The impact of sole water and acetone/water system on performance characteristics of bio-polyols based polyurethane foams

Abstract

It is well known that one of the factors causing ozone layer depletion and global warming is the use of refrigerants, which, in the nearly future, will be phased out; therefore, it is of great interest to find alternative solutions. Water was chosen as an alternative environmentally friendly blowing agent, which has ozone depletion potential equal to 0. However, a need for the alternative auxiliary blowing agent that could be used in the production of polyurethane foams still exists. It is as well important to keep in mind that traditional raw materials used for the production of polyurethanes are greatly petroleum based; therefore, lots of researches are dedicated to the synthesis of such bio-polyols with sufficient functionality, which could withstand the difference between internal and atmospheric pressures during the last stage of foaming. The aim of this research is to test the impact of sole water and acetone/water system as blowing agents for the production of rigid polyurethane foam from rapeseed oil-based polyol obtained via chemo enzymatic route. Compared to the control water blown bio-polyurethane foam, acetone has increased moulded and free-rise densities by approximately 8%, compressive strength by 22% and 10%, respectively. Furthermore, acetone and acetone/water system based bio-polyurethane foams were characterized by high shrinkage level due to the higher acetone’s diffusion rate out of the cells. In order to reduce the settle back in height and initial shrinkage, rapeseed-based glycerine may be used. The obtained results from short-term water absorption were related to the structure, which showed that the sole water and acetone/water system form closed cell structure of the final products. The obtained water blown foams were characterized by short-term water absorption equal to 0.18 kg/m2 and acetone/water system – 0.22 kg/m2.