Antimicrobial Polyethylene through Melt Compounding with Quaternary Ammonium Salts
Table 1
HPLC/MS results showing the leaching of quats into water after storing the samples for 1 month in 50°C warm water. (a) The water aliquots were removed successively after the amount of days indicated, without exchanging the water. (b) After the removal of each aliquot, the water was completely exchanged with a fresh batch.
(a)
No water exchange
Quats
1 d
2 d
3 d
8 d
14 d
21 d
32 d
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
1– (5 wt-%)
0
—
0
—
0
—
0
—
0
—
0
—
0
—
6 (5 wt-%)
0.29
2.9
0.42
4.1
0.47
4.6
0.31
3.1
0.41
4.0
0.45
4.4
0.52
5.1
7 (5 wt-%)
0.65
5.4
0.35
3.0
0
—
0.29
2.4
0.84
6.9
0
—
1.37
11.0
(5 wt-%)
10.54
65
11.45
70
11.38
70
12.37
76
13.42
82
10.91
67
13.50
82
(b)
With water exchange
Quats
3 d
6 d
10 d
20 d
30 d
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(μg mL−1)
(quats nm−2)
(5 wt-%)
0
—
0
—
0
—
0
—
0
—
6
(5 wt-%)
0.117
0.21
0
—
0
—
0
—
0
—
(3 wt-%)
0.060
0.09
0
—
0
—
0
—
0
—
(1 wt-%)
0
—
0
—
0
—
0
—
0
—
7
(5 wt-%)
0.153
0.17
0.042
0.05
0.033
0.04
0.063
0.07
0.087
0.10
(3 wt-%)
0.154
0.24
0.042
0.07
0.023
0.04
0.142
0.23
0.076
0.12
(1 wt-%)
0.160
0.23
0.035
0.05
0.037
0.05
0.042
0.06
0.034
0.05
value “0” means “below the detection limit,” that is, in this case < 0.020 μg mL−1. to the very high leaching of quat 9, which deems it not adequate as an antibacterial additive, no further leaching experiments were performed. monoquats were not found to leach in the experiment with no water exchange, the second experiment was only repeated with two representative quats 1 and 4.
