- 學位論文
水溶性 N-取代丙烯酸聚苯胺之結構與物性研究
Studies on the Structure and Properties of Water-soluble Poly(aniline-co-N-acrylic acid aniline)
摘要
摘 要 本論文合成出水可溶性 N-取代丙烯酸聚苯胺（Poly(aniline-co-N-acrylic acid aniline)，PAAn）， 利用 GPC、13C-NMR、各種光譜分析法、熱分析法、X-ray 繞射分析、動態機械分析及變溫導電度來探討此聚合體之結構與物性，並且推導其反應機構。 由真實溶液（true solution）之紫外光-可見光光譜（UV-Vis）分析，證實我們合成出的聚合體（PAAn）可溶於水與高極性有機 DMSO 及 NMP溶劑中。此聚合體在高溫反應進行下，AIBN 會產生自由基進而打斷PAn分子鏈，使 PAn分子量隨反應溫度的升高而降低，這由 GPC 的結果可看出。此外，DMSO 在高溫下會行鏈轉移反應（chain transfer reaction），將 PAn中 imine 還原成 amine，由 UV-Vis 與 IR 光譜皆可看出。聚合體之結構可由13C-NMR 光譜與 IR 光譜結果判斷 PAAn 聚合體中 AA 是接在 PAn中amine結構的 N 上，而不是接在 PAn 的苯環或@環。 由 IR 光譜看出，聚合體中PAn會與接上的AA產生氫鍵作用。由 DMA 與 DSC 可知，PAAn 只有一個 Tg，此 Tg 不會因反應時AA 含量的增加而改變。XRD 分析結果顯示 AA 可使 PAn 鏈在 2q = ~ 12° 有較規則的排列。熱重分析顯示 PAAn 可耐熱溫度達 250 ℃ 左右。由變溫導電度結果可知，PAn 於溫度 129 ℃ 時有最大導電度大約為 10-9 S/cm，而 PAAn 於溫度 160 ℃ 左右最大導電度約為 10-6 S/cm，造成 PAAn 導電度高於 PAn 的原因是 AA上的質子可摻雜 PAn，但由於可被摻雜的位置在@環，PAAn 經各種光譜分析鑑定得知，其@環位置大部份被還原成苯環，使其摻雜度降低因而導電度無法提升。
並列摘要
Abstract Polyaniline (PAn) is currently considered to have high potentiality toward practical applications due to its cheap, good environmental stability and protonation with a protonic acid. However, it is very difficult to be dissolved in common organic solvents owing to its inherent rigid backbone. Thus, the aim of this research is to study the mechanism of PAn by react with 2,2¢-azobis-isobutyronitrile (AIBN) and acrylic acid (AA) in dimethylsulfide (DMSO) solution, and to investigate structure of the polymers. After the modification of PAn, water soluble and doping occurs. The doping level of new water soluble polymers are lower than that of PAn doped with poly(acrylic acid) (PAA), since the former have the few imine structure so that the doptable positions are few than that of the latter. The tools used for the studied are gel permeation chromatograph (GPC), 13C-nuclear magnetic resonance spectroscopy (13C-NMR), ultraviolet-visible spectroscopy (UV-Vis), infrared spectrometer (IR), X-ray diffractometer (XRD), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA), thermogravimetric analyzer (TGA), and conductivity measurements. In the true solution test, it was found that the new polymers (poly(aniline-co-N-acrylic acid-aniline)s, PAAns) could be dissolved in H2O. Results of GPC evidenced PAAns have only one molecular weight distribution. 13C-NMR Results indicated that the AA group is bonding with the nitrogen atom (N) of amine ring of PAn chain. For IR spectra, all the absorption bands at 1721 and 3488 cm-1 of C=O and N-H stretching vibration of PAA, respectively, and at 3220 and 1310 cm-1 of N-H and Caromatic-N stretching vibration of PAn, respectively, shifted toward low frequency. These results indicate the presence of hydrogen-bond interactions of PAn added with AA. For UV-vis results, the PAAns DMSO solutions, two absorption peaks exist at 358 nm (π-π* transition of the benzenoid ring) and 600 nm (excition absorption of the quinoid ring), and in the aqueous solutions, doping occurs. All of the decreasing of ratio of lmax,imine/lmax,amine in PAAns DMSO and aqueous solutions, and thin solid films. It is due to the thermal dissociation of DMSO into H· free radical, which will attack imine form of PAn to amine form, causing the decreasing of imine structure. XRD results indicate AA group help PAn chain to form a more regular phase resulting in the formation of a new phase at 2q = ~ 12°. The co-existence of two-phase strongly supports those hydrogen-bond interactions between the two components. For conductivity measurement as measured using the four-probe method, the decreasing of conductivity of PAn with the increasing of AA is due to the decreasing of imine in the reaction and the dropping of doping level.