摘要：本发明属于环保领域，尤其涉及一种生物质材料及其制备方法。本发明提供的生物质材料由秸秆外皮经化学改性后热压制成；所述化学改性所采用的改性剂为氢氧化钠和亚硫酸钠。本发明采用秸秆外皮作为原料，通过对其进行化学改性，去除秸秆中的部分木质素、半纤维素以及果胶等影响力学性能的物质；最后通过热压，使秸秆外皮致密化，达到提高秸秆外皮力学性能的目的。本发明提供的技术方案无须将秸秆外皮粉碎，极大的维持了秸秆外皮纤维的原始结构，工艺过程简单，生产成本低；更重要的是，致密化后的秸秆外皮力学性能得到极大的提升，从而使其可成为木材、竹子、苎麻和铝合金的潜在替代品，极大的扩展了秸秆外皮在材料领域的应用范围。

Abstract: The present invention belongs to the field of environmental protection, and particularly relates to a biomass material and a preparation method thereof. The biomass material provided by the invention is prepared by hot-pressing the outer bark of straw after chemical modification, wherein the modifiers used for chemical modification are sodium hydroxide and sodium sulfite.The invention takes straw outer bark as raw material. Through chemical modification, part of lignin, hemicellulose, pectin and other substances that impair mechanical properties in straw are removed. Subsequent hot pressing densifies the straw outer bark to improve its mechanical performance.The technical scheme of the invention does not require pulverization of straw outer bark, so the original fiber structure of straw outer bark is largely preserved. The process is simple with low production cost. More importantly, the densified straw outer bark exhibits greatly enhanced mechanical properties, making it a potential substitute for wood, bamboo, ramie and aluminum alloy, and significantly broadening the application scope of straw outer bark in the material industry.