Cannabinoid-Based Polymers Materials Ecosystem

To mitigate the negative health and environmental impacts of synthetic petroleum-based plastics, new methods to use natural resources must be developed. Materials such as poly(lactic acid) have established that cost-competitive polymers with favorable properties can be leveraged to replace plastics in some applications, notably additive manufacturing. Bio-derived polymers with a greater range of properties may help to increase the market penetration of products based on natural resources. This work explores printed electronics created with a new class of biopolymers created from polymerized hemp oil. Some benefits of cultivating hemp include an increased capacity as a carbon sink, improved water consumption, and scrubbing of heavy metals from soil (phytoremediation). The resurgence of hemp with the passing of the Farm Bill in 2018 has led to larger supplies of hemp oils (cannabinoids) such as cannabidiol (CBD).<br/>Poly(cannabinoid)s are prepared through step growth polymerization of bifunctional carboxylic acids with hemp-derived cannabinoids containing two hydroxyl groups. With over 120 naturally occurring cannabinoids and hundreds of dicarboxylic acids, a large range of properties can be achieved. This is demonstrated notably with 3 plastics that possess different desirable properties, such as high glass transition temperature &gt;100 °C, hydrophobicity with water contact angles &gt;120°, and a block-copolymer with high adhesion to a variety of surfaces including skin.<br/>Practical applications of these materials are demonstrated through the fabrication of additively manufactured biomedical devices. Electrocardiogram electrodes illustrate the advantages of these materials when applied in aqueous environments, not possible for long periods with conventional silver/silver chloride electrodes. Conformal on-skin heating elements that show self-limiting at 35 °C reducing the potential for thermal runaway present with conventional heaters. Devices were fabricated with multi-material additive manufacturing whereby conductive metal/polymer composites and adhesives were printed.<br/>PolyCBD materials have been demonstrated to be susceptible to base-catalyzed hydrolysis leading to depolymerization of polyCBD into component monomers and varying molecular weight oligomers. Different base solutions such as sodium hydroxide, ammonium hydroxide and phosphene buffered saline impact the duration of the depolymerization and the number of oligomers left in solution. Identifying the right media that does not denature CBD or result in incomplete depolymerization will enable repolymerization of monomers.