脱氢枞酸基ATRP引发剂的合成与表征

以脱氢枞酸为原料,通过酰氯化得到脱氢枞酸酰氯(DA-Cl)后与乙二醇(EG)反应合成脱氢枞酸羟乙酯(DA-EH),然后再与2-溴代异丁酰溴(2-BiBr)进行酯化反应,合成了脱氢枞酸基原子转移自由基聚合(ATRP)引发剂——脱氢枞酸(2-溴代异丁酸乙基)酯(DA-2-iBBrEH)。通过单因素试验考察了不同条件对合成DA-EH和DA-2-iBBrEH的影响规律。结果表明,DA-EH合成的优化条件为:催化剂为4-二甲氨基吡啶(DMAP),n(DA-Cl)∶n(EG)∶n(DMAP)为1∶5∶5,反应时间5h,反应温度50℃;DA-2-iBBrEH合成的适宜条件为:催化剂为DMAP,n(DA-EH)∶n(2-BiBr)∶n(DMAP)为1∶2∶2。利用傅里叶红外光谱(FT-IR)、核磁共振氢谱(1HNMR)和核磁共振碳谱(13CNMR)对两者的结构进行了确证。以DA-2-iBBrEH为引发剂,采用ATRP法制备了聚甲基丙烯酸甲酯均聚物(PMMA)。GPC测试结果表明,DA-2-iBBrEH具有良好的ATRP反应引发活性,所制备的PMMA的数均相对分子质量(Mn)为8500,相对分子质量分布(PDI)为1.3。

Synthesis and Characterization of Dehydroabietic Acid Derived ATRP Initiator

Dehydroabietic acid derived ATRP initiator, dehydroabietic acid (2-isobutyric acid bromide) ethyl ester of (DA-2-iBBrEH), was synthesized by esterification of 2-bromoisobutyryl bromide (2-BiBr) and dehydroabietic acid 2-hydroxyethyl ester ( DA-EH ) which was obtained from the reaction of ethylene glycol ( EG ) and dehydroabietic chloride ( DA-Cl ) with dehydroabietic acid as raw material. Single-factor experiments were employed to investigate the effects of reaction conditions on the preparation of DA-EH and DA-2-iBBrEH. The results showed that the optimized conditions of DA-EH preparation were summarized as 4-dimethyaminopyridine (DMAP) using for catalyst,n(DA-Cl)∶n(EG)∶n(DMAP) =1∶5∶5, reaction time 5 h and reaction temperature 50℃. The optimized reaction ratio and catalyst of the preparation of DA-2-iBBrEH were n( DA-EH)∶n(2-BiBr)∶n(DMAP) =1∶2∶2 and DMAP, respectively. Then the resulting products were characterized by FT-IR, 1H NMR and 13C NMR. Subsequently, poly ( methyl methacryalte) ( PMMA) was prepared using DA-2-iBBrEH as initiator. The GPC results showed that the molecular weight of PMMA was about 8 500 and PDI was 1. 3. This indicated that DA-2-iBBrEH was a good ATRP initiator.