Role of adhesives in the dimensional stability of polycarbonate structural panels

This paper evaluates the function of adhesives much beyond their traditionally well-understood role of adhesion in emerging thermo-plastic applications. The influence of adhesives has been studied on the dimensional stability of large polycarbonate (PC) panels to be used in automotive applications such as panoramic roofs and backlights. Few commercially available grades of adhesives were characterized. PC roof panels bonded to supporting steel frames using these adhesives were then subjected to thermal cycling tests. In parallel, finite element models were built to simulate the whole system and correlations with experiments were established. Subsequently, a Design of Experiments (DoE) study was carried out using geometric parameters of the roof and the adhesive. Suitable transfer functions were built with the study of various effects of these parameters and an optimal design was obtained for a given configuration of a roofing system. The key role of adhesives in the thermo-mechanical performance of PC panels is clearly brought out in this study.