【作者】 张宇；

【导师】 李杨；

【作者基本信息】 大连理工大学 ， 高分子化学与物理， 2014， 博士

【摘要】 光敏性树形聚合物是一种新型智能高分子材料,聚合物独特的三维结构给材料光敏性能带来的巨大影响引起了人们的广泛关注。高支化聚合物是继树枝状聚合物和超支化聚合物之后的一类新型树形聚合物,由于其兼具树枝状聚合物结构规整和超支化聚合物合成简便的优势而具有极大的功能化价值,但光敏性高支化聚合物的研究未见报道。本文结合活性阴离子聚合技术和“点击”化学方法合成了两类光敏性高支化聚丁二烯,系统考察了聚合物的高支化结构对材料光敏性能的影响,纵观全文总结如下：(1)基于活性阴离子聚合技术设计合成了0-3代线形梳状及星形梳状高支化聚丁二烯(LGn-PB和SGn-PB, n=0-3);通过化学修饰在聚丁二烯链中引入叠氮基团,获得叠氮基团摩尔含量为17-22%的高支化聚丁二烯模板LGn-N3和SGn-N3(n＝0-3)。通过考察分子支化参数可知：代数从0增加到3,LGn-PB和SGn-PB的结构逐渐变紧密；当代数相同时,LGn-PB和SGn-PB支化臂数及侧链长度相似但SGn-PB比LGn-PB结构更紧密。(2)采用“点击”化学方法成功将炔基修饰的香豆素小分子和炔基修饰的螺吡喃小分子分别连接到LGn-N3和SGn-N3(n=0-3)上,获得含香豆素基团的高支化聚丁二烯LGn-C和SGn-C(n=0-3)及含螺吡喃基团的高支化聚丁二烯LGn-SP和SGn-SP (n=0-3)。(3)研究LGn-C和SGn-C (n=0-3)的高支化结构对材料荧光性能的影响发现：香豆素基团的荧光量子产率(ΦF)从小分子的1.7%提高到LG1-C的7.3%和SGl-C的5.4%；不同代数产物的ΦF依次为φF(G1)><DF(G2)> φF(G3)>φF(G0);聚合物结构较松散的LGn-C的ΦF较相同代数SGn-C的ΦF高。上述结果说明,LGn-C和SGn-C同时存在高分子链间/高分子链内荧光猝灭且材料的荧光性能受二者共同影响。(4)研究LGn-C和SGn-C (n=0-3)的高支化结构对材料光致交联性能的影响发现：LGn-C和SGn-C的最大交联度(Ed,max)和最大恢复率(Er,max)均随代数增加而增大,聚合物结构较紧密的SGn-C较相同代数LGn-C的Ed.max更大且Er.max更高,其中SG3-C和LG3-C的Ed,max分别高达94.0%和92.8%。上述结果说明,LGn-C和SGn-C内同时存在高分子链间／高分子链内交联且材料的光致交联性能受二者共同影响。(5)研究LGn-SP和SGn-SP (n=0-3)的高支化结构对材料光致变色性能的影响发现：与小分子螺吡喃相比,聚合物的增色速度变慢,褪色速度变快。代数从0增加到3,LGn-SP和SGn-SP的增色速度变慢,褪色速度变快；相同代数下,LGn-SP较SGn-SP的增色速度和褪色速度均慢。更多还原

【Abstract】 Photosensitive dendritic polymers are a new class of smart polymer materials, the unique three-dimensional structure of polymer backbones have a big impact on the photosensitive material properties and have been drew more and more attention. Dendrigraft polymers are a new class of dendritic polymers after dendrimer and hyperbranched polymers. Due to their regular controllable structures and convenient synthesis, dendrigraft polymers have a great advantage of functional value, but the photosensitive dendrigraft polymers have been barely reported. In this paper, it combined the anionic polymerization techniques and "click" chemistry to synthesize two kinds of photosensitive dendrigraft polybutadiene and the effect of dendrigraft architecuture on photosensitive material properties were systematically investigated. The main conclusions were summarized as follows:(1) A series of multicoumarin-functionalized dendrigraft polybutadienes with linear-comb or star-comb architecture were synthesized from generation0to3(LGn and SGn, respectively, n=0-3) via anionic polymerization. LGn-PB and SGn-PB (n=0-3) were functionalized by17-22mol%azide groups through chemical modification, obtaining linear-comb and star-comb dendrigraft polybutadiene template LGn-N3and SGn-N3(n=0-3). From the results of the molecular branching parameters, it showed that:with increasing the generation from0to3, the polymer architecture converted from one-or two-dimensional structure to aflexible branched structure, then advanced into a compact structure; meanwhile, the LGn-PB exhibited a relatively looser structure than its SGn-PB analog did.(2) The alkynyl-modified coumarin and alkynyl-modified spiropyran were linked to LGn-N3and SGn-N3(n=0-3) via "click" chemistry, obtaining coumarin-functionalized dendrigraft polybutadiene LGn-C and SGn-C (n=0-3) and spiropyran-functionalized dendrigraft polybutadiene LGn-SP and SGn-SP (n=0-3), respectively.(3) For LGn-C and SGn-C (n=0-3), the effect of dendrigraft structure on the fluorescence properties were summarized as follows:the fluorescence quantum yield (φDF) grew from1.7%of coumarin small molecules to7.3%and5.4%of LG1-C and SG1-C, respectively. The φf of LGn-C and SGn-C (n=0-3) with different generation were exhibited in an order of φF(G1)> OF(G2)> OF(G3)>φF(G0), and the OF of LGn-C were always better than those of SGn-C due to its looser architecture. These resluts indicated that there are inter-macromolecules fluorescence quenching and intra-macromolecules fluorescence quenching at the same time, while the fluorescence properties of LGn-C and SGn-C (n=0-3) were affected by the "inter-/intra-macromolecules quenching" pattern.(4) For LGn-C and SGn-C (n=0-3), the effect of dendrigraft structure on the photo-crosslinking properties were summarized as follows:maximum crosslinking degree (Ed, max) and the maximum recovery degree (Er,max) of LGn-C and the SGn-C were increased with increasing generation. SGn-C with the more compact structure exnibited higher Ed. max and Er.max than its LGn-C analog did. SG3-C and LG3-C exhibited.Ed,max as high as94.0%and92.8%, respectively. These results indicated that there are inter-macromolecules crosslinking and intra-macromolecules crosslinking at the same time, while the photo-crosslinking properties were affected by the "inter-/intra-macromolecules photo-crosslinking" pattern.(5) For LGn-C and SGn-C (n=0-3), the effect of dendrigraft structure on the photochromic properties were summarized as follows:Compared with spiropyran, LGn-SP and SGn-SP exhibited a slower colored speed and a faster fade speed. For LGn-SP and SGn-SP, the colored speed is slower and the fade speed is faster with increasing the gerneration from0to3. LGn-SP exhibited a slower colored speed and fade speed than its its SGn-PB analog did.更多还原