稀土/高分子复合材料制备及其亚微观结构与发光、射线屏蔽及磁性能的关系研究

【作者】 刘力；

【导师】 金日光；

【作者基本信息】 北京化工大学 ， 材料学， 2004， 博士

【摘要】 本论文中利用稀土的物化特性,从光性能、射线屏蔽性能和磁性能这三大方面入手,制备多种具有不同性能的有机稀土配合物,并制备了多种具有不同用途的无机、有机稀土/高分子复合材料,较为系统地研究了这些材料的特异性能以及复合结构与性能之间的关系。同时,使用第四统计理论-JRG群子理论对材料的性能从理论上进行了阐述。在发光性能研究上,主要成果是:(1)合成了具有反应活性和高发光性的Re(tta)2(aa)phen配合物、高发光性的Re(tta)3phen配合物和具有反应活性的Sm(aa)3配合物。Re(tta)2(aa)phen和Re(tta)3phen均具有很高的荧光强度,并且均发射RE3+离子的特征荧光谱峰。(2) 本实验进行了将稀土配合物与橡胶结合起来制备发光材料的新尝试,采用易与稀土离子配位的NBR橡胶和具有优良化学稳定性的SiR与高发光性的Re(tta)3phen(RE=Eu,Sm)配合物复合制备了具有优良荧光性能的稀土/高分子复合材料。(3)本文首次提出了利用原位反应法制备稀土/高分子复合发光材料的方法,并首次用原位反应法制备了具有优良力学性能的Sm(aa)3/NBR复合材料和荧光性能优异的Re(tta)2(aa)phen/NBR复合材料,特别是Re(tta)2(aa)phen/NBR复合材料的硫化胶荧光强度比混炼胶荧光强度成倍增强。通过SEM、TEM观察材料的微观相态结构,可以看出,原位反应法制备的复合材料中,稀土分散相粒径和数量在硫化前后变化显著,并达到良好的分散,验证了通过原位反应的方法可以制备出高稀土含量、分散均匀和高荧光强度的稀土/聚合物复合材料这一事实。在射线屏蔽性能研究上,主要成果是:(1)通过填加原子序数不同的4 种无机稀土[碳酸镧(LaCO3)、碳酸镨(PrCO3)、氧化钐(Sm2O3)、氧化钆(Gd2O3)]至橡胶中,来制备射线屏蔽复合材料,我们发现复合材料的防辐射性能随着所填加的稀土元素的用量的增加而增加,并且随着所填加的稀土元素的原子序数的增加而增加。(2) 在采用过氧化物作为硫化体系时,通过延长硫化时间,可以降低Gd(aa)3在橡胶基体中的分散颗粒的粒径,增加其分散的均匀性,从而提高材料的P值和拉伸强度。当采用相同的硫化体系时,使用NR作为基体胶的橡胶试样的防辐射性能优于使用NBR为基体胶的试样,即基体胶的选择对材料的防辐射性能也存在一定影响。(3)在金属含量很小(即稀土元素的添加量很小)时,使用氧化钆作为填充物比使用丙烯酸钆作为填充物的防辐射性能要好。但随着金属含量的增加,使用丙烯酸钆作为填充物的体系的P值反而比使用氧化钆作为填充物的体系的P值大。在磁性能研究上,主要成果是:(1) 在常温 (300K) 下,Gd(ba)3是顺磁性的物质,这与低温下呈现强铁磁性的金属Gd有所不同。(2)Nd(aa)3在常温 (300K) 下也显顺磁性。(3)<WP=3>上述稀土配合物的磁矩与稀土离子的实测磁矩比较吻合,说明它们的磁性来源于稀土离子本身,而与配体所提供的配位环境关系不大。(4)Nd(aa)3/PU复合材料在常温下为顺磁物质,在5-300K温度变化范围内,该复合材料的克饱和磁化强度均低于Nd(aa)3的性能,说明材料的磁性能取决于Nd3+本身,且与其含量相关。在Eu(tta)2(aa)phen/NBR复合材料发光强度与群子理论标度间关系研究中,主要成果是:(1)经过硫化以后,R1和R2值都减小,说明体系中的大、小粒子的尺寸都不同程度地降低。硫化胶的R1·R2值大大降低,趋近于0,说明体系的稀土粒子分散的均匀性增加,原位反应有利于稀土在基体中的分散。经过硫化后,R2/R1值增加,同时体系的发光强度增强,说明R2/ R1与体系的荧光强度有着直接关系,即更细小的粒子对发光强度产生更大的影响。(2)硫化胶的 R1·R2变得很小,说明在原位反应的作用下,反应热能已有效地转化稀土子分散所需的活化能,使体系的总活化能达到较高,符合高度均匀分散的能量最高原理。可见,硫化胶比混炼胶更容易受外界能量的激发,因此硫化胶的发光效率和发光强度比混炼胶的要高。在Sm(tta)2(aa)phen/NBR复合材料发光强度与群子理论标度间关系研究中,主要成果是:(1)硫化胶的R1和R2值较为接近,说明体系中的大、小粒子存在的倾向都变小,也就是大粒子尺寸在下降,小粒子的尺寸在增加,形成重心粒径分布的情况。硫化胶的R1·R2值降低,趋近于0,说明体系的稀土粒子分散的均匀性增加,原位反应有利于稀土在基体中的分散。硫化胶的R2/R1值比混炼胶的高,说明体系中由稀土有机配合物单体形成的低聚物有不断地从基体中析出并聚集的倾向,当然这种聚集的粒子尺寸仍远小于混炼胶中分散的稀土粒子尺寸。这种变化事实上是提高了分散的均匀度。(2)硫化胶的 R1·R2变得更小,说明在原位反应的作用下,反应热能已有效地转化稀土粒子分散所需的活化能,使体系的总活化能达到较高,符合高度均匀分散的能量最高原理。可见,硫化胶比混炼胶更容易受外界能量的激发,因此硫化胶的发光效率和发光强度比混炼胶的要高。在Gd(aa)3/NR复合材料的屏蔽性能(P和M值)与群子理论标度间关系研究中,主要成果是:(1)随着硫化的进行,R1和R2值都不断变大,说明体系中存在着“大粒子”变多,小粒子也有变多的倾向。这里所说的“大粒子”并不是指事先分散于混炼胶中的稀土大颗粒。随着硫化的进行,这些“大粒子”将由2部分组成:一部分来自于经过原位反应被“刻蚀”的稀土粒子,另一部分更多还原

