CPIA-SiO2-7的原子氧侵蚀率(2.6%)仅为不含SiO2气凝胶CPIA-SiO2-0的原子氧侵蚀率(12.3%)的1/5左右。     

Poly [2-(cinnamoyloxy)ethyl methacrylate-co-octamethacryl-POSS] nanocomposites: Synthesis and properties

Poly [2-(cinnamoyloxy)ethyl methacrylate-co-octamethacryl-POSS] nanocomposites were synthesized from octamethacryl-POSS and 2-(cinnamoyloxy)ethyl methacrylate (CEM) by free radical polymerization. The chemical structures and morphologies of these nanocomposites were determined by FTIR, ²⁹Si NMR, energy-dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) techniques. The XRD data showed that the materials were amorphous in nature, indicating that POSS formed an aggregate instead of a crystalline form in the polymer matrix. The POSS-CEM nanocomposites exhibited high thermal stability. Excitation and emission of the CEM-incorporated POSS nanocomposites, studied in the solid state, exhibited blue emission with CIE (x, 0.178; y, 0.137) coordinates, in addition to an emission intensity that increased with increasing CEM (monomer) concentration.     

Kinetics analysis and physical properties of photocured silicate-based thiol-ene nanocomposites: The effects of vinyl POSS ene on the polymerization kinetics and physical properties of thiol-triallyl ether networks

The kinetics and thermal/physical properties of the trithiol-TAE (triallyl ether) system were measured with respect to increasing polyoligomeric silsesquioxane (POSS) concentrations in order to understand how the presence of POSS nanoparticles affects network formation at low loadings. Vinyl POSS monomer (vPOSS-Bu₄) with both vinyl and carboxylate pendant groups was synthesized via a thermally initiated, free-radical reaction to improve the compatibility of the inorganic particles with the trithiol and triallyl ether comomoners. Chemically modified vPOSS-Bu₄ particles were incorporated into the trithiol-TAE polymer networks by a thiol-ene free-radical photopolymerization at molar concentrations of 0, 1, and 5 ene mol%. The polymerization rates were analyzed using real-time FTIR and photo-DSC. The polymerization rates showed no significant changes with increasing vPOSS-Bu₄ concentration. Thermal analyses of the films by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) demonstrated that thermal stability improves without affecting T _g as the POSS concentration increased. Additionally, scratch resistance increased and flame spread decreased markedly with increasing POSS concentration for concentrations up to 5 mol% vPOSS-Bu₄.