Synthesis of chromophores modified porous clay heterostructure for preparing ethylene scavenger and optical sensor packaging film

Abstract

Smart packagings for detecting climacteric fruit freshness were prepared based on low density polyethylene (LDPE)/chromophores (bromothymol blue) modified PCH (PCH-BTB) nanocomposite films. The incorporation of chromophores in porous materials was investigated by N₂ adsorption-desorption, XRD and SEM. The nanaocomposite was prepared by twin screw extruder and fabricated into nanocomposite film by compression molding. The color change of LDPE/PCH-BTB nanocomposite films from green to yellow correlated with standard CO₂ levels, which can be compared to CO₂ levels from respiration during fruit ripening. Porous clay improved the barrier properties of nanocomposite indicated by the reduction of oxygen transmission rate. Thus, LDPE/PCH-BTB nanocomposite films can be applied for detecting the quality of climacteric fruit by color change. In addition, this pH indicator can prolong the shelf-life of product by incorporated porous materials into the films.