Nonisothermal fusion bonding in semicrystalline thermoplastics

Abstract

ABSTRACT:The development of the interfacial bond strength as a function of bonding conditions has been investigated in two representative semicrystalline thermoplastics, isotactic polypropylene and polyamide 12. If one side of the interface is well above the melting point immediately before contact, more rapid effective bonding is obtained for a given estimated interface temperature than under isothermal conditions. This is discussed in terms of a simple two-parameter model for the critical strain energy release rate associated with crack propagation along the interface, which incorporates the rate of establishment of intimate contact at the interface. The model provides a self-consistent phenomenological description of the time and temperature dependence of the bonding kinetics in polyamide 12 joints, although questions remain regarding the detailed mechanisms of bonding.

Failure of multimaterial fusion bonding interface generated during over‐injection molding/thermoforming hybrid process

“…The importance of the thermal gradient has also been pointed out in some other investigations 2,12 where, for a given interface temperature above melting temperature, it has been shown that most rapid bonding is obtained for the highest thermal gradients.…”

“…The results obtained on each test were the mode of failure and shear strength of the interface, which is calculated by dividing the failure force by the bonding interface area (10 ϫ 13 mm 2 ). Given values of strength are calculated as the average of a minimum of eight specimens.…”

“…[1][2][3][4] Establishing strong bonded interfaces between different materials, or between components with different thermomechanical histories is essential to the success of the proposed approach, and is the motivation of this research, where the main objective is to establish the effects of the processing parameters on the strength of the substrate/skeleton interface.…”

Computational and experimental analysis of fusion bonding in thermoplastic composites: Influence of process parameters

“…Depending on the degree of crystallinity, the healing is reduced. In Plummer et al (2003), the achievement of residual adhesive strength in non-isothermal bonding at interface temperatures below T m is presented.…”

“…The manufacturing of semi-crystalline thermoplastic composites in particular requires a well defined thermal process history. (Bureau et al, 2002;Bureau and Denault, 2004;Perrin et al, 2003;Trudel-Boucher et al, 2006;Youssed and Denault, 1998;Plummer et al, 2003;Cho and Kardos, 1995;Ghasemi Nejhad, 1993;Ye et al, 1995;Schultz, 1984). The primary objective of this study is to investigate the influence of the process parameters on the bond strength.…”