تهيه پلي اكسي متيلن با استفاده از فرمالدهيد و تري اكسان

Preparation of Polyoxymethylene Using Formaldehyde and Trioxane

Polyoxymethylene (POM) was prepared from formaldehyde and trioxane using anionic and cationic methods, respectively. Preparation of diacetate and dietherate derivatives of the polymer were studied via acetylation and alkylation reactions. Solution polymerization of trioxane using cyclohexane, toluene, methylene chloride and carbon tetrachio-ride shows more uniform polymer than the melt polymerization method. The optimum temperature for melt polymerization of trioxane was 90-100°C. The melting temperature of the polymer was 170 tol82^C. BF3.OEt2 was used as initiator for the polymerization of trioxane. The highest yield of polymer was obtained when cyclohexane was used and it showed the highest melting temperature as well. Increasing temperature from 25 to 60C decreased the yield of the polymer obtained. The effects of temperature and initiator concentration on the polymerization were studied, while, prior to this, the effect of formaldehyde concentration (25 to 46%) and catalyst concentration on trioxane preparation were investigated. An optimum value for both temperature (70^C) and catalyst concentration (8.8x10-2 mmol) were obtained based on polymer yield.