I-Corps: Translation Potential of Compostable Core-Shell Impact Modifiers

This I-Corps project is based on the development of key additives that are compostable and turn brittle, plant-based plastics into durable materials suitable for everyday products. Currently, unmodified bioplastics like polylactic acid (PLA) break on impact, limiting use despite global demand for sustainable packaging. Each year, more than one million tons of PLA are produced, however, to improve impact strength, it must be blended with petroleum-derived additives, which negates compostability. This technology addresses the challenge by raising PLA’s impact strength by an order of magnitude while maintaining industrial compostable certification. Also, the additive may be supplied as pellets, allowing compounders, film converters, and molders to create tough, monolayer parts without changing equipment. The technology uses glycerol, which is a low-cost by-product of U.S. biodiesel, as its sole feedstock, so it may potentially displace non-degradable modifiers, streamline manufacturing, and enable new markets for bioplastics.

This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of compostable core-shell particles (CCSPs) as biodegradable impact modifiers for polymer composites. The technology focuses on scalable monomer synthesis, polymerization, and integration of CCSPs into high-dosage master batches, ensuring compatibility with existing processing techniques like extrusion and compounding. The CCSPs are synthesized from glycerol-ketal acrylate monomers and the technology employs seed-fed semi-batch emulsion polymerization to produce 200–350 nm particles with an ester cross-linked rubbery core and an acrylic shell that bonds seamlessly with the bioplastic matrix. At modest loading, CCSP-modified PLA exceeds 200 J m⁻¹ Izod impact strength, which is ten times unmodified PLA strength, without sacrificing compostability. Hydrolysis studies show 90% mass loss within ten weeks under accelerated compost conditions, confirming rapid end-of-life degradation. The technology addresses key limitations of bioplastics: brittleness and limited durability. Compostable CCSPs may offer a sustainable alternative to conventional impact modifiers, enabling industries to enhance the mechanical properties of biodegradable plastics without compromising environmental responsibility.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Award Number: 2534242
Principal Investigator: Eric Cochran
Funds Obligated: $50,000
State: IA