High moisture permeable cellulose diacetate films by reactive polyethylene glycol plasticizers

Intrinsic moisture permeability of bio-based polymer cellulose diacetate (CDA) is not sufficient for some requirements. Herein, isophorone diisocyanate (IPDI) modified polyethylene glycol (IPEG200) was served as a reactive plasticizer to enhance the water vapor permeability (WVP) of CDA films without plasticizer migration problems. The performances of CDA films were further improved by adding hydrophilic nanometer Al 2 O 3 fillers. Fourier transform infrared spectroscopy (FTIR) was used to the synthesis processes of the prepolymers and their reaction with CDA chains. The crosslinking reaction was indicated by monitoring the gel content. When IPEG200 is 9.66 phr and Al 2 O 3 filler is 5 phr, the WVP is raised to 8.9 × 10 −13  g·cm/cm 2 ·s·Pa, which is much higher than CDA’s. WVP 14.2 × 10 −13  g·cm/cm 2 ·s·Pa of CDA film can be obtained by adding 60 phr PEG600 and 25 phr Al 2 O 3 when using IPEG200 as the compatibilizer. This study provides a simple, feasible, low-cost method for preparing high moisture permeable film by reactive plasticizers.