Xylene Solvent Etching

Morphological Revelation

Specimen preparation begins by exposing a polished cross-section of the molded part to hot xylene for a controlled duration. During xylene solvent etching, the solvent selectively dissolves the amorphous or polypropylene phases while leaving the polyethylene or crystalline phases intact. This leaves empty voids where the dissolved phase once sat.

An analyst can then measure the size and shape of these voids using scanning electron microscopy. This method exposes the true morphology without deformation or smearing of the soft domains.

Compression Damage

Severe mechanical cutting of polymers creates plastic deformation that conceals the true distribution of fillers and phases. Bypassing this problem, xylene solvent etching reveals the undistorted boundary of each domain because the chemical process avoids any shear. This method provides highly accurate input data for image analysis software.

It prevents the underestimation of domain sizes due to smearing.

Mold Diagnostic

Injection molders use this technique to troubleshoot weaknesses along the weld lines of molded parts. If the domains are poorly distributed or aligned parallel to the weld line, xylene solvent etching will highlight these orientation defects. This analysis allows the mold designer to reposition the gates to change the flow front behavior.

Adjusting the processing parameters then enhances the strength of the finished product.