Thermo-mechanical behavior of poly(butylene terephthalate)/silica nanocomposites (original) (raw)
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Thermal and Thermo-mechanical Properties of Poly(ethylene terephthalate) Nanocomposites
Journal of Industrial and Engineering Chemistry, 2007
In this study poly(ethylene terephthalate) (PET)/clay nanocomposites with two different weight percentages of montmorillonite (MMT) have been prepared by melt-extrusion technique. The X-ray diffraction (XRD) patterns and transmission electron microscopic (TEM) images reveal the formation of intercalated nanocomposites. The melting and crystallization behaviors of neat polymer and nanocomposite samples have been investigated by using both conventional and temperature modulated differential scanning calorimetry (TMDSC). The DSC results for compression molded samples after cooling show successive melting with an endothermic peak accompanied by a shoulder for nanocomposite samples. This is due to the presence of two different sizes of crystallites. DSC and TMDSC results for quenched samples show melting is followed by cold crystallization and in this state initial percent of crystallinity present in nanocomposite samples are higher than that of neat PET sample. For all samples, TMDSC results also confirm the melting is associated with re-crystallization phenomenon. The dynamic mechanical analyses (DMA) show in all temperature range, noticeably in the higher temperature region the nanocomposites exhibit tremendous improvement of modulus; but the slight difference in clay content doesn't effect significantly. The thermogravimetric analyses (TGA) reveal the overall thermal stability of PET matrix slightly improves after nanocomposite preparation.
Thermal and Thermomechanical Properties of Poly(butylene succinate) Nanocomposites
Journal of Nanoscience and Nanotechnology, 2008
In this study poly(ethylene terephthalate) (PET)/clay nanocomposites with two different weight percentages of montmorillonite (MMT) have been prepared by melt-extrusion technique. The X-ray diffraction (XRD) patterns and transmission electron microscopic (TEM) images reveal the formation of intercalated nanocomposites. The melting and crystallization behaviors of neat polymer and nanocomposite samples have been investigated by using both conventional and temperature modulated differential scanning calorimetry (TMDSC). The DSC results for compression molded samples after cooling show successive melting with an endothermic peak accompanied by a shoulder for nanocomposite samples. This is due to the presence of two different sizes of crystallites. DSC and TMDSC results for quenched samples show melting is followed by cold crystallization and in this state initial percent of crystallinity present in nanocomposite samples are higher than that of neat PET sample. For all samples, TMDSC results also confirm the melting is associated with re-crystallization phenomenon. The dynamic mechanical analyses (DMA) show in all temperature range, noticeably in the higher temperature region the nanocomposites exhibit tremendous improvement of modulus; but the slight difference in clay content doesn't effect significantly. The thermogravimetric analyses (TGA) reveal the overall thermal stability of PET matrix slightly improves after nanocomposite preparation.
ACS omega, 2018
Poly(trimethylene terephthalate) (PTT)/silica nanocomposite films were successfully fabricated using a novel sol−gel approach. The synthesis of these nanocomposites is being carried out by hydrolysis and condensation of tetraethoxysilane using trifluoroacetic acid with a small amount of water. The scanning electron microscopy and zetasizer result showed that the silica particles with a size range of 80−100 nm were homogeneously dispersed in the PTT matrix. The effect of different amounts of silica on crystallization of PTT was investigated using X-ray diffraction, differential scanning calorimetry (DSC), and optical microscopy. Polarized light microscopic results revealed that the spherulite size gradually decreased with increasing silica loading and increased with crystallization temperature for a given nanocomposite during isothermal melt crystallization. PTT with a small amount of SiO 2 melt crystallized at low temperatures showed banded spherulites. DSC results revealed that nonisothermal cold crystallization temperature decreased with silica content, whereas no significant change in nonisothermal melt crystallization behavior was observed with silica content. The crystallinity of isothermally melt crystallized PTT increased with both crystallization temperature and silica loading.
Journal of Polymer Research, 2012
High density polyethylene was melt compounded with various untreated (hydrophilic) or surface treated (hydrophobic) fumed silica nanoparticles, having different surface areas. The thermo-mechanical properties of the resulting nanocomposites have been thoroughly investigated. Field emission scanning electron microscopy revealed that nanofiller aggregation was more pronounced as the silica surface area increased, while nanofiller dispersion improved with a proper filler functionalization. The homogeneous distribution of fumed silica aggregates at low filler content allowed us to reach remarkable improvements of thermal stability, evidenced by an increase of the degradation temperature and a decrease of the mass loss rate with respect to neat matrix, especially when surface treated nanoparticles were utilized. Interestingly, the stabilizing effect produced by fumed silica nanoparticles was accompanied by noticeable enhancements of the ultimate tensile mechanical properties, both under quasi-static and impact conditions. Concurrently, a progressive enhancement of both elastic modulus and tensile stress at yield with the filler amount, was observed.
Innovative Poly(Butylene Terephthalate) Based Nanocomposites: a Preliminary Investigation
Macromolecular Symposia, 2007
A polymer-clay nanocomposite based on Poly(butyleneterephthalate) (PBT) and an innovative organoclay has been synthesized via intercalation of Bis(hydroxyethyl terephthalate) (BHET) in Na-Montmorillonite layers. Chemical and physical properties of this nanocomposite have been studied in comparison to other PBT/nanocomposites based on two commercial organoclay: Cloisite 25A and Somasif MEE. Nanocomposites have been prepared via melt compounding using a twin-screw extruder, with extrusion rate of 150 rpm. Samples were characterized by using wide-angle X-ray diffraction, TEM, thermal and mechanical analysis.
