Time-temperature superposition principle application to the hygrothermal discoloration of colored high-density polypropylene/wood composites

Discoloration kinetics of wood plastic composites (WPCs) made of recycled high density polyethylene (HDPE) during accelerated hygrothermal aging test at 45–65°C was conducted by means of time‐temperature superposition principle (TTSP). Color parameters measured with a spectrophotometer by CIELAB color system showed that L* and Δ E* increased while a* and b* decreased with aging time and temperature. A single horizontal shift was adequate for the...