【Abstract】 In this thesis, we firstly utilized the physical-chemistry characteristics of rare-earths to have prepared many organic rare-earth complexes with different properties and many all-purposed polymer composites doped with inorganic or organic rare-earth complexes in order to develop some value materials with novel luminescence, radiation protection or magnetism properties. Then we studied on the relationship of these materials’ novel properties and structures in detail. At the same time, we used the JRG Forth-Statistic Theory to discuss the mechanism of some properties.On the study of the luminescence properties, the main success is that (1) we synthesized rare-earth tris-(2-thenoyltrifluoroacetone)-1,10-phenanthroline-acrylic acid (with reactive and high lighting properties, rare-earth tris-(2-thenoyltrifluoroacetone)-1,10-phenanthrolin (Re(tta)3phen) with high luminescent properties and samarium acrylic acid (Sm(aa)3) complex with reaction activity. The results showed that the Re(tta)2(aa)phen and Re(tta)3phen complexes all possessed high fluorescence emission intensity, the characteristic emission of RE ions were all observed. (2) In our work, we firstly attempted to combine the rubber and rare-earth complex to prepare the luminescent materials. The NBR could coordinated with rare-eath, SiR with good chemical stability and some other polymer matrixes were chosen to prepared novel fluorescent composites by blending with Re(tta)3phen(RE=Eu,Sm). (2)A new way of in-situ reaction to prepare rare-earth-doped-polymer composites was firstly mentioned in our work, and using this method we firstly made the Sm(aa)3/NBR (nitrile rubber) composite with high mechanical property and the Re(tta)2(aa)phen/NBR composites with high fluorescence. We observed that the fluorescence emission intensity of the cured material of Re(tta)2(aa)phen/NBR composite was higher several times than that of the uncured one. All kinds of macrostructure analysis (SEM,TEM and XRD) showed that the rare-earth organic complexes are homogenously and fined dispersed into polymer matrix by in-situ reaction. It indicates that in-situ reaction method is a feasible way to prepare rare-earth/polymer composites with high content of rare-earth organic complex, fine dispersion and high fluorescence intensity. On the study of radiation protection, the main success is that (1) we prepared four kinds of composites by blending LaCO3, PrCO3, Sm2O3 and Gd2O3 with rubber and we found that radiation shielding properties of these composites were increased with the adding contents of rare-earth and improved with the increasing of atomic number. (2) When the peroxide was used as vulcanizator, the particle size of Gd(aa)3 complex could be decreased and the distribution degree of Gd(aa)3 complex was increased, that result in the P value and tensile strength of composites was increased. We also found that polymer matrix also affected on the radiation <WP=6>properties of composites when the vulcanization system was same, the NR was better than NBR matrix.(3) When we used NR as matrix, we observed that Gd2O3 was more efficient than Gd(aa)3 at the same but little contents of Gd3+ ions. While the P value of Gd(aa)3/NR composite was higher than that of Gd2O3/NR composite as the contents of Gd3+ increasing. On the study of magnetism, the main success is that (1) Gd(ba)3 is a paramagnetic material at 300K, that is different with gadolinium which is one ferromagnetic material at low temperature. (2) Nd(aa)3 is also one paramagnetic material at 300K. (3) The two rare-earth complex magnetic torque is same as that of the rare-earth ions, which proves the magnetism of complexes root in rare-earth ions and there is no more relationship with coordination environment of ligands. (4) The Nd(aa)3/PU composites revealed paramagnetic properties, at the range of 5-300K the susceptibility is lower than of Nd(aa)3, which indicated that magnetism of composites lied on the contents of Nd3+ ions.On the study of the relationship of JRG sub-cluster parameters and Eu(tta)2(aa)phen/NBR composites’ f更多还原