Biopolymers are gaining importance as they tackle the plastics problem and are being recognized as a possible alternative. However, some issues such as their thermomechanical, barrier properties, and biodegradation are putting them at risk as replacements of traditional polymers. All the aforementioned properties were analysed for five biopolymers: PLA, PBS, PVA, starch, and PBAT.

A strong correlation (0.98) was found between the elongation at break and the ultimate tensile strength (UTS); however, none of these properties were connected with the Young modulus. This could be because during plastic deformation the polymer undergoes atom displacement and breakage of the bonds, that keeps moving further away until rupture occurs; this is related to the viscoelastic properties of the polymers. On the other hand, during elastic behavior, the displacement comes back to their original state so that the polymer structure does not change. The Young modulus (MPa) was 28.77 for starch, 134.45 for PBAT, 141.18 for PBS, 461.07 for PVA, and 701.67 for PLA.

The Young modulus is related to the water vapor transmission rate (WVTR). It is inversely proportional (-0.79), which means that the greater the permeation, the weaker the material. It could be explained by picturing the polymer with its crosslinks, where the more crosslinks are present, the harder it would be for the water to cross through the polymer and the stiffer the polymer would be as the chains would not unfold so easily. The WVTR in g/daym2 for the biopolymers was 43.35 for PLA, 43.8 for PVA, 222.2 for PBS, 457.5 for PBAT, and 901.37 for PBAT.

As for biodegradation, all polymers biodegraded between 7 and 28 days; this was done by composting at 60ºC following ISO 20200: 2015. PVA degraded at 15 days, PLA and starch at 21, and PBS and PBAT at 28 days.