Abstract: Actinic radiation curable compositions comprising at least one actinic radiation curable, cationically polymerizable compound and at least one cationic photoinitiator, may be stabilized by the use of a stabilizer which is a complex of a Lewis acid (other than a fluorine-containing boron compound) and a Lewis base.

Abstract: The present invention relates to a process for the fast and efficient filling of voids of both simple and complex shape which can be carried out at room temperature. In particular, the present invention consists of the use of free flowing thermally expanding and curing powders which are poured into the voids and then heated causing the powder to expand, coalesce and cure and thus filling or partially filling the void space as required. The process according to the present invention is particularly suitable for filling the spaces in, around and between honeycomb or pre-formed foam cores as required to produce a filled or partially filled honeycomb or foam core or any other material used in sandwich panel construction. This process is also a simple and efficient method for filling moulds suitable for use in cellular artefact production. The filled or partially filled mould or honeycomb core can then be cured to produce bonded sandwich panels or moulded cellular artefacts.