ABSTRACT Melt strength and fade resistance of a random propylene–ethylene copolymer (PEC) were enhanced by generating long‐chain branched (LCB) structures using two amine‐polyfunctional chain‐linking agents (CAs). A maleic‐anhydride‐grafted copolymer (PECg) was first obtained as a precursor to the LCB polymers that were obtained by reactive melt mixing using various concentrations of m‐xylylenediamine (XDA) and Basic Fuchsin (BF). The resulting changes in molecular structure were analyzed using FTIR and shear and extensional rheometry, while color characteristics and fastness were studied using UV–visible spectroscopy, colorimetry, and solvent extraction. The results demonstrate that both CAs react with PECg to form polymers with LCBs and complex molecular structures, being BF being less efficient than XDA. However, the simultaneous use of both CAs produces a significant synergistic effect. For example, the rate of change of the strain‐hardening coefficient with CA concentration (SHI exp ~ 36.5 c CA ) is greater than the value predicted by a Linear Mixing Rule based on Xi and Fi data (SHI LMR ~ 27.8 c CA ). All colored materials exhibit excellent fade resistance, as demonstrated by the color permanence of films exposure to solvents for 10 days. Altogether, the selected approach allows for the generation of dye‐grafted polyolefins with improved melt strength and fade resistance.
Schmidt et al. (Fri,) studied this question.