Delamination is one of the major areas of failure for laminated composite materials and ‘Interlaminar stresses’ are the source of this failure. These ‘stresses’ can be caused by a number of factors including (but not limited to): internal voids / volatiles that are not properly removed during the laminating process, improper curing of resin, and the environmental conditions in its final application. Understanding the bond between laminations and amongst the resin molecules of thermosetting materials is essential in understanding how these composites are tested, and what applications are best for each.
Quite often in the process of manufacturing & fabricating industrial laminates a specific surface roughness is indicated. Be it the purpose of reducing electrical arc tracking across the surface of the composite material, or to make sure the surface is rough enough to hold an adhesive; surface roughness can be a vital component of a machined composite part’s integrity.
Lamitex ® composites have been the chosen materials in the aerospace industry for many years due to their high material strength and dimensional stability under extreme conditions. When considering a composite material for spacecraft or aerospace applications it is often imperative that you take into account their outgassing properties. ‘Outgassing’ refers to the discharge of gaseous material (many times water vapor) as a result of an atmospheric change in the environment. For example; if the material or part is exposed to a vacuum or high heat. Due to the manufacturing process and nature of the base material of most laminate composites, trace amounts of water vapor and other gases tend to get into the finished product, making them ‘outgassers’ under extreme conditions. As you can see from the table below, different composites will vary among each other in moisture absorption due to the nature of the filaments and resins used.