PIBOLEO project: Eco Innovative process for multi-functional bi-oleothermal treatment for wood preservation and fire proofing

Although they are usually quite effective, typical wood treatments are not necessarily very environment-friendly, in terms of the treatment itself and of the active substances used (flame retardants, biocides). In this day and age, as the ecological aspects are becoming more and more important, many research projects aim at improving wood treatment in an environment-friendly manner.
In France a simple bi-oleothermal© process has been developed by CIRAD and FCBA in order to make the treated wood more stable and less sensitive when used outdoors. The interest of this now well mastered alternative method for wood protection is to allow wood drying as well as wood treatment in a single process. This two stage process operates at atmospheric pressure and uses two hot oil baths. Nevertheless, the formulation of the oils used needs major improvement in order to adapt the performances of the treated wooden material (durability towards wood destroying organisms, fireproofing, etc...) to its end-use.
The improvement of this bi-oleothermal wood treatment is the subject of the PIBOLEO project, which is supported by the French National Agency for Research (ANR - ADEME). This project is currently in its early stages and focuses for now on the optimization of the composition of the second bath, which is the one containing the active substances.
The nature of the second bath depends a lot on the active substances used for improving the fire, fungus or insect resistance of the treated wood. If these substances are not miscible with oil but soluble in water, it is then necessary to develop an emulsion containing enough of each of the substances to impart the desired properties to the treated wood. In that case, the use of surfactants is required. Therefore, a major axis of the PIBOLEO has been to optimize the surfactant systems in these water-in-oil (W/O) emulsions. It is quite challenging to design emulsions that can withstand the thermal shocks and the addition of impurities coming from the wood (water, sap, etc.) associated with the treatment without dephasing.
In the case of active substances that are not soluble in oil, chemical modification and grafting of those substances onto oil can be an alternative option. They can then become soluble in oil without losing their properties as fire retardants or biocides. Several synthesis routes are currently under investigation in the PIBOLEO project. In that case or if the active substances are naturally soluble in oil, there is no need to add water in the second bath and a simple formulation of the oil is sufficient. The stability of the bath is then improved (the only concern is the oxidative stability of the oil and the active substances since dephasing is not a possibility).