A novel chitin-degrading aerobe, Chitinibacter tainanensis, was isolated from a soil sample from southern Taiwan, and was proved to produce N-acetyl glucosamine (NAG). Chitin degrading factors (CDFs) were proposed to be the critical factors to degrade chitin in this work. When C. tainanensis was incubated with chitin, CDFs were induced and chitin was converted to NAG. CDFs were found to be located on the surface of C. tainanensis. N-Acetylglucosaminidase (NAGase) and endochitinase activities were found in the debris, and the activity of NAGase was much higher than that of endochitinase. The optimum pH of the enzymatic activity was about 7.0, while that of NAG production by the debris was 5.3. These results suggested that some factors in the debris, in addition to NAGase and endochitinase, were crucial for chitin degradation.

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Chitosan is prepared by the deacetylation of chitin, the second-most abundant biopolymer in nature, and has applicability in the removal of dyes, heavy metals and radioactive waste for pollution control. In weight-reduction remedies, chitosan is used to form hydrogels with lipids and to depress the intestinal absorption of lipids. In this study, an experimental method was implemented to simulate the effect of chitosan on the adsorption of humic acid in the gastrointestinal tract. The adsorption capacity of chitosan was measured by its adsorption isotherm and analyzed using the Langmuir equation. The results showed that 3.3 grams of humic acid was absorbed by 1 gram of chitosan. The adsorption capacity of chitosan was much greater than that of chitin, diethylaminoethyl-cellulose or activated charcoal. Cellulose and carboxymethyl-cellulose, a cellulose derivative with a negative charge, could not adsorb humic acid in the gastrointestinal tract. This result suggests that chitosan entraps humic acid because of its positive charge.

It has been proved in our previous study that during the melt-blending of an epoxy oligomer based on the diglycidyl ether of bisphenol-A (DGEBA) with polycarbonate (PC) at 200°C, the secondary hydroxyl groups in the DGEBA react with the carbonate groups in PC through transesterification, resulting in degraded PC chains with phenolic end groups and also in PC/DGEBA copolymers. Yet, in the same study, it was found that the prereactions between DGEBA and PC can be minimized or eliminated if a solution-blending process was used. Therefore, it was expected that, after being cured with a curing agent, different epoxy-network structures should result as a consequence of the two different premixing processes of DGEBA and PC. In addition, we also expect that in the melt-blending process, the fracture toughness of epoxies should be increased due to the incorporation of ductile PC chains into the epoxy network. In this study, therefore, we attempted to examine and compare the structures and properties of PC-modified epoxies through these two different blending processes.

BACKGROUND: Polytetrafluoroethylene (PTFE) is utilized in many engineering applications, but its poor wettability and adhesion properties with other materials have limited its use. The study reported was aimed at achieving surface modification of PTFE films by radiofrequency NH3 and N2 plasma treatment, followed by graft copolymerization, in order to improve the interfacial adhesion of PTFE and bismaleimide.RESULTS: X‐ray photoelectron spectroscopy results showed that a short‐time plasma treatment had a distinct defluorination effect and led to nitrogen functional group formation. The nitrogen chemical bonding form was different for NH3 and N2 plasma treatments. Under the same experimental conditions, the NH3 plasma exhibited a better etching effect than did the N2 plasma. Contact angle measurement showed an improvement in both surface energy and wettabliity by short‐time plasma treatment. The concentration of the surface‐grafted bismaleimide on PTFE increased after the plasma pretreatment. The lap shear strength between PTFE and bismaleimide increased significantly after surface modification.CONCLUSION: This study found that plasma treatment caused changes in surface chemistry, thus leading to an increase of the wettability of PTFE surfaces. Hence, the adhesion properties of PTFE with bismaleimide were significantly improved. Copyright © 2008 Society of Chemical Industry