Journal of Applied Polymer Science, 2009
Layered-silicate-based polymer–clay nanocomposite materials were prepared depending on the surface modification of montmorillonite (MMT). Nanocomposites consisting of poly(butylene terephthalate) (PBT) as a matrix and dispersed inorganic clay modified with cetyl pyridinium chloride (CPC), benzyl dimethyl N-hexadecyl ammonium chloride, and hexadecyl trimethyl ammonium bromide by direct melt intercalation were studied. The organoclay loading was varied from 1 to 5 wt %. The organoclays were characterized with X-ray diffraction (XRD) to compute the crystallographic spacing and with thermogravimetric analysis to study the thermal stability. Detailed investigations of the mechanical and thermal properties as well as a dispersion study by XRD of the PBT/clay nanocomposites were conducted. X-ray scattering showed that the layers of organoclay were intercalated with intercalating agents. According to the results of a differential scanning calorimetry analysis, clay acted as a nucleating agent, affecting the crystallization. The PBT nanocomposites containing clay treated with CPC showed good mechanical properties because of intercalation into the polymer matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal degradation investigation of poly(ethylene terephthalate)/fibrous silicate nanocomposites
Polymer Degradation and Stability, 2008
Based on the fibrous silicates (palygorskite, PT) organically modified by water-soluble polyvinylpyrrolidone (PVP), poly(ethylene terephthalate) (PET) nanocomposite with good dispersion of the PT nano-particles was prepared via in situ polycondensation. The thermal degradation behavior of PET and PET/PT nanocomposite was investigated by thermogravimetric analysis (TGA) under non-isothermal conditions at various heating rates in air and nitrogen, respectively. The apparent activation energies of the samples were evaluated by Kissinger and FlynneWalleOzawa method. It is suggested that, during thermal decomposition in nitrogen, the clay as a mass-transport protective barrier can slow down degradation of polymer, but the catalytic effect of metal derivatives in clays may accelerate the decomposition behavior of PET. The combination of these two effects determines the final thermal stability of nanocomposite. However, in air atmosphere, the oxidative thermal stability of PET/PT nanocomposite was obviously superior to that of pure PET.
Journal of Applied Polymer Science, 2000
Silica nanoparticles and poly(butylene succinate) (PBS) nanocomposites were prepared by a melt-blending process. The influence of silica nanoparticles on the nonisothermal crystallization behavior, crystal structure, and mechanical properties of the PBS/silica nanocomposites was investigated. The crystallization peak temperature of the PBS/silica nanocomposites was higher than that of neat PBS at various cooling rates. The half-time of crystallization decreased with increasing silica loading; this indicated the nucleating role of silica nanoparticles. The nonisothermal crystallization data were analyzed by the Ozawa, Avrami, and Mo methods. The validity of kinetics models on the nonisothermal crystallization process of the PBS/silica nanocomposites is discussed. The approach developed by Mo successfully described the nonisothermal crystallization process of the PBS and its nanocomposites. A study of the nucleation activity revealed that the silica nanoparticles had a good nucleation effect on PBS. The crystallization activation energy calculated by Kissinger's method increased with increasing silica content. The modulus and yield strength were enhanced with the addition of silica nanoparticles into the PBS matrix. V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 902-912, 2010
Journal of Polymer Science Part B: Polymer Physics, 2007
Poly(trimethylene terephthalate) (PTT)/silica nanocomposite films were successfully fabricated using a novel sol−gel approach. The synthesis of these nanocomposites is being carried out by hydrolysis and condensation of tetraethoxysilane using trifluoroacetic acid with a small amount of water. The scanning electron microscopy and zetasizer result showed that the silica particles with a size range of 80−100 nm were homogeneously dispersed in the PTT matrix. The effect of different amounts of silica on crystallization of PTT was investigated using X-ray diffraction, differential scanning calorimetry (DSC), and optical microscopy. Polarized light microscopic results revealed that the spherulite size gradually decreased with increasing silica loading and increased with crystallization temperature for a given nanocomposite during isothermal melt crystallization. PTT with a small amount of SiO 2 melt crystallized at low temperatures showed banded spherulites. DSC results revealed that nonisothermal cold crystallization temperature decreased with silica content, whereas no significant change in nonisothermal melt crystallization behavior was observed with silica content. The crystallinity of isothermally melt crystallized PTT increased with both crystallization temperature and silica loading.
2011
Polybutylene Terephthalate (PBT) / Polyethylene Terephthalate (PET) nanocomposite blend was fabricated using melt blending technique in a twin extruder. The blend composition was optimized at PBT-PET weight ratio of 8020. The effect of incorporation of Organically Modified Montmorillonite (OMMT) and naturally occurring sodium Montmorillonite (MMT) on the mechanical, thermal and morphological properties of the nanocomposites blend has been investigated. It was observed that the Izod impact strength, tensile strength and flexural strength demonstrated a significant increase with the increase in clay loading from 1-7 weight % due to homogeneous dispersion of clay within the blend matrix. Thermo gravimetric analysis revealed an increase in thermal stability of the blend with the incorporation of nanoclay. There is also decrease in the melting temperature and crystallisation temperature as observed from DSC thermograms. DMA add the evidence for TGA, DSC and mechanical results. PBT - PET ...