Nonisothermal crystallization kinetics of poly(butylene terephthalate)/montmorillonite nanocomposites

Abstract

ABSTRACT:The melt intercalation method was employed to prepare poly(butylene terephthalate) (PBT)/montmorillonite (MMT) nanocomposites, and the microstructures were characterized with X-ray diffraction and transmission electron microscopy. Then, the nonisothermal crystallization behavior of the nanocomposites was studied with differential scanning calorimetry (DSC). The DSC results showed that the exothermic peaks for the nanocomposites distinctly shifted to lower temperatures at various cooling rates in comparison with that for pure PBT, and with increasing MMT content, the peak crystallization temperature of the PBT/MMT hybrids declined gradually. The nonisothermal crystallization kinetics were analyzed by the Avrami, Jeziorny, Ozawa, and Mo methods on the basis of the DSC data. The results revealed that very small amounts of clay (1 wt %) could accelerate the crystallization process, whereas higher clay loadings reduced the rate of crystallization. In addition, the activation energy for the transport of the macromolecular segments to the growing surface was determined by the Kissinger method. The results clearly indicated that the hybrids with small amounts of clay presented lower activation energy than PBT, whereas those with higher clay loadings showed higher activation energy. The MMT content and the crystallization conditions as well as the nature of the matrix itself affected the crystallization behavior of the hybrids.

Effects of filler type on the nonisothermal crystallization kinetics of poly(butylene terephthalate) (PBT) composites

“…[2][3][4][5][6] In recent years, isothermal or nonisothermal crystallization kinetics of PBT blends and composites has also been studied. [7][8][9][10][11] Wu et al 12 studied the nonisothermal crystallization kinetics of PBT/organo-montmorillonite nanocomposites by differential scanning calorimetry (DSC) method. They reported that small amounts of clay (1 wt %) could accelerate the crystallization process, whereas higher clay loadings reduced the rate of crystallization.…”

Structure and Mechanical Properties of Nanocomposites Based on an Amorphous Copolyester

“…Using this method, PNs based on pure polymeric matrices, such as polyamides, [3,4] polyolefins, [5] polyesters, [6][7][8][9] and other engineering thermoplastics, [10] have been studied. When dispersion is difficult to achieve in the pure matrix, chemical modification of the matrix [11] has been carried out with the aim of ameliorating the compatibility with the organoclay.…”

“…The mechanical properties and the morphology of recycled PET, [9,16,17] and the toughening by rubber addition [18] have been studied, as well as the effect of organoclay addition on nucleation [19] and the enhancement of barrier properties. [20] In the case of poly(butylene terephthalate) (PBT)-based PNs, the clay acted as a heterogeneous nucleating agent at low content [8] but as a physical hindrance to retard crystallization at high content. [21] A surfactant with medium polarity [22] or with hydroxyethyl terephthalate groups [23] led to large dispersion.…”

Crystallization kinetics of polyamide 11 in the presence of sepiolite and montmorillonite nanofillers

“…For many polymers including polypropylene [18][19][20], polyoxymethylene [21], poly(ethylene terephthalate) [22], poly(butylene terephthalate) [23], poly(butene-1) [24], but in particular polyamides [25][26][27][28][29][30][31][32][33][34], it has been shown that addition of nanofillers often enhance crystallization and even support the formation of specific crystal polymorphs. In fewer cases, however, a retardation of the crystallization process has also been reported, likely due to an immobilization of polymer chain segments at the polymer/nanofiller interface [35,36].…”