Acrylic Acid “Reversed” PolyHIPEs

Abstract

Summary: An oil‐in‐water high internal phase emulsion consisting of acrylic acid, water, and a crosslinker (N,N′‐methylene bisacrylamide) as the water phase, and toluene as the oil phase was successfully stabilised to sustain thermal initiation of radical polymerisation resulting in porous open‐cellular monolithic material. The type of initiator used influenced the average pore size ranging from approx. 708 nm to approx. 1 087 nm, as determined by mercury porosimetry.Schematic of the preparation of an oil‐in‐water‐type polyHIPE (high internal phase emulsion).imageSchematic of the preparation of an oil‐in‐water‐type polyHIPE (high internal phase emulsion).

Porous Poly(Acrylic Acid) from High Internal Phase Emulsion: Effects of Emulsification Parameters on Porous Structure

“…Therefore it is necessary to introduce a statistical correction [6]. The average void diameter (D) of each polyHIPE material in this (2) where N was the average number of interconnecting pores per void, r was the average interconnecting pore diameter. At least 50 voids were calculated for each sample.…”

“…In traditional HIPE, the concentration of surfactant is always very high, normally 5-50% relative to the continuous phase, which is not environmental friendly and is the most cost factor. For example, porous poly (acrylic acid) (PAA) from oil-in-water (O/W) HIPE with the concentration of surfactant up to 21wt% was prepared [2]. Although great efforts have been done to eliminate or reducing the amount of the surfactant in the preparation of HIPEs, such as particle-stabilized [3,4] and CTAB-stabilized HIPEs [5], HIPE stabilized by non-ionic surfactant of low concentration is still highly desired, due to the easy removal of the residue surfactant from the resulting porous materials.…”

Tailoring the mechanical and thermal properties of dicyclopentadiene polyHIPEs with the use of a comonomer

“…In recent years, the preparation of polyHIPEs via oil-in-water (o/w) templates has attracted attention despite the difficulties in achieving a stable emulsion [1]. For instance poly(acrylic acid) polyHIPEs have been prepared by Krajnc et al [21] from an o/w HIPE consisting of acrylic acid. More recently, Pulko and Krajc [4] succeeded to prepare hierarchically porous functional polyHIPEs from acryl amide (AAm) by using water soluble surfactants.…”

Amine Functionalisations of Glycidyl methacrylate Based PolyHIPE Monoliths

“…Such monoliths, described first by Bonin [2] and patented by Unilever under a trade name polyHIPE (poly High Internal Phase Emulsions). [3] Recently, various chemistries have been applied for the preparation of polyHIPE monoliths [4] , and even reversed polyHIPEs (from water in oil emulsions) [5,6] from water soluble monomers. PolyHIPE structured beads [7,8,9] and membranes [10,11] have also been reported.…”