Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials

Preparation and Characterization of Polymer/phosphonium Montmorillonites Nanocomposites

Author YuBiao
Tutor TanShaoZao
School Jinan University
Course Polymer Chemistry and Physics
Keywords Quaternary phosphonium salt modified montmorillonite Nanocomposites Preparation Thermal stability Mechanical properties
CLC TB383.1
Type Master's thesis
Year 2011
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Since the special structure of montmorillonite, polymer / montmorillonite nanocomposites with conventional composites exhibit different mechanical properties, thermal stability and electrical properties and other properties, is considered to be a new generation of nano-composite materials. Currently, most montmorillonite modified with a quaternary ammonium salt, a quaternary ammonium modified montmorillonite poor thermal stability, thermal decomposition temperature is generally lower than 200 ℃. This article was prepared by ion exchange quaternary salt scales modified montmorillonite (P-MMT), the thermal decomposition temperature reaches 275 ℃; then prepared by melt intercalation several typical polymer / quaternary salt scales modified Mongolia bentonite composite materials, using a variety of methods to characterize the structure and properties of materials, and a detailed discussion of the structure and combustion properties, thermal stability and mechanical properties of the relationship. First, the quaternary salt scales modified montmorillonite as flame retardant synergist prepared polypropylene / magnesium hydroxide / quarter scale salt modified montmorillonite nanocomposites. By thermal gravimetric analysis and cone calorimeter scales studied quaternary salt modified montmorillonite synergies. Compared with sodium montmorillonite, found that the addition of 3.0% mass fraction of quaternary salt of modified scales Mongolian soil, increases the thermal stability of the composite material, extending the ignition time (TTI), reduces the heat release rate (HRR) and quality loss rate (MLR), notched impact strength increased by 12.5%. By scanning electron microscopy of the composite material combustion residues morphology, discovered that adding a quaternary salt modified montmorillonite scales, the formation of more solid and dense carbon layer. Second, the preparation of a series of different mass fractions of wood flour and season salt modified montmorillonite scales polylactic acid / wood flour / quarter scale salt modified montmorillonite (PLA / WF / P-MMT) nanocomposites. Studied the P-MMT clay and wood flour content on the dispersion of the material's physical and mechanical properties. X-ray diffraction analysis showed the formation of the structure of intercalated nanocomposites. With the wood flour content increases, the elastic modulus of the composite material is increased, but the breaking elongation, tensile strength and impact strength will decline. Considering the thermal stability and mechanical properties, mass fraction of 5.0% P-MMT is an optimal addition amount of time nanocomposite decomposed 10.0% mass loss temperature is 314 ℃, while the tensile strength and notched impact strength respectively 40.66MPa and 2.30kJ/m2. Finally, the preparation of polyethylene terephthalate / quaternary salt scales modified montmorillonite (PET / P-MMT) nanocomposites of different levels of P-MMT on structure and properties of composites. X-ray diffraction analysis showed that with P-MMT content increased, P-MMT dispersion state in PET release into the condensation. Compared to pure PET, mass fraction of 0.5% when the P-MMT, PET / P-MMT nanocomposites by the tensile strength of 55.8MPa up to 59.67MPa, increased elongation rate of 6.6% to 9.4%; However, when the mass fraction of P-MMT to 5.0%, the material will accelerate the degradation, the tensile strength decreased to 46.37MPa, elongation is decreased to 5.36%, and the maximum temperature of thermal degradation rate decreased from the 433 ℃ 352 ℃.

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