Effect Of Degumming Treatment On The Structure And Properties Of Hemp Fibers And Simulation By Monte Carlo Method

Natural fibres such as hemp, sisal, flax, kenaf and jute have been used extensively in the textiles. They consist of different hemicellulose and are bonded together with pectins and small amounts of lignin, which have to be removed before they are used. Many chemicals have been screened in experiments to degum, such as biological degumming, chemical degumming, biological and chemical degumming and physical degumming. However, these methods have certain limitation during the manufacturing process. Simulating the degumming process provides an effective method to reduce the environmental pollution.The main purpose of degumming is to remove non-cellulosic components in cellulose fibres, such as excessive pectins and lignin, and to improve the content of cellulose. This paper is attempts to characterize the structures and properties of hemp fibers before and after treatments in different degumming conditions by SEM observation, analysis of single fiber strength, FT-IR, X-ray diffraction and axial compression experiments. The conclusions can be drawn as follows:(1) The fiber fineness and the smooth degree increase with the variety of concentration due to the removal of non-cellulosic. However, when the concentration increases to some extent, the cellulose will be destroyed in hemp fibers, which leads to full of bumps and holes on the surface due to over-degumming, influencing smooth degree and lustrousness. Both temperature and time can improve the fiber fineness and smooth degree, whereas high temperature will lead to charring of hemp fiber.(2) The weightlessness rate of hemp fiber increases with increase of sodium hydroxide concentration. Tensile strength firstly increases and then decreases with increase of sodium hydroxide concentration, while tensile strain first decreases and then increases. Both temperature and time make a similar effect on hemp fiber.(3) The composition and crystallization index of hemp fiber are also influenced by concentration, temperature and time. When sodium hydroxide concentration increases, semi-cellulose is removed obviously, and the characteristic group (-OH) is also reduced which means reduction of cellulose; the crystallization index of X-ray differential interference is influenced and increase compared to the raw hemp fibres; the flexible rigidity of fibres will reduce with the variety of concentration, time and temperature.This paper is an attempt to simulate the process of degumming by Monte-Carol and describes the process of random probability. And a model of probability was built to make numerical simulation characterization, which the results of simulation will be statistically treated. This method preliminarily stimulates the chemical degumming process of hemp fiber:it is from surface to interior, and inner pores equal to fiber surface which is more probable to be removed.