Propylene-ethylene copolymers with improved melt strength and resistance to discoloratio

LUCÍA N. SCHMIDT; JORGE A. GUAPACHA; DAHIANA X. HAURE; LIDIA .M. QUINZANI; MARCELO D. FAILLA

Buenos Aires

Congreso; WCCE11- 11th World Congress of Chemical Engineering; 2023

Propylene-ethylene copolymer (PEC) with improved melt strength and resistanceto discoloration is produced by reactive processing in two consecutive steps.In the first one, a low level of anhydride groups is grafted onto a commercialrandom PEC (PECg). Then, branched PEC (PECb) is obtained by reactive mixingPECg with m-xylylenediamine (XDA) and Basic Fuchsin (BF), which act ascrosslinking agents (CA). Both CA have primary amines in their molecularstructure. Before being added to the molten polymer, BF is dispersed/dissolvedin XDA. Changes in molecular structure are confirmed with FTIR analysisfollowing the evolution of anhydride, amine and amide/imide groups. Rotationaland extensional rheology is used to analyze the flow dynamic of the system. Allresults confirm the existence of branched structure in PECb, which presentssignificant strain hardening. Fade resistance of colored materials has alsobeen analyzed by submerging thin films in ethanol and measuring dyeconcentration in the solvent. PECb displays good colorfastness.