甲基双酚类单体共聚-溴化-羧化法制备羧基化聚醚醚酮

Preparation of Carboxylated Polyether Ether Ketone via Copolymerization of Methoxyphenol Monomer-Bromination-Carboxylation

针对2,5-二羟基甲苯、对苯二酚和4,4’-二氟二苯甲酮共聚反应进行研究。结果表明,随着固含量、反应温度以及碱金属碳酸盐中碳酸钾比例的增加,产物含甲基的聚醚醚酮(PEEK-CH_(3))的分子量分布先降低后增加,其最佳反应条件:固含量为25%,缩聚温度为200℃,碱金属碳酸盐与双酚单体物质的量比为1.05:1,碱金属碳酸盐中碳酸钠与碳酸钾的物质的量比为19:1,反应时间为3.5 h。PEEK-CH_(3)溴化反应中二溴取代产物(PEEK-CHBr_(2))最为重要,在液溴用量为—CH_(3)摩尔当量的20倍、反应温度为160℃、365 nm长波紫外线光照下反应2 h后,PEEK-CHBr_(2)占比达到95.8%。最后,通过次氯酸钠氧化PEEK-CHBr_(2),成功制备了数均分子量为4.6×10^(4)、特性黏度为1.5 dL/g的羧基化聚醚醚酮,其水接触角从未改性的PEEK的133.9°降至29.9°。

The copolymerization reaction of 2,5-dihydroxytoluene,hydroquinone and 4,4’-difluorobenzophe was studied.The results showed that the molecular weight distribution of the PEEK-CH_(3) initially decreased and then increased with an elevation in solid content,reaction temperature,and the ratio of potassium carbonate to phenolic monomers in alkali metal carbonate.The optimal reaction conditions were identified as follows:a solid content of 25%,condensation temperature of 200℃,molar ratio of alkali metal carbonate to phenolic monomer was 1.05:1,molar ratio of sodium carbonate to potassium carbonate in alkali metal carbonate was 19:1,and reaction time was 3.5 h.In the PEEK-CH_(3) bromination reaction,the proportion of the crucial dibromide substitution product(PEEK-CHBr_(2))was critical.With a liquid bromine dosage 20 times that of the—CH_(3) molar equivalent,a reaction temperature of 160℃,UV light conditions at 365 nm,and reaction time 2 h,the PEEK-CHBr_(2) proportion reached 95.8%.Finally,through the oxidation of PEEK-CHBr_(2) with sodium hypochlorite,carboxyl-functionalized polyether ether ketone(PEEK-COOH)was successfully synthesized with an average molecular weight of 4.6×10^(4) and a characteristic viscosity of 1.5 dL/g.The water contact angle decreased from 133.9°of unmodified PEEK to 29.9°.