共查询到20条相似文献,搜索用时 109 毫秒
1.
选用4种聚合单体:4,4'-六氟亚异丙基一邻苯二甲酸酐(6FDA)、双酚A二酐(BPA-DA)、4,4'-二氨基二苯甲烷(MDA)、3,3'-二甲基-4,4'-二氨基二苯甲烷(DMMDA),采用低温溶液缩聚-化学亚胺化合成了3种可溶性的聚酰亚胺:6FDA-MDA,6FDA-DMMDA,BPADA-DMMDA,利用FI-IR、NMR等对其结构进行了分析表征,测试了它们的溶解性能与热性能.将这3种聚酰亚胺溶于氯仿溶液中,在高湿度环境下浇铸形成规整多孔膜结构;研究了其规整孔结构的拉伸与吹扫特定形变,最后还研究了所得的规整多孔膜的高温热稳定性,发现在350℃仍能保持规整结构的稳定. 相似文献
2.
3.
本工作采用超临界CO2作为物理发泡剂,通过快速泄压法制备了三元乙丙橡胶(EPDM)微孔泡沫材料,并系统深入地研究了发泡条件及硫化条件对EPDM泡沫结构等方面的影响.通过一系列的实验发现:硫化条件决定EPDM基体的强度、交联度以及弹性,是泡孔结构形成的关键因素,预硫化程度过高或过低都不利于形成较好的泡孔结构;scCO2饱和温度降低有利于制备孔径更小的泡孔;scCO2饱和压力的增大明显改善了泡孔形貌的规整度,提高了泡孔的均匀性,泡孔的密度随饱和压力的升高而呈指数级增加;不同硫化条件和发泡条件下制得的EPDM基微孔泡沫,其最小平均孔径达到了1.24μm,最大孔密度达到了1.33×1011个/cm3. 相似文献
4.
5.
以单一组分醋酸纤维素(CA)为成膜材质,不添加任何添加剂条件下,利用水蒸气辅助法层-层自组装制备了三维蜂窝状CA多孔膜。利用扫描电镜观察了多孔膜形貌;研究了溶剂、环境湿度和浓度等因素对所成多孔膜结构影响。实验结果表明,以二氯甲烷为溶剂,制备得到的孔结构规整、排列紧密;环境湿度由43%增加到91%,孔径大小由(1.36±0.24)μm增加到(3.71±0.18)μm;CA的质量分数为1%~2%有利于规整孔的形成。扫描电镜断面观察发现CA膜内部全部成孔,且内部孔径大小为(1.09±0.13)μm,约为表面孔径大小的一半。利用界面能最小化理论解释了三维蜂窝孔的形成机理。此三维多孔膜有利于细胞的粘附、铺展、分化和增殖,可作为一种良好的组织工程支架材料使用。 相似文献
6.
以单组分聚碳酸酯(PC)为膜材质,在一定的湿度环境下,利用Breath Figure法在玻璃基板上成功制备了蜂窝状孔结构的聚碳酸酯多孔膜。研究了溶剂、溶液浓度和湿度对所成多孔膜结构和形貌的影响。实验结果表明,采用二氯甲烷为溶剂所制得的孔结构规整,排列均匀紧密,孔径大小为(3.30±0.19)μm,而以三氯甲烷为溶剂只能得到孔径大小不均且无紧密排列的孔。环境湿度从43%增加到91%,孔径大小由(2.28±0.63)μm增加到(9.07±1.42)μm,且湿度与孔大小基本上呈现一阶线性关系,通过理论推导得出直线斜率为0.15μm/%,即在此体系中湿度每增加1%,所形成的孔大小增加0.15μm。 相似文献
7.
以单一组分醋酸纤维素(CA)为成膜材质,不添加任何添加剂条件下,利用水蒸气辅助法层-层自组装制备了三维蜂窝状CA多孔膜。利用扫描电镜观察了多孔膜形貌;研究了溶剂、环境湿度和浓度等因素对所成多孔膜结构影响。实验结果表明,以二氯甲烷为溶剂,制备得到的孔结构规整、排列紧密;环境湿度由43%增加到91%,孔径大小由(1.36±0.24)μm增加到(3.71±0.18)μm;CA的质量分数为1%~2%有利于规整孔的形成。扫描电镜断面观察发现CA膜内部全部成孔,且内部孔径大小为(1.09±0.13)μm,约为表面孔径大小的一半。利用界面能最小化理论解释了三维蜂窝孔的形成机理。此三维多孔膜有利于细胞的粘附、铺展、分化和增殖,可作为一种良好的组织工程支架材料使用。 相似文献
8.
