José A. Jofre-Reche, Andrés J. Yáñez-Pacios & José Miguel Martín-Martínez, Adhesion And
Adhesives Laboratory, University Of Alicante, Alicante, Spain
Manuel Colera & Víctor Costa, Ube Chemical Europe S.A., Castellón, Spain
Introduction
Several substrates are severely exposed to aggressive out- door environments (abrasion, corrosion, resistance to chemical or solvents, degradation by moisture or water),
and to prevent the reduction of their properties due to degradation several coatings of different nature are commonly used.
In the particular case of piping for the oil and mining industry,
degradation is a key concern as inside the pipeline corrosive fluids containing solid particles are circulating. For increasing the
durability of the pipelines they are internally coated to increase
their lifetime and increase the time for maintenance [1]. These
coatings are commonly based on polymeric materials, more specifically semi-rigid polyurethanes [2]. Polyether diol-based polyurethane coatings are currently used for pipelines due to their
relatively good water resistance but their wear resistance and
stability against oils and solvents, as well as thermal stability
are not fully satisfactory [ 3]. Typically, the drawbacks of these
polyurethane coatings have been solved by incorporating additives particularly fillers of different nature and size (nano-silica,
zinc oxide, alumina particles [ 4-6]) for increasing their abrasion
resistance.
As compared to the polyurethanes obtained with polyether or
polyester, due to the higher molar attraction constant of the car-
bonate groups, the polyurethanes prepared with polycarbonate
diol can be a feasible alternative for improving the mechanical
properties and increase the hydrolytic stability, imparting ad-
ditionally good elastomeric properties and adequate behavior
at low temperature [ 7, 8] (Figure 1). Because these particular
and unique features of the polycarbonate diol, in this study
several polyurethane coatings were synthesized by using dif-
ferent polyether diol + polycarbonate diol mixtures as polyol
for preparing polyurethane coatings with improved hardness
and wear resistance in pipeline internal coatings, additional
to improved mechanical properties and hydrolytic stability.
Novel Polyurethane Coatings
Obtained with Polycarbonate
Diol for Pipelines with
Improved Mechanical Properties
and Hydrolysis Resistance
Figure 1. Molar attraction constant (units: J3/2cm3/2mol-1) of different groups in
the polyols.
