Investigating the effect of cure schedules and cure initiators on sustainable composites for large offshore structures

This study evaluates the effect of post-cure schedules and cure initiator form on the mechanical properties of Glass fibre reinforced polymer (GFRP) laminates manufactured using an infusible reactive thermoplastic resin. Tensile, flexural, shear and dynamic mechanical analysis tests were conducted. Fractography was also performed. Specimens fabricated using liquid cure initiator and subjected to an elevated temperature post-cure were the control specimens. Ambient cured specimens decreased by no more than 12% in the case of tensile properties (modulus of 90° specimens) and by < 14.3% in the case of flexural properties (also modulus in 90° specimens). Furthermore, the difference in mechanical properties of 0° specimens fabricated using a powder cure initiator was observed to be within ≈ 7% of respective properties of control specimens. In the context of fabricating thick laminates for large-size offshore structures, the results suggest that an extended ambient post-cure cycle in conjunction with an initiator in powder form can be employed instead of an elevated temperature post-cure schedule with initiator in liquid form. This is economically beneficial since it eliminates infrastructure required for elevated temperature curing/post-curing. The risk of porosity induced due to liquid-based initiators is also avoided.