Improved Adhesion in Pultruded Composite Materials And Test Methods for Evaluation

摘要

Many composite materials are subcomponents of a larger assembled structure. Adhesives are an excellent way to attach these smaller components into a larger structure, distributing load across a large surface area without damaging the composite, as compared to mechanical fasteners which can concentrate the load at what is often a site of damage in the composite. Typically pultruded composites are completely cured coming from the die and will have a mold release on the surface. Both of these factors can reduce the ability to achieve maximum adhesion to a pultruded surface. Depending on part geometry, a peel ply material may be pultruded onto the part, which can be removed to prepare the surface before adhesive is applied. Alternatively, sanding or abrading the part followed by thoroughly cleaning the surface is a typical - and labor-intensive - method for preparing a part to maximize adhesion. This paper will discuss the addition of a modifier to the resin formulation that acts as a "primer" on the pultruded surface of the part. This eliminates the need to prepare the surface beyond the removal of dust and other particulates that accumulate on most surfaces. Cleanliness of the surface to be bonded is still essential to creating a bond of maximum strength. This unique process of surface preparation eliminates the time consuming and expensive methods typically required to prepare an adhesively bonded structure. This novel "priming" process does not significantly affect the thermal or mechanical properties of the underlying composite. Comparison of composite properties and adhesive bond strength of parts made and bonded in various ways will be discussed.