Wood-pulp plastic dissolves in seawater without forming microplastics

Researchers at Japan’s RIKEN Center for Emergent Matter Science, led by Takuzo Aida, have developed a novel plant-based plastic made from cellulose that dissolves rapidly in seawater without forming harmful microplastics. Unlike many biodegradable plastics that degrade slowly or fragment into microplastics, this new material combines durability and flexibility during use with fast decomposition in natural marine environments. The plastic, termed CMCSP, leverages a cross-linked network formed by negatively charged carboxymethyl cellulose (a wood-pulp derivative) and positively charged polyethylene-imine guanidinium ions. Saltwater disrupts these salt bridges, triggering the plastic’s breakdown, while a protective coating can prevent premature degradation. To overcome initial brittleness, the team incorporated choline chloride, an FDA-approved food additive, as a plasticizer, allowing the material’s flexibility to be finely tuned—from rigid and glass-like to stretchable up to 130% of its length. The resulting plastic is transparent, strong, and