RESUMEN

A functional starch (TPS-E) was designed and constructed by incorporating epoxy soybean oil (ESO) and an antibacterial agent polyhexamethylene guanidine hydrochloride (PHMG), then the film was prepared by reaction extrusion and blow molding using TPS-E and poly(butylene adipate-co-terephthalate) (PBAT). The micro-crosslinking structure, forming through ring-opening reaction between the epoxy active site of TPS-E and the end group of PBAT, improved the compatibility of starch/PBAT blend and reduce the dispersed starch phase size, leading to significantly increase the tensile strength. Compared to starch/PBAT films, the tensile strength of TPS-E/PBAT in the longitudinal direction increase by 112% with the same starch content of 30%. Furthermore, these TPS-E/PBAT films demonstrated long-lasting antibacterial performance with a 98% inhibition ratio even after 10 cycles, without any observed leaching of the antibacterial agent, highlighting the high coupling efficiency of PHMG. TPS-E with the degradable ESO also promotes the degradation of PBAT. Thus, an important method of synergistic improving the mechanical, degradable and antibacterial properties of blown films through the design of reactive micro-crosslinked starch structures was established.

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RESUMEN

With increasing global energy consumption, oil/gas drilling has gradually expanded from conventional shallow reservoirs to deep and ultra-deep reservoirs. However, the harsh geological features including high temperature and high salinity in ultra-deep reservoirs have become a critical challenge faced by water-based drilling fluids (WDFs), which seriously deteriorate the rheology and fluid loss properties, causing drilling accidents, such as wellbore instability and formation collapse. In this study, a novel temperature- and salt-resistant micro-crosslinked polyampholyte gel was synthesized using N,N-dimethylacrylamide, diallyldimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid, maleic anhydride and chemical crosslinking agent triallylamine through free radical copolymerization. Due to the synergistic effect of covalent micro-crosslinking and the reverse polyelectrolyte effect of amphoteric polymers, the copolymer-based drilling fluids exhibit outstanding rheological and filtration properties even after aging at high temperatures (up to 200 °C) and high salinity (saturated salt) environments. In addition, the zeta potential and particle size distribution of copolymer-based drilling fluids further confirmed that the copolymer can greatly improve the stability of the base fluid suspension, which is important for reducing the fluid-loss volume of WDFs. Therefore, this work will point out a new direction for the development of temperature- and salt-resistant drilling fluid treatment agents.

RESUMEN

Currently, high strength nacre-inspired PVA/MMT (polyvinyl alcohol/montmorillonite) nanocomposites with high MMT nanofiller content (50-70 wt%) have been constructed successfully. However, this seriously sacrifices the elongation and reduces the corresponding transparency. In this paper, high elongation and transparent PVA/MMT nanocomposites with high MMT content are prepared by the evaporation-induced assembly with the introduction of the micro-crosslinking. Results demonstrate that the micro-crosslinking can inhibit the formation of rod-shaped arrays, and contribute to a more ordered layered microstructure, where an elongation of 76.2% in 47.8 wt% MMT content nanocomposites is gained, nearly 19 times of that of non-crosslinked nanocomposites (ultimate strain is 4.1%). This provides a potential approach for compromise between high strength and excellent elongation at the same MMT content. Moreover, disappearance of rod-shaped arrays and resultant ordered layered microstructure make eventual films more transparent.

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