A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our prod...A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.展开更多
Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the im...Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the improvement of CNC colloidal stability by surface chemical grafting with polyacrylic acid(PAA)was investigated,and the zeta potential and the charge density of the chemically modified CNC were analyzed.The results showed that an acrylic dosage of 1%(based on the dry weight of CNC)was sufficient to significantly enhance the colloidal stability.CNC,after chemical grafting with PAA,showed better stability against the increase in storage time or solid content of the aqueous medium,compared with the un-modified CNC.展开更多
Microfibrillated cellulose(MFC)-collagen composite films were prepared with a dispersion of acid swollen collagen fibers and carboxylated MFC at different ratios in an alkaline homogenous system.The surface topographi...Microfibrillated cellulose(MFC)-collagen composite films were prepared with a dispersion of acid swollen collagen fibers and carboxylated MFC at different ratios in an alkaline homogenous system.The surface topographic results obtained from SEM analyses indicated that the MFC entangled uniformly with collagen in the film and formed a closely interwoven network to reinforce the film structure.However,the MFC addition decreased the smoothness and light transparency of the films due to the aggregation of MFC.Compared to the film prepared with pure collagen,the hybrid composite film showed a higher strength and Young’s modulus but lower elongation.The swelling of the composite film in water increased with the increase of the MFC ratio in the film matrix.DSC and TG analyses demonstrated that adding MFC to collagen benefited the thermal stability of the films,due to the conformational and crystal changes in the MFC/collagen structure indicated by the FT-IR and XRD results.The MFC/collagen composite film can potentially be used as an edible material in the food and packaging industry,in particular for meat products.展开更多
A kind of novel environmental-friendly composite absorbent material was designed and prepared in this paper.Nanoscale metal-organic frameworks(MOFs)were embedded in the skeleton of cotton micro fibrillated cellulose.B...A kind of novel environmental-friendly composite absorbent material was designed and prepared in this paper.Nanoscale metal-organic frameworks(MOFs)were embedded in the skeleton of cotton micro fibrillated cellulose.By scanning electron microscope(SEM),we observed that a large number of MOFs were attached to the cellulose skeleton.In addition,under the condition of 1800 r/min vortex,the structure of the composite material was stable and was not easily damaged by external forces.The water contact angle test showed that the composite material had excellent hydrophilicity and could be used for the adsorption of pollutants.Then,the material was characterized by energy dispersive X-ray spectroscopy(EDX),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and BET adsorption.Through verification,the material had very stable reusability(n=10).The composite material was applied to the solid phase extraction of water samples,such as rain water,toning water and fruit juice,and was quantitatively analyzed by high performance liquid chromatography(HPLC)-UV.This method was then applied to the extraction of four parabens(methyl-,ethyl-,propyl-,and butylparaben)from real samples,yielding limits of detection(LODs)of 0.29-0.58 ng/mL.The linear range was 2-500 ng/mL.The inter-day and intra-day recoveries were 90.7%-106.0%and 87.1%-109.3%,respectively(relative standard deviation<10.8%).展开更多
基金This work was supported by the Special Funds for Major State Basic Research Projects (95-12 and G1999064800).
文摘A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.
基金support from the Tianjin Municipal Science and Technology Commission (Grant No.12ZCZDGX01100).
文摘Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the improvement of CNC colloidal stability by surface chemical grafting with polyacrylic acid(PAA)was investigated,and the zeta potential and the charge density of the chemically modified CNC were analyzed.The results showed that an acrylic dosage of 1%(based on the dry weight of CNC)was sufficient to significantly enhance the colloidal stability.CNC,after chemical grafting with PAA,showed better stability against the increase in storage time or solid content of the aqueous medium,compared with the un-modified CNC.
基金The authors would like to acknowledge the financial support provided by,National High Technology Research and Development Program of China(No.2013AA102204)Special Fund for Agro-scientific Research in the Public Interest of China(No.201303082)。
文摘Microfibrillated cellulose(MFC)-collagen composite films were prepared with a dispersion of acid swollen collagen fibers and carboxylated MFC at different ratios in an alkaline homogenous system.The surface topographic results obtained from SEM analyses indicated that the MFC entangled uniformly with collagen in the film and formed a closely interwoven network to reinforce the film structure.However,the MFC addition decreased the smoothness and light transparency of the films due to the aggregation of MFC.Compared to the film prepared with pure collagen,the hybrid composite film showed a higher strength and Young’s modulus but lower elongation.The swelling of the composite film in water increased with the increase of the MFC ratio in the film matrix.DSC and TG analyses demonstrated that adding MFC to collagen benefited the thermal stability of the films,due to the conformational and crystal changes in the MFC/collagen structure indicated by the FT-IR and XRD results.The MFC/collagen composite film can potentially be used as an edible material in the food and packaging industry,in particular for meat products.
基金This work was supported by the National Natural Science Foundation of China(Nos.22074052 and 22004046)the Science and Technology Developing Foundation of Jilin Province of China(No.20200404173YY).
文摘A kind of novel environmental-friendly composite absorbent material was designed and prepared in this paper.Nanoscale metal-organic frameworks(MOFs)were embedded in the skeleton of cotton micro fibrillated cellulose.By scanning electron microscope(SEM),we observed that a large number of MOFs were attached to the cellulose skeleton.In addition,under the condition of 1800 r/min vortex,the structure of the composite material was stable and was not easily damaged by external forces.The water contact angle test showed that the composite material had excellent hydrophilicity and could be used for the adsorption of pollutants.Then,the material was characterized by energy dispersive X-ray spectroscopy(EDX),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and BET adsorption.Through verification,the material had very stable reusability(n=10).The composite material was applied to the solid phase extraction of water samples,such as rain water,toning water and fruit juice,and was quantitatively analyzed by high performance liquid chromatography(HPLC)-UV.This method was then applied to the extraction of four parabens(methyl-,ethyl-,propyl-,and butylparaben)from real samples,yielding limits of detection(LODs)of 0.29-0.58 ng/mL.The linear range was 2-500 ng/mL.The inter-day and intra-day recoveries were 90.7%-106.0%and 87.1%-109.3%,respectively(relative standard deviation<10.8%).
