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改性羟基磷灰石/聚乳酸纳米复合材料的结晶行为 总被引:1,自引:0,他引:1
利用溶剂复合的方法制备了具有良好生物相容性的表面接枝聚(γ-苄基-L-谷氨酸)的改性羟基磷灰石/聚乳酸纳米复合材料, 并研究了其熔融与结晶行为. 结果表明, 聚乳酸的玻璃化转变温度为60.3 ℃, 而复合材料的玻璃化转变温度达到65.8 ℃, 不同样品在140 ℃等温结晶后, 改性羟基磷灰石/聚乳酸复合材料的球晶直径仅为聚乳酸(PLLA)球晶直径的16.7%~66.7%. 复合材料的熔点提高到184.4 ℃. 相似文献
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结合固相剪切碾磨和分子复合技术制备了适合于微型注塑加工的聚乙烯醇/纳米羟基磷灰石(PVA/n-HA)复合材料,实现了n-HA含量达30%的PVA/n-HA复合材料的微型注塑加工。采用差示扫描量热法(DSC)、热重分析仪(TGA)和高压毛细管流变仪研究了PVA/n-HA复合材料的热性能和流变性能,结果表明:改性PVA/n-HA复合材料的熔点降低,热分解温度升高,获得120℃以上的热塑加工窗口;PVA/n-HA复合材料呈现剪切变稀特性,在高剪切速率下具有较低的熔体粘度,适合微型注塑加工,具有良好的充模性能。采用扫描电子显微镜(SEM)和X射线衍射(XRD)研究了PVA/n-HA微型注塑样品的结构与性能,结果表明n-HA均匀分散于PVA基体中,提高了复合材料的尺寸稳定性;受微型注塑过程中高剪切应力诱导结晶作用的影响,PVA/n-HA微型注塑样品的结晶度高于常规注塑样品的结晶度。 相似文献
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结合固相剪切碾磨技术(S3M),以胶原纤维(Col)在熔融挤出过程中原位降解成明胶(Gel),通过Gel与聚乙烯醇(PVA)分子间形成氢键复合增塑PVA,改善聚乙烯醇/纳米羟基磷灰石(PVA/n-HA)复合材料的热塑加工性能.采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)、示差扫描量热仪(DSC)、热重分析仪(TGA)、X射线衍射仪(XRD)和高压毛细管流变仪等研究了复合材料的结构与热塑加工性能.结果表明,通过S3M技术实现了n-HA在PVA基体中的均匀分散;FTIR表明Gel与PVA间形成了氢键作用和部分接枝反应;Gel和PVA分子间的氢键作用使PVA/Gel/n-HA复合材料的初始分解温度提高到287.6℃,改善了PVA的热稳定性,PVA的结晶度由纯PVA的58.2%降低到复合材料中的24.5%,使其熔点降低至130.5℃,拓宽了PVA/n-HA复合材料的加工范围,获得超过140 K的热塑加工窗口.Gel有效降低了PVA/nHA复合材料表观黏度,改善了PVA/n-HA复合材料的热塑加工性能. 相似文献
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硬脂酸改性纳米羟基磷灰石表面性能的研究 总被引:1,自引:0,他引:1
采用硬脂酸(C17H35COOH)对纳米羟基磷灰石(n-HA)表面进行处理,并研究了n-HA与C17H35COOH的界面作用。透射电子显微镜(TEM)、傅立叶红外光谱(FTIR)以及X光电子能谱(XPS)分析表明,C17H35COOH在n-HA表面黏附,其中羧酸根离子(-COO-)与钙离子(Ca2+)之间形成了稳定的离子键,以羧酸钙形式存在。C17H35COOH改性后的n-HA与聚碳酸酯(PC)复合后,复合材料的力学性能与未改性n-HA相比有明显提高。扫描电子显微镜(SEM)结果显示,经处理后的HA微粒在PC中分散均匀,两者间结合紧密,无明显界面,复合材料的断裂呈明显的韧性断裂,随着n-HA无机粒子含量增加,复合材料的断裂也逐渐向韧性与脆性断裂共存转变。 相似文献
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化学沉淀法制备羟基磷灰石纳米粒子 总被引:10,自引:0,他引:10
采用化学沉淀法以 Ca(NO3 ) 2 · 5 H2 O和 (NH4) 2 HPO4为主要原料 ,制备了短棒状或针状的羟基磷灰石纳米粒子 (HA) ,考察了各反应参数对纳米粒子性能的影响 ,并由透射电镜、X射线晶体衍射、电子衍射、红外、比表面积等手段对其进行表征。实验结果表明 ,所制备的 HA粒子粒径长约 30~5 0 nm,直径约 10~ 15 nm;通过严格控制各反应参数可以基本上实现纳米羟基磷灰石粒子粒径、形态等部分性质的可控制备 相似文献
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改性纳米羟基磷灰石/PLGA复合材料的制备及生物活性 总被引:2,自引:0,他引:2
以低聚乳酸接枝改性的羟基磷灰石纳米粒子(op-HA)和聚丙交酯-乙交酯(PLGA)制备的生物可降解纳米复合材料(op-HA/PLGA)为研究对象, 采用FTIR, TGA, ESEM和EDX分析其接枝反应、接枝率、表面形貌和钙磷沉积情况, 通过在材料膜表面接种兔成骨细胞进行体外培养, 采用荧光染色、NIH Image J图像分析和Real-time PCR综合评价细胞在材料表面的形态、黏附面积比、增殖能力和基因表达水平, 以此评价新型骨修复纳米复合材料op-HA/PLGA的表面性质和生物活性. 研究结果表明, op-HA的表面接枝率为8.3%, 掺入至PLGA后可形成富含钙磷的粗糙表面, 促进成骨细胞的黏附、扩展和增殖, 提高Ⅰ型胶原蛋白(Collagen-Ⅰ)、骨形态蛋白-2(BMP-2)和骨连接蛋白(Osteonectin)的基因表达水平, 提高材料的钙磷沉积能力. op-HA/PLGA具有良好的细胞相容性和成骨活性. 相似文献
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本文以Ca(NO3)2和(NH4)2HPO4为原料,采用重结晶法,在水热条件下制备了羟基磷灰石(HA)纳米棒;利用X-射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、红外光谱(FTIR)等分析测试手段,研究了pH值和晶化时间对HA组成和结构的影响。实验结果表明,室温混合pH值为7.5的沉淀物和pH值为10.5的清液,于180 ℃下水热处理10 h重结晶制得的HA纳米棒的平均长径比最长(约为28);采用不同pH值的清液,体系的单体浓度(即化学势)改变时,得到的HA纳米棒的长径比不同;随着晶化时间延长,纳米棒的长径比先增大后减小。 相似文献
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羟基磷灰石/胶原/植物多酚复合材料的研究 总被引:1,自引:0,他引:1
