New sustainable approaches in the synthesis of epoxy-silica hybrids with tuneable properties

Project leaders

Marino Lavorgna, Libor Matejka

Agreement

REPUBBLICA CECA - CAS (ex AVCR) - Czech Academy of Sciences

Call

CNR/AVCR 2013-2015

Department

Molecular Design

Thematic area

Chemical sciences and materials technology

Status of the project

New

Research proposal

Epoxy resin represents the most important industrial category of thermosetting materials widely used in several applications, especially as adhesives, coatings, and matrices for composites. Moreover there is a continuous demand for improved and novel performances, either for new applications/markets or for materials working in severe environmental conditions. For this reason the research addressed to the study of epoxy systems is always encouraged to develop innovative solutions. Within this perspective, the development of epoxy hybrids is widely recognized as a valuable approach to enhance the performances of traditional epoxy systems. These materials, generally known as organic-inorganic hybrids (O-I), present a multiphase morphology. Unlike the conventional nanocomposites, in O-I hybrids the inorganic phase is generated in situ by a sol-gel method which allows the intimate integration of organic and inorganic components. Their interesting properties are determined mainly by the interactions of the inorganic domains, which range between 1 and 100nm size, with the polymer and by restriction of molecular dynamics at the interface. Several routes have been developed for the production of epoxy hybrids where the silica phase is produced by the hydrolitic polycondensation of tetraethoxysilane (TEOS) in presence of silane coupling agents to control the organic-inorganic interface. However in order to make the epoxy hybrids useful for practical applications the development of more solid and sustainable preparation approaches needs to be further investigated and better refined. In this respect, the main aim of this proposal is to get a comprehensive knowledge of hybrids by investigating some unexplored research areas: a) the development of new hybrids curing approaches by using more sustainable technologies and b) the development of new chemical approaches to obtain tuneable and multifunctional hybrids through a fine control of the inorganic domains morphology.
It is worth noting that the use of microwave processing for curing of epoxy hybrids offers several advantages over the conventional thermal processing methods, including rapid, selective and volumetric heating, energy savings, eco-friendly, reduced processing time and improved processing control. A considerable amount of research has been addressed to the microwave curing of epoxy composite systems and epoxy nanocomposite filled with carbon nanotubes. The results are quite prominent because the speed up of the crosslinking epoxy reactions brings about a significant modification of the epoxy morphology with consequent enhancement of their properties. The implementation of a microwave manufacturing method for epoxy hybrid materials by sol-gel approach however, has not yet been exploited and it really deserves to be investigated.
Another area which may bring new avenues in the field of multifunctional epoxy hybrids is that related to the development of new innovative and scalable approaches to control the morphology of inorganic domains. In this respect it appears extremely interesting the use of ionic liquids which was already shown to be a promising strategy to modify the properties and the morphology of epoxy systems filled with carbon nanotubes. Due to their peculiar structure and molecular arrangements the ionic liquids can be used as molecular templates in the sol-gel process and may enable silica structure control. The research group headed by prof Matejka has recently developed some epoxy hybrids by sol-gel approach by using the ionic liquids. The preliminary results have demonstrated that ionic liquids work as catalyst for the sol-gel process, as silica morphology controllers and also as surfactants controlling the organic-inorganic interactions. Further investigations are still needed to have a better understanding of the mechanisms which rule the formation of silica domains as well as the catalytic effect of ionic liquids on the crosslinking of the epoxy resins.
The present proposal is focused on the development of new technological and chemical approaches to prepare epoxy hybrids materials with tuneable mechanical and functional properties. In particular it will be investigated the effect of microwave curing of hybrid materials by sol-gel approach alongside with the comprehensive evaluation of the effects of ionic liquids as both “absorbing agents” for microwave and “template agents” for silica morphology. The attention will be also devoted to the development of approaches which may let the hybrids to be attractive for different applications field, i.e structural composites, coatings and electronic packaging.
The proposal consists of the following three main tasks:
1)      New approaches for synthesis of multifunctional epoxy hybrids. The main objectives of this task are to investigate both the effect of Ionic liquids as silica templates to control the inorganic domain morphology and the formation of silica through non-aqueous methods.
2)      Microwave curing of epoxy hybrids. The objective of this task is to investigate the microwave as sustainable curing technology of hybrids and to use the ionic liquids as microwave absorbing agents.
3)      Exploration of hybrids applications. The main objective of this task is to obtain a complete and exhaustive characterization of the hybrids with respect to different applications fields.
The Institute of Macromolecular Chemistry of Prague (Prof. Matejka) and the Institute of Composite and Biomedical Materials (Dr. Lavorgna), have carried out intensive researches and their results constitute a valuable background for the development of advanced epoxy hybrids. The two research partners have been cooperating since October 2010 when Dr Lavorgna spent, within the AVCR-CNR cooperation named "scambio libero", a short study period in IMC working on the multiscale characterization of epoxy hybrids. The two partners believe that this proposal may further strengthen their established cooperation with fruitful results.

Research goals

The present proposal is focused on the development of new technological and chemical approaches to prepare multifunctional epoxy hybrids with tuneable mechanical and functional properties.
The main objectives of the proposal are the followings:
1)      Definition of new experimental approaches to control the morphology of silica domains due to the self-aggregation capacity of imidazolium ionic liquids and the establishment of interactions between ionic liquids and inorganic domains.
2)      Study of the structure-properties relationship of epoxy hybrid by sol-gel approach modified with ionic liquids with different organic structures.
3)      Definition of an innovative protocol to synthesize in situ nanosilica by using a non aqueous sol-gel process.
4)      Development of epoxy hybrids cured by an ionic liquid assisted microwave process.
5)      Exploration of possible applications of epoxy hybrids through a comprehensive mechanical and functional characterization.

Last update: 03/08/2025