Evaluation of forming mixture composition impact on properties of water blown rigid polyurethane (PUR) foam from rapeseed oil polyol

• Glycerine works as a reaction start time extender and curing accelerator.
• Acetone reduces temperature during the foaming reaction.
• Acetone increases foam density when the boiling point is not reached.
• Glycerine softens cell walls and reduces foam density.

Rapeseed oil based water blown rigid polyurethane foam was prepared by two shot method. Water was used as a blowing agent on purpose to increase the green nature of the foams. In order to reduce the temperature and shrinkage, acetone and glycerine were added. The influence of these additives on foaming characteristics, density, closed cell content, compressive strength and water absorption was described. It was found that reduction in shrinkage using glycerine leads to greater open cell content and water absorption, lower compressive strength (by almost 72% and 53%), density (by almost 64% and 74%) for moulded and free rise specimens, respectively, and delayed cream time of foaming mixture. The use of acetone reduced foam formation temperature by 15 °C, increased moulded and free rise densities by approximately 8%, as well as compressive strength by 22%, and by 10% for moulded and free rise water blown polyurethane specimens.