Magnetic ion-imprinted microspheres (IIM) with core-shell structure were successfully prepared by reverse emulsion polymerization and applied to adsorb heavy metal ions from sewage. The semi-interpenetrating polymer network composed of cross-linked polyacrylamide (PAM) and linear chitosan (CTS) was used as the microgel shell of microspheres, which can not only fully retain the active sites of CTS but also tightly encapsulate magnetic particle nuclei. In addition, ion imprinting technology was used to further improve the adsorption capacity. In this study, the effects of PAM to CTS ratio on the thermal stability, magnetic properties, and microstructure of microspheres were investigated. Adsorption studies showed that IIM exhibited excellent selective adsorption of Cu(II), and the effects of initial concentration of metal ions, adsorption time, adsorbent dosage, pH, ionic strength, and cycle times on adsorption of Cu(II) by IIM-2 were also studied. In addition, it was revealed that pseudo-second-order kinetic model and Langmuir isotherm model could better simulate the adsorption kinetic and isotherm of IIM-2 for Cu(II), respectively. At 30 C and pH 5.0, the theoretical maximum adsorption capacities for Cu(II) by IIM-2 were 151.13 mg/g. X-ray photoelectron spectroscopy and Zeta potential study showed that the adsorption mechanism of IIM-2 was a combination of electrostatic interaction and ion exchange.
Multi‐walled carbon nanotubes (MWCNT) were first non‐covalently functioned by tannic acid (TA), then blended with nitrile rubber (NBR) and ethylene propylene diene monomer (EPDM) with NBR:EPDM:TA‐MWCNT = 70:30:5. TA‐MWCNT and the composites had been characterized by various techniques, including Fourier transform infrared spectroscopy (FT‐IR), Raman analysis, transmission electron microscopy (TEM), mechanical properties testing, thermal‐oxidative aging testing, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Results indicated that TA molecules were successfully absorbed to the surface of MWCNT. And compared with NBR/EPDM/MWCNT composites, the compatibility between NBR and EPDM had been significantly improved. The NBR/EPDM/TA‐MWCNT exhibited excellent mechanical properties and thermal‐oxidative aging properties due to the phenolic hydroxyl groups on the surface of TA‐MWCNT, which had high chemical reactivity and physical adhesion. These phenolic hydroxyl groups gave TA‐MWCNT better dispersion in the rubber matrixes and can participate in the vulcanization process, creating the firm interface between the rubber matrixes and the surface of MWCNT.
Biodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) has excellent processing and mechanical properties. However, PBAT is expensive and its relatively slow biodegradation rate limits its wide application. In this paper, PBAT/thermoplastic starch (TPS) complexes were prepared by a two‐step process using epoxidized soybean oil (ESO) as a reactive compatibilizer. The compatibilizing ability of ESO was investigated by FT‐IR and GPC. Results showed ESO could form a chemical bonding interface with PBAT and TPS. Compared to PBAT/TPS, tensile strength, elongation at break and tear strength of PBAT/TPS/5%ESO composites increased by 84%, 53%, and 68%, respectively. The optical transparency of the PBAT/TPS/5%ESO film improved by 6% compared to the PABT/TPS film. This research offers a viable solution for the preparation of high performance, green PBAT/TPS complexes.
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