modulus
Carrier Films Behavior During Thermoforming Process Studied Using Dynamic Mechanical Thermal Analysis (DMTA)
Fri, 2012-12-14 15:07 — Shehdeh JodehDynamic mechanical thermal analysis was used to investigate the thermal transitions and modulus/temperature behavior of thermoformable carrier films, and to relate the information obtained to carrier film behavior during the thermoforming process. In this study the glass transition temperatures (T g) and the temperatures at which crystallization occurred during heating (T c) of four thermoformable carrier films were measured by using a dynamic mechanical thermal analyzer (DMTA). These films are good candidates for the automotive process, which uses painted carrier films as moldable automotive coatings (MAC). The modulus/temperature behavior of the films was also observed over a wide temperature range, which included thermoforming temperatures. Although films of PETG and PCTG 5445, co-polyesters based on poly(1,4-cyclohexylene dimethylene terephthalate), are thermoformable, their T g values, 92 and 99 °C, respectively, are not high enough to allow current paint systems (with bake temperature of 100–110 °C) to cure on the films without causing severe film deformation.
Facebook
Google
LinkedIn
TwitterA New Composition–Processing–Property Relationship for Studying the Tensile Modulus-Phase Plastic Blends
Fri, 2012-12-14 11:57 — Shehdeh JodehBased on thermodynamic principles, a composition–processing–property relationship for predicting the modulus properties of multiphase plastic blends has been developed. This relationship describes the relative modulus of the blend in terms of the volume fraction and the index for the degree of mixing of an inclusion-polymer in the matrix-polymer. The relative modulus is defined as the ratio between the modulus of the blend and that of the matrix polymer. These blends include a nylon 6,6/polymethyl methacrylate(PMMA) system mixed using an injection molding process arid a nylon 6/ethylene-vinyl acetate copolymer system mixed using a corotational extrusion process. Based on the values determined for the mixing index of the nylon 6,6/PMMA blends, a relationship between the mixing index and the fill time used in the injection molding has been developed. The results also imply that the degree of mixing of the blend mixed using a correlation extrusion process is better than that of the blend processed using an injection molding process. Using the above results, we now can scientifically develop new plastic blends and design optimum processing conditions for various automotive applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
