Applied Science BTEC Nationals/Chemical Laboratory Techniques/PVC Extract

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"PVC is typically composed of resins, stabilisers, pigments and plasticisers. Plasticisers soften the polymer, aid in the manufacturing process and provide form and function to various PVC materials. Plasticisers may account for 30-35 % of the PVC formulation."[1]

"Traditionally, plasticisers (Such as dioctyl adipate (DOA), trioctyl phosphate (TOP), dioctyl phthalate (DOP) and trioctyl trimellitate (TOTM)) are extracted from PVC using a 6 hour Soxhlet method and identified using IR spectrometry or gas chromatography."[1]

The solvent used during extraction can be petroleum ether[1] or cyclohexane[2]. Extracts were evaporated to dryness and then redissolved in dichloromethane (methylene chloride).[1]

By simply refluxing with solvent some, but not nearly 100% of the plasticisers can be extracted.

See w:Plasticizer for a good summary of why different plasticisers are chosen.

Octyl group

The octyl group is attached at its CH2 end to the position marked ‘R’ in the structures below:

Phosphate ester
Adipate
Phthalate
Trimellitate

For example:

Dioctyl adipate.svg

DiOctyl Adipate

References[edit]

  1. a b c d [1]
  2. BTEC specification