介绍了一种基于传统水滴模板法的新型表面图案化致孔技术,并利用这一技术成功在微米尺寸聚合物球形粒子表面实现多孔结构的制备。这种直接致孔技术通过对传统水滴模板法实施方法的改造,成功实现了在微观尺寸三维结构表面的致孔。首先通过微流道法制备得到尺寸均一的微米级聚苯乙烯(PS)微球;之后在高湿度条件下,对聚苯乙烯(PS)微球进行溶剂的直接致孔处理,得到表面具有多孔结构的"高尔夫球"型聚苯乙烯(PS)微球;并进一步通过对溶剂种类、溶剂用量以及湿度的调控,对实现微球致孔的条件进行了讨论。基于这一溶剂直接致孔实施方法的建立,在水滴模板法实施对象的几何造型局限性上进行了突破。 相似文献
9.
10.
作为一种多孔固体材料的,由于其结构和功能的特殊性,金属蜂窝在缓冲吸能领域应用广泛。为了得到不同拓扑结构下金属蜂窝的异面压缩特性及缓冲特性,为其用于缓冲吸能领域提供依据,本文应用数值仿真软件Patran/DYNA对5种不同拓扑结构的金属蜂窝进行了压缩仿真。由于蜂窝结构的多样性,基于PCL语言编写金属蜂窝参数化有限元分析程序,实现有限元模型自动建立。采用全因素实验设计法对仿真点进行了规划,基于仿真结果,使用响应面方法建立了金属蜂窝吸能特性的近似函数模型,并分析模型精度。以金属蜂窝比吸能为优化目标,蜂窝主要结构参数为设计变量,针对腿式着陆器用金属蜂窝缓冲结构进行了优化设计, 结果表明正六边形金属蜂窝在五种蜂窝结构中吸能效果最优。 相似文献
11.
12.
以线性聚苯乙烯(PS)为膜材料,采用Breath Figures法制备了高度规整的蜂窝状结构多孔膜.研究了溶液浓度、环境湿度、气体吹扫速度及不同溶剂对多孔膜结构的影响.结果表明,相比于苯和二氯甲烷,氯仿作为溶剂因其挥发度适宜,PS浓度在20~80mg/mL的铸膜溶液可形成规整的蜂窝状结构多孔膜,且膜孔分布均匀、大小均一;制膜的湿度需高于环境湿度,但随着湿度的增加孔径增大;气体吹扫速度可在400~1000mL/min范围,但吹扫速度较大时孔径略有降低.该膜可作为固定诸如辣根过氧化酶等活性酶的载体,用于酶催化反应. 相似文献
13.
An analysis is made of the possible formation of a honeycomb domain structure directly from a labyrinth structure in uniaxial
magnetic films exposed to a series of uniform magnetic field pulses. It is shown that the scenario for the formation of a
honeycomb structure depends on the pulse parameters and on the magnitude of the static magnetizing magnetic field.
Pis’ma Zh. Tekh. Fiz. 23, 46–51 (May 12, 1997) 相似文献
14.
Takehiro Nishikawa Jin Nishida Ryusuke Ookura Shin-Ichiro Nishimura Shigeo Wada Takeshi Karino Masatsugu Shimomura 《Materials science & engineering. C, Materials for biological applications》1999,10(1-2):141-146
In this report, cell adhesion to honeycomb-patterned films is described with respect to the dimensions of the honeycomb structure. The honeycomb-patterned films can be fabricated by casting a dilute solution of amphiphilic polymers on solid substrates. The honeycomb structure is not homogeneous in all dimensions. Analysis of distribution of the honeycomb hole sizes demonstrates a gradual decrease in honeycomb hole diameter along the radius of the cast area. The largest holes were located near geometric center of the cast area. The diameter of the largest honeycomb holes in the cast area could be controlled by varying the cast volume of the polymer solution. Cell cultures on the honeycomb films demonstrated that cell adhesion could be inhibited at the outer region of the cast area. The extent of the inhibition of cell adhesion was influenced by the chemical properties of the polymers constituting the honeycomb films. 相似文献
15.
