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The Effect of Dyestuffs on the Mechanical and Thermal Properties by yurtgc548

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									The Effect of Dyestuffs on the Mechanical and Thermal Properties of
       Nylon Fibers Recycled from Post - Consumer Carpets

                 Yasser Gowayed and Weiping Lin
    Effect of Acid Dyes on the           Objectives
Melt Processing of Nylon Recycled
   from Post-Consumer Carpet             • Establish an environmentally-friendly and
                                           cost-effective technique to collect nylon
                                           fibers from post-consumer carpets
                                         • Study the thermal stability and structure of
   Yasser Gowayed and Weiping Lin          melt-reprocessed nylon
     Department of Textile Engineering
            Auburn University




                                         Existing Separation Methods

                                         • Mechanical Separation is simple, but
     The Separation                        produce low purity fibers
       Technique                         • De-polymerization produces high purity
                                           nylon at high cost

                                         • Selective Dissolution produces good purity
                                           fibers but is solvent-dependent, cost?




 The New Separation Technique
                                          Advantages of the New Technique
              Apply a latex swelling
             agent to carpet backing
                                         • Swelling agent is environmentally benign
            Remove secondary backing
                                           and cost-effective
                      -*-
                Clean fibers with
                 swelling agent          • Collected PP secondary backing maintains
                      J*-                  its shape and architecture
              Mechanical shredding
                      M-
                Water separation          • Reclaimed nylon fiber has a purity of
                      JU                    (99.3±0.07 w t % )
               9 9 . 3 % Pure Nylon
Dyes remain in t h e collected nylon !!!!




                    • Thermal stability
                    • Crystalline structure
                    • Mechanical properties




Details of Experiment

• Seventeen acid dyes were selected to dye
  nylon fiber: Anthraquinone acid dyes,
  Polyazo acid dyes, Monoazo acid dyes,
                                                  Thermal Stability of
  Pyrazolone acid dyes, Diamino derivatives
  of triphenylmethane, Metal-complex acid
                                                      Dyed Nylon
  dyes and UV-active acid dyes

 •i    Dyed nylon was re-processed using
       a compression molding machine




I n t r i n s i c Viscosity of Compression-     Thermal Degradation of Nylon 66
Mold Nylon
                                                • Anthraquinone dyes and azo dyes have no
        6min                      270 t           influence on the thermal stability of nylon

                                                • Metal-complex dyes cause more thermal
                                                  degradation of nylon

                                                • The influence of metal-complex dyes can
      Tamporature (»C)             Time (min)     be explained by a mechanism of acid-
                                                  catalyzed nucleophilic acyl substitution
                  Stress-Strain Behavior


  *—k
      70

   TO bO .
                                                                       Structure and Property
                                                   • Acid Blue 158
  i<    50-
                                                   • Acid Blue 4 5
                                                                       of Re-processed Nylon
    /
    >   40
        30 , -
                      a


   f          , a
                  A
                      •                            A without dye
  S
  03
        20.

        10
         0,   i               1        1       1
                             5         10
                          Percent Strain (%)




Influence of Acid Dyes on the Structures
                                                                     Color of the Re-processed Dyed Nylon
and Property of Re-processed Nylon 66

• Non-metal acid dyes do not influence the                           • Chroma and hue decreased
  structure and property of nylon
                                                                     • Lightness is decreased when its original
• Metal complex dyes reduce the crystallization                        level is higher than 40
  rate of nylon melt and decrease itscrystallinity
                                                                     • Color variation is due to chemical
• Reprocessed nylon containing metal complex                           reactions and physical motion of dyes
  dyes have inferior mechanical property




  Conclusions

  • Developed an environmentally-friendly
    and cost-effective technique to collect
    nylon fibers from post-consumer
    carpets
  • Reprocessed nylon containing metal
    complex dyes have inferior mechanical
    property and thermal properties

   • Color variations will occur during
     reprocessing

								
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