A Novel and Green Method of Polymerizing Plant-Based Fatty Acids

We have discovered a new process of polymerizing certain plant-based fatty acids that results in a biopolymer of unusual characteristics and with high potential impact in both the construction and energy sectors. More specifically, it is an iron-based ionomer produced by a carbon-negative process. We call it Polymiron (polymer + iron, po LIM er on). The main ingredients are unsaturated fatty acids and particularly oleic acid that is commonly found in plant oils. The oil is then mixed with metallic iron powder, which can be in the form of waste steel dust, a readily available industrial by-product that is typically not recycled. When carbonic acid (CO₂ dissolved in water) is added to the steel-and-oil slurry, it preferentially adsorbs onto the particles and partially dissolves the iron. This releases Fe(II) ions that replace hydrogens on the carboxyl groups of the fatty acids, which creates bridges and forms dimers. What happens next is not completely understood yet, but apparently the displacement of hydrogens continues up the chains causing more cross-bridging and eventually complete solidification. Due to the oxidation of iron during the curing process, protons are reduced and free H₂ gas is generated as a by-product. The Polymiron production process is thus doubly beneficial for simultaneously capturing a greenhouse gas as well as producing a clean fuel gas. The resulting solid ionomer is electrically conductive and this opens the potential for certain important applications. Our initial practical goal is to develop a self-sensing composite. The conductivity of Polymiron is not a simple metallic type and can vary depending on several factors including intramolecular, like the amount of incorporated iron, and macroscopically, such as the conductivity of embedded fibers in the surrounding polymer matrix. Therefore, we may be able to tune its conductivity so that it is sensitive enough to be correlated with changes in its internal state and especially with strain, cracking, and other damage. If this can be done then it would move Polymiron to the cutting edge of advanced materials for applications in manufacturing and construction where, for example, the integrity of structural components in a building could be monitored continuously in real time. Its conductivity also suggests that it might be re-reduced with photovoltaic DC so that it again reacts with water and CO₂ to create more hydrogen and other fuel gases in an ongoing cycle. If this can be demonstrated, then Polymiron could function as the reactive substrate in a gas conversion reactor that stores excess solar energy by using it to turn water and CO₂ into hydrogen and reduced monocarbon products such as formic acid and methane. There is an intense effort globally to develop biopolymers that are derived from sustainable sources and not petroleum. But these plant-based materials are then typically processed in the usual ways to reach the same product goals. What we have in Polymiron is an entirely new kind of biopolymeric material derived from some of the most readily available and non-toxic materials. The curing process is initiated with nothing more than drinkable seltzer water without heat, pressure, or exotic catalysts. With the increasing interest in green chemistry, this is the kind of promising chemical platform that needs to be fully explored scientifically as well as fully exploited for any practical benefits. Some limited field trials have already been done to test its suitability for simple applications as a thin anti-corrosion coating and a thick, tar-like sealer. Further development is currently underway to find additives and methods to optimize it so that it may function well enough as a resin to replace polyester or epoxy for structural purposes.