Nanocellulose,a natural polymeric nanomaterial,has attracted significant attention in enhanced oil recovery(EOR)applications due to its abundance,nanoscale,high oil-water interfacial adsorption ef-ficiency.In this stu...Nanocellulose,a natural polymeric nanomaterial,has attracted significant attention in enhanced oil recovery(EOR)applications due to its abundance,nanoscale,high oil-water interfacial adsorption ef-ficiency.In this study,surface-functionalized cellulose nanocrystals(SF-CNCs)were prepared via hy-drochloric acid hydrolysis and chemical modification,with adaptable nanosize and considerable dispersion stability in low-permeability reservoirs.The SF-CNCs were structurally characterized by FT-IR,Cryo-TEM,which have a diameter of 5-10 nm and a length of 100-200 nm.The SF-CNC dispersions possessed higher stability and stronger salt-tolerance than those of corresponding CNC dispersions,due to the strong hydrophilicity of the sulfonic acid group.It was synergistically used with a non-ionic surfactant(APG1214)to formulate a combined flooding system(0.1 wt%SF-CNC+0.2 wt%APG1214).The combined flooding system exhibits strong emulsification stability,low oil-water interfacial tension of o.03 mN/m,and the ability to alter the wettability for oil-wetting rocks.Furthermore,the combined system was_able to provide an optimum EOR efficiency of 20.2%in low-permeability cores with 30.13×10^(-3)μm^(2).Notably.it can enlarge the sweep volume and increase the displacement efficiency simultaneously.Overall,the newly formulated nanocellulose/surfactant combined system exhibits a remarkable EoR performance in low-permeability reservoirs.展开更多
Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to an...Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to any clinical application.This manuscript addresses the evaluation of thermo-mechanical properties and of cell proliferation of cellulose nanocrystals(CNC),poly(butylene adipate-co-terephthalate)(PBAT),poly(ε-caprolactone)(PCL)films and their bionanocomposites with 2 wt% of CNC obtained by casting technique.Cellulose nanocrystals extracted from Balsa wood by acid hydrolysis were used as a reinforcing phase in PBAT and PCL matrix films.The films and pure CNC at different concentrations were cultured with osteoblasts MG-63 and the cell proliferation was assessed by AlamarBlue?assay.The thermal-mechanical properties of the films were evaluated by dynamic-mechanical thermal analysis(DMTA).It was found by DMTA that the CNC acted as reinforcing agent.The addition of CNCs in the PBAT and PCL matrices induced higher storage moduli due to the reinforcement effects of CNCs.The cell viability results showed that neat CNC favored osteoblast proliferation and both PBAT and PCL films incorporated with CNC were biocompatible and supported cell proliferation along time.The nature of the polymeric matrix or the presence of CNC practically did not affect the cell proliferation,confirming they have no in vitro toxicity.Such features make cellulose nanocrystals a suitable candidate for the reinforcement of biodegradable scaffolds for tissue engineering and biomedical applications.展开更多
In order to improve the dispersibility of cellulose nanocrystal(CNC)particles,three different grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The mai...In order to improve the dispersibility of cellulose nanocrystal(CNC)particles,three different grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advan-tages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier trans-form infrared spectroscopy(FT-IR),13C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated that after desiccation,the modification products could be dis-persed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite dif-ferent.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.展开更多
The aim of this paper is to incorporate cellulose nanocrystals(CNCs) into the polyelectrolyte complex(PEC)matrix to construct polyelectrolyte hydrogels,utilizing carbon dioxide(CO_2)-induction to achieve sol-gel trans...The aim of this paper is to incorporate cellulose nanocrystals(CNCs) into the polyelectrolyte complex(PEC)matrix to construct polyelectrolyte hydrogels,utilizing carbon dioxide(CO_2)-induction to achieve sol-gel transition.The mechanical properties of the hydrogels were tunable with different CNC loadings.The increasing CNCs contributed to significant mechanical reinforcement of the PEC/CNC hydrogels.The study on swelling characteristics of hydrogels manifested the entanglements between CNCs and the polymer chains.The hydrogels also showed good moldability property.A cell counting kit-8(CCK-8)cytotoxicity study showed that the as-prepared composite hydrogels had good biocompatibility to confluent osteoblasts(SD rat) cells.展开更多
Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding a...Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding at elevated temperatures.This study shows a mixed acid hy-drolysis method to produce CNC with improved thermal stability and high productivity.The use of phosphoric acid(H_(3)PO_(4)),as a mild acid,in combination with a strong acid either sulphuric acid(H_(2)SO_(4))or hydrochloric acid(HCl)leads to reduced use of strong acids and low impact on our environment.The influences of acid combination and sequence of addition on the production yield were investigated by retaining the proportion of H_(3)PO_(4)to corrosive acid(H_(2)SO_(4)and HCl)4 to 1,and solid to liquid ratio 1꞉75.This methodology has enabled to isolate CNC with higher thermal stability,dispersibility and productivity in terms of amount acid used 1 g of CNC,as compared with single acid hydrolysis.The CNC produced using the combination of H_(3)PO_(4)and HCl exhibits high thermal stability,dispersibility and rod-like shape morphology with length and width of(424±86)and(22±3)nm,respectively.Moreover,this approach has reduced H_(3)PO_(4)consumption by 54%as compared with single acid hydrolysis method for the production of same amount of CNC.展开更多
According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual ...According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual biomass,even though researches have highlighted important applications for this biomass,most of it is discarded as organic waste.Thus,it is relevant to envisage in-depth studies about how to use these residues,particularly regarding the environmental impact of its target destination.Nanocrystalline cellulose(CNC)and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass.Both are abundant and currently considered as biopolymers because of their structural characteristics and their diverse applications in food and the medical field.This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry.A statistical design was used to define the influence of process variables as temperature,reaction time and fiber size on the yield of these byproducts.A maximum yield close to 64%of type I CNC,with 45%of crystallinity degree was achieved at the minimum condition of temperature and fiber size.Additionally,through rheological analysis,it was possible to predict the nanocrystal aspect ratios,ranging from 71 to 125.The extracted lignin was rich in methoxy groups,p-coumaryl alcohol and p-coumaric acid,and its structural unit’s low state of aggregation can be an indication of low molecular weight,which envisions an appropriate use for this lignin to produce commodity chemicals.展开更多
基金the China National Postdoctoral Program for Innovative Talents(Bx20200386)China Postdoctoral Science Foundation(2021M703586)+1 种基金Key Program of National Natural Science Foundation of China(52130401)National Natural Science Foundation of China(52204064,52104055)for financial support.
文摘Nanocellulose,a natural polymeric nanomaterial,has attracted significant attention in enhanced oil recovery(EOR)applications due to its abundance,nanoscale,high oil-water interfacial adsorption ef-ficiency.In this study,surface-functionalized cellulose nanocrystals(SF-CNCs)were prepared via hy-drochloric acid hydrolysis and chemical modification,with adaptable nanosize and considerable dispersion stability in low-permeability reservoirs.The SF-CNCs were structurally characterized by FT-IR,Cryo-TEM,which have a diameter of 5-10 nm and a length of 100-200 nm.The SF-CNC dispersions possessed higher stability and stronger salt-tolerance than those of corresponding CNC dispersions,due to the strong hydrophilicity of the sulfonic acid group.It was synergistically used with a non-ionic surfactant(APG1214)to formulate a combined flooding system(0.1 wt%SF-CNC+0.2 wt%APG1214).The combined flooding system exhibits strong emulsification stability,low oil-water interfacial tension of o.03 mN/m,and the ability to alter the wettability for oil-wetting rocks.Furthermore,the combined system was_able to provide an optimum EOR efficiency of 20.2%in low-permeability cores with 30.13×10^(-3)μm^(2).Notably.it can enlarge the sweep volume and increase the displacement efficiency simultaneously.Overall,the newly formulated nanocellulose/surfactant combined system exhibits a remarkable EoR performance in low-permeability reservoirs.
