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

Abstract

In this study, melt-crystallization behaviors of poly(butylene terephthalate) (PBT) composites including different types of inorganic fillers were investigated. Composite samples having 5 wt % of fillers were prepared by melt processing in a twin screw extruder using commercial grades of calcite (CA), halloysite (HL), and organomontmorillonite (OM) as filler. Depending on the filler type and geometry, crystallization kinetics of the samples was studied by differential scanning calorimetry (DSC) methods. Effect of filler type on the nonisothermal meltcrystallization kinetics of the PBT was 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, Takhor, and Augis-Bennett models. From the kinetics study, it was found that the melt-crystallization rates of the samples including CA and HL-nanotube were higher than PBT at a given cooling rate. On the other hand, it was also found that organo-montmorillonite reduced the melt-crystallization rate of PBT. It can be concluded that organic ammonium groups in the OM decelerate the crystallization rate of PBT chains possibly due to affecting the chain diffusion through growing crystal face and folding. This study shows that introducing organically modified alumina-silicate layers into the PBT-based composites could significantly reduce the production rate of the injection molded parts during the processing operations. V C 2011Wiley Periodicals, Inc. J Appl Polym Sci 123: [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91] 2012

Effects of SEBS-g-MA copolymer on non-isothermal crystallization kinetics of polypropylene

“…The inter-relationship between these two parameters governs the activation energy for crystallization, DE. Following the isokinetic method of Augis-Bennet, DE values were evaluated [56][57][58][59]: where T 0 is the initial reference temperature from the melt state, T p the crystallization peak temperature, R g the universal gas constant (R g = 8.314 J mol -1 K -1 ), and R is the cooling rate. The activation energy was calculated from the slopes, of the plots, Fig.…”

Nonisothermal crystallization kinetics of poly(butylene terephthalate)/multiwalled carbon nanotubes nanocomposites prepared by in situ polymerization

“…Furthermore, the PBT/MWNT nanocomposites have higher T p than the neat PBT at all cooling rates. Oburoğlu et al studied the crystallization behavior of PBT and PBT‐based composites including 5 wt % of different types of filler, halloysite (tubular alumina‐silicate as 1D filler), organo‐montmorillonite (organically modified layered alumina‐silicate as 2D filler), and calcite (spherical CaCO 3 particles as 3D filler). They found that 1D and 3D fillers acted as efficient nucleating agent and thus enhanced the crystallization rate of PBT, which was contributed to geometrically less efficient restriction effect of such fillers on the polymer chains, but 2D filler had considerably high surface area which could reduce the crystallization rate of PBT.…”

Process–structure–property relationships in poly(butylene terephthalate) nanocomposites

“…is important for the crystallization behavior of polymers (Oburoğlu et al, 2012b). On the other hand, it was found that OMMT reduced the melt-crystallization rate of PBT.…”

“…It is PBT nanocomposites systems important to understand relationships between processing conditions, crystallization behaviors, structures, morphological developments, and final properties to obtain polymer products that meet industry requirements (Zhang et al, 2010;Shukla et al, 2011;Oburoğlu et al, 2012b). It is PBT nanocomposites systems important to understand relationships between processing conditions, crystallization behaviors, structures, morphological developments, and final properties to obtain polymer products that meet industry requirements (Zhang et al, 2010;Shukla et al, 2011;Oburoğlu et al, 2012b).…”