Degradation of Polymers in the Presence of Sulfate Reducing Bacteria Microbes

In exploration and production (E&P), the transportation of hydrocarbon is through carbon steel pipeline, which is exposed to various corrosion attack. One of the difficult corrosion issue is related to Microbiologically Influenced Corrosion (MIC) caused Sulfate Reducing Bacteria (SRB). Thus, extensive chemical treatment in the form of corrosion inhibitor and biocide is required for corrosion inhibition and microbial treatment. The new initiative is application of polymeric pipelines to forgo requirement on chemical treatment, and as a substitute to overcome the corrosion of metal pipelines due to the claims that polymers is not affected by MIC. This implies some uncertainties in how resistant polymer is towards microbes, since degradation of polymer in MIC is not well quantified. The objective of this project was to investigate the degradation process of High Density Polyethylene (HDPE), Polyethylene (PE) and Polyvinylidene Fluoride (PVDF) in the presence of SRB and to characterize the degradation in terms of change in tensile strength. The project was conducted where polymer samples were immersed in solution which contains formation water, nutrients and SRB microbes, in room temperature and ambient pressure. The characterization methods which were used in this project was visual testing, weight change measurement for water uptake and tensile testing. The results from this project was that the polymer samples have undergone slight degradation within the immersion period of 6 weeks, with small extent of weight loss and reduction in tensile strength after degradation. PVDF was determined to have the highest reduction in tensile strength after degradation, a reduction of 11.62% in tensile strength. The least reduction in tensile strength after degradation is PE, with a reduction of 1.65%. The results from water uptake measurement was not taken into consideration as there were no significant weight change of the polymer samples. Further studies of immersion process in a longer period should be conducted to obtain significant weight change measurement.