Rethinking cellulose lightweight materials: how to build flexible cellular structures without deconstructing the lignocellulosic complex?

• Grant number: 23/09659-7
• Support Opportunities: Research Grants - Young Investigators Grants
• Start date: October 01, 2025
• End date: September 30, 2030
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Elisa Silva Ferreira
• Grantee: Elisa Silva Ferreira
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Associated researchers: Bjorn de Koeijer ; Elina Pääkkönen ; Emily Cranston ; Holmer Savastano Junior ; Mark Martinez

Abstract

CCellulose materials with very low density are produced using costly techniques like freeze-drying and supercritical drying, limiting their practical applications. Foam-forming is an alternative method for producing cellulose foams using oven-drying. However, even with improvements, cellulose foams are unlikely to match the performance to replace plastic foams in many applications, as prospective cellulose foams are expected to have relatively high density, limited flexibility, and poor wet-resilience. These projections indicate that novel approaches are essential to make plastic replacement a reality. This project aims to develop flexible, lightweight materials from lignocellulosic particles using foam-forming. The direct use of unrefined particles (sugarcane bagasse and eucalyptus bark) brings a new perspective that contrasts with the conventional approach of deconstructing biomass. Two classes of composites will be developed: (I) solid foams and (II) porous substrates, using three steps: (1) production of aqueous foams; (2) drainage of aqueous foams; (3.I) oven-drying; or (3.II) collapsing foam structure, followed by oven-drying. The aqueous foams will assemble a lightweight framework, confining particles in liquid films between bubbles. Pectin and starch will enhance resistance by connecting the particles with a biopolymer layer cross-linked with citric acid. These citric acid cross-links and the natural wet-resilience of unrefined biomass will maintain stability upon water exposure. For flexibility, the biopolymer layer will be assembled as thin domains plasticized with glycerine. The porous materials' morphology and performance will be assessed using microscopy techniques and technical standards to develop alternatives to plastic foams used in packaging and construction, and refined paper substrates used in packaging. (AU)