Environmental Engineering Reference
In-Depth Information
LDPE (containing a metal catalyst pro-oxidant) quantify their rates of
degradation. The ECO copolymer is the same as that used in
photodegradable six-pack rings (and supplied by the manufacturer ITW
HiCone Company) and is a product intended to breakdown at a faster rate
outdoors. The metal-catalyzed LDPE film contained low levels of an iron
catalyst and was supplied by the manufacturer (Plastigone Inc., Miami, FL).
Again, the rates of degradation of these enhanced photodegradable plastics
(as well as control LDPE laminates) are much slower for samples floating
in water compared to those exposed in air (on land), at the same location.
Thetablealsoshowsthatenhancedphotodegradableplastictechnologiesdo
perform with plastics floating in water, though the rates of weakening are
relatively slower compared to exposures in air. The values of coefficients A
and B can be estimated by fitting the tensile data with the above equation.
Table 10.4
Summary of Results for Degradation of LDPE Control
Samples, ECO Copolymer, and Metal-catalyzed Polyethylene
Exposed in Air and Floating in Water at Different Locations
Source: Based on data from Andrady et al. (1993a, b).
Location
Air
Floating
B
(days
−1
)
r
2
B
(days
−1
)
r
2
Biscayne bay
LDPE
14
0.91 —
—
ECO copolymer
69
0.92 45
0.86
LDPE with metal catalyst 72
0.97 27
0.97
Puget sound (WA)
LDPE
4
0.77 —
—
ECO copolymer
40
0.88 11
0.65
LDPE with metal catalyst 54
0.96 18
0.87
Freshwater lake (VA)
LDPE
14
0.91 1
0.66
ECO copolymer
89
0.83
LDPE with metal catalyst 8
0.78 8
0.83
