Poly(vinyl acetate) (PVAc) is an important polymer for use in many applications due to its various bulk and surface characteristics. The structure of poly(vinyl acetate) results in a relatively low glass transition temperature (Tg) and makes it important for processing and applications such as paints, adhesives, thin films and surface coatings. Poly(vinyl acetate) can also be easily plasticized, widening its range of applications. The term "plasticizer" refers to a species that will decrease Tg of a polymer.1 Polymer-plasticizer systems have been studied for years and continue to be of current interest. The effects of polymer-plasticizer interactions2 and plasticizer structure3 on polymer chain motions have been studied extensively, but there is still much to be learned in this area. Deuterium NMR is an excellent tool for studying the mobility of polymer chains. In this work, we report the investigation of the effect of plasticizer content on the Tg of poly(vinyl acetate) using deuterium nuclear magnetic resonance (2H NMR) spectroscopy. The methyl groups of poly(vinyl acetate) were deuterated in order to probe the mobility of their segments using the 2H NMR technique. Random orientations of the methyl groups, with respect to a magnetic field, are reflected as a powder pattern in the 2H NMR spectrum for segments with little or no motion. Segmental mobility averages the quadrupole couplings and ultimately leads to the collapse of the powder pattern into a single resonance for rubbery polymers when the motion is on the scale of or faster than the interactions.4
R. R. Nambiar and F. D. Blum, "Effect of Plasticizer on PVAc-d3 Dynamics using 2H Solid-State NMR," Polymer Preprints, American Chemical Society (ACS), Jan 2005.
National Science Foundation (U.S.)
Keywords and Phrases
Deuterium NMR; Poly(Vinyl Acetate); Deuterium Nuclear; Mobility of Polymer Chains; Polymer Chain Motions; Polymer-Plasticizer Interactions; Segmental Mobility
Article - Journal
© 2005 American Chemical Society (ACS), All rights reserved.