Adhesion of chlorinated-rubber based lacquers to mild steel

Thesis



This thesis reports work carried out to investigate the adhesive properties of chlorinated-rubber based lacquers on mild steel. Tensile tests were used to measure the failure stresses of such coatings, and it was established that a mixture of cohesive and weak boundary layer failure occurred. Consideration was given to the influence of lacquer storage, film thickness, drying time and binder molecular weight on the failure stress of the coating.

In Chapters 1 and 2 the theories of adhesion are discussed, the system under investigation is described and methods of testing the adhesive and cohesive strengths of coating/substrate systems are considered. The development of a suitable test method, preparation and testing of specimens are described in Chapter 3, and the experimental values of stress to cause failure of the coating are discussed. Chapter 4 describes the detailed surface analytical work which was carried out to establish the mode of failure of the coating, and investigate the inhomogeneities occurring within the cured film. It was found that the plasticiser migrated towards the lacquer/air interface as the film cured, leaving a "binder-rich" region at the lacquer/substrate interface. It was also found that chemical interaction occurred between the lacquer and the substrate, under certain circumstances, and in Chapter 5 these interactions are considered.

Theoretical work was carried out to investigate the application of various expressions for calculating the Van der Waals forces acting between two molecules, to the system under investigation. This is described in Chapter 6. The numerical values of the Van der Waals forces obtained using these expressions are compared, and their relevance to the experimentally measured failure stresses considered.

The conclusions which may be drawn from the results of the work described in Chapters 3-6 are considered in Chapter 7, and suggestions made of areas for further work.

Authors: Smelt, D

• Publication date: 1979
• DOI: 10.5287/ora-00bbwxp5m
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Subjects: Steel; Adhesion