基于响应面法研究梁山慈竹材梯度结构理化性能的相关性

Study on the correlation of physical and chemical properties of Dendrocalcamus farinosus gradient structure based on response surface methodology

【目的】为了提高竹材的高附加值和利用率,竹材梯度结构理化特性相关性的研究对复合材料结构的优化设计显得尤为重要。【方法】以梁山慈竹为研究对象,从竹黄至竹青逐层制备厚度为1 mm的薄竹篾,通过环境扫描电镜(ESEM)、X-射线衍射(XRD)仪等对其梯度结构的力学性能、化学成分和维管束分布进行表征;利用聚类分析和响应面法对影响薄竹篾力学性能的主要因子进行深入研究。【结果】竹篾取样部位随竹黄至竹青的变过过程中,维管束占比逐渐增加3~4倍,木质素含量增高3.54%,半纤维素含量下降4.39%,纤维素结晶度呈先增后降并趋于稳定的变化规律,灰分介于2.55%~3.53%之间,抽提物含量在10%左右。通过聚类分析发现,梁山慈竹中部1~8层(竹黄至竹青)呈梯度结构,分成四大类:Ⅰ类={1层,2层},Ⅱ类={3层,4层},Ⅲ类={5层,6层,7层},Ⅳ类={8层};拉伸强度逐渐增加,维管束个数与力学强度呈线性递增关系。梁山慈竹力学强度与化学成分和维管束分布存在线性关系,呈梯度分布趋势。【结论】通过响应面分析木质素、结晶度和维管束分布对力学强度的贡献,发现各因素对梁山慈竹抗拉强度的影响顺序为:维管束占比>结晶度值>木质素含量,且模型预测误差值不高于1.78%,为竹基复合材料体系配比和结构设计的优化提供基础理论和科学依据。

【Objective】In order to improve the high added value of bamboo and the utilization rate of bamboo,the research on the correlation between the physical and chemical properties of bamboo bamboo gradient structure is particularly important for the optimization design of composite material structure.【Method】Dendrocalcamus farinosus is the research object.Thin bamboo sticks with a thickness of 1 mm are prepared layer by layer from bamboo yellow to bamboo green.The mechanical properties,chemical composition and vascular bundle distribution of the gradient structure are characterized by environmental scanning electron microscope(ESEM)and X-ray diffraction(XRD)instruments.In-depth study of the main factors affecting the mechanical properties of thin bamboo strips through the use of cluster analysis and response surface methodology.【Result】The proportion of vascular bundles from bamboo yellow to bamboo green gradually increased 3-4 times,the content of lignin in the chemical composition increased by 3.54%,and the content of hemicellulose decreased by 4.39%,the degree of crystallinity of cellulose increased first and then decreased and tended to be stable.The ash content is between 2.55%and 3.53%,and the extract content is about 10%The 1-8 layers(Bamboo Yellow to Bamboo Green)in the middle of Dendrocalcamus farinosus are in a gradient structure and are divided into four categories:Class I={layer 1,layer 2},Class II={layer 3,layer 4},Class III={layer 5,layer 6,layer 7},Class IV={layer 8}.The mechanical strength of bamboo has a linear relationship with the chemical composition and vascular bundle distribution,showing a gradient distribution trend and found through cluster analysis.【Conclusion】Contribution of lignin,crystallinity and vascular bundle distribution to mechanical strength.The order of influence of various factors on the tensile strength of bamboo is:vascular bundle proportion>crystallinity value>lignin content,the model prediction error value is not higher than 1.78%by response surface analysis.The analysis and prediction of the response surface model of the mechanical properties of the bamboo gradient structure have important test value and guiding significance for the optimization of the composite material system ratio and structural design of the bamboo unit.