Researchers pioneer greener way to create interwoven polymers with blue light

Engineering on a blue streak
University of Delaware researchers made the University logo using their newly developed polymerization technique. Credit: Abhishek Shete/ University of Delaware


Abhishek Shete, graduate research assistant in science and engineering, and Christopher Kloxin, assistant professor in materials science and engineering and chemical and biomolecular engineering, describe their method in a paper featured on the cover of the 24th issue of Polymer Chemistry. The paper is titled "One-pot blue-light triggered tough interpenetrating polymeric (IPN) using CuAAC and methacrylate reactions."


"These chemistries independently are used in a broad range of applications," from dental composites, automobile bumpers to drug delivery materials, Shete said.



They use 470-nanometer blue light, which is similar to blue LED light used to detect certain body fluids in . This light triggers reactions with a photosensitizer called camphorquinone and an activator called amine. These materials are commonly utilized in polymeric dental composites for filling cavities.

The light irradiates the materials to photostimulate the two chemical reactions, but not simultaneously. First up is a called the copper-catalyzed azide-alkyne cycloaddition (CuAAC) click polymerization. This reaction is facilitated by copper, and polymerization occurs in steps. Next is a reaction called the methacrylate polymerization, which forms a plastic-like material in a manner similar to adding links to a growing chain. "This is unique in the way the blue light induces sequential reactions," says Kloxin.

The end result is a material that Kloxin and Shete describe as a "glassy film," less brittle than pure methacrylate and stronger than pure CuAAC at higher temperature. The films made from this IPN material also exhibit shape memory— when deformed, it can be returned to its original size and shape with 15 minutes of heating at 80 degrees Celsius.



The team has filed a provisional patent for the method described in the new paper. "These chemistries could be attached to other molecules," Kloxin said, and the team will test their applications to form hydrogels, dental materials and other networks.

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Citation: Researchers pioneer greener way to create interwoven polymers with blue light (2017, July 29) retrieved 18 July 2019 from https://phys.org/news/2017-07-greener-interwoven-polymers-blue.html

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