Preparation and properties of organic–inorganic hybrids based on poly(methyl methacrylate) and sol–gel polymerized 3-glycidyloxypropyltrimethoxysilane

Liquid oxygen compatibility and cryogenic mechanical properties of a novel phosphorous/silicon containing epoxy-based hybrid

A novel phosphorous/silicon containing epoxy-based hybrid was synthesized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) containing epoxy resin and 3-glycidoxy-propyltrimethoxysilane (GLYMO).

Microgel Modified UV-Cured Methacrylic-Silica Hybrid: Synthesis and Characterization

An innovative photopolymerizable microgel modified UV-cured acrylic-silica hybrid formulation was developed and characterized for possible use as protective coating for different substrates. A deep investigation, aiming at providing a strong scientific basis for the production of organic-inorganic (O-I) hybrids exhibiting phase co-continuity, was firstly carried out. The O-I hybrid first proposed in this study was obtained from organic precursors with a high siloxane content, which are mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silica nanodomains dispersed within the crosslinked organic phase, as a result of the sol-gel process. The first part of the research deals with the selection and optimization of suitable systems through appropriate chemical modifications, in order to ensure that curing reactions can be carried out at room temperature and in the presence of UV radiation. Firstly, the silica domains are formed, followed by crosslinking reactions of the acrylic groups in the oligomer via a free radical polymerization. The crosslinking reaction was controlled with the use of a suitable photoinitiator. Most of the experimental work was devoted to understanding the morphology of the hybrid system, both in uncured and cured states, and to assess its final thermal and optical properties, using different experiential techniques.

Thermal degradation, mechanical behavior and Co60 gamma-irradiation induced effects of poly(methylphenylsiloxane)/phenylene-silica hybrid material

Poly(methylphenylsiloxane) (PMPS)/phenylene-silica hybrid material was prepared by a two-step sol-gel process. In the structure of the hybrid system, the phenylene-silica framework was imported into the crosslinked PMPS matrix to obtain interpenetrating networks. The results of thermogravimetric analysis (TGA) and mechanical tests show that the products exhibit excellent thermal stability at ~400ºC in an inert atmosphere and a tensile strength up to 25.9 ± 1.7 MPa. The investigation of thermal degradation mechanism by TGA coupled with Fourier transform infrared (FTIR) spectroscopy (TGA-FTIR) reflects the linear segments unzipping (430–580ºC), the elimination of benzene (450–680ºC) and the rupture of Si-CH3 and Si-OH (620–850ºC), within which the first degradation step can be retarded by the steric effect of the phenylene-silica framework. In order to study Co60 gamma-irradiation induced effects, the hybrid products after irradiation were also studied by the same characterization, showing slightly increased crosslinking degree of PMPS and unchangeable initial degradation temperature at an irradiation dose of 1.6 × 105 Gy. The mechanical behavior for hybrid products, including tensile strength and coating film properties, was well maintained under the effect of irradiation. An increase of phenylene groups inserted in the phenylene-silica framework was confirmed to induce more significant steric interactions to polymer backbones. This effect permits the hybrid products to enhance thermal and irradiation resistance, as well as mechanical strength.