Fabrication of a highly stretchable cellulose with internally and externally dual-plasticized structure

Abstract

In this study, we developed a highly stretchable internally- and externally-plasticized (i.e., dually-plasticized) cellulose, which is composed of a polydecalactone (PDL)-grafted cellulose copolymer (CgPD) and a hyperbranched polycapmlactone (PCL) external plasticizer (HPC). To investigate the effect of molecular structure of PCL external plasticizers on the plasticization behavior of dually-plasticized celluloses, a linear PCL (LPC) and a star-shaped PCL (SPC) were prepared as control groups. It is observed that specific molecular interactions existed between CgPD and external plasticizers in the dually-plasticized celluloses (i.e., CgPD_LPC, CgPD_SPC, and CgPD_HPC, respectively). Especially, CgPD_HPC exhibited the lowest apparent activation energy (E-a = -128.8 kJ mol(-1)) required to achieve the plasticizing behavior, which resulted in an enhanced ductility (epsilon = similar to 136%) compared to those of the CgPD (epsilon = -75%), whereas CgPD_LPC and CgPD_SPC displayed severely deteriorated values (epsilon = similar to 25 and similar to 59%, respectively). In addition, the dually-plasticized cellulose bearing bulkier HPC exhibited further improved stretchability. These results comprehensively indicate that the highly-branched flexible segments of external plasticizer and structural uniformity induced by effective specific interactions between the plasticizing components play crucial roles in improving plasticization abilities of the dually-plasticized cellulose.