INVESTIGADORES
BARBOSA Silvia Elena
artículos
Título:
PP/PS blends. In-situ compatibilization by Friedel-Crafts alkylation reaction
Autor/es:
DÍAZ, MÓNICA FÁTIMA; BARBOSA, SILVIA ELENA; CAPIATI, NUMA JOSÉ
Revista:
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
Editorial:
Wiley
Referencias:
Año: 2004 vol. 42 p. 452 - 462
ISSN:
0887-6266
Resumen:
The application of Friedel-Crafts alkylation reaction to the compatibilization of
PP/PS blends was assessed. A polypropylene macrocarbocation is chemically bonded to the PS
benzene ring by aromatic electrophilic substitution. The graft copolymer formed at the interphase
(PP-g-PS) showed relatively high emulsification strength, suggesting an effective behavior as in-situ
compatibilizer. The critical micelle concentration (CMC) was related to Friedel-Crafts catalyst
concentration. The amount of PS grafting and possible appearance of crosslinking and chain scission
side reactions was also analyzed. The reaction products were characterized by a combination of Size
Exclusion Chromatography and Fourier Transform Infrared techniques applied after a careful
solvent extraction separation. It was found, from the emulsification curve, that CMC was achieved
when 0.7 wt % AlCl3 was added. This value was confirmed by Scanning Electron Microscopy
observation of phase adhesion on fractured sample surfaces. Mass balances of extracted PS showed
that at least 15 wt % of the initial PS resulted grafted at the CMC condition. Chain scission reactions,
in parallel with grafting, were verified to occur for PP as well as for PS. Instead, crosslinking
reactions were not detected.3 was added. This value was confirmed by Scanning Electron Microscopy
observation of phase adhesion on fractured sample surfaces. Mass balances of extracted PS showed
that at least 15 wt % of the initial PS resulted grafted at the CMC condition. Chain scission reactions,
in parallel with grafting, were verified to occur for PP as well as for PS. Instead, crosslinking
reactions were not detected.