Emulsion Copolymerization Of N-butyl Acrylate Research Articles

Novel core-shell particles with poly( n-butyl acrylate) cores and chitosan shells as an antibacterial coating for textiles

A novel antibacterial coating for cotton fabrics has been developed using core-shell particles that consist of poly( n-butyl acrylate) (PBA) cores and chitosan shells. The spherical particles are prepared via a surfactant-free emulsion copolymerization of n-butyl acrylate in an aqueous chitosan solution induced by a small amount of tert-butyl hydroperoxide. The PBA-chitosan core-shell particles have a narrow particle size distribution with average particle diameter of approximately 300 nm, and display highly positive surface charges. Transmission electron microscopic (TEM) images clearly reveal well-defined core-shell morphology of the particles where PBA cores are coated with chitosan shells. The particle is composed of both the PBA homopolymer and the chitosan- g-PBA copolymer, which have been characterized with FTIR and 1H NMR spectroscopes. The cotton fabric is coated with PBA-chitosan particles by using a conventional pad-dry-cure method. Its antibacterial efficiency is then evaluated quantitatively against Staphylococcus aureus with the shake flask method. The cotton treated with PBA-chitosan particles demonstrates an excellent antibacterial activity with bacterial reductions more than 99%.

Formation of silver nanoparticles on a chelating copolymer film containing iminodiacetic acid

Poly(butyl acrylate-co-(glycidyl methacrylate-iminodiacetic acid)) microspheres were formed by batch soap-free emulsion copolymerization of n-butyl acrylate with a chelating vinyl monomer, glycidyl methacrylate–iminodiacetic acid (GMA-IDA). The mole content of GMA-IDA within the copolymer film was found to be 8.7% by elemental analysis of C, H, and N. The attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) displayed that the adsorption reactions between the copolymer surface and Ag + had reached equilibrium for 1 h. Silver nanoparticles, appearing on the surface of the film, were prepared through the reduction of the copolymer–Ag + complexes by ultraviolet irradiation and monitored by ATR-FTIR as well as ultraviolet–visible spectrometer. Scanning electron microscope and energy-dispersive X-ray spectrometer were employed to characterize the morphology of silver nanoparticles on the copolymer film. It was found that silver nanoparticles were about 30 nm in diameter, individually isolated, and uniformly dispersed on the copolymer surface.

Ultrasonically initiated emulsifier-free emulsion copolymerization of n-butyl acrylate and acrylamide. Part I: Polymerization mechanism

The polymerization mechanism of ultrasonically initiated emulsifier-free emulsion copolymerization of n-butyl acrylate (BA) and acrylamide (AM) was investigated. A four-step polymerization mechanism of the ultrasonically initiated emulsifier-free emulsion was put forward based on the monomer conversion and the main reaction locus. Improving the power output would increase the monomer conversion and the rate of polymerization. However, when the reaction temperature was 30 °C and the concentration of Na 2SO 4 was 0.1%, the monomer conversion and the rate of polymerization achieved maximum. The FTIR spectra showed that the sample obtained by this way was the copolymer of BA and AM, but not the blend of poly(butyl acrylate) and polyacrylamide.

Molecular weight development in emulsion copolymerization ofn-butyl acrylate and styrene

The seeded emulsion copolymerization of n-butyl acrylate and styrene in a weight ratio of 50/50 was investigated. The effect of the type of process (batch vs. semicontinuous) and the amounts of initiator and emulsifier charged into the reactor on the time evolution of the fractional conversion, number of polymer particles, and weight-average molecular weight (Mw) was analyzed. It was found that the Mw depends to a slight extent on the type of process and the emulsifier concentration and to a larger extent on the initiator concentration. The molecular weight distributions (MWDs) and the gel content of the final latexes were also analyzed. In the absence of chain transfer agents (CTAs), the fraction of gel was higher in the semicontinuous processes. It was also found that the gel content increased with increasing initiator concentration in the recipe. The addition of 1 wt % CTA avoided gel formation and led to an important reduction of the Mw. Nevertheless, the MWDs presented a shoulder or even a second peak at high molecular weights that was due to reactions of chain transfer to the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1918–1926, 2003

ON-LINE MONITORING AND COMPOSITION CONTROL OF THE EMULSION COPOLYMERIZATION OF VeoVA 9 AND BUTYL ACRYLATE BY RAMAN SPECTROSCOPY

The batch and semi-continuous emulsion copolymerization of n-butyl acrylate and vinyl neononanoate (VeoVA 9) were monitored by remote on-line Raman spectroscopy. Monomer concentrations were calculated in real-time by a classical least squares (CLS) approach using the vinyl regions of the Raman spectra. During the batch copolymerization, conversion and copolymer composition calculated from on-line data showed good agreement with off-line gravimetry and NMR results, indicating that the CLS procedure indeed enables the calculation of individual monomer concentrations and on-line characterization of the copolymer formed. Real-time analysis of the data enabled control of the copolymer composition by suggesting how one of the comonomers should be added in a semi-continuous polymerization. NMR and gradient polymer elution chromatography corroborated the Raman results for the copolymer composition. Further, it was shown that only at high conversions (>80%) monomer partitioning influences the copolymerization beha...

Batch emulsion copolymerization of n-butyl acrylate and methyl methacrylate in the presence of a nonionic surfactant

Batch emulsion copolymerization studies of n-butyl acrylate and methyl methacrylate have been investigated using potassium persulfate as initiator and a nonionic surfactant (REWOPAL HV 25) as emulsifier. Higher polymerization rates, shorter nucleation stage and complete conversion are obtained by comparison to the SDS-emulsified copolymerization. The kinetic and particle number data support a micellar-type mechanism for the formation of copolymer particles. Strong affinity between the two monomers and the nonionic surfactant results in significantly high solubilization of the surfactant in the initial monomer phase and its subsequent burial inside the final latex particles.