To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was pr...To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was prepared by graft copolymerisation using N,N’-methylenebisacrylamide as the cross-linking agent,sodium persulfate as the initiator,and acrylic acid as the monomer.Orthogonal optimisation experiments were designed to obtain optimal process parameters for hydrogel preparation with the cellulose dosage of 0.40 g,initiator dosage of 0.20 g,polymerisation temperature of 70°C,cross-linking agent of 0.25 g,and monomer dosage of 3.0 mL.The effect of initiator dosage on hydrogel synthesis was the most significant,followed by monomer dosage and reaction temperature.Characterisation using X-ray diffraction analysis and scanning electron microscopy revealed that the hydrogel was amorphous and exhibited a distinct three-dimensional double network structure.Hydrogel swelling kinetic analysis showed that the hydrogel swelling process was divided into three stages,and fitted the Schott secondary swelling kinetic model.The prepared hydrogel had a good adsorption effect on methylene blue;the adsorption of methylene blue by the hydrogel was 1.259 mg/g at 25°C when the initial concentration of methylene blue was 5 mg/L.The adsorption kinetics of the hydrogel fit the pseudo-first-order kinetic model,pseudo-secondorder kinetic model,Eovich model and particle diffusion model.The best fitting effect was obtained with the pseudo-second-order kinetic model.The adsorption isotherm analysis of methylene blue on hydrogel showed that the adsorption process was consistent with Langmuir and Freundlich models.The correlation coefficient of the Freundlich isotherm model was higher,indicating that the adsorption of methylene blue on hydrogel was mainly chemisorption.展开更多
In vitro mineralisation in simulated body fluid(SBF)of synthetic polymers continues to be an important area of research as the outcomes cannot be predicted.This study evaluates a series of ePTFE membranes grafted with...In vitro mineralisation in simulated body fluid(SBF)of synthetic polymers continues to be an important area of research as the outcomes cannot be predicted.This study evaluates a series of ePTFE membranes grafted with carboxylate-containing copolymers,specifically using acrylic acid and itaconic acid for grafting.The samples differ with regards to graft density,carboxylate density and polymer topology.The type and amount of mineral produced in 1.5×SBF was dependent on the sample characteristics as evident from XPS,SEM/EDX,and FTIR spectroscopy.It was found that the graft density affects the mineral phases that form and that low graft density appear to cause co-precipitation of calcium carbonate and calcium phosphate.Linear and branched graft copolymer topology led to hydroxyapatite mineralisation whereas crosslinked graft copolymers resulted in formation of a mixture of calcium-phosphate phases.This study demonstrates that in vitro mineralisation outcomes for carboxylate-containing graft copolymers are complex.The findings of this study have implications for the design of bioactive coatings and are important for understanding the bone-biomaterial interface.展开更多
基金This study was supported by the National Visiting Scholar Program for Key Young Teachers of Central and Western Universities,the Ministry of Education(19042)the Key Science and Technology Project of Henan Province(212102310064)the National Innovation and Entrepreneurship Training Program for College Students,Ministry of Education(202111517002).
文摘To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was prepared by graft copolymerisation using N,N’-methylenebisacrylamide as the cross-linking agent,sodium persulfate as the initiator,and acrylic acid as the monomer.Orthogonal optimisation experiments were designed to obtain optimal process parameters for hydrogel preparation with the cellulose dosage of 0.40 g,initiator dosage of 0.20 g,polymerisation temperature of 70°C,cross-linking agent of 0.25 g,and monomer dosage of 3.0 mL.The effect of initiator dosage on hydrogel synthesis was the most significant,followed by monomer dosage and reaction temperature.Characterisation using X-ray diffraction analysis and scanning electron microscopy revealed that the hydrogel was amorphous and exhibited a distinct three-dimensional double network structure.Hydrogel swelling kinetic analysis showed that the hydrogel swelling process was divided into three stages,and fitted the Schott secondary swelling kinetic model.The prepared hydrogel had a good adsorption effect on methylene blue;the adsorption of methylene blue by the hydrogel was 1.259 mg/g at 25°C when the initial concentration of methylene blue was 5 mg/L.The adsorption kinetics of the hydrogel fit the pseudo-first-order kinetic model,pseudo-secondorder kinetic model,Eovich model and particle diffusion model.The best fitting effect was obtained with the pseudo-second-order kinetic model.The adsorption isotherm analysis of methylene blue on hydrogel showed that the adsorption process was consistent with Langmuir and Freundlich models.The correlation coefficient of the Freundlich isotherm model was higher,indicating that the adsorption of methylene blue on hydrogel was mainly chemisorption.
文摘In vitro mineralisation in simulated body fluid(SBF)of synthetic polymers continues to be an important area of research as the outcomes cannot be predicted.This study evaluates a series of ePTFE membranes grafted with carboxylate-containing copolymers,specifically using acrylic acid and itaconic acid for grafting.The samples differ with regards to graft density,carboxylate density and polymer topology.The type and amount of mineral produced in 1.5×SBF was dependent on the sample characteristics as evident from XPS,SEM/EDX,and FTIR spectroscopy.It was found that the graft density affects the mineral phases that form and that low graft density appear to cause co-precipitation of calcium carbonate and calcium phosphate.Linear and branched graft copolymer topology led to hydroxyapatite mineralisation whereas crosslinked graft copolymers resulted in formation of a mixture of calcium-phosphate phases.This study demonstrates that in vitro mineralisation outcomes for carboxylate-containing graft copolymers are complex.The findings of this study have implications for the design of bioactive coatings and are important for understanding the bone-biomaterial interface.
