Preparation, properties, and mechanism of anionic and cationic cellulose nanocrystals/waterborne polyurethane composite films

Li, Yayu; Bai, Yan-Ru; Zhang, Xinqian; Liu, Xin; Dai, Zhijun; Liang, Ying-Long; Yan, Yongmin; Liu, Zunqi; Ma, Ming-Guo

doi:10.15376/biores.18.1.447-464

Cited by 3 publications

(1 citation statement)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This shift may be caused by the formation of hydrogen bonds between CNF and the hard segment -NH of WPU. In addition, the intensity of the -CH stretching vibration peak around 2921 cm −1 gradually decreases with the addition of CNF, which is caused by the change in the ratio of CNF and WPU in the composite [10] . In conclusion, no new single absorption peak is observed for the CNF/WPU composites, indicating that the chemical bond structure of the composite is not changed.…”

Section: Particle Size Analysis Of Cnf Wpu and Cnf/ Wpu Mixturesmentioning

confidence: 98%

Preparation and Characterization of Cellulose Nanofibril-Waterborne Polyurethane Composite Films

Li¹,

Chen²,

Liu³

et al. 2023

Paper and Biomaterials

View full text Add to dashboard Cite

To improve the performance of polyurethane films, small amounts of cellulose nanofibrils (CNF) were physically blended with a waterborne polyurethane (WPU) emulsion, and then CNF/WPU composite films were prepared by cast-coating and drying. The particle size of the emulsions and the chemical structure, micromorphology, thermal stability, mechanical properties, and water resistance of the composite films were characterized using a Malvern laser particle size analyzer, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), an electronic strength machine, water contact angle analysis (WCA), and water absorption tests, respectively. The results showed that at a low CNF content of 0.3 wt% , the particle size of the WPU emulsion and chemical structure of the film did not change significantly. In addition, the tensile strength of the composite film increased by up to 108% compared to the neat WPU film, and the thermal stability and water resistance were slightly improved. The addition of CNF greatly enhanced the tensile strength while maintaining the other original properties of the WPU film, which may greatly improve the service life and tear resistance of commercial coatings in the future.

show abstract

Section: Particle Size Analysis Of Cnf Wpu and Cnf/ Wpu Mixturesmentioning

confidence: 98%

Preparation and Characterization of Cellulose Nanofibril-Waterborne Polyurethane Composite Films

Li¹,

Chen²,

Liu³

et al. 2023

Paper and Biomaterials

View full text Add to dashboard Cite

show abstract

Waterborne polyurethane containing fluorosilicone coating: to endow leather with enduring hydrophobicity and mechanical properties

Zhao,

Sui,

Zhang

et al. 2024

Textile Research Journal

View full text Add to dashboard Cite

Natural leather-based materials possess a combination of air permeability, wear resistance, and plasticity. However, conventional leather products have inherent limitations that make them unsuitable for unconventional applications. Therefore, it is necessary to develop new capabilities in order to overcome these limitations. In this study, we explored the conversion of regular leather into a high-strength product with hydrophobic properties through surface engineering. To achieve this, we synthesized polysiloxane-modified fluorinated waterborne polyurethane emulsions as functional coatings using emulsion polymerization. The structure and properties of the treated leathers were characterized using techniques such as Fourier transform infrared, thermogravimetry, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results demonstrated that the synthesized polysiloxane-modified fluorinated waterborne polyurethane successfully penetrated and combined with the fibers of the leather, resulting in excellent hydrophobicity. The water contact angle increased to 124.3°. Furthermore, the tensile strength and tear strength of unfinished leather are 875 N and 114 N, respectively. The application of waterborne polyurethane-derived functional additives as coatings resulted in a significant increase in tensile and tear strength of the leather by 60 N and 16 N, respectively. In addition, the softness of the leather increased from 7.6 mm to 10.09 mm. Overall, the use of this functional waterborne polyurethane coating will contribute to the diversification of leather applications.

show abstract

Application of Thermochemical Method to Determine the Crystallinity Degree of Cellulose Materials

Ioelovich¹

2023

Applied Sciences

View full text Add to dashboard Cite

Currently, to characterize the crystallinity of cellulose, such an estimated parameter as the crystallinity index is used, measured by various methods and techniques. The main purpose of this article was to develop a thermochemical method for determining the real degree of crystallinity (X) of cellulose based on the measurement of the enthalpy of wetting. Various cellulose samples, such as MCC, pure cotton cellulose, bleached wood pulps, mercerized celluloses, and viscose rayon fibers, were used. For these samples, the exothermic wetting enthalpy (ΔHw), the maximum amount of sorbed moisture (Ao), as well as the X-ray index of crystallinity (CrI) were studied. The dependence of ΔHw on Ao was linear and can be expressed by the equation: ΔHw = k Ao, where the coefficient k = −336 (J/g). After substituting the theoretical value Ao,a = 0.5 (g/g) into this equation, the numerical value of maximum wetting enthalpy ΔHw,a = −168 (J/g) for completely amorphous cellulose was obtained. As a result, the equation for calculating the real crystallinity degree (X) expressed in mass fractions was derived: X = 1 − (ΔHw/ΔHw,a). Analysis of the obtained results showed that only the X parameter can characterize the real content of crystallites in cellulose samples, instead of the approximate CrI parameter.

show abstract

Preparation, properties, and mechanism of anionic and cationic cellulose nanocrystals/waterborne polyurethane composite films

Cited by 3 publications

References 42 publications

Preparation and Characterization of Cellulose Nanofibril-Waterborne Polyurethane Composite Films

Preparation and Characterization of Cellulose Nanofibril-Waterborne Polyurethane Composite Films

Waterborne polyurethane containing fluorosilicone coating: to endow leather with enduring hydrophobicity and mechanical properties

Application of Thermochemical Method to Determine the Crystallinity Degree of Cellulose Materials

Contact Info

Product

Resources

About