WA Branch Technical Meeting - 13 May 2024 Polymeric Materials- “The Heart and Soul” of Coating Materials, Composite Materials and Even Concrete

Source: Dr Bogdan Dana, Senior Engineer-Materials and Corrosion, TECHT

Bogdan Dana has been working as a Chemical Engineer/ Industrial Chemist since 1993. Originally from Romania, with his first degree from study in Bucharest, Bogdan holds an MSc from Warwick University in England and a PhD from Otago University New Zealand. He has worked in Perth 2006, with the first seven years in a number of roles in formulation, manufacture, specification and quality control of paints, pigments, protective coatings and composite materials. Then then spent ten years in the cement and concrete industry, with a particular focus on mix formulation and admixtures. He recently joined TECHT corrosion and integrity management consultancy.

Bogdan drew on his deep and extensive knowledge of polymers to give his audience of overview of the role of polymers in coating materials, composites and concrete. He started by summarising polymer nomenclature and their main properties and subdivision into types according to structure, properties and manufacturing process. Properties of particular relevance in protective coatings include the glass to rubbery transition temperature, viscoelasticity, permeability and resistance to photo-, thermal- and biodegradation.

He highlighted the importance of molecular weight and molecular weight distribution/polydispersity index in controlling polymer properties. Uncontrolled polymerisation produces polymer chains with a wide variation of length/ molecular weight. Bogdan’s research studies had centred on controlled polymerisation, particularly be Atom Transfer Radical Polymerisation (ATRP). This allows a high degree of control over molecular weight, molecular architecture and polymer composition. The process is used in manufacture of functional polymers (controlled structure) including those with biomedical uses in drug delivery and implantable devices.

Bogdan holds a patent in this field and was able to give an expert explanation of the chemical reaction processes in ATRP. Based on a metal halide catalyst, such as copper bromide, these allow precise specification and control of chain length by stopping reaction through establishing chemical equilibrium.

He based the next part of his talk on his experience in paint and coating manufacture. He showed examples of typical manufacturing formulations for different types of paint. These included the various resins, pigments, fillers, surfactants, solvents and additives, and how they are mixed. He also gave examples of how to interpret Material Safety Data Sheets, pointing out that they are available for all paints, including those from the local hardware shop.

Bogdan described a customised coating formulation he had developed while working for Matrix Composites. This was of particular interest to many in the audience since the WA Branch had a site visit to this facility a few years ago. Bogdan was able to expand on this in his description of the use of epoxy polymer in making the controlled-density spheres used in syntactic foams for subsea oil and gas riser flotation devices.

The last part of Bogdan’s talk concerned the role of polymers in cement and concrete. He pointed out that typically cement makes up about 12 percent of a concrete mix, and that polymer admixtures are typically only one percent of the cement. However, while only making up around 0.1 percent of the concrete mix, the polymers are critical in ensuring that all the sand and aggregate particles are covered with cement. Polymer admixtures are also essential in ensuring that the concrete can flow to fill all voids and can reduce the water addition by up to 30 percent, to just sufficient for the setting reactions.

Bogdan went on to explain the increasingly important role of supplementary cementitious material, such as fly ash and slag in reducing the carbon footprint of concrete. This has been one of his special interests and his work resulted in a patent for a surface-active additive that enables greater use of these materials.

Everyone in the audience has used materials he discussed, but as few would have much knowledge of the technology behind their design and manufacture, Bogdan’s insights were much appreciated.