Nonisothermal crystallization kinetics of poly(ethylene terephthalate)/clay nanocomposites prepared by melt processing

Abstract

In this study, cold and melt crystallization behaviors of amorphous poly(ethylene terephthalate) (PET)/clay nanocomposites were investigated. Two nanocomposite samples with the same amount of inorganic content were prepared by melt processing using natural montmorillonite (Na‐MMT) and organo‐modified montmorillonite (org‐MMT). Depending on the clay structure, clay dispersion into PET and crystallization behavior of the samples were studied using X‐ray diffraction and differential scanning calorimetry methods, respectively. Effects of clay structure and organic groups between clay layers in org‐MMT on the melt crystallization kinetics of the samples were analyzed with various kinetic models, namely, the Ozawa, Avrami modified by Jeziorny, and Liu‐Mo. Crystallization activation energies of the samples were also determined by the Kissinger and Augis–Bennett models. Exfoliated structures were obtained in the nanocomposite samples prepared with both the Na‐MMT and org‐MMT. From the kinetics study, it was found that the melt‐crystallization rate of the sample prepared with the Na‐MMT was higher than that prepared with the org‐MMT at a given cooling rate. It can be concluded that organic ammonium groups in the org‐MMT decelerate the crystallization rate of PET chains possibly by affecting the chain diffusion and folding. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

“…Crystallization studies are crucial in understanding the macroscopic properties of nanocomposites (vide infra) given that inclusion of inorganic particles in polymeric matrices can induce diverse effects such as heterogeneous nucleation [31,32], suppression of crystal growth [33], and preferential development of a certain crystalline phase at the expense of other phases [34,35]. In agreement with previous studies on PET/clay systems [26,27,36] the DSC curves shown in Fig. 4 reveal the nucleating effect of MMT-SPE and MMT-MSIm clays as evident by the higher crystallization temperature (T cr ) observed for the nanocomposites compared to the neat matrix (cooling run in Fig.…”

“…4 reveal the nucleating effect of MMT-SPE and MMT-MSIm clays as evident by the higher crystallization temperature (T cr ) observed for the nanocomposites compared to the neat matrix (cooling run in Fig. 4) and the position of the cold crystallization exotherms observed in the first heating run [36].…”

Non-isothermal crystallization kinetics of polyethylene-clay nanocomposites prepared by high-energy ball milling

“…All plots show a linear relationship between ln α and ln t, indicating that the combined Avrami and Ozawa equations could well describe the crystallization behaviour of MDPE and PECN15. Liu equation has been also successfully used to define the crystallization kinetics for alumina-filled poly(ether ether ketone)(Kuo et al 2006), polyethyleneorganic-montmorillonite NCs(Xu et al 2005), nylone 6-graphite NCs(Weng et al 2003), nylone 6-attapulgite NCs(Shi et al 2010) and polyethyleneterephhthalate-clay NCs(Durmus et al 2010).…”

Preparation, characterization, and applications of poly(ethylene terephthalate) nanocomposites

“…There have been many studies on melt processing methods to synthesize PET/ nanoclay nanocomposites (Ghasemi et al, 2011;Durmus et al, 2010;Wu et al, 2013Wu et al, , 2014Kim et al, 2013a;Ghanbari et al, 2013b;Gokkurt et al, 2013). Melt-blended PET nanocomposites have been made with different nanoclays such as montmorillonite (MMT), hectorite, and magadiite (Costache et al, 2006).…”