Problems with extrusion and subsequent processing of the material are caused, in part, by the presence of paper, metal, gels, incompatible polymers, or other extraneous contamination found in polymers.

1.1 This practice covers a means to separate the unmolten particles, gels, and impurities contaminating a polymer sample. The procedure may be used to remove gels and incompatible materials that may cause imperfections in the final extruded product. Under pressure, most gels will break up or deform and pass through a wire mesh filter, however high molecular weight gels may not break up or deform.

1.2 If desired, materials isolated on a wire mesh filter can subsequently be identified by spectroscopic or other analytical means.

Note 1—Although not presented as a quantitative method, the procedure presented in this practice may be used to provide quantitative results at the discretion of the user. The user assumes the responsibility to verify the reproducibility of quantitative results. Detection limit depends on the mesh size of the filter screen, but the procedure is generally applicable to the separation of immiscible contaminants present at concentrations greater than 0.1 %.

1.3 The values stated in SI units are to be regarded as standard.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards statements, see Section 8.

Note 2—There is no known ISO equivalent to this practice.