Isothermal crystallization kinetics of poly(butylene terephthalate)/attapulgite nanocomposites

Abstract

Poly(butylene terephthalate) (PBT)/organo-attapulgite (ATT) nanocomposites containing 2.5 and 5 wt % nanoparticles loadings were fabricated via a simple melt-compounding approach. The crystal structure and isothermal crystallization behaviors of PBT composites were studied by wide-angle X-ray diffraction and differential scanning calorimetry, respectively. The X-ray diffraction results indicated that the addition of ATT did not alter the crystal structure of PBT and the crystallites in all the samples were triclinic a-crystals. During the isothermal crystallization, the PBT nanocomposites exhibited higher crystallization rates than the neat PBT and the varied Avrami exponents when compared with the neat PBT. At the same time, the regime II/ III transition was also observed in all the samples on the basis of Hoffman-Laurizten theory, but the transition temperature increased with increasing ATT loadings. The fold surface free energy (r e ) of polymer chains in the nanocomposites was lower than that in the neat PBT. It should be reasonable to treat ATT as a good nucleating agent for the crystallization of PBT, which plays a determinant effect on the reduction in r e during the isothermal crystallization of the nanocomposites, even if the existence of ATT could restrict the segmental motion of PBT.

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

“…They reported that small amounts of clay (1 wt %) could accelerate the crystallization process, whereas higher clay loadings reduced the rate of crystallization. Chen et al 13 studied the isothermal crystallization kinetics of PBT/organo-attapulgite nanocomposites and concluded that the addition of attapulgite did not alter the crystal structure of PBT, whereas accelerated the isothermal crystallization rate of PBT. They also pointed out that organo-attapulgite could behave as a good nucleating agent for the crystallization of PBT by reducing fold surface free energy during the crystallization but it could also restrict the segmental motion of PBT.…”

Preparation and characterization of poly(butylene terephthalate)/silica nanocomposites

“…However, the disadvantages such as low impact strength and heat distortion temperature limit the applications of PBT. Many attempts have been made to obtain desirable properties of PBT by blending it with other polymers or fillers [7][8][9][10][11][12][13][14][15][16][17][18][19]. Among these blends, PBT/inorganic nanocomposites have attracted more and more interest, especially PBT/clay nanocomposites have been widely investigated.…”

A Review of the Recent Advances in Cyclic Butylene Terephthalate Technology and its Composites

“…figure 14). The α-crystal with gauche-trans-gauche conformation of the butylene moiety is the stable form under standard conditions, whereas the β form with all-trans conformation develops only under stretching of unoriented crystals 10,[56][57][58][59] or during crystallization at pressures above 2000 bar 60 . This α to β crystal transition is completely reversible when the stress is removed.…”