Available at: https://digitalcommons.calpoly.edu/theses/525
Date of Award
MS in Polymers and Coatings
Chemistry & Biochemistry
Philip J. Costanzo
Ever since the advent of polymer science, polyurethanes have played a huge role in the industrial world. They have been used in endless applications from furniture padding to aircraft coatings, to binders for insensitive munitions. It is therefore important that the chemistry of polyurethanes is well understood as well as the ability to draw relationships between the raw materials selected and the end-use properties of the polymer. Because of the multitude of practical applications, the development of an undergraduate polymer chemistry laboratory focused on polyurethane elastomers is developed and described herein. Polymer chemistry students are exposed to hydroxyterminated polybutadiene (HTPB) polyols as well as di- and multifunctional isocyanates for use in a tin-catalyzed reaction. The effect of catalyst concentration and crosslinking agent on cure time, prepolymer structure on end-use properties, and the effect of crosslink density on physical properties are explored. Students also receive a very important introduction to statistical experimental design. They learn when using statistical experimental design is necessary, and they learn how to manipulate, analyze, and interpret data using two-way ANOVA in Minitab.
The development of the lab experiment also led to extrapolating the use of polyurethane elastomers into a new application, the development of a polyurethane spinal muscular atrophy (SMA) brace. SMA is a neurodegenerative disorder that results in the mutation or deletion of the spinal motor neuron gene, resulting in the atrophy of a subject’s spine muscles throughout the continuation of their life. These patients are therefore forced to wear a brace for the entirety of their lives. The current brace technology in use by SMA patients is limited by the fact that SMA affects a very small amount of the population and therefore it is not cost-effective for industry to develop a brace technology designed for these patients. Scoliosis braces such as thoracolumbrosacral orthoses (TLSOs) are too hard and too uncomfortable for patients with SMA; therefore, the polyurethane elastomer was extrapolated to develop a brace with more flexibility and more durability. Two generations of polyurethane elastomeric brace were developed and evaluated by a subject and family with an SMA background. The brace is a much improved technology to the TLSO braces and provides more flexibility, more mobility, greater comfort, and superior modularity to the old technology. An instruction manual is also included with a step-by-step process of how to reproduce the brace.