以原花色素、茶多酚等植物多酚为交联剂,采用低温原位合成法制备羟基磷灰石/胶原/植物多酚(HA/COL/PP)复合材料。对材料的形貌、热稳定性、溶胀性质进行了表征。结果表明,植物多酚的加入使复合材料中各成分结合更紧密,增加了复合材料的热稳定性,降低了复合材料的溶胀度。比较研究表明,添加原花色素对上述性能的改善更有效。为了考察加入植物多酚后复合材料的生物活性,分别对羟基磷灰石/胶原/原花色素(HA/COL/PA)、羟基磷灰石/胶原/茶多酚(HA/COL/TP)复合材料进行了体外矿化能力研究,观察到两种材料的表面都形成了新的矿化沉积层,说明加入了植物多酚不影响复合材料的体外矿化能力。因而,羟基磷灰石/胶原/植物多酚复合材料是一种有潜力的骨替代材料。 相似文献
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The foremost material that closely mimics the mineral part of the bone tissue, and is therefore suitable for bone replacement, is nano-hydroxyapatite (nHAp) which exhibits low fracture toughness, and can be used for load-bearing scaffolds in biomedical applications. Therefore, for improved biomechanical features, composite materials are developed. This work focuses on the influence and contribution of bioactive alumina and nHAp on the biopolymer, i.e., gelatin matrix for the fabrication of load-bearing bone replacement composites. Incorporation of bioceramics alumina at the strengthening phase is essential for the improvement of mechanical properties for biomedical applications. The porosity of scaffolds varied from 79 to 85%. Fourier transform infrared (FTIR) and X-ray powder diffraction (XRD) analyses showed the presence of molecular interactions and chemical linkages between gelatin matrix, alumina, and nHAp particles. The compressive strength of alumina-reinforced nanocomposites scaffolds is three times higher than those of nHAp/gelatin. The elemental composition of the chemically synthesized nHAp particles was determined by SEM, FTIR, and XRD analyses. 相似文献
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Porous three‐dimensional collagen/chitosan scaffolds combined with poly (ethylene glycol) (PEG) and hydroxyapatite were obtained through a freeze‐drying method. Physical cross‐linking was examined by dehydrothermal treatment. The prepared materials were characterized by different analyses, eg, scanning electron microscopy (SEM), measurements of porosity and swelling, mechanical properties, and resistance to enzymatic degradation. The porosity of scaffolds and their swelling ratio decreased with the addition of hydroxyapatite. Moreover, after exposure to collagenase, the collagen/chitosan matrices containing PEG showed much faster degradation rate than matrices with the addition of hydroxyapatite. The results indicated that the addition of hydroxyapatite led to improvement of stiffness. The highest degree of porosity and swelling were demonstrated by collagen/chitosan/PEG matrices without hydroxyapatite. 相似文献
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Abuduheiremu Awati Halidan Maimaiti Bo Xu Shixin Wang 《Surface and interface analysis : SIA》2020,52(3):98-109
