A novel biological friendly shape memory polymer and self-healing polymer based on poly(propylene carbonate) (PPC)/microfibrillated cellulose (MFC) was prepared. MFC was firstly modified by a one-step mechanic-chemical approach involves ball milling and esterification reaction. In this way MFC could be incorporated into PPC up to 20 wt% with excellent dispersion. The formation of "MFC network" structure in the PPC matrix was verified via scanning electron microscopic and the strong interfacial interaction between PPC and MFC was confirmed by X-ray photoelectron spectroscopy. The incorporation of MFC not only significantly enhanced mechanical strength and thermal stability, but also acted as physical cross-linkers, which could improve the shape memory property of PPC at definite content (5~10 wt%). More importantly, with the assistance of shape memory effect and the reinforcement of MFC fibers, the polymer composites also showed much enhanced scratch resistance and scratch self-healing behavior. Our work provides a composite approach to tune the shape memory behaviors of polymer composites and may contribute to the application of PPC in smart materials field.

In this study, green composite films based on cellulose nanocrystal/chitosan (CNC/CS) were fabricated by solution casting. FTIR, XRD, SEM, and TEM characterizations were conducted to determine the structure and morphology of the prepared films. The addition of only 4 wt.% CNC in the CS film improved the tensile strength and Young’s modulus by up to 39% and 78%, respectively. Depending on CNC content, the moisture absorption decreased by 34.1–24.2% and the water solubility decreased by 35.7–26.5% for the composite films compared with neat CS film. The water vapor permeation decreased from 3.83 × 10−11 to 2.41 × 10−11 gm−1 s−1Pa−1 in the CS-based films loaded with (0–8 wt.%) CNC. The water and UV barrier properties of the composite films showed better performance than those of neat CS film. Results suggested that CNC/CS nanocomposite films can be used as a sustainable packaging material in the food industry.

Eco-friendly cellulose nanocrystal/silver/alginate (CNC/Ag/Alg) bionanocomposite films were successfully prepared by blending of CNC with Ag/Alg solution. The CNC was fabricated from cellulose microcrystal (CMC) by acid hydrolysis method. The Ag nanoparticles (AgNPs) were generated by using Alg as a reducing agent through hydrothermal process. AgNPs-included composite films showed characteristic plasmonic effect of the AgNPs with the maximum absorption at 491 nm and they also showed high ultraviolet (UV) barrier properties. The CNC/Ag/Alg composite films were analyzed by using scanning electron microscopy, transmission electron microscopy, optical microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction technique. Depending on the type of nanofillers, tensile strength of the composite films increased by 39–57% and water vapor permeation decreased by 17–36% compared with those of the neat Alg films. The Ag/Alg and CNC/Ag/Alg films showed brown color as detected from the increase of both ‘b’ and ‘a’ parameters by colorimeter. The UV and water barrier properties of Alg based composite films were found higher than the Alg films. The obtained results suggested that the prepared composite films can be used in food packaging applications.