Synthesis Of Functional Cellulose Acetate Mixed Ester And Preparation Of Its Fiber

Cellulose acetate has a wide range of applications.However,there are two major problems existing during the application such as insufficient functionality and low mechanical strength,which limits its application and using performance.Therefore,the development of multi-functional cellulose acetate(CA)material with good mechanical strength has a very important significance.In this work,commercial cellulose diacetate(CDA)with a degree of substitution(DS)of 2.45 was partly deacetylated to CA with different DSs by acid-catalyzed hydrolysis and then reacted with 1-naphthoyl chloride(NpCl)to synthesize cellulose acetate naphthoate(CANp).And the CA-mixed ester film and fiber were prepared.The major works were as follows:CD A was hydrolyzed through acid-catalyzed and saponification reaction,respectively.It could be found that the lowest DS of CA hydrolyzed by acid-catalyzed was 2.00,indicating the hydrolysis degree of acid-catalyzed is lower than that of saponification-But the products of acid-catalyzed hydrolysis possessed excellent solubility due to homogeneous reaction.These products were used to synthesize CANp in N,N-dimethylacetamide(DMAc)and pyridine respectively.FTIR and NMR were used to characterize the chemical structure of CANp.The DS of naphthoate(DSCANp)could be controlled through varying the reaction medium,the DS of CA(DSCA),the molar ratio of-OH of CA unit to NpCl(-OH:NpCl),and the reaction temperature and time.It could be found that when the reaction medium was pyridine,the DSCAwas 2.01 and the molar ratio was 1:6,the maximum DSCANp of the product was achieved after reaction at 80℃ for 2 h.Meanwhile,the reaction medium had significant impact on the structure of CANp.With DMAc,the substitution order was C-6>C-2>C-3,and with pyridine,the substitution order was C-2>C-6>C-3.However,different chemical structures had little effect on the crystallization behavior and thermal property of CANp.The thermal,anti-ultraviolet and liquid crystal properties of CANp were studied through DSC,TGA,UV-Vis and POM.The results showed that the thermal stability decreased slightly while the anti-ultraviolet property enhanced with increasing DScANp.When DSCANp was 0.98,the absorbance was 2.67.And 30%CANp can form cholesteric liquid crystals in trifluoroacetic acid.Moreover,the obtained CA-mixed ester films exhibited good ultraviolet resistance as well as chemical resistance.The CA-mixed ester fibers were prepared by dry-wet spinning technique.It could be found that the addition of 3%cellulose is beneficial to improve the spinnability of the solution.The blend fibers possess good mechanical property,and the maximum breaking strength of the nascent fibers can reach about 2.12 cN/dtex.