Fluorescent carbon nanoparticles (FCNPs) have broad application prospects in the fields of bioimaging, ion detection, and photocatalysis. In this paper, coal-based FCNPs were prepared by using mixed acid oxidation, hydrogen peroxide etching, and organic solvent extraction methods (marked as FCNPs-AO, FCNPs-HE, and FCNPs-OS, respectively), and the structures and properties of the as-prepared products were compared. It was found that the coal-based FCNPs obtained by three kinds of methods are all aromatic structural nanomaterials linked with oxygen-containing groups. Among them, FCNPs-AO is a kind of hollow annular spherical particles and FCNPs-HE and FCNPs-OS are solid spherical particles. These FCNPs not only have similar fluorescence properties as traditional quantum dots, but also can be photoexcited to generate photogenerated electrons and holes, and it can also suppress the recombination of photogenerated electrons and holes by using its own surface defects. In particular, the electron transport capability of the FCNPs-AO is stronger than that of FCNPs-HE and FCNPs-OS because of its lower charge transfer impedance, so it can be excited to generate more photogenerated electrons and has the best photogenerated carrier separation efficiency. 相似文献
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Thelma M. de Batista Virginia C. A. Martins Ana M. de Guzzi Plepis 《Journal of Thermal Analysis and Calorimetry》2009,95(3):945-949
In the present study porcine skin and bovine pericardium were used as a source of type I collagen. Both were submitted to
an alkaline treatment and mineralized by the alternate soaking method. Thermal stability and extent of mineralization have
been investigated using DSC and TG. After alkaline hydrolysis there is a decrease in thermal stability but mineralization
stabilizes collagen structure. Thermogravimetric data have shown that the amount of hydroxyapatite present in bovine pericardium
matrix (45%) was greater than on porcine skin matrix (20%). Presence of hydroxyapatite was confirmed by EDX. 相似文献
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A. S. Orde?ana-Martínez M. E. Rincón M. Vargas A. Estrada-Vargas N. Casillas M. Bárcena-Soto E. Ramos 《Journal of Solid State Electrochemistry》2012,16(12):3777-3782
We report the preparation and electrochemical characterization of carbon nanotubes (CNT)/carbon xerogel-nafion (CXN) electrodes obtained by casting carbon nanotube inks on carbon xerogel-nafion matrixes under terrestrial (g) and enhanced (13?g) gravity. The impregnated electrodes were compared with composites prepared by mixing CXN dispersions with CNT inks. For casted CNT, alternate current scanning electrochemical microscopy studies along the film-electrode area showed differences that can be correlated with the position of the electronic conducting CNT phase on the more resistive matrix. It revealed the transition from a conductive to dielectric surface when impregnation takes place at terrestrial and enhanced gravity, respectively. Although the addition of CNT enhances the capacitance and mechanical properties of CXN in all preparation methods, the largest specific capacitance was observed in electrodes impregnated at 1?g. Electrodes prepared by mixing and those casted at 13?g show similar capacitance values regardless of contrasting conductivity. A mechanism explaining the microstructural, electrical, and adsorptive differences brought out by the various preparation methods is proposed. 相似文献