本文選題：多面體低聚倍半硅氧烷(POSS) + 有機-無機雜化�。� 參考：《電子科技大學》2012年碩士論文

【摘要】：籠型多面體低聚倍半硅氧烷(Polyhedral Oligomeric Silsesquioxanes,POSS)是一種分子水平的有機-無機雜化材料,由于其獨特的分子結構,基于POSS制備的有機-無機雜化材料成為當今材料學領域的研究熱點。 本論文在POSS以及POSS基生物醫(yī)用材料的研究現(xiàn)狀的基礎上,圍繞多官能化POSS單體的合成及制備工藝改進,含有POSS結構的星型雜化生物可降解聚合物的合成和表征,以及雜化球狀分子增韌劑對聚乳酸材料的改性等方面展開,通過1H-NMR、GPC、FTIR、 DSC、TG、SEM和拉伸試驗等手段對雜化聚合物和復合材料的結構和性能等進行了研究。 首先,本文合成和表征了八聚四甲基銨倍半硅氧烷、八聚(二甲基硅氧基)倍半硅氧烷、八聚[2-(2-羥基乙氧基)二甲基硅氧基]倍半硅氧烷(POSS-OH)等三種具有不同官能團的POSS單體,獲得了高純度產(chǎn)物。在合成過程中,溶劑極性、反應溫度、催化劑、產(chǎn)物處理等對POSS的單體的產(chǎn)率和純度都有較大影響。 其次,本文通過“先核后臂”方法,以納米尺寸的含八羥基的POSS-OH為核,引發(fā)D,L-丙交酯開環(huán)聚合,合成了八臂星型有機-無機POSS-PDLLA雜化聚合物。GPC、DSC、TG結果顯示,該雜化聚合物分子量分布極窄,熱穩(wěn)定性良好,表現(xiàn)出與普通線性聚乳酸完全不同的特性。 第三,本文通過溶液聚合的方法,同樣以含八羥基的POSS-OH為核,先后引發(fā)ε-己內(nèi)酯(CL)和D,L-丙交酯(LA)發(fā)生次序開環(huán)聚合,制備了一系列具有不同組成(CL:LA=3:1;2:2;1:3),核為聚己內(nèi)酯(PCL)軟段、殼為聚乳酸硬段的星型有機-無機POSS-g-PCL-b-PLA雜化嵌段共聚物。1H-NMR譜圖證實了POSS-OH的羥基確實引發(fā)了聚合,且PCL和PLA鏈段之間形成了嵌段結構。GPC和DSC研究表明,三種雜化嵌段共聚物分子量分布很窄且PCL的結晶受到抑制,是潛在的球狀分子增韌劑。 最后,本文通過溶液共混法,以POSS-g-PCL-b-PLA (CL:LA=2:2)為增韌劑,制備了組成不同的POSS-g-PCL-b-PLA/PDLLA復合材料。拉伸試驗表明,當復合材料中增韌劑的含量低于10%時,它能有效改善基體材料的韌性；而當其含量增加到20%時,其增韌效果顯著下降。這主要是因為在低含量下,增韌劑能以分子級狀態(tài)分散在基體中,其PCL鏈段的結晶受到抑制,主要以無定形狀態(tài)存在,因而其增韌效果非常顯著。 綜上所述,將POSS引入到可生物降解高分子材料中,在分子水平上構建含有POSS結構的有機-無機雜化生物可降解材料,對發(fā)展具有新性能、新結構、新功能的納米醫(yī)藥材料具有重要的理論意義和實用價值。
[Abstract]:Polyhedral Oligomeric SilsesquioxanesPOSS is a kind of organic-inorganic hybrid material at molecular level. Because of its unique molecular structure, the organic-inorganic hybrid material based on poss has become a research hotspot in the field of materials science. On the basis of the research status of poss and poss based biomedical materials, the synthesis and characterization of star hybrid biodegradable polymers containing poss structure have been improved around the synthesis and preparation of polyfunctional poss monomers. The structure and properties of hybrid polymers and composites were studied by means of 1H-NMR-GPC-FTIR, DSC-TGX SEM and tensile test. Firstly, three kinds of POSS monomers with different functional groups have been synthesized and characterized, including tetramethylammonium tetrasiloxane, octamer (dimethylsiloxy) silicoxane and octamer [2- (2-hydroxyethoxy) dimethylsiloxane] multisilane (POSS-OH). High purity products were obtained. In the process of synthesis, the polarity of solvent, reaction temperature, catalyst and product treatment have great influence on the yield and purity of POSS monomer. Secondly, by means of the method of "first nucleation after arm", using the nano-size POSS-OH containing octyl group as the nucleus, the ring-opening polymerization of DHL-lactide was initiated and the octa-star organic-inorganic POSS-PDLLA hybrid polymer, .GPC-PDLLA hybrid polymer, was synthesized. The molecular weight distribution of the hybrid polymer is very narrow and the thermal stability of the hybrid polymer is good. Thirdly, by solution polymerization, we have initiated sequential ring-opening polymerization of 蔚 -caprolactone (CL) and DL- lactide (LA) with POSS-OH containing octyl groups. A series of polycaprolactone (PCL) soft segments with different composition (CL: LA-31: 2: 2: 1: 3) have been prepared, and the core of PCL is polycaprolactone (PCL) soft segment, and the core of PCL is polycaprolactone (PCL), the core of which is polycaprolactone (PCL). The star POSS-g-PCL-b-PLA hybrid block copolymers with poly (lactic acid) hard segments in the shell. 1H-NMR spectra confirmed that the hydroxyl groups of POSS-OH really initiated the polymerization, and the block structure. GPC and DSC showed that there was a block structure between the PCL and PLA segments. The molecular weight distribution of the three hybrid block copolymers is very narrow and the crystallization of PCL is inhibited. Finally, a POSS-g-PCL-b-PLA / PDLLA composite with different composition was prepared by solution blending with POSS-g-PCL-b-PLA (CLL: LA2: 2) as toughener. The tensile test shows that when the content of toughener in the composite is lower than 10%, the toughness of the matrix material can be improved effectively, but when the content of the toughener is increased to 20%, the toughening effect of the composite decreases significantly. This is mainly due to the fact that at low content the toughening agent can disperse in the matrix in the molecular state and the crystallization of the PCL segment is inhibited mainly in the amorphous state so the toughening effect is very remarkable. In conclusion, the introduction of poss into biodegradable polymer materials and the construction of organic-inorganic hybrid biodegradable materials with poss structure at molecular level have new properties and new structures. New functional nanometer medical materials have important theoretical significance and practical value.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2012
【分類號】：TB383.1;R318.08

【參考文獻】

相關期刊論文 前3條

1 田豐;劉長軍;高萬玉;張彥軍;;分子內(nèi)雜化納米結構體多面體低聚倍半硅氧烷研究進展[J];高分子材料科學與工程;2007年04期

2 趙京波,楊萬泰;合成生物降解性聚酯研究的進展[J];高分子通報;1999年02期

3 杜建科,楊榮杰;籠形低聚硅倍半氧烷納米材料及其應用[J];宇航材料工藝;2005年03期

相關碩士學位論文 前1條

1 張楠楠;官能化倍半硅氧烷的制備及其在聚合物復合材料中的應用[D];南京理工大學;2008年

，

本文編號：2104179