Coloration and branching of polypropylene by reactive processing

SCHMIDT, LUCIA N.; GUAPACHA, JORGE; QUINZANI, LIDIA M.; FAILLA, MARCELO D.

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Año: 2023

0021-8995

Reactive melt processing is a known technique used to produce long-chainbranched polypropylene. It involves polyfunctional substances that act aschain-linking agents (CA). In this work, polyfunctional amine dyes are used asCA in a novel method for simultaneously improving melt strength and faderesistance of polypropylene. Colored long-chain branched polymer is synthe-sized by reactive processing of maleic anhydride grafted polypropylene (PPg)in the molten state using glycerol, basic fuchsin and disperse blue 1. SelectedCA concentrations avoid gel-like structures and impart good color intensity.FT-IR spectroscopy confirms the reaction between PPg and the CAs whilerheological characterization supports the synthesis of long-chain branchedstructures. Covalent bonding of dye molecules to PPg is confirmed by bothUV–visible spectroscopy and colorimetry. A maximum total color difference,ΔE*, of about 20 was measured after xylene purification. New materials showgood color homogeneity and transparency with minimum bleeding after48 hours exposure to water and ethanol.