polyethylene glycol MW 600

wt%		log P (dynes/cm^2)

2.5		6.22
5.0		6.43
10.0		6.80
15.0		7.01
20.0		7.20
25.0		7.38
30.0		7.53
35.0		7.68	
5.0		6.15
10.0		6.72
15.0		6.96
20.0		7.13
25.0		7.30
30.4		7.42
35.2		7.57
40.5		7.64
45.0		7.92
61.5		8.35
67.5		8.49
45.0		7.92
40.0		7.80
5.0		6.34

An equation that fits this data is the following.

log P = a + b * (wt%) ^ c

where a = 5.63, b = 0.33 and c = 0.51

Note that it should be applied only over the range of pressures measured.