Study On Solution Polymerization Of Biological Vinyl Acetate

Sugar cane molasses and cassava starch are characteristic advantage resources of guangxi, those are the raw materials to product ethanol. Ethylene is producted by ethanol after catalytic dehydration, then reacting with acetic acid can make biological vinyl acetate(Bio-VAC). Bio-VAC is a new process to product polyvinyl alcohol(PVA) by ethanol-ethylene, first used by Guangxi Guangwei Chemical Co.. Guangxi is located in the south Asia tropics, rich in water resource, long summer time, dry wet season significantly, annual frost-free. It is conducived to the growth of crops such as cassava and sugar cane specialy, and being known as the "kingdom of biomass energy". The production of cane sugar and plant area of cassava are the first in the nation. The geographical advantage of Guangxi offer a richly biomass resources for promoting the use of bio-ethylene method. Therefore, it has a dual significance of environmental protection and renewable for Guangxi using the bio-ethylene method to product vinyl acetate(VAC). In this paper, with VAC which was made by the bio-ethylene method by Guangxi Guangwei Chemical Co., as the monomer of polymerization, the effects of temperature, stirring speed, initiator ratio, methanol dosage and polymerization time influenced the solution polymerization of VAC were studied by methanol(MeOH) as the solution, or green solvent dimethyl carbonate(DMC) and MeOH as the mixed solvent, and determined the optimum reaction conditions. The structures of products were characterized by gel-chromatography (GPC) and fourier transform infrared spectrometer(IR), offered the basic data of Bio-VAC solution polymerization reaction conditions for Guangxi Guangwei Chemical Co.. The main research contents are as follows:With azodiisobutyronitrile (AIBN) as initiator, the polymerization activity of biological vinyl acetate was determined, the result was562.8s, calcium carbide acetylene method was780s. The result showed that, polymerization activity of biological vinyl acetate lower than calcium carbide acetylene method217.2s. Choosing viscosity meter to measure the degree of polymerization of PVA. The comparison results showed the laboratory measurements results and factory professional measurements results within the error range, make sure that the accuracy of measurement method of the degree of polymerization. The molecular weight and molecular weight distribution of poly vinyl acetate were measured by gel chromatography, with monodispersity polystyrene samples fitting out a standard curve of the GPC: logM=26.511-2.6384V+0.1081V2-0.0016V3.With methanol as solvent, PVA with high polymerization degree was synthesized via solution polymerization. The effects of temperature, stirring speed, initiator ratio, methanol dosage and polymerization time on the polymerization reaction of Bio-VAC were discussed systematically. Orthogonal experiment was established to get the optimum technological conditions of polymerization. The structures of products were characterized by gel-chromatography (GPC). Using the integral balanceable method to estimate polymerization degree and conversion. The results showed that, the optimum reaction conditions of polymerization were:polymerization temperature65℃stirring speed200r·min-1, polymerization time2.5h, methanol dosage10%, initiator ratio0.010%, the polymerization degree of PVA could be3389, conversion was32.02%.With MeOH and DMC as mixted solvent, PVA with high degree of polymerization was synthesized via Solution polymerization. By Comparing the effect of pure solvents and mixed solvent, and exploring the joining way of two solvents. Make sure that, mixed solvent as polymerization solvent, solvent joining way was:the first is DMC, then MeOH. The principal factors affecting the polymerization reaction of VAC, including stirring speed, the joining way of methanol, initiator ratio, mixted solvent dosage, solvent ratio and polymerization time, were studied systematically. Orthogonal experiment was established to get the optimum technological conditions of polymerization. The structures of products were characterized by gel-chromatography (GPC) and fourier transform infrared spectrometer(IR). Using the integral balanceable method to estimate Polymerization degree and conversion. The results showed that, the optimum technological conditions were:stirring speed200r·min-1, joining MeOH after the total polymerization time reach two-thirds, initiator ratio was0.015%, mixted solvent dosage was10%, V (DMC):V (MeOH) was4:1, polymerization time was3h, The product with3429polymerization degree and41.95%conversion were synthesized under the optimum polymerization technique.The GPC showed that, the molecular weight distribution with MeOH as the solution was1.4; the molecular weight distribution with DMC and MeOH as mixed solvent was1.14, both were less than1.3, the dispersion of molecular weight is small. Thus the molecular weight distribution under different polymerization solvent were narrower.The IR showed structure of the products under the optimum polymerization technique with mixted solvent as solution remained the same. That DMC was not involved in the polymerization.