Carboxymethyl chitosan-based form-stable phase change materials with ultra-low leakage and excellent low-temperature buffering performance

In the cold chain transportation field, the commonly used polystyrene foam has drawbacks in degradation and temperature buffering, leading to considerable resource waste and environmental pollution. Here, a novel form-stable phase change material (FSPCM) based on carboxymethyl chitosan/sodium alginate/polyethylene glycol 400 has been prepared by a preforming post-enhancement approach combined with freeze-drying. The preforming post-enhancing strategy resolves the contradiction between mechanical support of natural polymer-based gels and controllable molding, thereby enabling FSPCM to be directly molded into shapes required for practical applications (e.g., packaging boxes). As one of the key performances, the high encapsulation efficiency (50.37 %) of polyethylene glycol 400 endows this FSPCM with robust temperature buffering properties compare to polystyrene foam. Furthermore, the lamellar shell endows the FSPCM with remarkable mechanical properties (Young's modulus of 10.27 MPa), resistance to leakage (no polyethylene glycol 400 leakage was detected after 5 days at 80 °C), and antibacterial properties (showing >99.5 % bactericidal rate against Escherichia coli and Staphylococcus aureus). Additionally, the FSPCM exhibited superior thermal stability and biocompatibility. This study provides new insight into an alternative package design for green and low-temperature buffering to cold chain transportation.