Swelling and Deswelling Kinetics of AT-O3S Polymer

In the oil industry, techniques decreasing unwanted water production have drawn large amounts of interest from many companies. During water injection operations, water is injected into the oil reservoir to extract oil trapped in the formation. Due to the heterogeneity in the reservoir formation, oil production will decline and water production will increase as the injected water sweeps the high permeability zones. In order to flush out the oil remaining in the low permeability zones, many treatments have been used. One such treatment involves the injection of an SAP （superabsorbent polymer） into the high permeability zones. The swelled polymer will decrease the heterogeneity of reservoir permeability, thus forcing water injection into the oil rich, unswept zones/areas of the formation. Proper application of an SAP can have a dramatic impact on both the production and lifespan of mature oil wells. Successful treatment is reliant upon the reservoir salinity, temperature, and pH.

A Novel Method for the Preparation of Octyl Bonded Styrene-divinylbenzene HPLC Packings

Monodisperse octyl bonded poly（styrene-divinylbenzene） （C8-PS-DVB） beads were prepared via a single-step swelling and polymerization method. Fourier transform infrared and chromatographic evaluation were used to confirm the reaction between the octene and divinylbenzene.

Tough Polyion Complex Hydrogel Films of Natural Polysaccharides

The developments of tough hydrogels in recent years have greatly expanded the applications of hydrogels as structural materials. However, most of the tough hydrogels are made of synthetic polymers. To develop biopolymer-based tough hydrogels has both fundamental and practical significances. Here we report a series of polysaccharides-based tough hydrogel films prepared by polyion complexation and solvent evaporation of chondroitin sulfate（CS） and protonated chitosan（CHT） solutions with different weight ratios. The obtained CS/CHT gel films with thickness of 40-80 μm and water content of 66 wt%-81 wt% possess excellent mechanical properties, with tensile breaking stress and breaking strain being 0.4-3 MPa and 160%-320%, respectively. We found that in the mixture solutions there are large amounts of excess CHT in terms of charges; after swelling the films in water, the acetic acid, which is used to protonate the amino groups of CHT, diffuses out of the gel matrix, enhancing the intermolecular interactions between CHT molecules and thus improving the mechanical properties of gel films, besides the ionic bonds between CS and CHT. Antimicrobial tests also showed that the gel films with low weight ratio of CS to CHT, corresponding to the case with excess CHT, have evident antimicrobial effect. These CS/CHT gel films with good mechanical properties and antimicrobial effect should extend the applications of hydrogels in biomedical fields.

Surface morphology of refractive-index waveguide gratings fabricated in polymer films

The characteristic modifications are reported on the surface of polymeric waveguide film in the process of vol- ume-grating fabrication. The light from a mode-locked 76 MHz femtosecond laser with pulse duration of 200 fs and wavelength of 800 nm is focused normal to the surface of the sample. The surface morphology modifications are as- cribed to a fact that surface swelling occurs during the process. Periodic micro-structure is inscribed with increasing incident power. The laser-induced swelling threshold on the grating, which is higher than that of two-photon initiated photo-polymerization （TPIP） （8 mW）, is verified to be about 20 mW. It is feasible to enhance the surface smoothness of integrated optics devices for further encapsulation. The variation of modulation depth is studied for different values of incident power and scan spacing. Ablation accompanied with surface swelling appears when the power is higher. By ootimizing the laser carvinR oararneters, hizhly efficient grating devices can be fabricated.