【作者】 黄火秀；

【导师】 关怀民；

【作者基本信息】 福建师范大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 本文基于层状双氢氧化物(LDH)的可插层性,以羧甲基纤维素(CMC)、羧甲基壳聚糖(CMCS)、羧甲基淀粉(CMS)和聚天冬氨酸-羧甲基壳聚糖为基体,分别用直接插层法、重构法和原位生成法制备几种新型的生物高分子/层状双氢氧化物纳米复合物。通过X-射线粉末衍射法、红外光谱法、透射电镜、扫描电镜等方法分析了生物高分子基复合材料的结构,研究了层状双氢氧化物的用量对复合物机械性能、热稳定性或药物控释性和电流变性的影响。结果表明,生物高分子阴离子均插入层状双氢氧化物层间,形成剥离型纳米复合材料。层状双氢氧化物的加入,均不同程度地提高了羧甲基纤维素、羧甲基壳聚糖和羧甲基淀粉的力学性能和热稳定性。当Mg-Al-LDH的含量为3%时,CMC复合膜的拉伸强度和弹性模量达到最大值,分别提高了120%和228%,但断裂伸长率降低。与纯CMCS相比,Mg-Al-LDH含量为5%的CMCS纳米复合物的硬度和模量分别提高了41%和30%。当Mg-Fe-LDH含量为50%时,CMS复合物电流变液的剪切应力最大,热稳定性最好,最大分解温度比纯CMS提高了93℃。同时,研究还表明Mg-Al-LDH的加入可提高聚天冬氨酸-羧甲基壳聚糖载药体系的释放速率,且释放速率随着Mg-Al-LDH含量的增多而增大。更多还原

【Abstract】 In this article, the exfoliated layered double hydroxide (LDH)/bioploymer nanocomposites have been prepared successfully in a one-stage process by the solution intercalation technique or reconstruction method and in-situ preparation, respectively. The above-mentioned biopolymers included carboxymethyl cellulose (CMC), carboxymethyl chitosan (CMCS), carboxymethyl starch (CMS) and polyaspartate-carboxymethyl chitosan. The structures and morphologies of the nanocomposited were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). And influences of different amounts of layered double hydroxides on the mechanical properties, thermal stability or controlled drug release and electrorheological effects of nanocomposites were investigated.The XRD results showed that the layered double hydroxides were almost exfoliated and incorporated within the bioploymer matrixes at the nanometer level. The mechanical properties and thermal stability of the nanocomposites are enhanced in varying degrees by adding layered double hydroxide. The tensile strength and elastic modulus of the CMC composite with a 3% of Mg-Al-LDH loading gave a dramatic improvement of 120 and 228%, respectively, while its elongation at break decreased. The decomposition temperature was a slightly higher than that of CMC from the thermogravimetric analysis (TGA) result. The hardness and modulus of the CMCS were increased by about 41% and 30%, respectively, with the addition of 5 wt% Mg-Al-LDH. When the content of Mg-Fe-LDH was 50%, the shear stress of the CMS composite electrorheological fluid reached to the maximum. The maximum decomposition temperature of the CMS composite with the addition 50% Mg-Fe-LDH increased by 93℃compared with pure CMS. To determine the release profile of guanine from the nanocomposite films, we conducted drug-release studies with UV method. The percentage cumulative drug release increased with the amount of guanine in the polyaspartic acid-carboxymethyl chitosan/LDH nanocomposites.更多还原