Preparation Of Oxidized Polyethylene Wax In A Solvent

Oxidized polyethylene wax（OPW）was versatile with high added value.In order to meet the development,application of new technologies and the different requirements of various fields,modification of polyethylene waxes（PEW）had gotten more attention.Waste PEW which was obtained by waste plastics cracking process was complicated with impurities.It had deep color.It was difficult to be infiltrated by the liquid and incompatible with polar materials because of the lower surface tension.Its scope of application was largely limited.Therefore modification and decolorization of waste PEW were of great significance.Firstly,the oxidized modification of waste PEW was studied in a solvent by adding air.The article investigated the effects of reaction temperature,reaction time and ratio of the solvent to feed.During the reaction,there was no any catalyst.By changing the conditions,it obtained OPW with high acid value and light color.The optimal conditions were as follows:reaction temperature was170℃,reaction time was 8 h,ratio of the solvent to feed was 2.5:1.The acid value of the product was 3.615 mgKOH·g^-1,which was about 25times the acid value of the raw material.Then the oxidation experiments were investigated.The acid value of the product inspired was higher than that of the direct oxidation of the product,but the color of the former was deeper than that of the latter.Under 185℃,when the reaction temperature was 170℃,reaction time was 7 h,the ratio of the solvent to feed was 2.5:1,the maximum acid value of the product was 6.416 mg KOH·g^-1.Under 190℃,when the reaction temperature was 170℃,the reaction time is 7 h,the ratio of the solvent to feed was 2.5:1,the maximum acid value of the product was6.836 mgKOH·g^-1.The oxidized experiments were studied with adding two kinds of additives which were stearic acid and hydrogen peroxide.Experimental results showed that the two additives can improve the acid value of the product,and the color of product after modification was significantly lighter.When the reaction temperature was 160℃,the reaction time was6 h,the ratio of the solvent to feed was 2:1,the acid value of the product adding 5%stearic acid was 13.564 mgKOH·g^-1.When the adding amount of hydrogen peroxide was 10 mL,the reaction temperature was 170℃,the reaction time was 8 h,the ratio of the solvent to feed was 2:1,the acid value of the product was 10.566 mgKOH·g^-1,which was about 74times the acid value of the raw material.The result of IR showed that there were the hydroxyl-and carbonyl-groups and other polar functional groups in OPW.The result of TG showed that the decomposition temperature of OPW decreases.With the increase of polar groups,the stability of the product reduces.At last,the decolorization of raw material was studied with hydrogen peroxide as bleaching agent.The effects of bleaching temperature,bleaching time and the amount of bleaching agents on the decolorization were investigated.The dye solution was characterized by UV and FT-IR.The pigment solution may contain a double bond closed substance cyclic structure,conjugated double bonds,or substance that may contain O unsaturated hetero atom seen from UV.The bleaching temperature,the bleaching time,and the bleaching agents were the three main factors influencing the decolorization.Within a certain range,the higher the adsorption temperature,the longer the adsorption time and the higher the amount of bleaching agent,the effect of decolorization was better.When the bleaching temperature was 90℃,the adsorption time of90min,the amount of bleaching agent was 3 mL,the decoloration effect of polyethylene wax was best.