Designing for Impact Resistance with New High Strength PPS Compounds

“Toughness” is a key word of both the automotive and the plastics industry, yet its current definition is too general. Building on the working definition that toughness is “a measure of the energy required to break a material,” the term is refined to include “resistance to impact” and other properties demonstrated in testing. Standard tests provide limited information, and after considering these, a new high-rate impact test is described, including the specific results it provides. The tests focus on two materials, Ryton^® R-4 and BR90, a new, developmental 40% glass reinforced PPS compound. Results indicate the superior toughness of BR90. Finally, computer aided engineering is being used to improve designs. New guidelines concerning corner radii, material thickness, and perpendicular ribbing offer additional toughness capabilities to specific applications thus offering enhanced impact resistance and part reliability. These findings have special relevance to automotive, under-the-hood applications and strongly support the value of PPS compounds.