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The dynamics of diblock copolymers organized into a lamellar microstructure has been simulated on a cubic lattice. The chains of AioBio are present at a volume fraction of 0.847 and the reduced pairwise interaction energy between A and B is 0.5, which places the system near the microphase separation transition. Parallel simulations were performed in which the voids participated in no interactions with either block and in which they behaved as monomeric species of B. The motion is monitored for the beads at the free ends of both blocks and for the beads at the junction between the blocks. At short times, the beads at the free ends experience greater motion than the beads at the junction points. The trajectory was long enough to estimate the self-diffusion coefficient for the chains in the system where the voids do not participate in interactions with either block. This self-diffusion coefficient could be decomposed into components in the plane of the lamellae and normal to the interface. These components differ by an order of magnitude, with the slower diffusion being in the direction normal to the plane of the interface. The bond autocorrelation function decays quickly to zero for the bonds at the free ends, but it does not decay to zero on the time scale of the simulations for the bond at the junction between the two blocks.

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ABSTRACT:The new acrylic monomer, 3,5-dimethylphenyl acrylate, was synthesized by reacting 3,5-dimethylphenol dissolved in ethyl methyl ketone (EMK) with acryloyl chloride in the presence of triethylamine. The homopolymer and copolymers of different feed compositions of 3,5-dimethylphenyl acrylate and glycidyl methacrylate were synthesized using free radical polymerization in ethyl methyl ketone solution at 70 Ϯ 1°C using benzoyl peroxide as initiator. The copolymers were characterized by Fourier transform infrared (FTIR), 1 H nuclear magnetic resonance (NMR), and 13 C-NMR spectroscopic techniques. The molecular weight (M n and M w ) and polydispersity index of the polymers were determined using gel permeation chromatograph. The glass transition temperatures of the polymers were determined by differential scanning calorimeter. Thermogravimetric analysis of the polymers was performed in air. The solubilities of the polymers were tested in various polar and nonpolar solvents. Copolymer compositions were determined using 1 H-NMR spectra. The monomer reactivity ratios were determined by the application of conventional linearization methods such as FinemanRoss, Kelen-Tü dös, and extended Kelen-Tü dös. The peel strength of the leather adhesives prepared from the copolymers was also determined.

ABSTRACT:The methacrylate monomer 4-methyacryloyloxyphenyl-3Ј,4Ј-dimethoxystyryl ketone (MPDMSK), having a free-radical polymerizable group and a photocrosslinkable functional group, was synthesized. The homopolymer and copolymers of MPDMSK with glycidyl methacrylate were synthesized by free-radical solution polymerization. The structures of the newly synthesized monomers, homopolymer, and copolymers were confirmed by different spectroscopic techniques. The average molecular weights of the polymers were determined by gel permeation chromatography. The thermal stability of the polymers was measured by thermogravimetric analysis in air and the glasstransition temperatures were determined by differential scanning calorimetry under nitrogen atmosphere. The copolymer compositions were determined by 1 H-NMR analysis. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman-Ross, Kelen-Tü dös, and extended Kelen-Tü dös methods. The photoreactivity of both the homopolymer and the copolymers having pendant chalcone moieties was studied in various solvents. The effects of various factors such as solvents, concentrations, copolymer ratios, and photosensitizers on the rate of photocrosslinking of the newly synthesized polymers were investigated and the results were discussed for using the polymers as negative photoresists.