Recycled Polyolefin Oligomer Identification and Toxicological Screening Basics
Verify recycled polyolefin food contact clearance by combining LC-GC-FID quantification of C10-C50 oligomers with toxicological screening under Cramer Class thresholds.
POHO
Meaning
Oligomeric substances known as polyolefin hyphenated oligomers consist of low molecular weight saturated and unsaturated hydrocarbons found in polyethylene and polypropylene. POHO represents the fraction of the polymer that is mobile and can potentially migrate from a molded part into its environment.
Migration Risk
These small molecules can leach into food or pharmaceuticals, affecting the sensory properties or safety of the product. Minimizing POHO content is a priority for manufacturers of sensitive packaging who must ensure that the plastic does not impart any odor or taste.
Resin Characterization
Specialized extraction and chromatography techniques identify the concentration and type of oligomers present in a sample. High levels of POHO indicate a broad molecular weight distribution or the presence of degradation products from the polymerization process.
Process Influence
High temperatures and shear during molding can increase the formation of these low-weight fractions. Controlling POHO involves optimizing both the resin synthesis and the subsequent processing conditions to maintain the stability of the polymer chain. Modern production lines use chilled molds and optimized screw designs to keep the material as cool as possible while still ensuring a full fill.
This thermal management reduces the risk of creating new oligomers during the cycle.