Atmospheric Corrosion
131
or reinforcing material used. Certain environments may weaken primary
and/or secondary polymer linkages, with resulting depolymerization. Other
environments may cause swelling or microcracking, whereas still others may
hydrolyze ester groupings or linkages. Extraction can occur in certain environments, while in other environments repolymerization can take place with
a resulting change in structure. Simple solvent action may occur or absorption
or attack at the interface between the glass and the resin will result in weakening. The mechanisms involved are complicated and not well understood.
TabLE 4.9
Atmospheric Resistance of Thermoplastic Polymers
Polymer
UV
Degradation
Moisture
Absorption a Weathering
Ozone
SO 2
NO x
H 2 S
ABS
RS
0.30
R
X
R b
R b
CPVC
R
0.03
R
R
R
R b
ECTFE
R
<0.1
R
R
R
R
R
ETFE
R
<0.029
R
R
R
R
R
FEP
R
<0.01
R
R
R
R
R
HDPE
RS
R
R
R
R
PA
R
0.6–1.2
R
X
R c
X
PC
RS
0.15
L
R
PCTFE
R
R
R
R
R
R
PEEK
RS
0.50
L
R
R
R
PEI
R
0.25
R
R
PES
RS
X
R
PF
R
R
PFA
R
<0.03
R
R
R
R
R
PI
R
R
R
PP
RS
0.02
L
L
R
R
R
PPS
R
0.01
R
R
R b
PSF
R
0.30
R
R
PTFE
R
<0.01
R
R
R
R
R
PVC
R
0.05
R
R
R d
X
R
PVDC
R
R
R
R
R
R
PVDF
R
<0.04
R
R
R
R
R
UHMWPE
RS
<0.01
R
R
R
R
Note: R = resistant; RS = resistant only if stabilized with a UV protector; X = not resistant; and
L = limited resistance.
a Water absorption rate 24 h at 73°F/23°C (%).
b Dry only.
c Wet only.
d Type 1 only.
Source: From Reference 10.