D. Shailaja et M. Yaseen, EFFECT OF ALKYL PHTHALATE PLASTICIZERS ON PERMEATION OF WATER-VAPOR THROUGH PVC MEMBRANES, Polymer international, 32(3), 1993, pp. 247-250
PVC membranes plasticized with various concentrations of a di-n-alkylp
hthalate (methyl, ethyl, butyl or octyl) were studied for their water
vapour permeation (WVP) properties. The rates of WVP through them were
estimated under steady state by permeating the vapour through the mem
brane under the vapour pressure differential of approximately 100% to
0% relative humidities at 25-degrees-C. The rates of WVP were found to
decrease with an increase in the size of the alkyl group of the phtha
late but increased with its concentration. The maintenance of the prop
erty by the membranes being critical for their long-term applications,
the measurements were also repeated on the membranes aged for 250 day
s at intervals of 50 days. The WVP data indicate that membranes contai
ning medium concentrations, i.e. 17.5-20% of the plasticizers have bet
ter maintenance of the property during ageing and also in handling wit
h good mechanical strength.