Materials science encompasses four classes of materials, the study of each of which may be considered a separate field: metals, ceramics, polymers and composites. This volume gathers important research from around the globe in this dynamic field including research on the structure and properties of polypropylene foams; sensitisation in TIG welding of austenitic stainless steel, tribotesting of polymers in line contact; the synthesis and crystal growth of non-linear optical materials and their application in telecommunications; poly (vinyl alcohol) hydrogels in drug delivery devices; developments in processing technologies of functionally graded materials and the indentation size effects in polymers.