Quantitative Characterization of Multicomponent Polymers by Sample-Controlled Thermal Analysis

Abstract

This paper explores the potential of Sample Controlled Thermal Analysis (SCTA) in order to perform compositional analysis of multicomponent polymeric materials by means of thermogravimetric experiments. In SCTA experiments, the response of the sample to the temperature determines the evolution of the temperature by means of a feedback system, thus, what is controlled is not the temperature-time profile as in conventional analysis, but rather the evolution of the reaction rate with time. The higher resolving power provided by the technique has been used for determining the composition of polymer blends composed of polyvinyl chloride (PVC) and different commercial plasticizers, a system where the individual components have very similar thermal stabilities, thereby rendering useless thermogravimetric experiments run under conventional conditions. Different SCTA procedures such as Constant Rate Thermal Analysis (CRTA), which has received special attention, Hi-Res and Stepwise Isothermal Analysis have been tested and the results obtained have been compared with linear heating rate technique. It has been proven that CRTA can be used to effectively determine the exact composition of the blend.

An improved model for the kinetic description of the thermal degradation of cellulose

“…Then, the experimental arrangement forces a to fit a straight line as a function of the time. It has been proven that CRTA experiments provide a much better resolution power for discriminating the kinetic model obeyed by the reaction since the shape of the T-a is intimately related to the kinetic model (Sánchez-Jiménez et al 2011;Sanchez-Jimenez et al 2010b;Perez-Maqueda et al 2002a). Thus, valuable information can be extracted from the shape of decomposition curves regarding the nature of the reaction.…”

Nanoclay Nucleation Effect in the Thermal Stabilization of a Polymer Nanocomposite: A Kinetic Mechanism Change

“…As a consequence, the results obtained by CRTA are more representative of the forward reaction than those obtained from conventional methods [43][44][45] and can be used to discriminate between overlapping steps. 46 Additionally, the shape of the CRTA experimental curves provides valuable information pertaining to the reaction mechanism. 47 In this work, a detailed kinetic description of the thermal degradation of both the pure polystyrene and a PS-MMT intercalated nanocomposite prepared by a solution casting route is presented and the results are compared in order to evaluate the influence of the nanoclay over the degradation mechanisms.…”

Kinetic characterization of multistep thermal oxidation of carbon/carbon composite in flowing air

“…6b) as in sample A. The possible feature of the partially overlapping two-step process is more clearly seen from the results of the SCTA measurements because of its higher potential of experimental resolution for partially overlapping multistep processes in comparison with conventional thermal analysis [49][50][51]. Figure 7 shows the results of the SCTA measurements.…”