HYDROLYSIS EFFECTS ON THE MASS OF A CROSS-LINKED POLYMER

An epoxy resin has been exposed to conditions of high humidity and temperature for various periods and then dried, Compared to the original value, the weight after drying initially increases with humidity exposure time and then falls below. A theory is presented which explains this behaviour by macromolecular chain scission. The initial weight gain is attributed to chemically attached water, whereas the following loss is associated with a phenomenon of leaching of free segments. The model explains satisfactorily the experimental results and leads to an estimation of mean inter-crosslink molecular weight.