稀土—紫外线吸收剂配合物对聚合物光稳定作用研究

【作者】 张祖华；

【导师】 吴茂英；

【作者基本信息】 广东工业大学 ， 应用化学， 2004， 硕士

【摘要】 合成了β-二酮和邻羟基二苯甲酮紫外线吸收剂（UVA）二苯甲酰甲烷（HDBM）、苯甲酰丙酮（HBA）、2-羟基-4-正辛氧基二苯甲酮（HOBP）、2-羟基-4-甲氧基二苯甲酮（HMBP）的稀土配合物，系统比较研究了它们的紫外吸收特性、热挥发性、耐热性、耐光性、溶解性等理化特性及其对聚合物的光稳定效能，初步探讨了这些UVA—稀土配合物对聚合物光稳定作用的可能机理，得到了以下主要结果和结论： （1）通过对外观性状、熔融行为、溶解特性和红外光谱的观测比较，确定了由HDBM、HBA、HOBP、HMBP在乙醇—水介质中与稀土氯化物或硝酸盐反应可得到组成分别为RE（DBM）₃（H₂O）_1-2、RE（BA）₃（H₂O）_1-2、RE（OBP）₃、RE（MBP）₃的配合物，在这些配合物中形成的RE-O键具有一定程度的共价键性质。 （2）形成稀土配合物对HDBM、HBA、HOBP、HMBP的紫外吸收特性和耐光性影响不明显，但可使其耐挥发和耐热性明显提高，在乙醇等极性溶剂中的溶解度明显降低，而在苯、环己烷等非极性溶剂中仍有一定溶解度。 （3）以聚1，4-顺丁二烯为模型聚合物的氙灯曝露试验研究表明，形成稀土配合物可明显提高HDBM、HBA、HOBP、HMBP对聚合物的光稳定效能，提高的幅度最高可达近3倍。对于同一稀土离子，光稳定效能提高幅度：HOBP＞HMBP＞HDBM＞HBA；当紫外线吸收剂相同时，光稳定效能提高幅度随镧系元素原子序数的增大呈现典型的“四分组效应”递变规律。 （4）UVA—镧系配合物对聚合物光稳定效能的“四分组效应”递变规律说明形成稀土配合物对UVA光稳定效能的改进作用与某种形式的稀土配位作用有关，由于研究表明形成稀土配合物并不对UVA的紫外吸收和耐光特性产生明显影响，而UVA—稀土配合物又不具有明显的氧化—还原和自由基链终止授体或受体特性，推测UVA形成稀土配合物光稳定效能提高的原因可能主要是由于稀土配合物能与聚合物链上的光敏基团（羰基、氢过氧基等）发生配位作用而使UVA在光敏基团周围得到浓聚，这样既有效地减少了光敏基团的光吸收又强化了紫外线吸收剂对其激发态的猝灭作用。更多还原

【Abstract】 Rare earth complexes of UV absorber "Dibenzoylmethan(HDBM), Benzoyl-acetone(HBA), 2-hydroxy-4-octoxyl-benzophenone(HOBP) and 2-hydroxy-4-meth-oxyl-benzophenone(HMBP)" have been synthesized. The physical and chemical property such as UV absorption, heat resistance, light fastness and soluability and photostabilization to polymer etal of those rare earth complexes have been discussed. And the photostabilization mechanics of those rare earth complexes were speculated. The main results and conclusion are:(1) By comparing the appearance, melt point, and Infra-red spectrum of the synthesized products, the method that rare earth complexes whose composition are RE(DBM)3(H2O)1-2, RE(BA)3(H2O)1-2, RE(MBP)3, RE(OBP)3 can be synthesized by HDBM, HBA, HOBP, HMBP react with rare earth chloride or nitrate in ethanol-water solution were confirmed, and the formed RE-O coordinate band have some covalent band character.(2) The influence on UV absorption character and light fastness property caused by the process of UV absorber change to rare earth complexes are not obvious, but the heat resistant ability has gotten obvious improvement, and the solubility in polar sovent such as ethanol etal is reduced obviously, But still have certain solubilities in nonpolarity solvent such as benzene and ring own alkane etal..(3) The test of photo-stabilization to polymer of rare earth - UV absorber complexes have been made in laboratory accelerate experiment, results showed that by forming rare earth complexes can improve the photostablization efficiency to polymer of UV absorber, the highest improvement effect will be triple to that of UV absorber. For same rare earth ions, the improvement effect are HOBP >HMBP> HDBM > HBA; while for same UV absober, the improve effect changed regularly as "Four Group Effect" with ith increase of the atomic number of rare earth element.(4) The fact the photostablization to polymer of rare earth-UV absorber complexes has "Four Group Effect" regularity disclosured that there will be exist some relationship between the photostabilization of rare earth complexes and coordination, while The influence on UV absorption character and light fastness property caused by the process of UV absorber change to rare earth complexes are notobvious. And rare earth complexes have no obvious oxidation-reduction and free radical seize ability, so the function mechanics of photostabilization to polymer of rare earth UV absorber complexes can be speculated that those complexes may coordinated with photo-senstive group on polymer band such as carbonyl or/and hydroperoxides etal, so concentration of complexes besides photo-senstive group can be accumulated that not only decreased the light absorption of photo-senstive group but also increased the quenching effect to excitation state of rare earth complexes.更多还原