NaOH-水热结合挤压制备稻秸纤维原料工艺参数优化

Optimization of Parameters for Preparation of Rice Straw Fiber Raw Material by NaOH-Hydrothermal Combined Extrusion

摘要:

针对传统农作物秸秆纤维原料制备过程效率低、化学污染严重等问题,以水稻秸秆为对象,提出了一种基于NaOH-水热结合挤压处理的稻秸纤维原料制备方法。系统考察了不同NaOH/水热结合挤压处理对稻秸纤维组成成分、微观形貌、化学结构及材料性能的影响,并以固体得率和抗张指数为指标,采用响应面法对工艺参数进行优化。结果表明,先碱后水热处理(A+HE)有利于纤维的温和解构,其长径比大于10的纤维占比达到89.09%,抗张指数最高为4.96N·m/ g;而NaOH-水热同步处理(AHE)的固体得率最低(35.99% ),抗张指数较A+HE降低26.01%。相关性分析表明,抗张指数的提升并非依赖单一因素,而是受组分、结构和氢键等多重效应的协同作用影响。响应面分析证实NaOH 质量分数和水热温度与抗张指数存在显著的交互作用,优化得到的最佳工艺参数为:NaOH质量分数1.43%、水热温度72.6℃,在此条件下材料抗张指数提升至5.75N·m/g,固体得率为59.13%,试验结果与模型预测高度一致。因此,通过NaOH-水热结合挤压处理可在降低化学污染和减少能耗的同时,实现对稻秸纤维原料的连续化制备。

Abstract:

Aiming to address the low efficiency and severe chemical pollution in conventional crop straw fiber preparation, an NaOH-hydrothermal combined extrusion method was proposed by using rice straw as the raw material. The effects of different NaOH/ hydrothermal extrusion treatments on fiber composition, microstructure, chemical characteristics, and material properties were systematically investigated. Solid yield and tensile index were selected as evaluation indicators, and response surface methodology was employed for process optimization. Results showed that sequential alkali followed by hydrothermal treatment (A+HE) facilitated mild fiber deconstruction, with 89.09% of fibers exhibiting a length-to-diameter ratio greater than 10, and the maximum tensile index reached 4.96N·m/g. In contrast, simultaneous NaOH-hydrothermal treatment (AHE) resulted in the lowest solid yield (35.99%) and a 26.01% reduction in tensile index compared with A+HE. Correlation analysis revealed that tensile index improvement was not governed by a single factor but rather by the synergistic effects of composition, structure, and hydrogen bonding. Response surface analysis confirmed a significant interaction between NaOH concentration and hydrothermal temperature on tensile index. The optimized parameters were determined as 1.43% NaOH concentration and 72. 6℃ hydrothermal temperature, under which the tensile index was increased to 5.75N·m/g with a solid yield of 59.13%. Experimental results were highly consistent with model predictions. Therefore, NaOH-hydrothermal combined extrusion enabled continuous preparation of rice straw fiber raw materials while reducing chemical pollution and energy consumption. The research result can provide fundamental data and process references for high-loading and continuous production of crop straw fiber raw materials.