Chapter 10: Study Guide and Self-Assessment
Polymer materials have a broad range of useful characteristics (notably light weight and ease of processing), but for many structural or semi-structural applications they need to be stiffer and stronger. Accordingly, they are often reinforced with mineral particles or fibers (which can be inorganic or organic). Their utility and value derives from their blend of properties – usually lightweight with a combination of strength, stiffness and toughness that exceeds that of many other materials. Naturally, properties depend on structure – the nature of the matrix and dispersed phases, their form (e.g., a fibrous or powder dispersed phase), their arrangement and their relative proportions. To cite an example that is probably crucial to your existence, mobile phones are now sleek, light-weight objects, as opposed to the clunky devices common just a few years back. The thin but stiff and tough structures used to house the electronics are often polymers reinforced with glass or carbon fibers.
Objectives
Upon successfully completing this chapter you should have:
- A familiarity with the most important types of polymer matrix composites: particle reinforced, fiber reinforced and structural composites (e.g., laminates).
- A knowledge of the types particles used to “fill” polymer materials and the nature of these composites – non-reinforcing, semi-reinforcing and reinforcing.
- An understanding of the importance of particle size, particle size distribution, particle dispersion and particle/polymer interfacial adhesion.
- A familiarity with the most common types of fibers used to reinforce polymer materials – glass, carbon and aramid.
- A knowledge of the the (basic) chemical nature of these fibers and the morphology of their structures.
- A familiarity with the most common thermosets used to make composites (epoxy, polyester and unsaturated polyester resins) and how they are cured.
- An understanding of the importance of the interface and interphase in composite materials and the use of surface coatings and coupling agents.
- A knowledge of the nature of two important structural composites – laminate and sandwich composites.
Self-Assessment Questions