title: Kinetic examination of the mechanical transition of polymethyl methacrylate films prepared from aqueous dispersions.
abstract: The activation energy of the phase transition of cast polymethyl methacrylate films produced from an aqueous dispersion (Eudragit NE30D) has been estimated from Dynamic Mechanical Thermal Analysis. The value was found to lie between 170 and 350 kJ mol(-1), the variation arising from the different specimen test geometry and testing conditions. From experiments conducted at a range of frequencies and temperatures it was found possible to utilise the concept of frequency shift to produce a master curve, which could relate viscoelastic properties over the temperature range of 5-55 degrees C and a frequency range of 0.1 to 50 Hz.
authors.affiliation: The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, England, UK.
authors.forename: S V
authors.initials: SV
authors.lastname: Lafferty
authors.forename: J M
authors.initials: JM
authors.lastname: Newton
authors.forename: F
authors.initials: F
authors.lastname: Podczeck
mesh_terms: D000465:Algorithms; D005079:Excipients; D007700:Kinetics; D011109:Polymethacrylic Acids; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D013314:Stress, Mechanical; D013535:Suspensions; D013696:Temperature
chemical_list: D005079:Excipients; D011109:Polymethacrylic Acids; D013535:Suspensions; C038300:methylmethacrylate-methacrylic acid copolymer; D019904:Polymethyl Methacrylate