| Miscanthus floridulus, Gramineae, about14meters and underground root system is flourishing.Miscanthus floridulus as a gramineous class of non-woody plant resources, which is characterized bywidely distributed, fast growing, high biomass, and very strong regeneration capacity. For develop andmanufacture Miscanthus floridulus culm board, and provide a theoretical basis for Miscanthusfloridulus’ efficient use of research and product development. This paper choosed the seed setting stageand the dry yellow stage of Miscanthus floridulus in Kaihua County, Quzhou City, Zhejiang Province asthe specimens. And did a systematic study of appearance size, microstructure, fiber morphology,chemical composition, crystallinity, surface functional groups, thermal decomposition, physical andmechanical properties in the different part of culm with bottom, middle and up. The conclusions are asfollows:1. Miscanthus floridulus culm is oval-shaped, each culm has about15nodes, with white powderunder node. The average internode length of culm in seed setting stage is150.33mm, dry yellow stage is146.60mm. The average long diameter and short diameter of culm in seed setting stage is10.25mm and8.99mm respectively, dry yellow stage is8.76mm and7.92mm respectively.2. Miscanthus floridulus culm is divided into three parts of cortex, xylem and pith. Cortex mainlyis epidermis, which is consists of epidermal membrane, long cell, short cell and stomatal apparatus.Xylem mainly is vascular bundle, which is consists of vascular bundle xylem, phloem and fiber cell.Pith mainly is basic tissue parenchyma cell.3. The average fiber length in the seed setting stage of Miscanthus floridulus culm internode is2005.13μm and dry yellow stage is1845.11μm, which belongs to slightly longer fiber range. Theaverage fiber width, in-diameter of fiber, ratio of cell-wall thickness to in-diameter of fiber in seedsetting stage is14.92μm,2.54μm and5.77respectively, in dry yellow stage is14.59μm,2.98μm and4.48respectively, which belongs to thick fiber range. Fiber in node is shorter, wider and thicker thanwhich in internode both in seed setting stage and dry yellow stage.4. The main chemical components of culm internode without pith are cellulose, hemicellulose andlignin. Holocellulose content is74.70%in seed setting stage,76.22%in dry yellow stage. Nitricacid-ethanol cellulose content is49.5%in seed setting stage,50.28%in dry yellow stage. Acid-soluble lignin and acid-insoluble lignin in seed setting stage is1.5%and19.63%respectively, in dry yellowstage is1.46%and20.27%respectively. And the lignin structure is similar to the G, S type of hardwood.Crystallinity is slightly lower than the straw, but slightly higher than the paulownia, fir and masson pine.5. Thermal decomposition of Miscanthus floridulus culm internode without pith in seed settingstage and dry yellow stage is divided into four stages, which including drying stage, early evaporationstage, main thermal decomposition stage and residues thermal decomposition. The initial temperature ofthermal decomposition is155℃and the ending temperature is420℃.The thermal stability temperatureis230℃. The half-life temperature is345℃and weight loss rate reaches the maximum in thistemperature. The largest residual quality in seed setting stage is the up, while in dry yellow stage is thebottom.6. The mean value of air-dry density and oven dry density of Miscanthus floridulus culm internodewithout pith in seed setting stage is0.709g.cm-3and0.663g.cm-3, in dry yellow stage is0.671g.cm-3and0.641g.cm-3. The level of density is medium. The shrinkage rate in seed setting stage is bigger than dryyellow stage, while both trend is longitudinal＜tangential＜radical. Water absorption in seed settingstage is smaller than dry yellow stage. After8days and nights, the water absorption reaches114.27%inseed setting stage and123.91%in dry yellow stage.7. The mean value of tensile strength parallel to grain, compressive strength parallel to grain,bending elastic modulus and flexural strength in the air-dry state of Miscanthus floridulus culminternode without pith in seed setting stage is274.5MPa,44.2MPa,4684MPa and261.1MParespectively, in dry yellow stage is175.8MPa,37.1MPa,2196MPa and210.0MPa respectively. Themechanical properties in seed setting stage are superior to the dry yellow stage.The basic characteristics of two periods of Miscanthus floridulus culm in the bottom, middle andup parts have some differences, but the difference is small. The culm of the two periods are suitable foruse as non-wood-based man made board raw materials. |
