Effect of hydrothermal ageing on structure and physical properties of one-phase and two-phase entirely lipid-derived thermoplastic poly(ester urethane)s

Abstract

The hydrothermal degradation of a one-phase and a two-phase segmented thermoplastic poly(ester urethane) (TPEUs) made entirely from lipids was studied by accelerated ageing in water at 80 °C. Extensive alteration to the morphology, hydrogen bonding index and phase separation of the TPEUs were observed in one day of immersion in the water. The TPEU also achieved a tensile half-life of one day. The evolution of the physical properties of the TPEU such as the thermal decomposition, thermal transition and tensile characteristics was directly linked to the changes caused by hydrolysis to their phase morphology and microstructure. The degradation occurred in three stages depending on the degree of phase separation and hydrogen bond density. The formation of aliphatic carboxylic acid and amine degradation products following hydrolysis of both the soft and hard segments was identified by 1H-NMR.The controlled life-cycle properties combined with the adequate thermal and mechanical properties of the materials demonstrate the viability of lipid derivatives as alternatives to petroleum for manufacturing TPEUs and credible potential in biomedical applications especially as bioresorbable implants or tissue scaffolds.