淀粉基薄壁泡沫炭材料形成机理的跨尺度研究

Carbon foam is a three dimensional spongy carbonaceous material. It has great potential to be applied in both military and civil use. However, non-renewable resources are usually used to prepare carbon foam and the products are mainly reticulated or cellular ones. Starch, an important product of photosynthesis for carbon storage, is an attractive raw material for the production of carbonaceous products. Among the reports on starch derived carbonaceous products, the effect of the fine structure of starch on the structure and controllable preparation of carbonaceous products have been poorly understood. In order to obtain value-added carbon foam with novel structure from starch, in-situ and pre-organization strategies will be applied to prepare carbon foam with ultra thin cell walls in this proposed project. Large amount of accessible porosity can be made without losing the conductivity of the material via constructing ultra thin porous cell walls with layered polycrystalline structure. The multi-scale formation mechanism of the carbon foam will be thoroughly studied. Internal and external causes (including the fine structure of starch, preparation technology and condition, etc.) on the morphology and structure of the carbonaceous product will be discussed. The proposed project is significant for the development of new carbon foam and the utilization of other polysaccharide biomass.

泡沫炭是一种三维类海绵状的炭质材料，在军用和民用领域都极具应用潜能。目前制备泡沫炭的原料仍以不可再生资源为主，而所得产品多为网状和球形气孔状两种结构。作为光合作用固定碳元素的重要产物，淀粉是制备炭质材料的上好原料。但在已有报道中，针对淀粉高分子复杂、多变的精细结构对炭质产物结构的影响和调控机制方面的研究还远远不足。为了更加有效地利用淀粉获得高附加值的新型泡沫炭材料，本课题将采用原位法和预组织构建两种思路制备结构新颖的淀粉基薄壁泡沫炭材料。通过构建层状多晶的多孔薄壁结构，既保证材料丰富、畅通的孔结构，又兼顾其导电性。我们将对材料的结构形成机理进行跨尺度深入细致的研究，探讨淀粉高分子精细结构、制备工艺、制备条件等内外因素对炭质产物形态结构的影响机制。这不仅对新型泡沫炭材料的开发有重要的推动意义，也对其他葡聚糖类生物质资源的利用具有重要的基础研究价值。

泡沫炭是一种军民两用的三维多孔炭质材料。针对当前泡沫炭主要以不可再生资源制备，以及生物质衍生泡沫炭的形成机制研究不足的问题，本项目采用原位法和预组织构建两种思路研究了淀粉衍生泡沫炭的形成机制。研究过程中，我们采用多种手段、多角度、跨尺度监测了淀粉原料向泡沫炭产品的转变过程，探讨和阐释了混酸、水分、水解刻蚀、外部压力、排气方式、热传递方式、升温速率、原料分子结构和构象、外掺剂等因素在泡沫炭形成过程中的作用机制。研究表明，从淀粉到泡沫炭的转变包括水解（热解）、熔融、发泡和炭化过程。各因素中，热传递方式和升温速率是影响泡沫炭孔泡结构的关键。值得注意的是，原料的分子结构和构象对泡沫炭孔泡结构具有重要影响，特别是原料构象的影响在以往的研究中很少被提及。总的来说，本研究获得了利用淀粉原料制备结构可调控的泡沫炭材料的关键科学和技术信息，为使用其他生物质制备泡沫炭材料提供了重要启示，也为后期深入开发新型功能性的泡沫炭复合材料提供了理论和实践依据。在此基础上，我们还开展了针对该材料的一些应用基础研究，取得了一些有益结果。