含肉桂酸酯基的聚丙烯酸丁酯共聚物研究

Study on the poly(butyl acrylate)with cinnamate groups

以丙烯酸丁酯(BA)和甲基丙烯酸-β-肉桂酰氧基乙酯(CEMA)为原料,通过自由基溶液共聚制备了具有光反应性的含肉桂酸酯基的聚丙烯酸丁酯共聚物(PBC),应用紫外光谱、红外光谱、核磁共振氢谱、凝胶渗透色谱、热重和示差扫描量热分析,对PBC共聚物的结构、热性能及光交联特性进行了表征。结果表明,随着CEMA单体投料比增加,共聚物的分子质量增大,分子质量分布变宽。随着共聚物中BA物质的量分数超过38%,共聚物材料的热稳定性得到明显提高。PBC共聚物的玻璃化转变温度,均在40℃左右。紫外光照射下,PBC共聚物中肉桂酸酯双键发生[2+2]二聚反应,在溶液中双键反应速率和转化率要比固体薄膜中快和高,随着共聚物组成中肉桂酸酯基团含量增加,在固体薄膜中的光反应性明显降低,而在溶液中基本不变。

The photoreactive poly(butyl acrylate)with cinnamate groups(PBC)was prepared by free radical solution copolymerization using butyl acrylate(BA)and β-cinnamyloxyethyl methacrylate(CEMA)as raw materials,the structure and thermal and photocrosslinking properties of PBC copolymers were characterized by ultraviolet spectroscopy, infrared spectroscopy,^(1)H-NMR spectroscopy, gel permeation chromatography,thermogravimetric analysis and differential scanning calorimetry. The results showed the molecular weights of the copolymers were increased and the distribution of the polymer became wider with increasing of CEMA monomer feed ratio. The thermal stability of the copolymer material was significantly improved as the molar fraction of BA species in the copolymer exceeded 38 %. The glass transition temperatures of PBC copolymers were all around 40 ℃. Under UV irradiation,the [2+2] dimerization reaction of the cinnamate double bond in the PBC copolymer occured, and the double bond reaction rate and conversion rate in solution are faster and higher than those in the solid film. With the increase of cinnamate group content in the copolymer composition, the photoreactivity in the solid film was decreased obviously,but remained unchanged in the solution.