Extrusion molding of cellulosic fibers using cellulose derivative

Abstract

According to the Paris Agreement, it is getting important to develop 100% plant-based materials which could substitute oil-based plastics. Cellulosic fibers are abundant in the earth and have both durability and biodegradability. However, products from cellulosic fibers are typically limited to sheeted materials. In this study, we aimed at developing all-cellulose material which could be applicable to various forming methods like injection and especially extrusion. In order to extrude cellulosic fibers without using any oil-based plastics, hydroxypropylmethyl cellulose (HPMC), one of cellulose derivatives were blended to the fibers and kneaded with water to give clay-like material with plasticity. Effect of water on the extrudability and shape retention was large. The best water content was chosen as 50% for paper powder used in this study. The material was successfully formed using hand-operated clay-extruder, dried at 60˚C to give molded pieces. Addition of HPMC to paper powder increased extrudability of the material and the strength of the molded piece. The best blending ratio of paper powder and HPMC was estimated to be 7:3. The molded piece was disintegrated in stirred water and most of HPMC was recovered from the water as HPMC solution. We demonstrated an idea to realize 3D forming of cellulosic fibers with sufficient extrudability, strength and recyclability.