Novel (meth)acrylate monomers for ultrarapid polymerization and enhanced polymer properties (original) (raw)
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Macromolecules, 2007
Polymerization studies in the presence of extensive amounts of solvent are used here to deconvolute the effects of intermolecular interactions such as bulk medium polarity, π-π stacking, and hydrogen bonding and characterize the contribution of intramolecular conformational effects to monomer reactivity. For that purpose the solution polymerization kinetics of various monomers in the presence of 95 wt % 1, 4-dioxane were measured and compared to bulk polymerization kinetics. The studies revealed that traditional aliphatic acrylates like hexyl acrylate exhibit approximately 2-3-fold reduction upon dilution. Monomers characterized by only hydrogenbonding features such as hydroxyethyl acrylate exhibit an 8-12-fold reduction upon dilution. Monomers possessing only aromatic ring stacking interactions such as phenyl acrylate exhibit approximately a 5-10-fold reduction upon dilution under similar conditions. Even at a concentration of 5 wt % monomer in 1,4-dioxane, there were approximately 2-5-fold differences in reactivity observed between various acrylates. These reactivity differences between various acrylates, which exist even upon extensive dilution, were inferred to arise solely from intramolecular interactions. The contribution of intramolecular interactions for various monomers was decoupled from the bulk effects, and the impact of various functionalities upon the reactivity of acrylate monomers was quantitatively estimated.
(Meth)acrylate vinyl ester hybrid polymerizations
Journal of Polymer Science Part A: Polymer Chemistry, 2009
In this study vinyl ester monomers were synthesized by an amine catalyzed Michael addition reaction between a multifunctional thiol and the acrylate double bond of vinyl acrylate. The copolymerization behavior of both methacrylate/vinyl ester and acrylate/vinyl ester systems was studied with near-infrared spectroscopy. In acrylate/vinyl ester systems, the acrylate groups polymerize faster than the vinyl ester groups resulting in an overall conversion of 80% for acrylate double bonds in the acrylate/vinyl ester system relative to only 50% in the bulk acrylate system. In the methacrylate/vinyl ester systems, the difference in reactivity is even more pronounced resulting in two distinguishable polymerization regimes, one dominated by methacrylate polymerization and a second dominated by vinyl ester polymerization. A faster polymerization rate and higher overall conversion of the methacrylate double bonds is thus achieved relative to polymerization of the pure methacrylate system. The methacrylate conversion in the methacrylate/ vinyl ester system is near 100% compared to only ~60% in the pure methacrylate system. Utilizing hydrophilic vinyl ester and hydrophobic methacrylate monomers, polymerization-induced phase separation is observed. The phase separated domain size is on the order of ~1 μm under the polymerization conditions. The phase separated domains become larger and more distinct with slower polymerization and correspondingly increased time for diffusion.
Macromolecules, 1992
It has been previously shown that p-coordinating inorganic salts, such as LiC1, were effective in preventing the anionic polymerization of methacrylic esters and hindered alkyl acrylates from being disturbed by secondary transfer and termination reactions. That strategy has opened the way to the "living" polymerization of these monomers and their controlled sequential polymerization with monomers lacking a carbonylconjugated group. That control is however limited to THF at low temperatures for methyl methacrylate and tert-butyl acrylate. It is reported now that the polymerization mechanism remains strictly controlled in apolar solvents, such as toluene, and at temperatures as high as 0 "C, when crown ethers are used in relation to their capability of chelating the alkali-metal counterion and surrounding it with a steric barrier blocking a large enough space area around the metal-containing ion pair.
Polymer Chemistry, 2013
The treatment of poly(glycidyl methacrylate) with nucleophilic agents yielded new linear homo/ co-polymers. The materials obtained have different physicochemical properties depending upon the nucleophiles utilized and thus, by this way, water soluble polymers are easily accessible. This approach is also very convenient for the synthesis of amphiphilic block copolymers. Additional chemical modifications can further transform the obtained polymers after the post-polymerization treatment. Starting from RAFT pre-synthesized/pre-functionalized polymers, the described procedures allow us to obtain a wide variety of chemically diverse materials characterized by controlled structure and specific functions. † Electronic supplementary information (ESI) available: 1 H-NMR spectra of the synthesized RAFT agent and polymers; FT-IR spectra of PGMA and PHMPMA polymers and of the PHMPMA-co-PHAPMA random copolymer. See
Polymer, 2004
The synthesis and radical polymerization of 1,4,7,10-tetraoxacyclododecan-2-ylmethylmethacrylate (CR4MA) is described. The polymerization reactions of CR4MA were carried out at different temperatures and the kinetic curves of monomer depletion against time were obtained by direct measurements of the instantaneous monomer concentrations by using nuclear magnetic resonance (NMR) spectroscopy. At the same time electron paramagnetic resonance (EPR) spectroscopy was used to determine the actual polymer radical concentration during all the reaction time. The conjunction of both techniques (NMR and EPR) allowed the determination of the polymerization rate parameter ð2fk p =kk t l 1=2 Þ and separately of k p and kk t l=f ; where f ; k p and kk t l are, respectively, the initiator efficiency factor and the overall averages of propagation (k p is considered to be practically independent of the chain length) and termination rate constants. The values found for this ratio and for k p were comparatively higher than those recently reported in the literature for its lateral open chain counterpart, the methacrylic monomer with equal number of oxyethylene units in the residue ester (TTEMA). However, the kk t l values were similar for the polymerization of both monomers CR4MA and TTEMA. The polymer, PCR4MA, is soluble in water as its open chain homologous, and exhibits a glass transition temperature in the vicinity of the ambient temperature (about 35 8C), much higher than the value found for the homologous polymethacrylate derived from the TTEMA. q
Journal of Polymer Science Part A-polymer Chemistry, 2000
The synthesis of di-and triblock copolymers using atom transfer radical polymerization (ATRP) of n-butyl acrylate (BA) and methyl methacrylate (MMA) is reported. In particular, synthetic procedures that allow for an easy and convenient synthesis of such block copolymers were developed by using CuBr and CuCl salts complexed with linear amines. Polymerizations were successfully conducted where the monomers were added to the reactor in a sequential manner. Poor cross-propagation between poly(n-butyl acrylate) (PBA) macroinitiators and MMA was minimized, and therefore control of molecular weights and distributions was realized, by using halogen exchange-a technique involving the addition of CuCl to the MMA during the chain extension of the PBA macroinitiator. High molecular weight (M n ϳ 90,000) and low polydispersity (M w /M n Ͻ 1.35) ABA triblock copolymers were also prepared and their structure and properties in bulk have been preliminary characterized indicating the potential of ATRP for the production of all-acrylic thermoplastic elastomers.