Reactivity ratios and copolymer properties of 2‐(diisopropylamino)ethyl methacrylate with methyl methacrylate and styrene

Abstract

Free radical copolymerization kinetics of 2-(diisopropylamino)ethyl methacrylate (DPA) with styrene (ST) or methyl methacrylate (MMA) was investigated and the corresponding copolymers obtained were characterized. Polymerization was performed using tert-butylperoxy-2-ethylhexanoate (0.01 mol dm −3 ) as initiator, isothermally (70 ∘ C) to low conversions (<10 wt%) in a wide range of copolymer compositions (10 mol% steps). The reactivity ratios of the monomers were calculated using linear Kelen-Tüdős (KT) and nonlinear Tidwell-Mortimer (TM) methods. The reactivity ratios for MMA/DPA were found to be r 1 = 0.99 and r 2 = 1.00 (KT), r 1 = 0.99 and r 2 = 1.03 (TM); for the ST/DPA system r 1 = 2.74, r 2 = 0.54 (KT) and r 1 = 2.48, r 2 = 0.49 (TM). It can be concluded that copolymerization of MMA with DPA is ideal while copolymerization of ST with DPA has a small but noticeable tendency for block copolymer building. The probabilities for formations of dyad and triad monomer sequences dependent on monomer compositions were calculated from the obtained reactivity ratios. The molar mass distribution, thermal stability and glass transition temperatures of synthesized copolymers were determined. Hydrophobicity of copolymers depending on the composition was determined using contact angle measurements, decreasing from hydrophobic polystyrene and poly(methyl methacrylate) to hydrophilic DPA. Copolymerization reactivity ratios are crucial for the control of copolymer structural properties and conversion heterogeneity that greatly influence the applications of copolymers as rheology modifiers of lubricating oils or in drug delivery systems.

Polyester Macromonomer Syntheses and Radical Copolymerization Kinetics with Styrene

“…Nowadays, elucidation of kinetic parameters in the complex RP scheme is greatly assisted by tools such as pulsed laser polymerization coupled with size exclusion chromatography (PLP-SEC) to study propagation kinetics, − quantum chemical simulation to estimate a variety of rate coefficients, − electron paramagnetic resonance (EPR) spectroscopy to determine radical structure and to follow termination kinetics, − and in situ proton nuclear magnetic resonance ( 1 H NMR) spectroscopy as an efficient means to simultaneously track monomer conversion and comonomer/copolymer composition. − The cumulative aim of these specialized techniques is a complete kinetic description for each polymerization system, as has been established for certain acrylic solution copolymerizations, , such that simulations can support the accurate prediction of structure/property relationships for new and existing monomer systems. These systematic studies have revealed generalized kinetic trends based on monomer structure so that, for example, copolymer composition can be described as follows: methacrylate/methacrylate copolymerizes with equal monomer addition probabilities, − methacrylate/acrylate yields methacrylate-rich copolymer, while methacrylate/styrene tends toward a more alternating structure. − However, deviations from these generalizations occur when monomers capable of hydrogen bonding, such as 2-hydroxyethyl methacrylate (HEMA), are introduced to the (co)­polymerization system. − …”

Reactivity Ratios of MMA and N,N-Dimethyl-N-{2-[(2-methylprop-2-enoyl)oxy]ethyl}undecane-1-aminium Bromide in Thermal and UV Initiation Copolymerization

“…Reactivity ratios of MMA and DOBA were reported to be 1.52 and 0.43 respectively in thermal copolymerization, showing that the MMA monomer has a higher reactivity compared to the DOBA monomer . In the copolymerization system of MMA and DPA, the reactivity ratio was 0.86–1.04 for MMA and 0.91–1.07 for DPA, showing nearly random copolymerization behavior . A relatively high reactivity ratio for MMA was reported for copolymerization with DADMAC in DMSO- d 6 with r MMA = 20.49–41.38 and r DADMAC = 0.09–0.33 .…”

“…20 In the copolymerization system of MMA and DPA, the reactivity ratio was 0.86−1.04 for MMA and 0.91−1.07 for DPA, showing nearly random copolymerization behavior. 21 A relatively high reactivity ratio for MMA was reported for copolymerization with DADMAC in DMSO-d 6 with r MMA = 20.49−41.38 and r DADMAC = 0.09−0.33. 15 By considering that both DOBA and DPA are conjugated monomers but DADMAC is not, these widely varying r values show that the reactivity ratios are sensitive to the other monomer with which MMA is copolymerized.…”