Structure–property relationship in aging acrylic latex films

We have used environmental scanning electron microscopy (ESEM) and mechanical testing to study the effect of aging parameters (temperature, T and relative humidity, RH) on the structure–property relationship of aged specimens from two acrylic latex compositions, referred to as ‘standard’ and ‘novel’. It was found that the tensile strength of the novel system increases as a function of aging time, whereas the tensile strength of the standard specimens remains almost unchanged. This was attributed to the formation of salt dendrites in the aged novel samples. It was also found that humidity does not have a significant effect on the microstructures observed. However, it was found that aging at lower temperatures results in decreased rate of dendritic formation, which is suggested to be due to decreased diffusion of the species taking part in the crystallisation process. Further examination of fractured surfaces of the studied latex systems revealed features indicative for a more ductile behaviour of the standard specimens and a more brittle behaviour for the novel latex samples.