Interpretation of size-exclusion chromatography of copolymers. I. Simulation studies: Scope and generation of the joint molecular weight-chemical composition distribution

1991 ◽  
Vol 48 (0) ◽  
pp. 141-160 ◽  
Author(s):  
Gloria L. Frontini ◽  
Luis H. García-rubio ◽  
Gregorio Meira
e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Iván García Romero ◽  
Harald Pasch

AbstractThe development of high-throughput liquid chromatographic techniques for the analysis of styrene-butyl acrylate (SBA) copolymers is discussed. The analysis time in size-exclusion chromatography (SEC) can be reduced to about 3 min per sample when high-throughput SEC columns and high flow rates are used. In gradient HPLC, small columns with improved separation efficiencies can be applied. The time requirements can be decreased to less than 2 min per sample. Using the high-throughput HPLC technique, the chemical composition distribution of high-conversion SBA copolymers can be analyzed in a fast and efficient way. The calibration of HPLC separation is conducted by coupling the HPLC system with FTIR through the LC-transform interface. A comparison of the chemical compositions of the copolymers obtained by 1H NMR, off-line FTIR and coupled HPLCFTIR verifies the accuracy of the high-throughput copolymer analysis approach.


e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Stefan de Goede ◽  
Robert Brüll ◽  
Harald Pasch ◽  
Niall Marshall

Abstract The degradation of polypropylene (PP) and a propene-1-pentene copolymer (P2) have been monitored with regard to chemical composition, molar mass distribution and chemical composition distribution. The increase in the carbonyl index can be monitored by IR and a decrease in molar mass can be observed from size-exclusion chromatography (SEC). CRYSTAF shows that the chemical heterogeneity of the samples broadens with continuing degradation. SEC-FTIR reveals that the degraded species are mainly found in the low-molecular-weight end of the molar mass distribution. Spatial heterogeneity of the degradation process has been proven by the analysis of abrased layers. It was found that the P2 copolymer degrades at a higher rate compared to PP.


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