Cellulose nanofibrils improve the properties of all-cellulose composites by the nano-reinforcement mechanism and nanofibril-induced crystallization

Abstract

All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials.

Facilitated Transport of CO2 Through the Transparent and Flexible Cellulose Membrane Promoted by Fixed-Site Carrier

“…The crystal structure of the α-C was exactly in line with the literature, preserving the pristine structure of native wood cellulose. ,, The distinct peaks centered at 15.2° and 23.1° are ascribed to the (101) and (002) planes of a cellulose I type crystal structure. However, the XRD patterns of the membranes indicate obvious diffraction peaks of cellulose II as a dominant component with representative peaks at approximately 12.0°, 20.2°, and 22.5°. , The cellulose II type crystallites with longitudinal direction are in-plane oriented, providing evidence for the well-stacked layers observed in the SEM cross section. The crystalline transformation is ascribed to the Zn ions enter the crystalline regions of the cellulose and break the pristine hydrogen bonding network.…”

Facilitated Transport of CO2 Through the Transparent and Flexible Cellulose Membrane Promoted by Fixed-Site Carrier

“…The crystal structure of the α-C was exactly in line with the literature, preserving the pristine structure of native wood cellulose. ,, The distinct peaks centered at 15.2° and 23.1° are ascribed to the (101) and (002) planes of a cellulose I type crystal structure. However, the XRD patterns of the membranes indicate obvious diffraction peaks of cellulose II as a dominant component with representative peaks at approximately 12.0°, 20.2°, and 22.5°. , The cellulose II type crystallites with longitudinal direction are in-plane oriented, providing evidence for the well-stacked layers observed in the SEM cross section. The crystalline transformation is ascribed to the Zn ions enter the crystalline regions of the cellulose and break the pristine hydrogen bonding network.…”

Formation of hairy cellulose nanocrystals by cryogrinding

“…7a), show that cellulose in these films has the cellulose II crystal structure. The spectra are different from previously published XRD spectra for ideal cellulose II produced with different kinds of solvents, which show different intensities and peak broadening (Tanvir et al 2017;Yang et al 2012Yang et al , 2015Lac ¸in et al 2019). To the best of our knowledge, this is the first attempt to prepare cellulose II by cryogrinding in an automated freezer mill.…”

“…7b). Similar resolution has been observed elsewhere (Yang et al 2015). The reason why the composite peak was resolved is not clear, as besides exposure time, the samples had different aging times and different washing conditions.…”

Cellulose Anionic Hydrogels Based on Cellulose Nanofibers As Natural Stimulants for Seed Germination and Seedling Growth

“…In comparison with CF, an absorption band at 1731 cm –1 appeared in the spectra curve of CNF07 and CNF15, and this was owing to the CO stretching of the protonated carboxyl groups. , It can be obviously seen that the intensity of CNF15 is stronger than that of CNF07 due to the increased contents of carboxyl groups. These results confirmed the successful preparation of CNF with various carboxylate contents Figures S2a and b showed the TG and DTG curves of CF, CNF07, and CNF15.…”

Facilitated Transport of CO2 Through the Transparent and Flexible Cellulose Membrane Promoted by Fixed-Site Carrier

“…The crystal structure of the α-C was exactly in line with the literature, preserving the pristine structure of native wood cellulose. ,, The distinct peaks centered at 15.2° and 23.1° are ascribed to the (101) and (002) planes of a cellulose I type crystal structure. However, the XRD patterns of the membranes indicate obvious diffraction peaks of cellulose II as a dominant component with representative peaks at approximately 12.0°, 20.2°, and 22.5°. , The cellulose II type crystallites with longitudinal direction are in-plane oriented, providing evidence for the well-stacked layers observed in the SEM cross section. The crystalline transformation is ascribed to the Zn ions enter the crystalline regions of the cellulose and break the pristine hydrogen bonding network.…”

Formation of hairy cellulose nanocrystals by cryogrinding

“…7a), show that cellulose in these films has the cellulose II crystal structure. The spectra are different from previously published XRD spectra for ideal cellulose II produced with different kinds of solvents, which show different intensities and peak broadening (Tanvir et al 2017;Yang et al 2012Yang et al , 2015Lac ¸in et al 2019). To the best of our knowledge, this is the first attempt to prepare cellulose II by cryogrinding in an automated freezer mill.…”

“…7b). Similar resolution has been observed elsewhere (Yang et al 2015). The reason why the composite peak was resolved is not clear, as besides exposure time, the samples had different aging times and different washing conditions.…”

Cellulose Anionic Hydrogels Based on Cellulose Nanofibers As Natural Stimulants for Seed Germination and Seedling Growth

“…In comparison with CF, an absorption band at 1731 cm –1 appeared in the spectra curve of CNF07 and CNF15, and this was owing to the CO stretching of the protonated carboxyl groups. , It can be obviously seen that the intensity of CNF15 is stronger than that of CNF07 due to the increased contents of carboxyl groups. These results confirmed the successful preparation of CNF with various carboxylate contents Figures S2a and b showed the TG and DTG curves of CF, CNF07, and CNF15.…”

Facilitated Transport of CO2 Through the Transparent and Flexible Cellulose Membrane Promoted by Fixed-Site Carrier

“…The crystal structure of the α-C was exactly in line with the literature, preserving the pristine structure of native wood cellulose. ,, The distinct peaks centered at 15.2° and 23.1° are ascribed to the (101) and (002) planes of a cellulose I type crystal structure. However, the XRD patterns of the membranes indicate obvious diffraction peaks of cellulose II as a dominant component with representative peaks at approximately 12.0°, 20.2°, and 22.5°. , The cellulose II type crystallites with longitudinal direction are in-plane oriented, providing evidence for the well-stacked layers observed in the SEM cross section. The crystalline transformation is ascribed to the Zn ions enter the crystalline regions of the cellulose and break the pristine hydrogen bonding network.…”

Formation of hairy cellulose nanocrystals by cryogrinding

“…7a), show that cellulose in these films has the cellulose II crystal structure. The spectra are different from previously published XRD spectra for ideal cellulose II produced with different kinds of solvents, which show different intensities and peak broadening (Tanvir et al 2017;Yang et al 2012Yang et al , 2015Lac ¸in et al 2019). To the best of our knowledge, this is the first attempt to prepare cellulose II by cryogrinding in an automated freezer mill.…”

“…7b). Similar resolution has been observed elsewhere (Yang et al 2015). The reason why the composite peak was resolved is not clear, as besides exposure time, the samples had different aging times and different washing conditions.…”

Cellulose Anionic Hydrogels Based on Cellulose Nanofibers As Natural Stimulants for Seed Germination and Seedling Growth

“…In comparison with CF, an absorption band at 1731 cm –1 appeared in the spectra curve of CNF07 and CNF15, and this was owing to the CO stretching of the protonated carboxyl groups. , It can be obviously seen that the intensity of CNF15 is stronger than that of CNF07 due to the increased contents of carboxyl groups. These results confirmed the successful preparation of CNF with various carboxylate contents Figures S2a and b showed the TG and DTG curves of CF, CNF07, and CNF15.…”