| With the serious pollution of human living environment and the decomposition of active components in the atmosphere,the ability of the atmosphere to block ultraviolet rays is reduced,which makes the living environment of human beings face great threats and challenges.Textiles,as the material that covers the most surface area of human body,play an important role in blocking ultraviolet rays.Among them,cotton fabric with its excellent hydrophilic softness,warmth and other comfort properties and green environmental protection characteristics become the first choice for many people to wear clothing materials,but cotton itself UV resistance is very poor.Therefore,by finishing the common cotton fabric,its UV resistance can be improved,and its application range and environment can be expanded.At present,the active ingredients in the finishing agent required for the preparation of UV resistant fabrics are mainly composed of inorganic nanoparticles or organic polymer materials containing a large number of unsaturated functional groups.However,in the actual preparation and use process,there are serious environmental pollution,excessive energy consumption,high cost and other shortcomings,which limit its further promotion and application.Therefore,the preparation of low cost green and environmental protection anti-UV finishing agent and its firm application in cotton fabrics will further promote the development of anti-UV fabrics.The specific research content of this topic is as follows:The preparation and properties of cellulose/casein dispersions are systematically studied.Under freezing condition(-12℃),the cellulose material is dissolved and dispersed by Na OH/urea solution system,and the water-soluble cellulose is prepared.Casein solution with mass fraction of 10%is prepared by alkaline dissolving and dispersing the casein.In alkaline environment,cellulose casein epichlorohydrin with different components is mixed by stirring dialysis,shear dispersion and static precipitation to prepare water-soluble dispersions.It can be found that the dispersions show good stability by long time static observation.Through measuring the particle size of the dispersion,it also is known that the particle size distribution of the material is uniform.The molecular weight of the dispersion is larger than the sum of the molecular weight of cellulose and casein by means of aqueous gel permeation chromatograph.The crosslinking reaction between cellulose and casein is confirmed by hydrogen magnetic resonance spectroscopy(~1H-NMR).The dispersions show good UV absorption and anti-penetration performance by UV test.(1)A series of dispersions prepared are rolled into film,and the related properties of the dispersions after film formation are studied.The moisture retention of the film is better than that of cellulose by measuring the moisture regain and moisture content of the film.The film is folded in half without breaking,showing good flexibility.The water contact angle of the film is no more than 90°,which indicates that the film has a good hydrophilicity.FT-IR and XPS tests show that new functional groups are formed in the materials,indicating that the cross-linking reaction between cellulose and casein has been realized.XRD,TG,DTG,DSC and other test conditions show that the original chemical structure and bond energy of the raw materials are destroyed and new cross-linking bond energy is generated.By observation of SEM,the dispersions have good film forming property.The ultraviolet absorptivity and transmittance of the films are measured,and the results show that the films have good ultraviolet resistance.(2)A series of prepared dispersions are impregnated and coated on cotton fabrics respectively to obtain the corresponding finished cotton fabrics.The moisture regain,moisture content and weight gain rate of cotton fabrics before and after dispersion finishing are tested and the weight of the finished fabrics increase.With the aid of the intelligent whiteness meter,it can be found that the whiteness of the finished fabric decreases slightly.But it does not affect the actual appearance.By testing the mechanical properties of the finished fabric,it can be concluded that the mechanical properties of the finished fabrics are obviously improved.The air permeability tests of cotton fabrics before and after finishing show that the air permeability of cotton fabrics after finishing decreases.According to the measurement of water contact angle,the fabrics before and after finishing are all hydrophilic.FT-IR and XPS tests show that there are casein components in the finished fabric,indicating that casein is successfully loaded into the cotton fabric.By observing the microstructure of the fabric before and after finishing,it is found that the dispersions formed film well in the fabric.The thermal stability analysis shows that the thermal stability of the finished fabric is poor,which indicates that the original chemical structure of the material has been destroyed.The UV absorption and UV penetration of the finished fabric were tested,and the finished fabric had good UV resistance.The UPF value test of the fabric after washing showed that the finished fabric still had good UV resistance. |
