Revisiting the Anionic Polymerization of Methyl Ethacrylate

Abstract

Synthesis of poly(methyl ethacrylate), (PMEA), in tetrahydrofuran at −78 °C using anionic polymerization techniques results in high molar mass (>30 kg mol−1), low dispersity (1.3), and high conversion (>81%). The molar masses of a series of samples are consistent with values anticipated by the monomer‐to‐initiator ratio and conversion. These results represent a significant improvement to earlier reported attempts to prepare PMEA using anionic methods. Successful diblock polymerization of polystyrene‐block‐PMEA, (PS‐PMEA), and poly(4‐tert‐butylstyrene)‐block‐PMEA, (PtBS‐PMEA), is achieved through sequential anionic polymerization techniques with dispersities as low as 1.06 and segment molar fractions close to those targeted. Broad principal scattering peaks observed by small‐angle X‐ray scattering (SAXS) for symmetric PS‐PMEA at relatively high molar mass (39 kg mol−1) suggests an effective interaction parameter (χeff) that is smaller than for PS‐block‐poly(methyl methacrylate). On the other hand, PtBS‐PMEA block polymers form a well‐ordered morphology based on SAXS measurements and is attributable to the more hydrophobic PtBS segment. These results confirm the viability of PMEA as a new constituent in the expanding suite of polymers suitable for preparing nanostructured block polymers.

Reversed Controlled Polymerization (RCP): Depolymerization from Well-Defined Polymers to Monomers

“…40 Polycyanoacrylates and polyisobutylene are also disubstituted and have been successfully depolymerized (sections 3.4 and 3.5). Other disubstituted vinyl monomer classes resembling methacrylates include itaconates, 41 ethacrylates, 42 α-methoxyacrylates, 43 and α-ethylsulfenyl acrylates, 43 all of which are known to depolymerize back to monomer. Geminal captodative (i.e., an electronic "push−pull") substitution is reported to significantly stabilize the resulting tertiary radical and decrease the strength of the C−C bond.…”

Exploration of mandelic acid‐based polymethacrylates: Synthesis, properties, and stereochemical effects

“…Density was determined utilizing a 10 ml glass pycnometer with methanol as the nonsolvent and a digital thermometer to monitor temperature. Density values were corroborated using a “sink/float” test by submerging an annealed, dried, bubble‐free piece of polymer in ethylene glycol/glycerol mixture of known densities 45,46 . Samples were submerged with a pair of tweezers, shaking off any bubbles and observing whether the polymer would sink or float, thus indicating that the polymer was more or less dense than the solution it was in, respectively.…”

Viscoelastic, Mechanical, and Glasstomeric Properties of Precision Polyolefins Containing a Phenyl Branch at Every Five Carbons

“…The band gap setting was automatically adjusted for thermal expansion of the geometries during analysis. Densities were determined using a “sink/float” test by suspending dry, bubble-free pieces of each material within known mixtures of ethylene glycol and water that have known densities. , Density values were also corroborated using a 10 mL glass pycnometer and methanol as the nonsolvent. For each test, a calibrated thermometer was used to monitor the solution temperature, which remained within 24 ± 1 °C.…”