A novel gas conductor–gas barrier (GC–GB) blending membrane with adjustable gas separation capacity

Abstract

A promising avenue to preserve harvested fruits and vegetables can be achieved by designing a “breathable” membrane named as equilibrium modified atmosphere packaging (EMAP). In this work, such “breathable” packaging was prepared using a gas conductor –gas barrier (GC–GB) blending membrane (BM). The miscibility between the GC and GB in the BM was displayed using structural scanning and thermal analysis, and the physicochemical properties of the BM were characterized by a series of assays. By changing the SPEEK content in the BM, CO₂ permeabilities of the BM in pure gas can be adjusted from 105 to 1494 kPa, while the O₂ permeabilities can be adjusted from 19 to 297 kPa. Thus, the CO₂/N₂ and O₂/N₂ ideal selectivity of the BMs were 20.48–33.95 and 5.38–6.75, respectively. On this basis, the membrane was used to preserve oranges and cauliflower. The equilibrium internal atmospheres included 4.6–7.9% of CO₂ + 7.8–4.4% of O₂ (p/p) and 3.6–8.7% of CO₂ + 9.2–4.2% of O₂ (p/p), which were respectively recommended to preserve the stored products. The results indicated such adjustable membranes will have promising applications to preserve different kinds of fresh products.