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A fast and reliable procedure to determine the copolymer composition by GPC‐IR: Application to ethylene/propylene copolymers and comparison with 13 C NMR
Author(s) -
Suárez Inmaculada,
Caballero Ma Joaquina,
Coto Baudilio
Publication year - 2011
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21811
Subject(s) - comonomer , copolymer , materials science , ethylene , post metallocene catalyst , ethylene propylene rubber , gel permeation chromatography , composition (language) , polymer chemistry , polymer , metallocene , proton nmr , analytical chemistry (journal) , catalysis , polymerization , organic chemistry , chemistry , composite material , linguistics , philosophy
Copolymer properties depend on several parameters and one of the most important is its composition. Typically, this composition is determined by 13 C nuclear magnetic resonance ( 13 C NMR) analysis, which requires a long acquisition time and a fine adjustment of parameters to obtain the desired resolution. In this article, a method to determine the comonomer content of polymers based on the analysis from gel permeation chromatography (GPC) with an infrared (IR) detector is described. This GPC‐IR method is faster than NMR and can be carried out routinely during the GPC analysis. Three sets of ethylene/propylene copolymers synthesized using metallocene and Ziegler–Natta catalyst over a wide composition range. Linear and second order polynomial equations were checked for the relation between the ethylene percent and the IR CH 3 /CH ratio. Average deviation between GPC‐IR and NMR composition values was about 1% and allow conclude that this technique can be considered to be a goodalternative. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers