A description is given of modifications to a dynamic mechanical analyser (DMA) to allow controlled relative humidity (RH) experiments to be performed under isothermal or thermal scanning conditions. Free film samples of polyester melamine paints
(under-cured, normal-cured and over-cured) were supplied and the viscoelastic properties measured in the tensile mode of the
DMA. A reduction in the glass transition temperature (Tg) of up to 10C was found as the controlled RH was increased.
Authors:Young Ho Kim, Bong Seok Moon, F. W. Harris, and S. Z. D. Cheng
A new high molecular weight polyimide based on 4,4′-oxidiphthalic anhydride (ODPA) dianhydride and 2,2′-dimethyl-4,4′-diaminobiphenyl (DMB) diamine has been synthesizedvia a one-step polymerization method. This polyimide is soluble in phenolic solvents. Films from 7 to 30 μm thick were cast from the polymer solution and show in-plane orientation on a molecular scale detected by Fourier transform infrared spectroscopy experiments. This anisotropic structure leads to anisotropic optical properties arising from two different refractive indices along the inplane and out-of-plane directions. ODPA DMB possesses high thermal and thermo-oxidative stability. The glass transition temperature has been determined to be 298 °C. Dynamic mechanical analyses show two relaxation processes appearing above room temperature: the β- and the α-relaxation processes. The α-relaxation corresponds to the glass transition while the β-relaxation is a secondary relaxation process associated with the non-cooperative subsegmental motion.
Authors:B. Ormsby, G. Foster, T. Learner, S. Ritchie, and M. Schilling
Issues encountered with dynamic mechanical analysis of artists’ acrylic emulsion paint films are presented alongside modifications
to improve controlled relative humidity (RH) experiments using isothermal and thermal scanning conditions. Free films of titanium
white (PW6) artists’ acrylic emulsion paints were cast as free films and their viscoelastic properties measured using the
tensile mode of the dynamic mechanical analyser (DMA). Artists’ acrylic emulsion paints are within their glass transition
temperature region at room temperature and are highly responsive to changes in ambient temperature and relative humidity,
hence controlling relative humidity during analysis is vital to the successful analysis of these paints.
Authors:S. C. Mojumdar, C. Moresoli, L. C. Simon, and R. L. Legge
Wheat gluten (WG) proteins can be utilized to make films with novel functional properties, such as selective gas barrier properties and rubber-like mechanical properties. WG-based materials are homogeneous
Authors:Olga V. Alekseeva, Vladimir P. Barannikov, Nadezhda A. Bagrovskaya, and Andrew V. Noskov
fullerene with PS in composite materials of different content was shown by IR data [ 8 , 9 ]. The aim of this study is to produce fullerene–PS composite films and to study effect of small additives on thermal and thermodynamic properties of polymer
Authors:A. Derafa, M.-C. Record, D. Mangelinck, R. Halimi, and A. Bouabellou
reactions between a metallic thin film and the silicon substrate. The investigation of the mechanism of phase formation is of great importance to understand the behavior of the materials and to optimize their properties. This study has already been performed
films followed by arylation. Absorption/adsorption of PFA on soy protein film was structurally characterised by Fourier transform infrared (FTIR) spectroscopy. The resulting native and modified soy protein films were characterized by thermogravimetric