The study investigates the photo-polymerization shrinkage behavior, dynamic mechanical properties, and biocompatibility of cyanoacrylate bioadhesives containing POSS nanostructures and TMPTMA as crosslinking agents. Adhesives containing 2-octyl cyanoacrylate (2-OCA) and different percentages of POSS nanostructures and TMPTMA as crosslinking agents were prepared. The 1-phenyl-1, 2-propanedione (PPD) was incorporated as photo-initiator into the adhesive in 1.5, 3, and 4 wt %. The shrinkage strain of the specimens was measured using bonded-disk technique. Shrinkage strain, shrinkage strain rate, maximum and time at maximum shrinkage strain rate were measured and compared. Mechanical properties of the adhesives were also studied using dynamic mechanical thermal analysis (DMTA). Biocompatibility of the adhesives was examined by MTT method. The results showed that shrinkage strain increased with increasing the initiator concentration up to 3 wt % in POSS-containing and 1.5 wt % in TMPTMA-containing specimens and plateaued out at higher concentrations. By increasing the crosslinking agent, shrinkage strain, and shrinkage strain rate increased and the time at maximum shrinkage strain rate decreased. The study indicates that the incorporation of crosslinking agents into the cyanoacrylate adhesives resulted in improved mechanical properties. Preliminary MTT studies also revealed better biocompatibility profile for the adhesives containing crosslinking agents comparing to the neat specimens.
Abstract. ZnO nanostructures were formed via a hydrothermal reaction mechanism between simple anionic (ammonia or sodium hydroxide) and cationic (zinc acetate dehydrate) precursors without using any organic templates. E ects of the reaction conditions, including the initial solution pH, type and concentration of the anionic and cationic precursors, and the reaction time and temperature, on the nanostructure particle size and morphology were investigated. The nanostructures formed were analyzed by powder X-ray di raction, energy dispersive X-ray analysis, and scanning electron microscopy. According to the results, the morphology of the nanostructures is highly pH-dependent. Needlelike nanostructures were formed using ammonia at initial solution pH value around 9, but plate-like nanostructures were formed using NaOH at pH value around 13, regardless of the reaction time or temperature. The precursors concentration could not be considered as an independent parameter per se as it consequently changes the reaction medium pH, which a ects the morphology in turn. In general, increasing the reaction time and temperature increased the mean particle size of the nanostructures with no signi cant change in their morphology. It was found that the nanostructure morphology changes from nanoneedle to star-like at higher addition rates of ammonia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.