In this work, the adhesion mechanism at the polymer-metal hybrid joints generated during the injection moulding process is presented. The joining of metals and polymers during the injection moulding process is relatively difficult due to the very short duration of this process and difficulties in parameter control. Injected polymer composites were based on polyamide 6 filled with mica (1% and 10% by mass) and talc (1%, 5% and 10% of mass content) and additionally were based on polypropylene filled by mica (5% of mass content) and talc (1%, 5% and 10% by mass). Metal inserts were made of 6061 aluminium alloy plates chemically prepared before the injection moulding process. Three types of samples for single shear lap joints were applied: one plate injected with polymer composite on its surface, two plates with pins with polymer composite injected between them and optionally two plates without pins with polymer composite injected between them. In order to evaluate the metal inserts’, surface susceptibility for wetting by polymers, measurements of the contact angle at the interface between the metal and measuring liquid were carried out. Shear tests were proposed as the evaluation of adhesion between the injected polymer composites and metal surfaces. Microscopic analysis of the polymer-metal interface was performed in order to show the mechanism of the generation of the adhesion during the injection moulding process.
The presented results were obtained as an outcome of the research project 2016/21/B/ST8/03152 “The evaluation of the generation of the joints at the interface metal-polymer with the application of the flow highlighters and the active method of the infrared thermography, holgraphic vibrometry and shearography”, financially supported the National Science Centre in Kracow (Poland).
Co-authors: dr inż. Roman Wróblewski, dr inż. Adam Kurzawa, dr inż. Oliwia Trzaska