文摘Although nanocomposites have recently attracted special interest in the tissue engineering area,due to their potential to reinforce scaffolds for hard tissues applications,a number of variables must be set prior to any clinical application.This manuscript addresses the evaluation of thermo-mechanical properties and of cell proliferation of cellulose nanocrystals(CNC),poly(butylene adipate-co-terephthalate)(PBAT),poly(ε-caprolactone)(PCL)films and their bionanocomposites with 2 wt% of CNC obtained by casting technique.Cellulose nanocrystals extracted from Balsa wood by acid hydrolysis were used as a reinforcing phase in PBAT and PCL matrix films.The films and pure CNC at different concentrations were cultured with osteoblasts MG-63 and the cell proliferation was assessed by AlamarBlue?assay.The thermal-mechanical properties of the films were evaluated by dynamic-mechanical thermal analysis(DMTA).It was found by DMTA that the CNC acted as reinforcing agent.The addition of CNCs in the PBAT and PCL matrices induced higher storage moduli due to the reinforcement effects of CNCs.The cell viability results showed that neat CNC favored osteoblast proliferation and both PBAT and PCL films incorporated with CNC were biocompatible and supported cell proliferation along time.The nature of the polymeric matrix or the presence of CNC practically did not affect the cell proliferation,confirming they have no in vitro toxicity.Such features make cellulose nanocrystals a suitable candidate for the reinforcement of biodegradable scaffolds for tissue engineering and biomedical applications.
文摘In order to improve the dispersibility of cellulose nanocrystal(CNC)particles,three different grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advan-tages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier trans-form infrared spectroscopy(FT-IR),13C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated that after desiccation,the modification products could be dis-persed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite dif-ferent.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.
基金National Natural Science Foundation of China(No.51403035)
文摘The aim of this paper is to incorporate cellulose nanocrystals(CNCs) into the polyelectrolyte complex(PEC)matrix to construct polyelectrolyte hydrogels,utilizing carbon dioxide(CO_2)-induction to achieve sol-gel transition.The mechanical properties of the hydrogels were tunable with different CNC loadings.The increasing CNCs contributed to significant mechanical reinforcement of the PEC/CNC hydrogels.The study on swelling characteristics of hydrogels manifested the entanglements between CNCs and the polymer chains.The hydrogels also showed good moldability property.A cell counting kit-8(CCK-8)cytotoxicity study showed that the as-prepared composite hydrogels had good biocompatibility to confluent osteoblasts(SD rat) cells.
文摘Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding at elevated temperatures.This study shows a mixed acid hy-drolysis method to produce CNC with improved thermal stability and high productivity.The use of phosphoric acid(H_(3)PO_(4)),as a mild acid,in combination with a strong acid either sulphuric acid(H_(2)SO_(4))or hydrochloric acid(HCl)leads to reduced use of strong acids and low impact on our environment.The influences of acid combination and sequence of addition on the production yield were investigated by retaining the proportion of H_(3)PO_(4)to corrosive acid(H_(2)SO_(4)and HCl)4 to 1,and solid to liquid ratio 1꞉75.This methodology has enabled to isolate CNC with higher thermal stability,dispersibility and productivity in terms of amount acid used 1 g of CNC,as compared with single acid hydrolysis.The CNC produced using the combination of H_(3)PO_(4)and HCl exhibits high thermal stability,dispersibility and rod-like shape morphology with length and width of(424±86)and(22±3)nm,respectively.Moreover,this approach has reduced H_(3)PO_(4)consumption by 54%as compared with single acid hydrolysis method for the production of same amount of CNC.
基金support for this work by Maranhão Research Foundation(FAPEMA(No.00848/18).
文摘According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual biomass,even though researches have highlighted important applications for this biomass,most of it is discarded as organic waste.Thus,it is relevant to envisage in-depth studies about how to use these residues,particularly regarding the environmental impact of its target destination.Nanocrystalline cellulose(CNC)and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass.Both are abundant and currently considered as biopolymers because of their structural characteristics and their diverse applications in food and the medical field.This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry.A statistical design was used to define the influence of process variables as temperature,reaction time and fiber size on the yield of these byproducts.A maximum yield close to 64%of type I CNC,with 45%of crystallinity degree was achieved at the minimum condition of temperature and fiber size.Additionally,through rheological analysis,it was possible to predict the nanocrystal aspect ratios,ranging from 71 to 125.The extracted lignin was rich in methoxy groups,p-coumaryl alcohol and p-coumaric acid,and its structural unit’s low state of aggregation can be an indication of low molecular weight,which envisions an appropriate use for this lignin to produce commodity chemicals.
