Environmental Engineering Reference
In-Depth Information
Figure 3.9
A sample of HDPE immersed in Bay of Bengal waters for six months
(damage to the polymer from wind, ocean currents and biofouling)
Studies carried out for one year indicated that maximum barnacle attachment was
seen on a hard surface (GFRP) and minimum barnacle attachment was found on
lexible surface SR. Attachment of barnacles and polychaetes are positively correlated
with surface energy or negatively correlated with contact angle. The fouling load is
positively correlated with surface energy and hardness of the surface. The surface
energy, hardness and tensile strength are reduced whereas the surface roughness was
considerably increased during this one year period. Increase in surface energy indicates
that the polymers have become relatively more hydrophilic. The maximum gravimetric
weight loss was seen in PET (7.49%) followed by PU (4.25%) and the minimum was
in CFRP (0.45%). The maximum thermogravimetric (thermogravimetric analysis
(TGA)) weight loss was observed in PET (73.5% at 400 °C) followed by PU (71.1%)
and the least weight loss was found with SR (2.4%).
3.5 Characterisation of Biodegradation
There are several, physical, chemical and mechanical techniques available that can
be used to characterise and quantify biodegradation:
• Visualobservation
