Cellulose acetate butyrate ester composite formulation

The Model 381-20 of cellulose acetate butyrate ester (CAB) was purchased from Eastman Chemical Company(Kingsport, TN, USA). We bought the EVOH Model ET3803 masterbatch from Nippon Synthetic Chemical Industry Co., Ltd.(Osaka, Japan). Glutaraldehyde aqueous solution (GA, 25 wt%), tert-butanol (>98%), acetic acid, polyphosphoric acid (PPA, phosphorus pentoxide content >85 wt%), butane tetracarboxylic acid (BTCA), acetone, phosphate buffer saline (PBS), phosphoric acid (H₃PO₄), NaOH, LiCl, KCl, MgCl₂, NaCl, and NaSO₄ were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Papain, lysozyme, ovalbumin, bromelain, bovine serum albumin, and pepsin were bought from Sangon Biotech Co., Ltd. (Shanghai, China).