【作者】 张瑞雪；

【导师】 李杨； 韩丽；

【作者基本信息】 大连理工大学 ， 化学工程（专业学位）， 2021， 硕士

【摘要】 螺吡喃基（SP）光致变色材料因其闭环体（SP）和开环体（MC）结构变化的可逆性以及光刺激的远程和精确控制等优点,在智能材料领域具有潜在的应用前景。聚苯乙烯（PS）作为通用聚合物材料,广泛用于改善功能高分子材料的机械加工性和稳定性。然而,当前共混SP或接枝/共聚SP的PS共混物或聚合物光致变色材料存在结构稳定性差、聚合物分子量和分子量分布可控性差、光致变色调控不明确等不足。因此,合成结构可控和光致变色可调的聚合物对光致变色材料的研究和应用具有重要的意义。活性阴离子聚合（LAP）具有独特的活性聚合特点,能够定制合成分子量可控、窄分布的PS均聚物及其嵌段共聚物模板,结合功能模块高效点击反应制备结构可控的功能化聚合物,对揭示结构对性能的影响机制至关重要。因此,本工作基于LAP和高效硅氢加成方法,制备结构可控的以PS均聚物和嵌段共聚物为主链的SP光致变色高分子。（1）基于LAP方法制备了Si-H官能化聚苯乙烯（PVPDMS）主链,通过硅氢加成方法,将两种炔基（Yne）末端的SP功能单体,即SP-phenyl-Yne（M₁）/SP-biphenyl-Yne（M₂）接枝到PVPDMS主链中,成功制备了以PS均聚物为主链的PVPDMS-SPM₁/SPM₂。¹H-NMR结果表明,在室温下,PVPDMS中的Si-H基团与Yne末端的SP单体接枝率接近100%。利用UV-Vis光谱研究了SP单体及其聚合物在不同溶剂中光诱导溶致变色行为。结果表明,在不同溶剂中,SP单体及其聚合物在365 nm紫外光开关过程中迅速发生开环和闭环异构化,同时伴随生色和褪色现象;提出了不同SP异构体之间可能的转变过程,证实了光诱导溶致变色与溶剂极性和分子结构的相关性以及H-聚集体和顺式结构MC的形成与溶剂极性的相关性。（2）基于LAP方法制备了PVPDMS（M_n=4 kg/mol）与不同分子量聚丁二烯（PB）（M_n=6 kg/mol;18 kg/mol;30 kg/mol）的嵌段共聚物主链,即,PVPDMS-b-PB_6k/18k/30k,其中,PB嵌段中1,2-PB含量约为8 mol%。以PVPDMS-b-PB_6k主链为例,通过硅氢加成方法,将SP-phenyl-Yne（M₁）功能单体接枝到嵌段共聚物主链中,成功制备了以PS嵌段共聚物为主链的（PVPDMS-g-SP）-b-PB_6k。¹H-NMR结果表明,在室温下,PVPDMS嵌段中Si-H基团优先与SP单体的Yne末端发生接枝率近100%的硅氢加成反应,而Si-H基团与PB嵌段中1,2-PB和1,4-PB基本不发生硅氢加成反应。此外,利用UV-Vis光谱研究了聚合物在不同溶剂中光诱导溶致变色行为。结果表明,在365 nm紫外光照开关过程中,（PVPDMS-g-SP）-b-PB_6k迅速呈现了生色和褪色现象,并且表现出与PVPDMS-SPM₁/SPM₂均聚物相似的光诱导溶致变色行为。本工作为后续研究不同PB分子量对光致变色和溶致变色行为的影响奠定了基础。更多还原

【Abstract】 Photochromic materials containing spiropyran（SP）group have potential applications in the field of smart materials due to their structural reverse ability of closed-loop（SP）to open-loop（MC）and the advantages of optically remote activation and precise control.As general polymer material,polystyrene（PS）is widely applied to improve the machinability and stability of functional materials.However,the PS blends and polymer photochromic materials doped with,or grafted/copolymerized by SP still have limitations,such as poor structural stability,poor controllability of molecular weight and polydispersity index（PDI）,and insufficient regulation of photochromism.Therefore,the synthesis of polymers with controllable structures and tunable photochromism is of great significance for the research and applications of photochromic materials.Living anionic polymerization（LAP）possesses unique characteristics of living polymerization that can tailor the PS homopolymer or block copolymer templates with well-defined molecular weight and narrow polydispersity index.Combining with the efficient click reaction of functional modules,the functional polymers with controllable structure are prepared,which is of great importance to reveal the influence mechanism of structure on property.In this work,based on LAP and high efficiency hydrosilylation,the desired structures of SP photochromic polymers with PS homopolymer or block copolymer backbones are obtained.（1）The backbone of Si-H functionalized polystyrene（PVPDMS）is prepared by LAP.Two kinds of SP monomers with the end of Yne group,i.e.,SP-phenyl-Yne（M₁）and SP-biphenyl-Yne（M₂）are synthesized and subsequently graft into PVPDMS by hydrosilylation.PVPDMS-SPM₁ and PVPDMS-SPM₂ with PS homopolymer backbone are successfully prepared.The calculation results of ¹H-NMR show that,the addition efficiency of Si-H group in PVPDMS with Yne ended SP monomers are close to 100%at room temperature.The photoinduced solvatochromic behavior of SP monomers and responding polymers in different solvents is studied by UV-Vis spectroscopy.The results confirm that in different solvents,SP monomers and polymers rapidly undergo open-loop and closed-loop isomerization during the 365 nm UV-light switching process accompaning by the color generation and fading.Possible transition processes between different SP isomers are proposed,the correlation between photoinduced solvatochromic with solvent polarity and molecular structure is confirmed,as well as the relationship between the formation of H-aggregation and cis-MC with solvent polarity.（2）The block copolymers containing PVPDMS（M_n=4 kg/mol）and polybutadiene（PB）with different molecular weight（M_n=6 kg/mol;18 kg/mol;30 kg/mol）,i.e.,PVPDMS-b-PB_6k/18k/30k are prepared through LAP,in which the content of 1,2-PBs in the PB block is about8 mol%.Taking the PVPDMS-b-PB_6k as example,SP-phenyl-Yne（M₁）is grafted into the block copolymer backbone by hydrosilylation and（PVPDMS-g-SP）-b-PB_6k is successfully prepared.The calculation results of ¹H-NMR show that at room temperature,the addition efficiency of Si-H groups in PVPDMS block with the SP monomer is close to 100%,while the 1,2-PBs and1,4-PBs in PB block can hardly react with the Si-H groups.In addition,the photoinduced solvatochromic behavior of functionalized polymer in different solvents is studied by UV-Vis spectroscopy.The results represent that（PVPDMS-g-SP）-b-PB_6k rapidly undergoes the process of coloring and fading during the switch of 365 nm UV-light,which exhibits similar photoinduced solvatochromic behavior to that of PVPDMS-SPM₁/SPM₂.The work provides foundation for further research about the effects of different PB molecular weights on photochromic and solvatochromic behavior.更多还原