the approximate weight 0.09 g, the ratio of sur-
RESULTS AND DISCUSSION
face area to solution volume 0.076, and the solu-
tion volume to PVC volume approximately 386:1.
Long-term methylene
Another difference with this experiment was that
chloride studies
the Teflon-lined caps were lined with aluminum
Table 4 gives the hardness readings and per-
foil to prevent any losses due to sorption by caps,
cent weight gain data for samples exposed to aque-
and as a result mercuric chloride was not added
ous solutions with relative solubilities of 0.01, 0.05,
to the test solutions because it would degrade the
0.10, 0.20, and 0.40. After 18 months' exposure,
aluminum foil. The relative solubility of each of
there was no significant change in the hardness
the analytes was either 0.010 or 0.020. The sum of
readings of samples that were exposed to aque-
the relative solubilities of the organic solutes was
ous solutions of methylene chloride with relative
either 0.18 or 0.36, respectively. Samples were
solubilities that were less than 0.1. With one ex-
taken after 20 and 40 weeks' contact.
Table 4a. Hardness (Barcol) readings of PVC exposed to methy-
Second long-term study
lene chloride solutions.
In this study, pieces of PVC were
exposed to four aqueous solutions
Relative
Contact time, months
of the same eighteen PVC solvents
solubility
3
6
9
12
15
18
and swelling agents (Table 3). This
0.00
71
74
78
77
78
78
time the relative solubility of the
0.00
71
73
79
77
78
80
analytes was either 0.001, 0.005,
0.00
72
73
78
78
76
79
0.010, or 0.020. This makes the sum
0.00
73
74
76
76
78
80
0.00
73
74
80
78
78
78
of the relative solubilities of the or-
72.0
73.6
78.2
77.2
77.6
79.0
ganic solutes either 0.018, 0.09, 0.18,
X
or 0.36, respectively. Samples were
0.01
73
74
78
77
78
79
taken after 3, 6, 9, 12, 15, and 18
0.01
72
74
79
79
77
79
months, and the test solutions were
0.01
71
72
80
76
78
80
0.01
70
73
77
78
79
79
changed every six months.
0.01
74
73
78
77
77
78
72.0
73.2
78.4
77.4
77.8
79.0
X
Studies on aqueous solutions
containing organics that are
0.05
72
74
76
77
76
77
0.05
72
74
78
78
79
80
miscible in water
0.05
71
73
79
76
78
79
0.05
70
73
76
76
76
78
Long-term acetone study
0.05
70
72
77
78
77
78
In this study, pieces of PVC were
71.0
73.2
77.2
77.0
77.2
78.4
X
exposed to aqueous solutions that
0.10
71
74
76
76
76
77
contained the following percent ac-
0.10
72
74
79
74
78
76
etone: 0.5%, 1%, 5%, 10%, and 20%
0.10
71
74
77
77
75
78
(w/v). Contact times were again 3,
0.10
72
73
78
76
76
77
6, 9, 12, 15, and 18 months. The test
0.10
71
73
80
75
74
75
solutions were changed every six
71.4
73.6
78.0
75.6*
75.8 *
76.6*
X
months.
0.20
71
73
77
75
73
77
0.20
71
74
76
76
74
76
Short-term study with acetone
0.20
70
72
77
75
73
74
and methylene chloride
0.20
71
73
76
73
74
74
0.20
72
73
74
77
73
73
PVC was exposed to different so-
71.0
73.0
76.0*
75.2*
73.4*
74.8*
lutions containing methylene chlo-
X
ride and acetone. The relative solu-
0.40
69
72
74
74
73
71
bility of the methylene chloride was
0.40
70
72
77
74
72
72
0.4, while the concentration of ac-
0.40
71
71
76
75
71
74
0.40
70
72
76
75
71
74
etone in the solution was either 0%,
0.40
69
73
76
73
72
73
0.5%, 1.0%, 5.0%, 10%, or 20% (w/
69.8*
72.0*
75.8*
74.2*
71.8*
72.8*
X
v). Contact times were 2, 4, 7, 14,
and 21 days.
*Significantly different from controls.
8
Previous Page
