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Nonisothermal crystallization behavior of exfoliated poly(ethylene terephthalate)‐layered silicate nanocomposites in the presence and absence of organic modifier

2008; Wiley; Volume: 46; Issue: 11 Linguagem: Inglês

10.1002/polb.21431

1099-0488

Jae Woo Chung, Se‐Bum Son, Sang‐Wook Chun, Tae Jin Kang, Seung‐Yeop Kwak,

Polymer crystallization and properties

Abstract Exfoliated poly(ethylene terephthalate) (PET)‐layered silicate nanocomposites (P et LSNs) excluding (P et LSN eom ) and including (P et LSN iom ) organic modifiers were obtained by solution methods with and without solvent‐nonsolvent system, respectively. From wide angle X‐ray diffraction and high resolution transmission electron microscopy, both P et LSNs were found to have exfoliated structure attributed to sufficient dispersion of silicate in prepared solvents, regardless of sample preparation method. However, organic modifier in P et LSN eom was confirmed to be well removed by elemental analysis, whereas organic modifier was still remained in P et LSN iom . Thus, the effect of the presence and absence of organic modifiers in P et LSNs on the nonisothermal crystallization behavior was investigated by differential scanning calorimetry (DSC) on the basis of a modified Avrami analysis and polarized optical microscopy (POM). From DSC results, it was found that both P et LSNs had higher degrees of crystallinity and shorter crystallization half‐times than neat PET, because of the dispersed silicate layers acted as nucleating agents in both P et LSNs. However, P et LSN iom exhibited a lower degree of crystallinity and longer half‐time of crystallization than P et LSN eom . Difference of crystallization behavior between P et LSN eom and P et LSN iom was ascribed to organic modifier in P et LSN iom , which may act as crystallization inhibitors. POM measurements also revealed the results which were in good agreement with crystallization behavior observed from DSC measurement. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 989–999, 2008