Long term water uptake of a low density polyvinyl chloride foam and its effect on the foam microstructure and mechanical properties

• Long term water absorption of a PVC foam was investigated.
• Tensile and compressive properties of a water-immersed PVC foam were investigated.
• Mechanical degradation was reflected in the elastic modulus and plasticization.
• Even for 1 year of immersion, the foam damaged was only superficial.

The water uptake, evolution of the cell morphology and basic mechanical properties of a 48 kg/m3 commercial polyvinyl chloride (PVC) foam immersed in distilled water and seawater for up to 12 months is investigated. The samples of PVC foam immersed in distilled water showed a faster water absorption rate and water uptake than the samples immersed in seawater. For both conditions, the tensile and compressive properties of the foam evidence a plasticization effect with a small reduction in the elastic modulus (∼10%) and an increase in the ultimate tensile strain (∼19%) for 12 months of immersion. The detailed micrographic analysis conducted provides conspicuous evidence that for both conditions the cells at the surface of the foam are severely damaged after a few days of immersion, but such cell damage is superficial and does not cause severe irreversible damage to the internal cellular microstructure of the foam.