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石油产品如钢铁,促战略储存石油

(2007-10-06 16:42:43) 下一个

运用纳米技术,密执根大学科研人员最近研制出新型塑制板块,其性能如钢铁般坚硬,同时具有玻璃一样的透明度。

从石油中提炼出来的多聚体 (polymer) 是一种高分子化合物,在纳米体积时,它们的坚硬度可以很高。但是在多聚体组合成塑胶时,形成的板块坚硬度下降。为了解决这一难题,密大的 Kotov 教授和他的助理研究人员研制了一台可以使用纳米技术组装多聚体的机器人(点击此处看机器人和涂料的有关资料的 PDF 文件)

利用这台机器人,他们采用了类似砌砖墙时的叠加方法,所用的材料是纳米级的多聚体 (类似砖块) 和纳米级的粘土 (制成玻璃用的原料,也类似砖块)。步骤是先将一块玻璃浸入具有水溶性和粘性的多聚体中,这等于涂上一层纳米级的粘料,再将涂有粘料的玻璃浸入装有粘土的容器里,涂上一层薄薄的粘土。等粘土层干了,再重复以上过程。这样的纳米层,一共涂了三百层。

这一层层制造出来的新型合成材料,在完成后的测试中,具有不锈钢一般的坚硬度,同时质量更轻盈,而且是透光的。

(金笔是外行,以上描述可能有错和漏的地方,请包涵)

部分原文的摘要如下

网址:

http://www.sciencemag.org/cgi/content/abstract/318/5847/80

Science 5 October 2007:
Vol. 318. no. 5847, pp. 80 - 83

Reports:
Ultrastrong and Stiff Layered Polymer Nanocomposites

Authors:
Paul Podsiadlo, Amit K. Kaushik, Ellen M. Arruda, Anthony M. Waas, Bong Sup Shim,1 Jiadi Xu, Himabindu Nandivada, Benjamin G. Pumplin, Joerg Lahann, Ayyalusamy Ramamoorthy, Nicholas A. Kotov*(corespondant author)

Abstract:
Nanoscale building blocks are individually exceptionally strong because they are close to ideal, defect-free materials. It is, however, difficult to retain the ideal properties in macroscale composites. Bottom-up assembly of a clay/polymer nanocomposite allowed for the preparation of a homogeneous, optically transparent material with planar orientation of the alumosilicate nanosheets. The stiffness and tensile strength of these multilayer composites are one order of magnitude greater than those of analogous nanocomposites at a processing temperature that is much lower than those of ceramic or polymer materials with similar characteristics. A high level of ordering of the nanoscale building blocks, combined with dense covalent and hydrogen bonding and stiffening of the polymer chains, leads to highly effective load transfer between nanosheets and the polymer.

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Fig. 1. Preparation of PVA/MTM nanocomposites. (A) Schematic representation of the internal architecture of the PVA/MTM nanocomposite (picture shows 8 bilayers). (B) ATM phase image of a single PVA/MTM bilayer adsorbed on top of a silicon wafer. (Inset) Close up of the main image showing individual MTM platelets more clearly. Scale bar in inset, 400 nm. (C) Compilation of UV/VIS absorbance spectra collected after multiples of 25 bilayers of PVA/MTM composite deposited on both sides of a microscope glass slide up to 200 bilayers. a.u., arbitrary units. (D) Free-standing, 300-bilayer PVA/MTM composite film showing high flexibility and transparency. The lower image was taken at an angle to show diffraction colors. [View Larger Version of this Image (26K GIF file)]

Image and video hosting by TinyPic
Fig. 2. Scanning electron microscopy characterization of a 300-bilayer, free-standing PVA/MTM nanocomposite. (A) Cross section of the film. Arrows indicate the span of the cross section. (B) Close-up of the cross section showing the separation of layers. (C) Top-down view of a fracture edge of the composite after tensile testing. Dashed line indicates edge of the sample. (D) Top-down view of the composite's surface. The slight separation of the layers seen in (A) and (B) is due to a shearing force resulting from cutting the sample with a razor blade during scanning electron microscopy sample preparation. [View Larger Version of this Image (141K GIF file)]

讨论和建议:

石油除了燃烧以外,其他更有价值的用途很多,包括各种塑制材料。比如上面所提的材料,因为钢硬度,轻型和透明,他们的用途很多。而且 Kotov 教授在采访中 (另外报道) 还谈到,这个工艺还不成熟,有待完善,因此这类的材料还很有发展潜力。

问题是,石油有这么多更宝贵的用途,今天我们只是将它燃烧了,既造成污染,又浪费了资源,金笔觉得实在太可惜了。正确的做法是应该将部分石油作为战略储备,为将来的更好的用途而储存起来。

谢谢阅读。
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