本文選題：稀土　切入點(diǎn)：高分子金屬復(fù)合物　出處：《東華大學(xué)》2014年碩士論文

【摘要】：本課題首先研究了不同濃度、不同pH條件下聚丙烯酸(PAA)與稀土離子(Ln)的絡(luò)合行為。在此基礎(chǔ)上,將稀土離子引入PAA與聚乙烯基吡咯烷酮(PVPON)的氫鍵復(fù)合體系,利用層層組裝技術(shù)制備了含有稀土離子的氫鍵復(fù)合薄膜。 研究發(fā)現(xiàn)PAA和Ln的絡(luò)合行為是一個復(fù)雜的過程。pH值、摩爾比以及濃度等都對PAA-Ln復(fù)合物的形成產(chǎn)生顯著影響。與COOH相比,COO-與稀土離子的絡(luò)合能力更強(qiáng)。當(dāng)pH值高于2.0時,PAA發(fā)生電離。隨著pH值的增加,PAA的電離程度增加,COO-的比例增加。當(dāng)pH值高于7.5時,稀土離子會形成Ln(OH)3,因此我們研究PAA和Ln相互作用的pH值范圍為2.0-7.5。在合適的pH值范圍內(nèi),當(dāng)稀土離子濃度較高時,PAA-Ln可以形成沉淀,通過過濾可以將沉淀分離；當(dāng)稀土離子的濃度低于1.0×10-3mol/L或者[AA]/[Ce]大于5時,PAA-Ln可以均勻分布于溶液中而不沉淀出來,此時可以利用透析的方法將PAA-Ln除去。 當(dāng)pH值增加時,PAA與稀土鈰離子(Ce3+)的絡(luò)合能力增強(qiáng),可以形成復(fù)合物。但pH值過高,PAA與PVPON之間很難形成氫鍵復(fù)合物,因此只有在特定pH值區(qū)間才可形成三元的復(fù)合物。pH值在2.5-4.0區(qū)間時,可以成功制備PAA-Ce-PVPON三元復(fù)合物,并且復(fù)合物中同時存在氫鍵作用和配位作用。隨著pH值增加,氫鍵作用逐漸減弱,配位作用逐漸增強(qiáng)。隨著pH值的增加,三元復(fù)合物中Ce元素的含量逐漸增加,這是因?yàn)镻AA電離程度逐漸增加,COO比例增加,由于COO-與Ce離子的絡(luò)合能力遠(yuǎn)大于COOH與Ce離子的絡(luò)合能力,因此復(fù)合物中的Ce離子含量增加。 在pH值小于3.5的條件下,(PVPON-Ce-PAA)n薄膜可以成膜,pH值大于等于3.5時無法成膜。這是因?yàn)殡S著pH值的增加,PAA的電離程度增加,Ce離子與COO-的配位作用會阻礙PAA與PVPON的氫鍵的形成,因此pH值高于3.5時無法成膜。 pH值在2.5-3.5范圍內(nèi),Ce離子濃度為0.01mol/L時,(PVPON-PAA-Ce)n薄膜中同時存在氫鍵作用和配位作用,此時Ce離子可以成功加入薄膜,而且PVPON和PAA之間的氫鍵作用仍然存在。
[Abstract]:In this paper, the complexation behavior of polyacrylic acid (PAA) with rare earth ion (Ln) at different concentrations and pH was studied. On the basis of this, rare earth ions were introduced into the hydrogen bonding composite system of PAA and polyvinylpyrrolidone (PVPON). The hydrogen bonding composite films containing rare earth ions were prepared by layer-by-layer assembly technique. It is found that the complex behavior of PAA and Ln is a complex process. The molar ratio and concentration all have a significant effect on the formation of PAA-Ln complex. Compared with COOH, the complexation ability of COOH with rare earth ions is stronger. When pH value is higher than 2.0, the ionization of PAA-Ln occurs. With the increase of pH value, the degree of ionization increases. When pH is higher than 7.5, Therefore, the pH range of the interaction between PAA and Ln is 2.0-7.5. When the concentration of rare earth ions is high, PAA-Ln can be precipitated, and the precipitation can be separated by filtration. When the concentration of rare earth ions is less than 1.0 脳 10-3mol/L or [AA] / [ce] > 5, PAA-Ln can be uniformly distributed in the solution without precipitation, and PAA-Ln can be removed by dialysis. When the pH value is increased, the complex can be formed by increasing the complexing ability of PAA with cerium ion Ce3, but it is difficult to form hydrogen bond complex between PAA and PVPON when pH value is too high. Therefore, ternary complexes can be formed only in a specific pH range. When pH is in the range of 2.5-4.0, PAA-Ce-PVPON ternary complexes can be successfully prepared, and there are hydrogen bonds and coordination roles in the complexes. With the increase of pH value, the content of ce in the ternary complex increases gradually, which is due to the increasing of PAA ionization degree. Because the complexing ability of COO- and ce ions is much higher than that of COOH and ce ions, the content of ce ions in the complexes increases. When pH value is less than 3.5, PVPON-Ce-PAAn film can not form film when pH value is greater than 3.5. This is because the coordination of ce ion with COO- will hinder the formation of hydrogen bond between PAA and PVPON with increasing the ionization degree of PAA. Therefore, when pH value is higher than 3.5, film can not be formed. When the concentration of ce in the range of 2.5-3.5 is 0.01mol/L, the hydrogen bond and coordination exist in the PVPON-PAA-CeOn film. At this time, ce ions can be successfully added into the film, and the hydrogen bond between PVPON and PAA still exists.
【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TB383.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 王殿勛,劉貴,楊紅波,何紀(jì)綱,江英彥;聚乙烯吡咯烷酮和聚丙烯酸與某些金屬或稀土元素的三元絡(luò)合物結(jié)構(gòu)的XPS研究[J];結(jié)構(gòu)化學(xué);1985年04期

2 生瑜,章文貢;摻雜三乙氧基釔聚苯乙烯的合成及其配位作用[J];中國稀土學(xué)報;1997年01期

3 孟建新,涂華民,龔孟濂,楊燕生;用Ce~(3+)離子熒光測量稀土配位體系的結(jié)合常數(shù)[J];中國稀土學(xué)報;1998年03期

4 溫耀賢,溫勇,王則民,曹錦榮,陳志榮,楊海峰;摻銪聚丙烯膜的研究[J];稀土;1998年02期

，

本文編號：1684394