A multi-stage scheme was developed for the separation of vinyl chloride
(VC) oligomers. A low molecular weight fraction was isolated from
poly(vinyl chloride) by Soxhlet extraction. The presence of VC oligomers up
to decamer was demonstrated by high-performance size exclusion
chromatography (HPSEC). Removal of polar impurities was accomplished
by preparative adsorption liquid chromatography of the low molecular
weight fraction. Recycle HPSEC with repeated injections permitted the
accumulation of fractions of VC pentamer oligomers which were resolved
into their isomers by high-performance liquid chromatography (HPLC) offline.
These results were duplicated utilising a coupled column system
comprising of recycle HPSEC connected on-line to HPLC. This coupled
technique was then applied to the hexamer and heptamer oligomers which
were resolved into their constituent isomers.
Multi-stage schemes were then developed for the extraction, characterisation
and quantification of low molecular weight compounds from nitrile (NBR),
ethylene-propylene-diene monomer (EPDM) and silicone elastomers. Low
molecular weight fractions were isolated from these elastomers by Soxhlet
extraction. HPLC and SEC analysis was performed on these extracts
followed by gas chromatography-mass spectrometry (GC-MS). Extracts
from these elastomers were shown to contain various phthalates, diamines,
phenols, hydrocarbons and thiazoles. In addition, analysis of the low
molecular weight extract from the silicone elastomer disclosed the presence
of a number of cyclic and linear silicone oligomers.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.