采用2,2,6,6-四甲基哌啶氧化物(TEMPO)氧化与超声破碎结合的方法制备了不同氧化程度的纳米纤维素(CNF)薄膜,探究次氯酸钠和TEMPO添加量以及Ca²⁺离子交联对CNF薄膜透光性和力学性能的影响。结果表明,增加次氯酸钠和TEMPO添加量,在一定程度上增加了CNF薄膜的透光率,降低了CNF薄膜的雾度;改变次氯酸钠的添加量对CNF薄膜的拉伸强度和弹性模量均有影响,其拉伸强度从50.2 MPa降低至34.7 MPa,弹性模量从4 123.4 MPa增加至5 063.4 MPa,而其断裂伸长率则从3.0%降低至1.6%;改变TEMPO的添加量使CNF薄膜的弹性模量升高,最高可达5 851 MPa,断裂伸长率则会降低,最低为2.9%;Ca²⁺会增强膜的力学性能,交联后CNF薄膜的拉伸强度最高可达122.37 MPa,弹性模量最高可达6 597.1 MPa。研究结果为制备具有良好的光学与力学性能的薄膜及包装材料等提供了技术支撑。

Cellulose nanofiber (CNF) film with different oxidation degrees are prepared via a method combining TEMPO oxidation and ultrasonic crushing,and the influences of sodium hypochlorite dosage,TEMPO dosage and Ca²⁺ cross-linking on the light transmittance and mechanical properties of CNF film are investigated.The results indicate that the larger dosages of sodium hypochlorite and TEMPO increase the light transmittance of CNF solution and CNF film,and reduce the haze of CNF film.The addition amount of sodium hypochlorite has an influence on both the tensile strength and elastic modulus of CNF film,making the tensile strength decrease from 50.2 MPa to 34.7 MPa,the elastic modulus increase from 4 123.4 MPa to 5 063.4 MPa,and the elongation at break decrease from 3.0% to 1.6%.Changing the addition amount of TEMPO increases the elastic modulus of CNF film up to 5,851 MPa,and decreases the elongation at break to 2.9%.Ca²⁺ can enhance the mechanical properties of the film.The tensile strength of CNF film after Ca²⁺ cross-linking is up to 122.37 MPa,and the elastic modulus is up to 6 597.1 MPa.This study can provide theoretical basis for the preparation of diaphragms,filter membranes and food packaging film with better optical and mechanical properties.