TG and DSC as tools to analyse the thermal behaviour of EVA copolymers

Abstract

This paper analyses the thermal behaviour of six EVA copolymers supplied by REPSOL Company. In relation to crystallization and melting temperatures, both of them decrease when the vinyl acetate percentage increases, in agreement with the fact that polyethylene is a semi-crystalline material, whereas polyvinylacetate is an amorphous polymer. Actually, when the vinyl acetate percentage reaches 30%, the copolymer is practically amorphous. The non-isothermal crystallization was modelled with the modified Avrami model that showed, with the exception of EVA-460 (the material with higher vinyl acetate percentage), the presence of a secondary crystallization due to spherulite impingement in the later stage of the non-isothermal crystallization. The TG analysis indicated two weight loss stages, the first one due to acetic acid loss and the second one due to fragments of polymer backbone, which appear as two separate peaks in the DTG plots. Finally, due to the linear dependence of melting and crystallization temperatures and of the minimum value of DTG peaks on vinyl acetate percentage, it can be concluded that both TG and DSC techniques can be employed to determine the vinyl acetate percentage of a certain copolymer.

The curing kinetics and properties of self-healing and thermally conductive polymeric composites based on ethylene vinyl acetate copolymer filled with nano alumina

“…The EVA-0 and NAEDS-0 exothermic peaks near 70°C corresponded to the ethylene crystallization in the EVA molecular chain. 39 The heat-absorbing peak near 80°C was attributed to the resin melting. The NAEDS-20 resin exothermic peak disappeared near 70°C, which may be because the nano alumina was not well dispersed in the EVA molecular chain, hindering the molecular chain movement and affecting the crystallization in the EVA ethylene segment.…”

Lower Levelized Cost of Energy Achievement of Silicon Heterojunction Solar Modules with Low Water Vapor Transmission Rate Encapsulants

“…[32] A recent study demonstrated that the higher the VA content, the more the first weight loss. [33] In POE and TPO, TGA underwent a long thermal stability phase, followed by a single-stage decomposition at 436 and 444 °C, respectively, associated with polymer main chain loss. [34] The crystallization and melting behaviors are depicted in DSC curves (Figure 1b).…”