Studies on physical blends and cathodic disbondment properties of polyethylene and maleic anhydride-grafted-polyethylene

Blends of various compositions of polyethylene (PE) and maleic anhydride-grafted-polyethylene (PE-g-MAH) have been physically characterized by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Crystallinity of the blend decreases with an increasing content of less crystalline PE-g-MAH, although the total value is a positive deviation from the value calculated by the rule of mixtures, indicating some level of additional nucleation of crystals by the included phase. The blends were examined for their cathodic disbondment (CD) performance (adhesion to metal under the influence of hydroxide ions) and this was compared with the performance of unmodified PE coatings. An improvement in the CD performance was observed as a result of the modification, with the best performance most occurring for the lower coating temperatures. This result has ramifications for the improved performance that these materials provide as coatings for pipes protected by cathodic protection.