Combining SEC & MALDI for characterization of the continuous phase in dispersion polymerization. (August 2018)

• Record Type: Journal Article
• Authors: Veloso, Antonio; Leal, G. Patricia; Agirre, Amaia; Leiza, José R.
• Is Part Of: European polymer journal. Volume 105(2018)
• Page Start: 265
• Page End: 273
• Publication Date: 2018-08
• Subjects: Dispersion polymerization -- Macromonomer -- Serum -- SEC -- MALDI-TOF MS; MALDI Matrix Assisted Laser Desorption Ionization -- TOF Time of Flight -- MS Mass Spectrometry -- MMD molar mass distribution -- SEC/RI Size Exclusion Chromatography/Refractive index -- St styrene -- AN acrylonitrile -- MMA methyl methacrylic acid -- EO ethylene oxide -- AIBN azobisisobutyronitrile -- THF tetrahydrofuran -- CHCA α-cyano-4-hydroxycinnamic acid -- NaTFA sodium trifluoroacetate; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2018.06.003
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: The combination of SEC & MALDI allowed to identify oligomeric species present in serums of latexes synthesized by dispersion polymerization using different comonomers (St/AN and St/MMA) and a macromonomer (polyethylene oxide methacrylate, Bisomer S20W) as stabilizer. In the serums obtained from both polymerizations, p(St-co-AN) and p(St-co-MMA) the presence of free or un-reacted macromonomer was confirmed. Moreover, in contrast to the p(St-co-MMA) serum where the presence of other oligomers was negligible, in the p(St-co-AN) serum, pAN (homo)oligomers and/or p(St-co-AN) oligomers were predominant over MPEGMA-co-AN species that although could be identified, their presence was substantially lower. Interestingly, in both serums species that could be assigned to [OH-(C2 H4 O)n -CH3 + Na] + was found. It was demonstrated that this species were formed by hydrolysis of the macromonomer during the reaction. This work demonstrates that the combination of SEC and MALDI techniques can be a very powerful tool for identifying oligomeric species presented in the serum from dispersion polymerizations and it could be used in other polymerization techniques, such as emulsion polymerization. Abstract: Dispersion copolymerization of styrene (St) with either acrylonitrile (AN) or methyl methacrylate (MMA) in 1-propanol/deionized water medium were carried out using Bisomer S20W (polyethylene oxide macromonomer with a methacrylic end group) as stabilizer. The serums of the St/AN and St/MMA latexes were characterized in terms of molar mass and composition by the combination of Size Exclusion Chromatography (SEC) and Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS). This work demonstrates that the combination of SEC and MALDI techniques is necessary for an accurate identification of the composition and molar mass of the oligomeric species present in the continuous phase of a dispersion polymerization that cannot be achieved by using either SEC or MALDI alone. For the particular latexes analyzed in this work it was found that unreacted macromonomer was present in both copolymer systems. However, in the case of the copolymerization with AN besides the presence of the macromonomer there were also some pAN oligomers.