5.9.4 Flame treatment of f‌ibre reinforced plastics2019-05-03T12:53:23+01:00

5.9.4 Flame treatment of f‌ibre reinforced plastics (FRPs)

Objective:

Flame treatment is used on thermoplastic matrices to increase the surface tension and hence improve the bonding properties.

Suitability:

Flame treatment is particularly suitable for PE (polyethylene) and PP (polypropylene) matrices, and also for other plastics.

Procedure:

  • Prior to flame treatment the surface must always be thoroughly cleaned and degreased.
  • Use a propane or acetylene flame with an excess of oxygen (blue, raging flame)
  • The flame is passed across the plastic surface
  • Visible roughening of shiny surfaces; Formation of polar structures on the surface, so enhancing the surface tension

Points to heed:

  • Clean the substrates beforehand
  • Ensure there is an excess of oxygen in the flame
  • Ensure the correct distance between the flame and substrate surface
  • Very rapid degradation of the pretreatment effect, so bond the substrates immediately after treating them
  • For thin substrates, too long contact and too small flame-substrate distances: Risk of combustion of the plastic surface