Microfibrillated nanocellulose from balsa tree as potential reinforcement in the preparation of ‘green’ composites with castor seed cake

Abstract

The search for and development of eco-friendly materials such as ‘green’ composites results from twin issues of sustainability and ‘environmental impact’. Towards achieving this goal, the use of industrial residues such as plant fibers as reinforcement along with natural polymers has been yielding good results. However, due to limitations of industrial uptake of these materials in structural applications, reducing the size of fibers below the normal micro level offers advantages because of the improved behavior and functionality exhibited by the nano-sized cellulosic fibrous materials. Considering successful previous efforts to develop biodegradable composites using castor seed cake, this paper focuses on the possibility of developing ‘green’ composites using this material as matrix and nanocellulose prepared from balsa tree as reinforcement. The preparation of nanofibrillar cellulose through mechanical fibrillation and its characterization as well as preparation of nanocomposites by thermo-molding with a matrix plasticized by glycerin are presented. The incorporation of nanocellulose resulted in increased flexural modulus, swelling thickness, and water absorption with increasing addition of nanocellulose, while both apparent density and flexural strength remained unchanged. The observed properties are discussed based on fractographic studies.