EFFECTS OF PRESSURE AND TEMPERATURE ON DENSITIES OF LIQUID POLYMERS

An equation is given which relates the pressure p, density d and absolute temperature T of unassociated liquids. This equation, in the following form, can be used for polymeric liquids (with c.g.s. units): 1·9X106p( T'c-T T'c)0·9=( 21P'd M')9-[ 8·24X105(T'c-T) T'c]2·7. P′ is the parachor and M′ is the molecular weight for the repeating unit and both can be calculated readily. For a given polymer, T′c is a constant and equals the temperature-reducing parameter proposed by A. Bondi. A considerable number of well known polymers of high molecular weight have almost the same value of T′c which seems to depend upon the molecular flexibility. © 1969.