[目的]针对环氧树脂(epoxy resin,EP)易燃性限制其应用范围、常规阻燃添加剂劣化其热稳定性等问题,设计合成了新型有机磷阻燃固化剂.[方法]利用4-咪唑甲醛和4,4'-二氨基二苯甲烷反应生成席夫碱,进一步与9,10-二氢-9-氧杂-10-磷杂菲-...[目的]针对环氧树脂(epoxy resin,EP)易燃性限制其应用范围、常规阻燃添加剂劣化其热稳定性等问题,设计合成了新型有机磷阻燃固化剂.[方法]利用4-咪唑甲醛和4,4'-二氨基二苯甲烷反应生成席夫碱,进一步与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物反应,合成含磷杂菲和咪唑基团的固化剂IDP.利用核磁共振(nuclear magnetic resonance,NMR)氢谱(^(1)H-NMR)、磷谱(^(31)P-NMR)和傅里叶红外光谱对制备的IDP进行结构表征,并通过相关测试研究IDP对EP/IDP材料的玻璃化转变温度(T_(g))、热稳定性和阻燃抑烟性能的影响.[结果]IDP分子的芳香结构使EP/IDP材料的T_(g)提高.在氮气条件下,EP/IDP材料的残炭率增加,最大热失重速率降低.添加5.0%(质量分数)的IDP时,EP/IDP-5.0的极限氧指数达33.0%,UL-94垂直燃烧测试达到V-0等级;添加7.5%(质量分数)的IDP时,EP/IDP-7.5的热释放速率峰值、总放热量和总产烟量分别降低约24.2%,16.4%和16.7%.[结论]本研究设计的含磷杂菲和咪唑基团的固化剂IDP可提高EP的火安全性,同时提高其T_(g),为开发新型有机磷固化剂提供指导.展开更多
Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hinder...Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hindered their translation into practical applications.In this study,two CPDT-based conjugated polymers with distinct substituent groups were designed and synthesized:PCPDT-Ph(copolymerized with unsubstituted benzene units)and PCPDT-PhOMe(copolymerized with dimethoxy-substituted benzene units).The influence of dimethoxy substitution on the electrochromic properties and stability of the polymers was systematically investigated.Electro⁃chemical and electrochromic characterizations demonstrated that the electron-donating ability of the dimethoxy groups not only effectively regulated the polymer’s intrinsic properties but also significantly enhanced its cycling stability.Compared with PCPDT-Ph,PCPDT-PhOMe exhibited a reduced onset oxidation potential from 0.66 V(vs.Ag/AgCl)to 0.46 V,an upshifted highest occupied molecular orbital(HOMO)energy level,and a narrowed optical band gap(calculated theoretically)from 1.73 eV to 1.61 eV.The PCPDT-PhOMe film showed magenta in the neutral state and transparency in the oxidized state,with a color difference(ΔE*a b)of 46.36.The coloring/bleaching response times were measured as 0.7/0.6 s,and the optical contrast retention reached 84%after 1000 cycles,outperforming the PCPDT-Ph film(79.5%retention after 500 cycles).Additionally,it exhibited a coloration efficiency of 543.9 cm^(2)/C,demonstrating favorable comprehensive electrochromic performance.Electrochromic devices assembled with PCPDT-PhOMe achieved reversible switching between magenta and transparent states,with a response time of≤1.0 s and a contrast retention of 71%after 30000 cycles,indicating good stability.This work clarifies the role of substituent electronic effects in regulating the electrochromic properties of CPDT-based polymers,providing experimental basis and theoretical support for the molecular design of solution-processable thiophene-based electrochromic materials.Furthermore,it validates the potential application of PCPDT-PhOMe in smart windows,electronic displays,and other related fields.展开更多
文摘[目的]针对环氧树脂(epoxy resin,EP)易燃性限制其应用范围、常规阻燃添加剂劣化其热稳定性等问题,设计合成了新型有机磷阻燃固化剂.[方法]利用4-咪唑甲醛和4,4'-二氨基二苯甲烷反应生成席夫碱,进一步与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物反应,合成含磷杂菲和咪唑基团的固化剂IDP.利用核磁共振(nuclear magnetic resonance,NMR)氢谱(^(1)H-NMR)、磷谱(^(31)P-NMR)和傅里叶红外光谱对制备的IDP进行结构表征,并通过相关测试研究IDP对EP/IDP材料的玻璃化转变温度(T_(g))、热稳定性和阻燃抑烟性能的影响.[结果]IDP分子的芳香结构使EP/IDP材料的T_(g)提高.在氮气条件下,EP/IDP材料的残炭率增加,最大热失重速率降低.添加5.0%(质量分数)的IDP时,EP/IDP-5.0的极限氧指数达33.0%,UL-94垂直燃烧测试达到V-0等级;添加7.5%(质量分数)的IDP时,EP/IDP-7.5的热释放速率峰值、总放热量和总产烟量分别降低约24.2%,16.4%和16.7%.[结论]本研究设计的含磷杂菲和咪唑基团的固化剂IDP可提高EP的火安全性,同时提高其T_(g),为开发新型有机磷固化剂提供指导.
基金Supported by the National Natural Science Foundation of China(No.52103232)the Natural Science Foundation of Zhejiang Province,China(Nos.LY24E030012,LY19E030006)。
文摘Cyclopentadithiophene(CPDT)-based polymers have emerged as promising research platforms for multi⁃color electrochromic materials due to their favorable color tunability.However,insufficient cyclic stability has hindered their translation into practical applications.In this study,two CPDT-based conjugated polymers with distinct substituent groups were designed and synthesized:PCPDT-Ph(copolymerized with unsubstituted benzene units)and PCPDT-PhOMe(copolymerized with dimethoxy-substituted benzene units).The influence of dimethoxy substitution on the electrochromic properties and stability of the polymers was systematically investigated.Electro⁃chemical and electrochromic characterizations demonstrated that the electron-donating ability of the dimethoxy groups not only effectively regulated the polymer’s intrinsic properties but also significantly enhanced its cycling stability.Compared with PCPDT-Ph,PCPDT-PhOMe exhibited a reduced onset oxidation potential from 0.66 V(vs.Ag/AgCl)to 0.46 V,an upshifted highest occupied molecular orbital(HOMO)energy level,and a narrowed optical band gap(calculated theoretically)from 1.73 eV to 1.61 eV.The PCPDT-PhOMe film showed magenta in the neutral state and transparency in the oxidized state,with a color difference(ΔE*a b)of 46.36.The coloring/bleaching response times were measured as 0.7/0.6 s,and the optical contrast retention reached 84%after 1000 cycles,outperforming the PCPDT-Ph film(79.5%retention after 500 cycles).Additionally,it exhibited a coloration efficiency of 543.9 cm^(2)/C,demonstrating favorable comprehensive electrochromic performance.Electrochromic devices assembled with PCPDT-PhOMe achieved reversible switching between magenta and transparent states,with a response time of≤1.0 s and a contrast retention of 71%after 30000 cycles,indicating good stability.This work clarifies the role of substituent electronic effects in regulating the electrochromic properties of CPDT-based polymers,providing experimental basis and theoretical support for the molecular design of solution-processable thiophene-based electrochromic materials.Furthermore,it validates the potential application of PCPDT-PhOMe in smart windows,electronic displays,and other related fields.
