Tough citric acid-modified cellulose-containing polymer composites with three components consisting of movable cross-links and hydrogen bonds

Cellulose-containing polymer composites have advantages in addressing environmental issues because cellulose is a biobased filler that enhances the mechanical properties of the polymer composites. The enhanced mechanical properties reduce the amount of polymer waste generated. Although it is important to establish strategies for enhancing the mechanical properties of polymer composites, there are limited nanoscale studies on the polymer matrices. Usually, polymer composites focus on interactions between the matrices and fillers on the molecular scale and the distribution degrees of the fillers. The lack of structural studies is particularly obvious for polymer composites containing citric acid-modified cellulose. Herein, we study the structures of polymer composites with X-ray scattering measurements, thermal property measurements, and the finite element method. We reveal that an appropriate phase separation structure enables the formation of effective hydrogen bonds with high toughness values. We expect this report to provide material designs for polymer composites.