K₂₃₂ Mean (SD)

Months

Glass

PET

HDPE

PLA

0

1.74 (0.05)^*

1.74 (0.05)^●

1.74 (0.05)^#

1.74 (0.05)^♦

3

1.90 (0.01)^a,b**

2.05 (0.01)^a,b●●

2.31 (0.01)^b#

2.30 (0.05)^a♦♦

5

2.67 (0.03)

2.45 (0.14)^●

2.90 (0.12)^#

2.74 (0.70)^♦

7

3.62 (0.02)^c,d*,**

3.21 (0.04)^c●,●●

3.48 (0.08)^c,d#

3.08 (0.01)^d♦

9

3.98 (1.21)^*,**

3.94 (0.43)^●,●●

4.03 (0.16)^#

3.89 (0.18)^♦,♦♦