Kinetics of the Aqueous Phase Copolymerization of MAA and PEGMA Macromonomer: Influence of Monomer Concentration and Side Chain Length of PEGMA

An in situ nuclear magnetic resonance spectroscopy (NMR) technique is used to monitor the aqueous-phase copolymerization kinetics of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomers. In particular, the study analyses the effect of the number of ethylene glycol (EG) groups along the lateral chains of PEGMA and is carried out under fully ionized conditions of MAA at different initial monomer ratios and initial overall monomer concentrations (5-20 wt % in aqueous solution). The composition drift with conversion indicates that PEGMA macromonomer is more reactive than MAA. Individual monomer consumption rates show that the rates of consumption of both monomers are not first order with respect to overall concentration of the monomer. The reactivity ratios estimated from the copolymerization kinetics reveal, that for the short PEGMA, the reactivity ratios r(MAA) and r(PEGMA) increase with the solids content (SC). A totally different trend is obtained for the longer PEGMA, whose reactivity ratio (r(PEGMA23)) decreases with solids content, whereas the reactivity ratio of MAA remains roughly constant.This work has been carried out in the framework of the BASKRETE initiative under the umbrella of the EUSKAMPUS project. Iraki Emaldi acknowledges the funding provided by EUSKAMPUS Fundazioa, POLYMAT and TECANLIA for his scholarship. Shaghayegh Hamzehlou and Jose Ramon Leiza acknowledge the funding provided by MINECO (CTQ 2014-59016P) and Basque Government (IT-999-16). Jorge Sanchez Dolado acknowledges the funding for the GEI Green Concrete Project given by the Basque Government (2015 Emaitek Program). The authors also thank the discussion with Jose arlos de la Cal on the estimation of the reactivity ratios and they are grateful to Jose nacio Miranda and the SGIker Gipuzkoa Unit (UPV/EHU) for the NMR facilities

Efficient cationic ring-opening polymerization of diverse cyclic imino ethers: unexpected copolymerization behavior

The recently developed fast microwave-assisted cationic ring-opening polymerization procedure for 2-oxazolines seems to be ideally suited for slower polymerizing cyclic imino ether monomers. In this study we report the effect of the cyclic imino ether structure on the polymerization rate under exactly the same microwave-assisted conditions revealing that indeed less reactive cyclic imino ethers, including 2-oxazines as well as 4- and 5-substituted 2-oxazolines, can be polymerized to at least 50% conversion for the slowest monomer, namely 5-methyl-2-butyl-2-oxazoline, within 10 h. In addition, the copolymerization behavior of 4-ethyl-2-butyl-2-oxazoline with 2-methyl-2-oxazoline and 2-phenyl-2-oxazoline unexpectedly revealed faster incorporation of the less reactive 4-ethy1-2-buty1-2-oxazoline monomer compared to 2-phenyl-2-oxazoline due to the increased bulk of the latter monomer amplifying the sterical hindrance for polymerization onto the 4-ethyl-2-butyl-2-oxazolinium propagating species

Synthesis of Multifunctional Polyethers: Anionic Ring-Opening Polymerization of Functional Epoxide Monomers

Department of ChemistryPolyethers, such as poly(ethylene glycol) (PEG), have been widely used for a variety of applications, owing to their high water solubility, superior biocompatibility, low toxicity, and flexible backbone. However, PEG possesses only two hydroxyl groups at both ends of the polymer chain, and this limits its functionalization. In this regard, the design and synthesis of functional epoxide monomers must be investigated for the preparation of various multifunctional polyethers, which have the potential for broad applications. This thesis describes the design and synthesis of functional epoxide monomers, followed by the synthesis of multifunctional polyethers using these monomers. Chapter 1 covers the general introduction and background of PEG and its derivatives, as well as the methods for further modification of polymers. The synthesis of thermoresponsive PEG-based functional polymers containing pendant amine groups is described in Chapter 2. Chapter 3 presents a one-pot synthesis of primary amine-containing hyperbranched polyglycerols (PGs) using a newly designed amino glycidyl ether monomer. Chapter 4 describes a series of novel azidoalkyl glycidyl ethers as universal monomers for the synthesis of azide-functional polyethers. Post-polymerization modification of the polymer through Cu-catalyzed azide-alkyne cycloaddition (CuAAC) and Staudinger reduction is demonstrated to propose the versatility of azide-functional polymers. Thus, this method acts as a new platform for the preparation of functional polyethers.clos

Reactivity ratio estimation for co- and terpolymerization of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl acrylate

N-butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and methyl methacrylate (MMA) are commonly used as monomers in coatings, adhesives and many other applications. Our current interest is in BA/MMA/EHA terpolymer formulations for the production of pressure sensitive adhesives. For the purposes of controlling polymer adhesive performance, kinetic parameters such as the reactivity ratios, are required. Reactivity ratios for BA/MMA are available in the literature1, while that for BA/EHA and MMA/EHA are not. The bulk copolymerization reactivity ratios for BA/EHA and MMA/EHA were determined at 60 C using statistically designed free-radical polymerizations at low-conversion (\u3c10%). The estimates were then validated using high-conversion copolymerizations. These reactivity ratio estimates were used, along with the literature values for the BA/MMA system, for the prediction of BA/MMA/EHA composition in a series of high conversion bulk terpolymerizations. Please click Additional Files below to see the full abstract