Mesoscopic 2-D ordering of inorganic/organic hybrid materials 总被引:1,自引:0,他引:1
O. Karthaus X. Cieren N. Maruyama M. Shimomura 《Materials science & engineering. C, Materials for biological applications》1999,10(1-2):103-106
Organic–inorganic hybrid materials with micronsized (i.e., mesoscopic) network structures are expected to have interesting properties and applications in various fields, such as separation, catalysis, biomineralization, or quantum optics. Here a new method is introduced to produce thin films of two-dimensionally ordered honeycomb structures. Casting a chloroform solution of a mixture of organic amphiphiles with metal acetylacetonates or -alkoxides at high atmospheric humidity leads to the formation of a closely packed layer of water droplets on top of the organic solvent. The water acts as a template, After evaporation of the chloroform and the water, a honeycomb structure remains. Pyrolysis of the metal alkoxides films lead to the formation of microporous metal oxide (e.g., anatase, one of the catalytic active titanium oxides). 相似文献
16.
17.
为了提高镀膜玻璃的可见光透过率, 本研究通过反胶束溶液刻蚀法制备出一种新型玻璃基板, 即表面多孔玻璃。玻璃表面形成了蜂窝状的多孔膜层, 减小了对可见光的反射率, 从而使可见光平均透过率提高了7%。通过一系列射频磁控溅射实验, 探索了可见光平均透过率高, 紫外阻隔率最高的最佳工艺条件。在此条件下, 分别在制备的表面多孔玻璃和普通玻璃上镀CeO2/TiO2防紫外线膜, 并采用紫外-可见分光光度计、SEM、XRD、XPS等测试手段对样品进行了分析表征。结果表明, 在相同的镀膜条件下, 当镀膜后表面多孔玻璃与镀膜普通玻璃的紫外光阻隔率均为99%时, 表面多孔玻璃镀膜后的可见光平均透过率为85%, 而普通玻璃镀膜后的可见光平均透过率仅为79%。此外, 玻璃表面上的孔结构还提高了薄膜与基板的接触面积, 使膜基结合力提高2倍左右。 相似文献
18.
19.
K. Nouneh K. J. Plucinski M. Bakasse I. V. Kityk 《Journal of Materials Science》2007,42(16):6847-6853
Nanocrystalline TiO2 porous films were prepared by a sol-gel dip coating method from a solution using poly(ethylene glycol) as a template, ethanol
as a solvent and terpineol as a highly viscous solvent. The thickness of films increases greatly by increasing the amount
of terpineol. However, the overmuch incorporation of terpineol hinders the formation of porous structure and accelerates the
crack creation. The crack-free film having a three-dimensionally extended porous structure was obtained at the ethanol/terpineol
ratio of 8:1, the film thickness with three depositions being 2.5 μm.
Pretreatment of the precursor at an appropriate temperature also plays an important role in pore formation. Single-phase anatase
TiO2 porous films were obtained after calcinations at 550°C for 1 h, and the crystal size increases with an increase in the amount
of terpineol. The pore formation mechanism is discussed primarily in relation to the phase separation in the system and self-assembly
of PEG. 相似文献
20.
Shaojing Bu Zhengguo Jin Xiaoxin Liu Tao Yin Zhijie Cheng 《Journal of Materials Science》2006,41(7):2067-2073
Nanocrystalline TiO2 porous films were prepared by a sol-gel dip coating method from a solution using poly(ethylene glycol) as a template, ethanol
as a solvent and terpineol as a highly viscous solvent. The thickness of films increases greatly by increasing the amount
of terpineol. However, the overmuch incorporation of terpineol hinders the formation of porous structure and accelerates the
crack creation. The crack-free film having a three-dimensionally extended porous structure was obtained at the ethanol/terpineol
ratio of 8:1, the film thickness with three depositions being 2.5 μm.
Pretreatment of the precursor at an appropriate temperature also plays an important role in pore formation. Single-phase anatase
TiO2 porous films were obtained after calcinations at 550°C for 1 h, and the crystal size increases with an increase in the amount
of terpineol. The pore formation mechanism is discussed primarily in relation to the phase separation in the system and self-assembly
of PEG. 相似文献