Preparation of All‐Cellulose Composites Based on Controlled Dissolution Procedure

In this study, all‐cellulose composite materials are prepared through the dissolution and regeneration process using waste kraft papers as raw material in the sodium hydroxide/thiourea/urea solvent system. The degree of conversion is controlled by adjusting the microenvironment of the cellulose solvents, and the composite membrane is prepared by mixing the regenerated cellulose with the insoluble cellulose, which aims at adjusting the morphology and mechanical properties of the composite material. The shape of the regenerated cellulose after the dissolution and regeneration change from the original fiber into a sphere as shown by SEM images. The composite films show different phenomena, the insoluble part, and the matrix phase form a dense and strong network structure. The presence of this insoluble part increases the strength of the matrix phase and fundamentally changes the brittleness of the regenerated cellulose. This work provides a green and promising method to prepare high‐performance, environmentally friendly all‐cellulose composite materials. In this study, all‐cellulose composite materials are prepared from waste kraft papers.The composite membrane is prepared by mixing the regenerated cellulose with the insoluble cellulose to change the brittleness of cellulose. This work provides a green and promising method to prepare high‐performance, environmentally friendly all‐cellulose composite materials.