Meaning
Laboratory techniques separate polymer components or additives by dissolving them in specialized fluids at elevated thermal levels. Efficient high temperature solvent extraction is necessary for analyzing the composition of impact copolymers and other multi-phase resins. Isolation concludes when the target fraction is recovered and the solvent is evaporated.
Extraction Method
Automated systems circulate heated solvents like xylene or decalin through the sample bed to wash out specific polymer chains. Success in high temperature solvent extraction depends on maintaining a constant temperature to prevent the premature precipitation of the material. Specialized glassware or stainless steel pressure vessels prevent the loss of flammable solvents during the hours-long cycle.
Fractionation Process
Varying the temperature or the solvent composition allows for the separation of the polymer into different crystalline phases. Accurate high temperature solvent extraction reveals the ratio of polyethylene to polypropylene in a recycled blend. This data is critical for moulders who need to adjust the injection pressure and cooling time for varying feedstock lots.
If the rubber content is too low the parts will crack under stress, while excess rubber leads to excessive shrinkage and warping. Manufacturers use the results to certify that the resin meets the performance requirements for structural automotive parts.
Material Analysis
Quantitative results from the dried residue provide a fingerprint of the polymer architecture. Precise high temperature solvent extraction supports resin development.
