Authors: Bindu Manchanda K K Vimal G S Kapur Shashi Kant Veena Choudhary
Publish Date: 2016/07/20
Volume: 51, Issue: 21, Pages: 9535-9550
Abstract
The purpose of this paper is to study the nonisothermal crystallization kinetics of polypropylene PP/Sepiolite nanocomposites in the absence/presence of compatibilizer maleic anhydridegrafted polypropylene PPgMA using differential scanning calorimetry Crystallization exotherms were recorded at four different cooling rates ie 5 10 15 and 20 °C/min Crystallization parameters were analyzed using Ozawa Avrami Jeziorny and Liu’s models Nucleation ability of Sepiolite was evaluated by employing Dobreva and Gutzowa models The activation energy of nonisothermal crystallization kinetics process was estimated using three isokinetic models Augis–Bennet Kissinger and Takhore DSC cooling scans of PP and PP/Sepiolite nanocomposites showed that the crystallization onset temperature T 0 and peak exotherm temperature T p increased in the presence of Sepiolite However T p decreased with the increasing amount of PPgMA in PP/Sepiolite nanocomposites The values of FT K A and halftime to crystallization t 1/2 showed that the rate of crystallization of PP was faster in the presence of Sepiolite at a given cooling rate The t 1/2 values also decreased slightly for compatibilized PP/Sepiolite nanocomposites The values of exponent ‘n’ determined using Avrami analysis indicated that nonisothermal kinetic crystallization corresponded to threedimensional growth with heterogeneous nucleation in all the samples Sepiolite shows its better nucleating effect in the presence of PPgMA as investigated by Dobreva and Gutzowa method The increase in ΔE values of PP/Sepiolite nanocomposites is proportional to the Sepiolite content which is in the range of 33–38 in case of PPS5 and 44–47 in case of PPS10 as compared to PP calculated using three different models while decreasing on adding compatibilizer Incorporation of Sepiolite in the presence of compatibilizer PPgMA in the optimized ratio results in accelerating the overall nonisothermal crystallization process of PP/Sepiolite nanocomposites
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