Apparent specific volume of polystyrene in benzene, toluene, ethylbenzene, and 2-butanone

Abstract

\1ea surem ent s have been made a t t emperat ures n ear 27 ° and 30 ° C of t he d en sities of pu rifi ed ben zene, to luene, ethylbenzene, a nd 2-but ano ne (m et hy lethylketone) , a nd of sol utions of a purifi ed sample of p oly sty r ene in t hese solven ts. ' Wi t hi n t he precision of t he meas urem ents (abo u t 1 or 2 in 10 5 density) t h e appa ren t s pecifi c volume of th e p oly-styr ene is a constan t indep end ent of t he concen t rat ion in a nyo ne solvent, bu t d epe nds to so me exten t upo n t he solven t. The lowes t values, which wer e obtained wi t h 2-bu ta none, a l'e a bo ut 1 p er cent lower t han t he hi ghest val ues, \ V hi ch were obt ained wit h ethyl be nzene. The va lu es ar e a ll lower t han t hose of th e vir t ua l liquid p olym er , ob tained by extrapolation of data on specifi c volume above t he glass t ra nsi t io n temperat ure, altho ugh t h e data of o t her obser vers indi ca te t hat t hi s is n ot t ru e fo r all solvents. I n a ll fo ur solven t s t he cha nge of t he appa ren t sp ecifi c vol ume wi t h temp erat ure is less t han fo r t he liq uid p olym er. The changes in vol ume upon mi xin g of polystyr ene wi t h t he solven ts ar e sh ow n to have a sig nifi cant cffect on s uch t hen nod. v na mi c proper t ics as heat, Free energy , a nd cnt ropy of mi x in g .