CHAIN REGULARITY OF ISOTACTIC POLYPROPYLENE DETERMINED BY DIFFERENT THERMAL FRACTIONATION METHODS

Horváth, Zsuzsanna and Menyhárd, Alfréd and Doshev, Petar and Gahleitner, Marcus and Varga, József and Tranninger, Cornelia and Pukánszky, Béla (2014) CHAIN REGULARITY OF ISOTACTIC POLYPROPYLENE DETERMINED BY DIFFERENT THERMAL FRACTIONATION METHODS. JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 118 (1). pp. 235-245. ISSN 1388-6150

Preview

Text Horvath-JTAC2014-real.pdf Download (1MB) | Preview

Abstract

Abstract The chain regularity of isotactic polypropylene (iPP) homo- and random copolymers was characterized by different thermal fractionation methods in this study. Different stepwise temperature programs were applied in a calorimeter (DSC), in order to develop a method which is significantly faster than SIST and provides reliable information about the chain regularity of iPP. Our studies prove that self-seeding accelerates the crystallization process during annealing in SSA-DSC experiments (successive self-nucleation and annealing). Consequently, the time of isothermal steps can be shortened significantly in the SSA-DSC method. On the other hand we found that step time should not be too short if the goal of the measurement is the determination of average chain regularity. Our results clearly indicate that both the experimental conditions and the evaluation technique influence the obtained results. A standard experimental procedure is proposed for reliably determining the average chain regularity of iPP. The length of the SSA-DSC temperature program developed in this study is much shorter compared to that of the conventional SIST (stepwise isothermal segregation technique) measurements used recently for such experiments. The proposed SSA-DSC program makes the reliable characterization of a large number of samples on an acceptable timescale possible.

Actions (login required)

Edit Item