摘要
研究了甲苯对水介质中合成的聚2,6-二甲基-1,4-苯醚(PPO)分子量及聚合物粒子形态的影响。研究发现,2,6-二甲基苯酚(DMP)氧化聚合过程中引入一定量甲苯后,可显著提高PPO的分子量。采用差示扫描量热仪测定了PPO/甲苯混合物的玻璃化温度,发现PPO/甲苯混合物的玻璃化温度随甲苯用量的增加而降低,其与甲苯用量的关系符合Fox方程。关联了PPO分子量与PPO/甲苯混合物的玻璃化温度的关系,结果显示玻璃化温度对PPO分子量起重要作用,这可能是由于在搅拌作用下甲苯能够溶胀聚合物粒子,降低其玻璃化温度,导致预聚物分子链的活动性增加,促进预聚物的后氧化聚合。采用透射电镜研究了水介质中合成的聚合物粒子形态,发现加入甲苯后聚合物最终粒子呈紧密的鹅卵石形,甲苯使初级粒子融合在一起,初级粒子的轮廓模糊甚至消失。
The effects of toluene on the molecular weight of poly（2,6-dimethyl-1,4-phenylene oxide） （PPO） and the morphology of polymer particles synthesized in an aqueous medium were studied. It was found that the molecular weight of PPO increases after adding a certain amount of toluene during the oxidative polymerization of 2,6-dimethylphenol （DMP）. The glass transition temperature （Tg） of PPO/toluene mixtures was studied by differential scanning calorimetry. It shows that Tg decreases with the increase of toluene content and the relation between Tg and toluene content obeys Fox equation. The molecular weight of PPO was correlated with Tg of PPO/toluene mixture, and it reveals that Tg plays an important role in the molecular weight of PPO, which is probably because toluene can swell polymer particles under the action of agitation and lower its Tg, the latter results in the increase of the mobility of oligomer chains and the facilitation of the oxidative polymerization at the later period. The morphology of the polymer particle synthesized in the aqueous medium was observed by transmission electron microscope and it was found that after the introduction of toluene the final polymer particle shows compact cobblestone morphology. Toluene makes primary particles fuse together and the profile of primary particles is so ambiguous that can not be seen.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2008年第5期906-910,共5页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金资助项目(20674075)
浙江省自然科学基金资助项目(Y404299)
