Matricial foaming

We designed an innovative pressure vessel for a high throughput study of batch foaming of thermoplastic polymers. With the new pressure vessel, the foaming process can be conducted concurrently on sixteen samples (arranged in a 4 x 4 wells matrix) at four different temperatures and at four different pressure drop rates, at the same saturation pressure. We herein describe the design principle, the working conditions and the first results gathered on poly(epsilon-caprolactone) samples foamed with carbon dioxide as the blowing agent. We explored the processing variables space: foaming temperature in the range 30-40 degrees C; pressure drop rate in the range 1-5 MPa/s; saturation pressure fixed at 5 MPa within a single experiment. The expected dependence of density as well as morphology on processing variables proves the suitability of the method for the high throughput study of novel polymers and can be utilized for the fast development of resins suitable for foaming.