Facile fabrication of porous open-cell polymer structures from sacrificial “natural templates” and composite resins
Résumé
In this paper, we investigate several types of “natural or bio sourced templates” (sugar, salt, bone, coral, PLA 3D-printed scaffolds) for a the simple elaboration of macro porous thermoplastic or thermosetting polymers, especially based on resins commonly used in composites manufacturing. Open-cell, macro porous polymer foams are obtained from resin impregnation of the template. The process consists of 3 simple steps: (a) impregnation (infiltration/infusion) of the template, (b) polymerization of the resin, (c) removal of template, mainly by water. We compared several resins and showed that a low viscosity and a sufficient wettability enable fast impregnation of templates, where impregnation times are < 4 min for samples on 10 to 30 mm thicknesses. The resulting polymeric porous structure is the overall replication of the template, exhibiting mainly open pores in the range of 100 to 500 μm, and densities from 0.25 to 0.4 g cm−3. Such open foams behave as sponges and can (re) absorb liquids either polar (water), alcohols or non polar liquids such as silicon oil, which are filling the entire void volume. We proved the feasibility of an easy and fast impregnation by composite resins to provide either rigid or soft porous polymers (or ‘foams’) that can be further chemically modified. On the other side, before polymerization, the introduction of a functional additive to the reactive infusion formulation, provides homogeneously functionalized foams. Here an impact modifier is tested.