Preparation And Shape Memory Properties Of Cellulose/Agarose Composite Fiber

The strategy of sustainable development has become a global consensus,and the rational development and utilization of natural renewable biomass resources has attracted more and more attention.In particular,oil and coal resources will be exhausted one day.Using renewable resources to replace renewable resources to produce fiber is the trend of material development in the future.Shape memory fiber is a kind of intelligent fiber material that can be shaped and fixed into a temporary shape,and then return to its original shape under the stimulation of external heat,water,p H and so on.At present,it is widely found that the reported shape memory fibers are all synthetic polymers,which do not meet the requirements of green chemistry.Cellulose and agarose are hydrophilic as natural polymers,and their molecular chains contain a large number of hydrogen bonds.The breaking and recombination of hydrogen bonds can give water stimuli response to materials,while the characteristics of gelatin melted at low temperature under high temperature can give the material thermal stimulus response.In this paper,cellulose/agarose composite film and fiber materials were successfully prepared by alkali/urea aqueous solution,which showed the response to hydrothermal stimulation,and had potential application value in the fields of clothing,medical treatment,craft jewelry and so on.This paper studies the following three aspects:(1)Cellulose/agarose composite films with shape memory properties stimulated by water and heat were prepared by using alkali/urea aqueous solution as cosolvent and epichlorohydrin as crosslinking agent.The film shows good transparency and mechanical properties.The transmittance exceeds 90%,and the dry strength and wet strength can reach132 MPa and 5.4 MPa.At the same time,the fixation rate(R_f)and recovery rate(R_r)of the film under water stimulation were more than 95%and 84%respectively,and the R_fand R_runder thermal stimulation were more than 58%and 85%respectively,showing a good shape memory effect.The mechanism analysis shows that the fracture and formation of hydrogen bond leading to the water stimulated shape memory behavior of the composite film,and the destruction and formation of agarose crystal is the key to the thermal stimulated shape memory behavior of the composite film.(2)Cellulose/agarose composite membrane showed good shape memory behavior under hydrothermal stimulation.On this basis,through the preparation of composite fibers,the fibers were endowed with shape memory function under hydrothermal stimulation.Using Li OH/urea aqueous solution as cosolvent,a viscous cellulose/agarose mixed solution was successfully prepared.The mixed solution has good stability and spinnability at room temperature.By studying the effect of the composition of coagulation bath on the mechanical properties of fiber,it is found that the breaking strength of composite fiber spun in 25.81 g/L trisodium citrate/70.45 g/L citric acid coagulation bath is the best,reaching 154 MPa.In addition,other cellulose/agarose fibers with different ratios spun through this coagulation bath also showed good mechanical properties.(3)Shape memory fiber needs to have good shape memory effect,dyeing performance,weavability and other characteristics before it can be used in garment production.Therefore,all aspects of properties of composite fiber are characterized.The results showed that the shape fixation rate and recovery rate of the composite fiber under water stimulation were more than 95%and 78%respectively,and the shape fixation rate and recovery rate under heat stimulation were more than 74%and 68%respectively.After ten repeated shape memory tests,the composite fiber still showed good shape memory effect.In addition,the composite fiber also shows good weavability and excellent dyeing effect.The dye uptake of reactive dyes is more than 1.7 times that of cotton fiber.This work successfully developed a regenerated fiber with simple preparation process,mass production,green environmental protection and hydrothermal response function,which is expected to promote the progress and development of textile fiber.