Industrial & Engineering Chemistry Research, Vol.59, No.51, 22163-22172, 2020
Fabrication of Poly(epsilon-caprolactone)-Based Biodegradable Packaging Materials with High Water Vapor Barrier Property
Poly(epsilon-caprolactone)/glycerol tristearate (PCL/C18) composites with excellent oxygen and water vapor barrier properties were developed through melt blending. After the addition of C18, a significant decrease of 81.4% in water vapor permeability (50% relative humidity) was obtained for the PCL/C18 blend (sample PCL-30) compared to that of pure PCL. Moreover, when the humidity increased from 50 to 90%, the barrier property of PCL/C18 blends only sacrificed a little, exhibiting noticeable humidity stability. C18 was evenly distributed in the PCL matrix with various particle sizes, and hydrophobic "bulk barrier" was formed. The PCL/C18 composites not only had the low surface solubility coefficient on the surface of the material but also had the tortuous diffusion path in the bulk material. Moreover, the addition of C18 with excellent hydrophobicity resisted the penetration of water vapor through the PCL/C18 blends and decreased the swelling and plasticization effects on PCL matrices, leading to the remarkable barrier stability in high humidity. The barrier performance of PCL-30 at 90% RH was only deteriorated by 0.63 x 10(-14) g.cm.cm(-2).s(-1).Pa-1 compared with that at 50% RH. Based on the excellent water barrier property and barrier stability in high humidity, especially considering the simple and effective manufacture processing, this method exhibited a great value in packaging applications.