Gemstone Team Research

Permanent URI for this collectionhttp://hdl.handle.net/1903/9070

The Gemstone Program at the University of Maryland is a unique multidisciplinary four-year research program for selected undergraduate honors students of all majors. Under guidance of faculty mentors and Gemstone staff, teams of students design, direct and conduct significant research, often but not exclusively exploring the interdependence of science and technology with society. Gemstone students are members of a living-learning community comprised of fellow students, faculty and staff who work together to enrich the undergraduate experience. This community challenges and supports the students in the development of their research, teamwork, communication and leadership skills. In the fourth year, each team of students presents its research in the form of a thesis to experts, and the students complete the program with a citation and a tangible sense of accomplishment.

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Author: search.filters.author.Acha, ChrisStart date: 2020

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    On the Mechanism of Electron Beam Radiation-Induced Modification of Poly(lactic Acid) for Applications in Biodegradable Food Packaging
    (2022) Acha, Chris; Blanchard, Robert; Brodsky, Jon; Ding, Lilly; Fox, Andrea; Grosvenor, Eleanor; Gibson, Kalina; Hoy, Annie; Hughes, Justin; Lee, Kristen; Mihok, Olivia; Stanfield, Cade; Uniyal, Ananya; Whitaker, Sydney; Al-Sheikhly, Mohamad
    Poly(lactic acid) (PLA) is a biodegradable polymer used for food packaging. The effects of electron beam radiation on the chemical and physical properties of amorphous PLA were studied. In this study, amorphous, racemic PLA was irradiated at doses of 5, 10, 15, and 20 kGy in the absence of oxygen. Utilizing electron paramagnetic resonance spectrometry, it was found that alkoxyl radicals are initially formed as a result of C-O-C bond scissions on the backbone of the PLA. The dominant radiation mechanism was determined to be H-abstraction by alkoxyl radicals to form C-centered radicals. The C-centered radicals undergo a subsequent peroxidation reaction with oxygen. The gel permeation chromatography (GPC) results indicate reduction in polymer molecular mass. The differential scanning calorimetry and X-ray diffraction results showed a subtle increase in crystallinity of the irradiated PLA. Water vapor transmission rates were unaffected by irradiation. Further mechanical testing showed mechanical properties in line with reduced molecular mass. In conclusion, these results support that irradiated PLA is a suitable material for applications in irradiation of food packaging, including food sterilization and biodegradation.