High moisture permeable cellulose diacetate films by reactive polyethylene glycol plasticizers

Cellulose diacetate (CDA) is a bio-based polymer with high hydrophilicity and low crystallinity that is used as an intrinsic moisture conductor. Adding ahydrophilic plasticizer such as polyethylene glycol (PEG) can improve chain mobility and moisture permeability but has the potential to cause damage to materialperformance due to plasticizer migration. Herein, isophorone diisocyanate (IPDI) modified PEG 200 (IPEG200), which served as a reactive plasticizer, can significantly enhance the water vapor permeability (WVP) and mechanical properties. Hydrophilic nanometer Al2O3 fillers were also added to improve the all-around performance of CDA films. Fourier transform infrared spectroscopy (FTIR) was used to monitor the synthesis of the prepolymers, IPEG200, and their reaction with CDA chains. The gel content indicates the crosslinking reaction. When IPEG200 is 9.66 phr and Al2O3 filler is 5 phr, the WVP is raised to 8.9 × 10−13 g · cm/cm2 · s · Pa. When using IPEG200 as the compatibilizer for PEG and CDA, CDA film can reach WVP 14.2 × 10−13 g · cm/cm2 · s · Pa by adding 60 phr PEG 600 and 25 phr Al2O3. This study provides a simple, feasible, low-cost method for preparing intrinsic moisture permeable film by reactive plasticizers