Chromatography deformulation

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Kilz, R, Kruger, R., Much, H., Schulz, G. (1995). Two-Dimensional chromatography for the deformulation of complex copolymers, in Chromatographic Characterization of Polymers Hyphenated and Multidimensional Techniques. T. Provder, H.G. Barth, M.W. Urban, Editors, American Chemical Society, Washington. DC. 

If additional information pertaining to the rubber composition were sought, FTIR analysis of the pyrolysis products would have been performed. Even more detailed analysis can be obtained by gas chromatography (GC) separation of the multiple pyrolysis products followed by mass spectrometric (MS) detection. The gas chromatography-mass spectrometry (GC-MS) method is well suited to deformulation and contaminant analysis. 

The versatility of the 2D approach is illustrated with a four-arm starshaped block copolymer (a mixture of 16 components), which was synthesized in our laboratories to understand and demonstrate the advantages of 2D chromatography. These 16 components are a mixture of four different styrene-butadiene (St-Bd) copolymer compositions, each consisting of four molar masses (the St-Bd precursor with one to four arms). Another polymer investigated is a real-world application the deformulation of a telomeric aliphatic polyester. 

The deformulation of a polyester was done with liquid-adsorption chromatography under critical conditions (LACCC) that was coupled to an SEC system. The dimension was separated by the end-group functionality to study byproducts formed during polycondensation. By 2D chromatography a number of species (e.g., cycles, ethers, alkyl terminated chains, and so on) could be identified. Some of them influenced the mechanical and thermal properties of the polyesters significantly. 

The high resolution of LC-SEC separations and the full automation using 2D-CHROM software enable the reliable and comprehensive characterization and deformulation of complex analytes like copolymers, polymer blends, and additives. 2D chromatography will become a powerful tool with flexible and easy-to-use software. Basically, all types of LC methods can be combined to give superior resolution and reproducibility. 

KUz P, Kruger RP, Much H, Schulz G (1995) Two-Dimensional Chromatography for the Deformulation of Complex Copolymers. In Provder T., Barth H.G., Urban M.W. (Eds.) Chromatographic Characterization of Polymers, Hyphenated and Multidimensional Techniques. ACS, Washington, DC, p 223... 

Comprehensive two-dimensional separations have become a classical method for analyzing and deformulating macromolecular samples. In the analysis of small molecules, two-dimensional chromatography is mostly used as a sample preparation step for advanced detection techniques (MS, NMR, etc.). Obviously, the analytical goal is very different and sample preparation techniques will not be discussed here. 

Kilz P, Kruger RP, Much H, Schulz G. Two-dimensional chromatography for the deformulation of complex copolymers. Chromatogr Char Poly 1995 247 223-41. 

Kilz P, KrUger R P, Much H and Schulz G (1995) 2-Dimensional chromatography for the deformulation of complex copolymers, Adv Chem 247 223-241. 

The ultimate application of the LC-Transform system is to use it as a detector in two-dimensional liquid chromatography (2D-LC). Adrian et presented the deformulation of a... 

One very t5 ical example for the useful application of 2D-LC is the deformulation of graft copolymers. The combination of styrene and butadiene in different copolymer stmctures is important for a huge variety of technical polymeric materials. The present application describes the analysis of the grafting reaction of methyl methacrylate onto polybutadiene by online coupled 2D chromatography. Such graft copolymers are interesting as compatibilizers for polymer blends. In order... 

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