Polyolefin Degradation Mechanics in Post-Consumer Resin Recyclate Streams
Polyolefin recyclate degradation occurs via PP chain scission and PE crosslinking; verification requires dual-weight MFR sweeps and 30-minute OIT testing.
Polyvinyl Chloride Dehydrochlorination Hcl
Meaning
Chemical degradation reaction that occurs when polyvinyl chloride is exposed to high temperatures, resulting in the release of hydrochloric acid and the formation of conjugated double bonds along the polymer backbone. This polyvinyl chloride dehydrochlorination Hcl release leads to rapid polymer discoloration and severe corrosion of processing equipment and molds. It is prevented by adding thermal stabilizers to the resin compound.
Degradation Pathway
Autocatalytic degradation occurs as the liberated acid accelerates the decomposition of the surrounding polymer chains. This polyvinyl chloride dehydrochlorination Hcl generation is monitored by measuring the time required for the resin to release free acid.
Processing Protection
Corrosion of expensive tool steel can occur within hours if the melt runs too hot or resides too long in the barrel. Preventing polyvinyl chloride dehydrochlorination Hcl requires precise temperature control and the use of specialized screw designs that minimize shear heating. Melt temperatures must be kept below the decomposition threshold.
Quality Impact
Severe acid release results in black spots and surface pits in the molded vinyl parts. This polyvinyl chloride dehydrochlorination Hcl degradation also reduces the flame-retardant properties of the material and ruins its electrical insulation performance, which means that molders must run scrap parts through rigorous stability testing before using any regrind in high-value applications where even tiny traces of hydrochloric acid would cause catastrophic corrosion of electrical terminals or contact points.