Free Radical Polymerization Of Butyl Acrylate Research Articles

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil-Water Separation.

Oily wastewater has caused serious threats to the environment; thus, high-performance absorbing materials for effective oil-water separation technology have attracted increasing attention. Herein, we develop a magnetic, hydrophobic, and lipophilic hyperporous elastic material (HEM) templated by high internal phase emulsions (HIPE), in which free-radical polymerization of butyl acrylate (BA) and divinylbenzene (DVB) is employed in the presence of poly(dimethylsiloxane) (PDMS), lecithin surfactant, and modified Fe3O4 nanoparticles. The adoption of the emulsion template with nanoparticles as both stabilizers and cross-linkers endows the HEM with biomimetic hierarchical open-cell micropores and elastic cross-linked networks, generating an oil absorbent with outstanding mechanical stability. Compressive fatigue resistance of the HEM is demonstrated to endure 2000 mechanical cycles without plastic deformation or strength degradation. By exploiting the synergistic effect of hierarchical structures and low-surface-energy components, the resulting HEM also possesses excellent and robust hydrophobicity (water contact angle of 164°) and good oil absorption capacity, in which Fe3O4 nanoparticles lead to convenient magnetically controlled oil recyclability as well. Notably, the unique biomimetic microporous structure demonstrates superior oil retention capacity (>95% at 1000 rpm and >60% at 10,000 rpm) over the state-of-the-art porous materials for a diverse variety of oils to reduce the risk of secondary oil leakage, along with good recoverability by squeezing owing to the excellent compression resilience. These excellent performances of our HEM provide broad prospects for practical applications in oil-water separation, energy conversion, and smart soft robotics.

Electromagnetic wave absorption of inexpensive C/ZnO composites derived from zinc-based acrylate resins

Based on the abundant and low-cost zinc-based acrylate resins, C/ZnO composites were fabricated via one-step carbonization at 700 °C in a N2 atmosphere for 2 h. Zinc-based acrylate resins, which were synthesized by free-radical polymerization of butyl acrylate (BA), acrylic acid (AA) and vinyl acetate (VAc) and dehydration condensation of Zn(OH)2, provided a common source for carbon and ZnO. These materials demonstrate enhanced electromagnetic wave absorption (EMWA) behavior with tunable microwave absorption bands at 2–18 GHz, which is related to the molar ratio (mol%) of Zn(OH)2 to acrylate monomers in zinc-based acrylate resins. Remarkably, the 0.11 mol% C/ZnO composite exhibits outstanding absorption properties: the minimum reflection loss (RLmin) at 16.7 wt% loading of −34.66 dB is observed at 3.0 mm and 10.32 GHz, and an RLmin of −24.83 dB is observed at a small thickness of 1.5 mm with an effective absorption bandwidth (EAB) of 3.61 GHz. Moreover, the EAB (RL ≤ −10 dB) from the C band to Ku band is achieved by simply adjusting the thickness of the absorbers, which are superior to the other hybrids of organic carbon and ZnO. These results provide a new strategy for the preparation of carbon-based composites containing metal oxides and their application in high-performance microwave absorption.

Photo-induced actuator using temperature and light dual responsive azobenzene containing ion gel in ionic liquid

A series of well-defined random copolymers comprising butyl acrylate (BA) and 4-phenylazophenylmethacrylate (AzoMA) (P(AzoMA-r-BA)) are prepared successfully by reversible addition fragmentation chain transfer (RAFT) polymerization. P(AzoMA-r-BA)s show LCST-type phase transition in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfone)amide ([C4mim][NTf2]). LCST depends on the photoisomerization state of azobenzene, as well as on the AzoMA composition in the random copolymers. LCST of (P(cis-AzoMA-r-BA) is significantly higher than that of P(trans-AzoMA-r-BA), because cis-AzoMA and trans-AzoMA behave as solvato-philic and solvato-phobic comonomer, respectively. At a bistable temperature, photo-induced phase separation is completely reversible. Secondly, based on this phenomenon, a thermo-/photo- responsive ion gel (BA-AzoMA ion gel) can be prepared by free radical polymerization of BA and AzoMA using ethylene glycol dimethacrylate (EGDMA) as crosslinker in [C4mim][NTf2]. BA-AzoMA ion gel shows high temperature contraction and low temperature expansion behavior, due to LCST-type phase behavior of polymer system consisting of AzoMA and BA. Contraction temperature of BA-AzoMA ion gel depends on photoisomerization state of the azobenzene group in polymers. At a bistable temperature, photo-induced expansion-contraction is reversible. Finally, a Photo-induced actuator can be realized using BA-AzoMA ion gel at suitable temperatures, featuring reversible bending by alternate irradiating with visible and UV light. The bending behavior is also demonstrated.

Waterborne Polyurethane Modified by Hydroxyl-Terminated Polyacrylate

In the presence of mercaptoethanol as chain-transfer agent,hydroxyl-terminated polyacrylate(PA) with a certain molecular mass was synthesized by solution free-radical polymerization of butyl acrylate( BA) and methyl methacrylate ( MMA ). The PA-PU-PA hybrid emulsion was obtained by reacting PA with polyurethane(PU) prepolymer in water. FTIR and 1H NMR results of the copolymer chain structure show that when PU /PA mass ratio declined,the acrylic content in the copolymer increased and the role of hydrogen bonds between PU soft and hard segment weakened. The composite particles had homogeneous core-shell structure in TEM photograph. Waterproof and heat resistant performance of the modified latex film were improved with the decrease of PU /PA mass ratio. Water absorption of the modified film dropped from 25% to 5% and the maximum mass loss temperature was increased from 369 ℃ to 432 ℃ .

Measurement of Transfer Constant for Butyl Acrylate Free-Radical Polymerization

Arrhenius parameters for the transfer constant to monomer (CM) for the free-radical polymerization of butyl acrylate (BA) are determined by a combination of techniques. A seeded emulsion polymerization with conditions designed so that “zero−one” kinetics are obeyed, i.e., where entry of a radical into a particle causes instantaneous termination, such that transfer to monomer can be shown to be the dominant chain-stopping event. The seed comprised small polystyrene particles, which reduces the likelihood of chain transfer to polymer provided the polymer:monomer ratio is sufficiently low. Since the dominant chain-stopping events are then entry and transfer to monomer, CM can then be obtained from the number molecular weight distribution for different initiator concentrations and conversions and isolating the component due to transfer to monomer. The transfer constant so obtained, over the temperature range 50−72 °C, fits CM = (0.016 ± 0.003) exp(−(15.2 ± 0.6) kJ mol-1/RT).