Stretchable and Fast Composting Polyester Films with High-Performance Oxygen Barrier

Abstract

This work presents one of the fastest composting aliphatic–aromatic polyesters with a good balance of mechanical and barrier properties, making it a sustainable alternative for low-density polyethylene in packaging. The polyesters (PB x BDM y S) are prepared by melt polycondensation of 1,4-butanediol (B), 1,4-benzenedimethanol (BDM), and succinic acid (S). One composition exhibited a tensile strength of 20 ± 2 MPa, a modulus of 150 ± 8 MPa, and a very high elongation at break of 581 ± 46%. The low oxygen transmission rate (152 cm3·m–2·day–1·bar–1) measured at 65% relative humidity and 23 °C confirms excellent barrier performance. A 3 μm water-borne nanocomposite coating of glycol chitosan and sodium fluorohectorite further reduced the gas permeability to a value of 0.75 cm3·m–2·day–1·atm–1, which is competitive with materials suitable for demanding packaging applications such as poly­(vinylidene chloride) while maintaining good mechanical properties and high stretchability. After studying the enzyme-catalyzed hydrolysis under controlled conditions, the full fragmentation, assimilation, and mineralization in thermophilic, aerobic composting could be confirmed in less than 5 weeks using a combination of different analytical methods. The mechanism of degradation was proven to be bulk degradation.

Synthesis and degradation study of graft copolymers of poly(limonene carbonate)

“…The surface erosion mechanism was also observed in our previous work during the degradation of polyesters made by condensation polymerization. 35 Some prominent changes at the surface with porous structures were obvious from SEM images (Fig. 6(e-h)).…”