A Research On The Modification Of Chitosan And Properties Of Chitosan-pu Combinations

There are certain drawbacks of present traditional wool anti-felting treatment processes.To overcome all the problems of the traditional processes,a lot of work was done.Chitosan(Cs)is a good natural material,which is easy to film.It has certain properties,such as,good biodegradation and compatibility,as well as antibacterial and safety properties.It does great economic and environmental benefits to discovering a finishing agent of excellent performance and Eco-friendly properties by compounding Chitosan with other materials.In this article,Cs of high molecular weight was modified by composite degradation method with microwave-H2O2 firstly.A key study of the influence of H202 and treating time on the molecular weight,yield and stability of the products was done to determine the optimum parameters of degradation process.And the result showed that the molecular weight of the modified chitosan decreased as microwave time and H2O2 concentration increased,while the color burned and the yield declined.And when 2 gram Cs were treated with 2ml H2O2 that the mass fraction is 30%for 2 min in microwave condition,the ideal product was got.Secondly,the modified Cs was compounded with polyurethane(PU),then it was used to treat the wool fabrics.This chapter focused on researching the effect of the following three factors,mass ratio of the two components,molecular weight of Cs and dosage of PU,on stability and homogeneity of the mixture.The area-shrinking rate,anti-bacterial and mechanical performances were tested to ensure the optimum formula.It suggested that the result was best when the concentration of PU was 60 g/L and the mass ratio of Cs with molecular weight of 30000 to PU was 4%.It can overcome low compatibility of the two components greatly to get a mixture with good stability and homogeneity via compounding technology.The addition of chitosan decreased the PU consumption,while better anti-felting effect,certain antibacterial property and good handle were also got.Finally,based on the antifelting treatment,a series of blend membranes were prepared via polymerization with the mixed agent of different mass ratio,when the Mv of Cs is 3 × 104 and the concentration of PU is 60g/L.The mechanical and biodegradation properties,as well as hydrophilic properties of the membranes were studied through related experiments.The results showed that the aqueous mixture was easy to film,to a certain extent,not only the mechanical and thermal properties,but also hydrophility and biodegradation of the membranes were enhanced as the increasing of chitosan.