Considering the wide-spreading applications of polymers in our daily lives that far exceed that of any other class of materials available, interest in enhancing the presence and attractiveness of polymer chemistry in undergraduate curriculum has continued to grow over the years.  This laboratory experiment exposes students to the free radical polymerization behaviors of the monomer system commonly found in acrylic bone cement for orthopedic surgery.  More particularly, the chosen monomer system is composed of methyl methacrylate (MMA) and a small amount of beta-carotene.  Beta-carotene is a deeply red-orange colored terpenoid abundant in plants and fruits.  Due to its visually-recognizable color loss after free radical reaction, beta-carotene conveniently serves as the <i>in situ</i> indicator for the degree of polymerization or practically, the setting time indicator for bone cement.  Thereby, the monomer system is expected to significantly increase the success rate of orthopedic surgeries by easing the difficulty and ambiguity in determining setting time of bone cement.  The relatively simple monomer system and the interesting chemistry as well as its intriguing real-life application make the inclusion in an undergraduate curriculum appropriate.  The polymerization kinetics is monitored by an Infrared (IR) and an in-house made Raman Spectrophotometer.  IR and Raman have been proven to provide complementary information for C=C bond conversion over the course of polymerization.  In addition, fluorescence microscopic techniques will be explored to shed light on the spatial-temporal behavior of the polymerization process.  This investigation is intended to be a starting point for developing a variety of undergraduate projects for polymer analysis and characterization.  Also, our low-cost custom made Raman Spectrophotometer intends to address the issue of the limited accessibility to a Raman Spectrophotometer for undergraduate students.

Monitoring polymerization kinetics with IR and Raman spectroscopy in undergraduate laboratory

251st National Meeting (2016)

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