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Investigation of the Effective Parameters on the Morphological and Mechanical Properties of Polyamide 6/Rubber/Carbon Nano Tube Nanocomposites Prepared by Melt Mixing

Faghihi, Morteza | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47216 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shojaei, Akbar; Bagheri, Reza
  7. Abstract:
  8. Preparation of binary polyamide 6 (PA6) / carbon nano tube (CNT) and ternary PA6 / EPR-g-MA / CNT has been carried out using melt mixing. Four PA6s were selected with different viscosities (and molecular weights) and molecular structures (linear or branched). Effect of CNT content (up to 2 wt%) and mechanical mixing conditions (rotor speed, temperature and time of mixing) have been investigated. Ethylene- propylene rubber grafted maleic anhydride (EPR-g-MA) was selected at 20 wt% as toughening agent for ternary nanocomposites and mixing sequence of PA6 , EPR-g-MA and CNT has been investigated. Morphological observations showed that dispersion of CNT is done by erosion mechanism at low melt viscosity PA6s. Moreover, linear PA6 is entered into CNT agglomerates easier than branched PA6s due to its more molecular flexibilities. Mixing speed and time increasing and temperature decreasing caused decreased size and number of CNT agglomerates. Rheological measurements showed that increase in storage modulus and complex viscosity with incorporation of CNT to neat PA6 which represents good interaction between PA6 and CNT. Presence of CNT led to increase in crystallization temperature and crystallinity. Experimental data and theoretical modeling showed that potential ability of CNT for enhancing tensile strength and E-modulus is up to 15% in our work. Moreover, with addition of CNT to PA6s, enhancement in flexural properties and decrease in impact strength was observed. The best enhancement in mechanical properties for different mixing conditions was observed at 140 rpm and 225 °C. For ternary nanocomposites, morphological observations showed that the best CNT dispersion and distribution was occurred at PA6 + CNT + EPR mixing sequence. Moreover, this mixing sequence led to most localization of CNTs at PA phase compared to rubber phase that caused more enhancement in mechanical and crystallization properties
  9. Keywords:
  10. Polyamide 6 ; Mechanical Properties ; Carbon Nanotubes ; Melt Mixing Conditions

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