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

LUCIA SCHMIDT; JORGE GUAPACHA; DAHIANA HAURE; LIDIA MARÍA QUINZANI; MARCELO DANIEL FAILLA

Buenos Aires

Congreso; 11th World Congress of Chemical Engineering (WCCE11), XXX IACCHE, XI CAIQ y IICIBIQ; 2023

Asoc. Argentina de Ing. Químicos

Propylene-ethylene copolymer (PEC) with improved melt strength and resistance to discoloration is produced by reactive processing in two consecutive steps. In the first one, a low level of anhydride groups is grafted onto a commercial random PEC (PECg). Then, branched PEC (PECb) is obtained by reactive mixing PECg with m-xylylenediamine (XDA) and Basic Fuchsin (BF), which act as crosslinking agents (CA). Both CA have primary amines in their molecular structure. Before being added to the molten polymer, BF is dispersed/dissolved in XDA. Changes in molecular structure are confirmed with FTIR analysis following the evolution of anhydride, amine and amide/imide groups. Rotational and extensional rheology is used to analyze the flow dynamic of the system. All results confirm the existence of branched structure in PECb, which presents significant strain hardening. Fade resistance of colored materials has also been analyzed by submerging thin films in ethanol and measuring dye concentration in the solvent. PECb displays good colorfastness.