Study On Quality And Microbe Retting Of Flax

Flax,as one kind of bast fibers,is preferred by consumers and used widely in clothing and garment because its fabric has many virtues,such as,fast moisture absorption and carry-off,natural grain,bland color,unique style,etc..Therefore,the production scale in China is so expanded constantly that it has been listed the second globally,next only to Russia now.But the yield in China is too deficit to meet textile industry about seventy percents of flax materials are imported.Furthermore,import quantum of flax is increasing.The main properties and components ofscutched flax from Holand,Belgium,Fance,Russia and China are tested in this paper,such as, fineness,strength,length,elongation.In addition,SEM,infrared and x-ray diffraction are also used in comparison,so that more informations about different scutched flax can be obtained and more rational and concrete parameters can be set down in manufacture.The results indicate that scutched flaxes from Holand and France have few gum,while that from Russia and China have more gum.The tenacity of flax from Holand is biggest followed by that of Russia and China,flaxes from France and Belgium have smaller tenacity.As far as softness is concerned,flaxes from Holand, France and Russia have better softness,while flaxes from China and Belgium have worse softness.In addition,the average length and discreteness of flax of Holand is best,followed by that of Belgium and Russia,that of China is worst.In conclusion, the properties of flax from Holand is relatively better,scutched flax from China has more pectin and lignin and is coarse.The quantity and quality of fiber come into being during growing period. Therefore,the key problem of improving fiber quality is to find out the form law of fiber.So fibers in Xinjiang and Heilongjiang,which are the main fields in China,are studied in detail.Fibers with different growing time are harvested and analysed.The datas prove that the optimal strength and elongation of fiber are best when flax is harvested one week after blossom.Therefore,the optimal harvesting time is one week after blossom when textile properties are taken into account.Not only cellulose that can be used in textile industry but also non-cellulose lie in bast fiber,non-cellulose is also named gum including pectin,hemicellulose and lignin, which glues cellulose into stiff sheet bundle fiber,which can not be spinned,therefore, gum must be removed before spinning,this process is retting.Thus,the degree and quality of retting can affect downstream process.As pectin is one important component in gum and its removal can influence postprocessing in textile,so research on pectin is theoretical foundation of retting.The results prove that pectin lies in the junction of cells and its macromolecule is linked by electrovalent bond in outer and lamella,while pectin is connected by covalent bond in inner bast.At the same time, more calcium ion distributes in outer and junction of cell and few lies in inner of cell, so the distribution trends of pectin and calcium ion are same.The quantity of calcium ion is analysed in this paper and the ralation between pectin and calcium ion is also studied,the results indicate that calcium ion lies in pectin of flax.Calcium ion makes macromolecule of pectin turn into egg-box structure,which is meshy and intricate. The structure of pectin makes retting more difficult.Therefore research on pectin is carried in the paper in order to treat flax efficiently.Pectin is extracted with two methods and tested by mass spectrum,liquid chromatogram and infrared.As a result, the hydrotrope and the pectin in which calcium ion is removed are the same matter, that is,hydrotrope is soluble pectin,while pectin is the calcium ion of pectic acid.Since calcium ion chelateds the macromolecule of pectin,chelating agents,such as elhylene diamine tetraacetic acid,sodium salt of triphosphoric acid,oxalic acid and ammonium oxalate,are involved in the pretreatment experiments of flax.The evaluation is based on modified Fried Test.The results manifest that ammonium oxalate is effective,bast and xylem can be separated fully when flax is treated with ammonium oxalate,the conditions are:the concentrationof ammonium oxalate 5g/L, 60℃,5h.Microbe treatment of flax is also studied in the paper in order to conquer the defects of traditional retting,for example,unmanageable,intensity of labor, environmental pollution and unstable quality of fiber.A effective fungus strain is separated and screened from retting water and soil in planting area of flax,pH, temperature,carbon source and nitrogen source are involved in optimization experimnts of pectinase production.The results show that the optimal production conditions ofpectinase are:nitrogen source potato,carbon source pectin,pH6,30℃, culture time 60h,speed of shaker 200r/min,the optimal pH and temperature of pectinase are pH5.5,40℃,respectively.Then flax roving is treated,evaluation is based on residual gum content.Datas indicate that effect of flax roving treated based on residual gum content is better than that treated under optimal pectinase productin conditions,which is proved by treatment of kenaf that is similar to flax in structure. All these show that enzyme activity is not suitable for evaluating retting.In addition, the colony of the strain is big,loose,opaque and arachnoid,connection between strain and substrate is tight,the colors of two sides of colony are different,marginal and central colors are also different,that is,the surface of colony is pitchy or carbonarius,the other side is yellow with different brightness,differences of colors of two sides are obvious,spherical gleba of strain is saccate whose top expands into roundness,its spore results from podocyte differentiated by nutrient hypha,one or two radialized trichidiums come into being at the top of gleba,from which spores are produced.All these are observed with microscope.This strain is aspergillus certificated by certification handbook of China fungus.Last,raw flax is treated with ammonium oxalate followed by microbe retting, thus,bast separate from xylem fastly proved by infrared and diffraction.Mechanism of microbe retting is also studied.The results indicate that aspergillus niger,as one kind of mcirobe whose carbon source and energy come from external organics,can absorb carbon source and energy from organics and its oxidation reaction to grow. Therefore,microbe retting of flax begins at the stage of fast growing period of strain, strain use oligomer in flax as its nutrient to propagate,which damage tight structure of gum and make it easy for mycelium to enter molecule,thus,cleavage appears in molecule of gum.Furthermore,glucosidic bond in macromolecule of pectin breaks due to pectinase excreted by increasing strain,which makes great change and damage occur in macromolecule,at this time,strain can use nutriment from pectin easily, during which retting completes.Therefore,there is not a significant linear correlation between retting effect and enzyme activity in practical flax treatment.