Mass spectrometry Polymers

M. W. F. Nielen. MALDI Time-of-Flight Mass Spectrometry of Synthetic Polymers. Mass Spectrometry Reviews, 18, no. 5 (1999) 309-344. 

Although FAB has been used in polymer analysis, problems with fragmentation and the relatively low mass limit has made this less popular as new techniques have emerged. Plasma desorption has been used successfully but this too has waned in popularity with commercial spectrometers not really readily available. To a large extent polymer mass spectrometry equates to MALDI time-of-flight and the remainder of this article will bear this in mind. However, the use of electrospray ionisation (ESI) will be considered in conjunction with either quadrupole detectors or ion cyclotron resonance (ICR) N. B. ICR detectors can also be used with MALDI, as this is important and probably not as widely used as it could be. 

In a separate study we utilized ESI quadrupole mass spectrometry to analyse MMA/methacrylic acid copolymers. For each degree of polymerisation the distribution of monomer units are seen giving again chain length dependence information. This is extremely powerful application of mass spectrometry applied to polymers. Mass spectrometry has even been used for the measurement of kp for MMA polymerisation in conjunction with PLP. 

Fortunately, the use of mass spectrometry for polymer analysis took on a new dimension at the turn of the century. Figure 1 lists the number of polymer mass spectrometry publications in the CAplus (Chemical Abstracts) database over the years 1965-2000. Up until the mid-1990s there was a steady— but not dramatic— increase in the number of articles. Starting in 1995, however, there has been a marked increase in the number of polymer mass spectrometry reports in the literature. Also the number of symposia and conferences devoted to the subject has grown considerably in the last few years. 

Wallace, W.E. and Guttman, C.M. (2002) Data analysis methods for synthetic polymer mass spectrometry autocorrelation. J. Res. Natl. Inst. Stand. Technol, 107, 1-17. 

Mass spectrometry is the study of the mass, or molecular weight, of ions created via ionization or fragmentation and determined electrically in the gas phase. In the study of polymers, mass spectrometry has two broad applications ... 

After the initial hype of polymer mass spectrometry by MALDI a more cautious approach now focuses on issues like matrix selection, repeatability, quantitation, mass bias, etc. 

Schulten H-R and Lattimer RP (1984) Applications of mass spectrometry to polymers. Mass Spectrometry Reviews 3 231-315. 

Isopropyl group (Section 2 13) The group (CH3)2CH— Isotactic polymer (Section 7 15) A stereoregular polymer in which the substituent at each successive chirality center is on the same side of the zigzag carbon chain Isotopic cluster (Section 13 22) In mass spectrometry a group of peaks that differ in m/z because they incorporate differ ent isotopes of their component elements lUPAC nomenclature (Section 2 11) The most widely used method of naming organic compounds It uses a set of rules proposed and periodically revised by the International Union of Pure and Applied Chemistry... 

Montaudo, G. and Lattimer, R.P., Mass Spectrometry of Polymers, CRC Press, Boca Raton, FL, 2001. Montaser, A., Inductively Coupled Plasma Mass Spectrometry, Wiley, Chichester, U.K., 1998. 

The incidence of these defects is best determined by high resolution F nmr (111,112) infrared (113) and laser mass spectrometry (114) are alternative methods. Typical commercial polymers show 3—6 mol % defect content. Polymerization methods have a particularly strong effect on the sequence of these defects. In contrast to suspension polymerized PVDF, emulsion polymerized PVDF forms a higher fraction of head-to-head defects that are not followed by tail-to-tail addition (115,116). Crystallinity and other properties of PVDF or copolymers of VDF are influenced by these defect stmctures (117). 

Styryl sulfonyl chloride Friedel-Crafts cyclization benzo[h]thiophenes from, 4, 873 Succinic anhydrides polymers, I, 277 mass spectrometry, 4, 585 structure, 4, 552... 

Other technique—for example, dynamic secondary ion mass spectrometry or forward recoil spectrometry—that rely on mass differences can use the same type of substitution to provide contrast. However, for hydrocarbon materials these methods attain a depth resolution of approximately 13 nm and 80 nm, respectively. For many problems in complex fluids and in polymers this resolution is too poor to extract critical information. Consequently, neutron reflectivity substantially extends the depth resolution capabilities of these methods and has led, in recent years, to key information not accessible by the other techniques. 

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. 

Jones, F.R., Interfacial aspects of glass fibre reinforced plastics. In Jones, F.R. (Ed.), Interfacial Phenomena in Composite Materials. Butterworths, London, 1989, pp. 25-32. Chaudhury, M.K., Gentle, T.M. and Plueddemann, E., Adhesion mechanism of poly(vinyl chloride) to silane primed metal surfaces. J. Adhes. Sci. Technol, 1(1), 29-38 (1987). Gellman, A.J., Naasz, B.M., Schmidt, R.G., Chaudhury, M.K, and Gentle, T.M., Secondary neutral mass spectrometry studies of germanium-silane coupling agent-polymer interphases. J. Adhes. Sci. Technol., 4(7), 597-601 (1990). 

Low ionizing potentials or soft ionization methods are necessary to observe the parent ions in the mass spectra of many S-N compounds because of their facile thermal decomposition. Mass spectrometry has been used to investigate the thermal breakdown of S4N4 in connection with the formation of the polymer (SN). On the basis of the appearance potentials of various S Ny fragments, two important steps were identified ... 

H. J. Goites, B. M. Bell, G. D. Pfeiffer and J. D. Graham, Multidimensional chromatography using on-line coupled microcolumn size exclusion cliromatography-capillary gas chromatography-mass spectrometry for determination of polymer additives , J. Microcolumn Sep. 1 278-288. (1989)... 

Thermogravimetric analysis has also been used in conjunction with other techniques, such as differential thermal analysis (DTA), gas chromatography, and mass spectrometry, for the study and characterisation of complex materials such as clays, soils and polymers.35... 

Two relatively new techniques, matrix assisted laser desorption ionization-lime of flight mass spectrometry (MALDI-TOF) and electrospray ionization (FS1), offer new possibilities for analysis of polymers with molecular weights in the tens of thousands. PS molecular weights as high as 1.5 million have been determined by MALDI-TOF. Recent reviews on the application of these techniques to synthetic polymers include those by Ilantoif54 and Nielen.555 The methods have been much used to provide evidence for initiation and termination mechanisms in various forms of living and controlled radical polymerization.550 Some examples of the application of MALDI-TOF and ESI in end group determination are provided in Table 3.12. The table is not intended to be a comprehensive survey. 

Table 3.12 Application of MALDI-TOF or ESI Mass Spectrometry to Polymers Prepared by Radical Polymerization...

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