Aliphatic esters as mould release agents for polyurethanes; the role of interface morphology
| Autor: | B J Briscoe, S S Panesar |
|---|---|
| Rok vydání: | 1986 |
| Předmět: |
Materials science
Acoustics and Ultrasonics Nucleation Fracture mechanics Adhesion engineering.material Condensed Matter Physics Bead test Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Coating law engineering Particle Crystallization Composite material Layer (electronics) |
| Zdroj: | Journal of Physics D: Applied Physics. 19:841-856 |
| ISSN: | 1361-6463 0022-3727 |
| DOI: | 10.1088/0022-3727/19/5/016 |
| Popis: | This paper describes the use of the blister test to examine the efficiency of a homologous series of aliphatic ester films in reducing the strength of adhesion of the interface between polyurethane and a smooth stainless steel plate. The measured works of adhesion indicate that low values are only produced when the interface comprises of a rather friable solid particle array. These arrays may be produced by the deposition from suspensions in suitable solvents. If the solid coating is created by heterogeneous nucleation on the steel surface from a homogeneous solution, the work of adhesion is relatively large-comparable with that found with liquid interlayers. The especially low adhesion produced by particle arrays is readily destroyed by protracted aging or by the melting and cooling of the deposited layer. These treatments appear to produce secondary surface reordering or crystallisation of the coating and hence a rather strong interface. In its simplest form the blister test measures the force or pressure required to rupture the interface. However, the weaker the interface, the faster the initial crack propagation rate. For these systems the rupture work is an increasing function of this crack velocity. The efficiency of the coatings may be ranked according to the force to rupture the interface or the calculated work to rupture the interface at a constant initial crack velocity. In either case the relative performance is the same although the latter criterion provides a greater scale for the relative evaluation. |
| Databáze: | OpenAIRE |
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