Fusion bonding of polyamide 12

The strength of fusion, bonds between polyamide 12 plaques has been investi gated as a function of processing conditions, using the double cantilever b eam geometry to measure the mode I critical strain energy release rate, G(C ). Bonding was carried out using an instrumented press, which allowed syste matic variation of the bonding time, the holding pressure, the interface te mperature and the initial difference in temperature between the plaques. G( C) was generally found to increase with hold time and interface temperature . However, for a given hold time, hold pressure and estimated interface tem perature, the highest G(C) were obtained under nonisothermal conditions, th at is, when the initial temperatures of the plaques were different, Based o n fractographic analysis and observations of the effect of the hold pressur e, it is concluded that enhanced wetting is an important factor in the impr oved efficiency of non-isothermal bonding.