Free radical polymerization of caffeine‐containing methacrylate monomers. Issue 24 (28th July 2015)

• Record Type: Journal Article
• Authors: Nelson, Ashley M.; Hemp, Sean T.; Chau, Jessica; Long, Timothy E.
• Is Part Of: Journal of polymer science. Volume 53:Issue 24(2015:Dec.)
• Page Start: 2829
• Page End: 2837
• Publication Date: 2015-07-28
• Subjects: photochemistry -- renewable resources -- structure‐property relations; 547
• DOI: 10.1002/pola.27756
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: The incorporation of acrylic functionality into caffeine enables the preparation of a vast array of novel thermoplastics and thermosets. A two‐step derivatization provided a novel caffeine‐containing methacrylate monomer capable of free radical polymerization. Copolymers of 2‐ethylhexyl methacrylate and caffeine methacrylate (CMA) allowed for a systematic study of the effect of covalently bound caffeine on polymer properties. 1 H NMR and UV‐vis spectroscopy confirmed caffeine incorporation at 5 and 13 mol %, and SEC revealed the formation of high molecular weight (co)polymers (>40, 000 g/mol). CMA incorporation resulted in a multistep degradation profile with initial mass loss closely correlating to caffeine content. Differential scanning calorimetry, rheological, and thermomechanical analysis demonstrated that relatively low levels of CMA increased the glass transition temperature, resulting in higher moduli and elucidating the benefits of incorporating caffeine into polymers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2015, 53, 2829–2837 Abstract : A two‐step synthesis involving a UV‐induced photoreaction transformed the renewable resource caffeine into a polymerizable methacrylate. Free radical polymerization with 2‐ethylhexyl methacrylate afforded novel copolymers containing covalently bound pendant caffeine. 1 H NMR and UV‐vis absorbance spectroscopy confirmed caffeine incorporation and SEC elucidated high molecular weight copolymers resulted. Caffeine increased both the glass transition temperature and modulus of the copolymers at low mol % incorporation revealing the potential for caffeine as a comonomer in thermoplastic elastomers.