淀粉造孔剂对多孔碳化硅木陶瓷微观结构及性能影响  

Effect of starch pore former on microstructure and properties of porous SiC woodceramic

作　　者：徐多 阙荣君 唐梦雪 游茜[1] 陈瑶[1] 高建民[1] XU Duo;QUE Rongjun;TANG Mengxue;YOU Xi;CHEN Yao;GAO Jianmin(Beijing Forestry University,MOE Key Laboratory of Wooden Material Science and Application,Beijing 100083,China)

机构地区：[1]北京林业大学木质材料科学与应用教育部重点实验室

出　　处：《林业工程学报》2019年第5期107-114,共8页Journal of Forestry Engineering

基　　金：国家自然科学基金(51572028);国家级大学生创新训练计划项目(201710022036)

摘　　要：为解决现有模板法制备多孔碳化硅木陶瓷材质呈各向异性、孔结构不可控的问题,实现多孔碳化硅木陶瓷的功能化利用,利用聚碳硅烷(PCS)将杨木木粉通过浸渍改性为木陶瓷粉体,采用粉末烧结法制备多孔碳化硅木陶瓷,并通过施加淀粉造孔剂对木陶瓷的孔结构进行调节。采用热重?红外联用手段(TG?FTIR)分析了木陶瓷粉体的裂解特性,采用X射线衍射(XRD)、扫描电镜(SEM)和压汞仪(MIP)表征了木陶瓷的物相组成、微观形貌及孔径分布,利用阿基米德法和同轴环施力法测定了木陶瓷的开口孔隙率及抗弯强度,分析了不同种类淀粉造孔剂对其开口孔隙率及力学性能的影响规律。结果表明,淀粉造孔剂的加入基本不影响木陶瓷的烧结过程及物相组成。木陶瓷的成分主要是β?SiC,材质呈各向同性。3种淀粉造孔剂的成孔趋势类似,当淀粉的添加量较低时(5%~10%),由分散的淀粉颗粒可形成直径10μm左右的形状较为规则的开孔。造孔剂添加量高于10%后,团聚的淀粉颗粒将形成直径达30~40μm的大孔。随着造孔剂添加量的增加,木陶瓷开口孔隙率由68%提高到80%,但抗弯强度逐渐降低,由5 MPa左右下降至3 MPa左右。从实用角度考虑,淀粉造孔剂应选为红薯淀粉,理想添加量应为10%~15%,此时,木陶瓷开口孔隙率为71%~77%,并且具有4.0~4.7 MPa的抗弯强度。Bio?templating is a traditional route to fabricate porous biomorphic SiC woodceramic.However,this approach has encountered challenges,such as anisotropic structure and uncontrollable pore properties.To address these challenges,in this study,wood flour was modified by polycarbosilane(PCS)to produce woodceramic powder,and the powder?sintering method was utilized to fabricate porous SiC woodceramic,in which starch was selected as the pore former to adjust the pores in woodceramic.The pyrolysis behavior of woodceramic powder was examined by the thermogravimetric analyzer coupled with the Fourier transform infrared technique.The X?ray diffraction,scanning electron microscope and mercury intrusion porosimetry were used to characterize the microstructure,phase composition and pore size distribution of the as?prepared porous SiC woodceramic.The porosity and flexural strength were also determined by the Archimedes method and the monotonic equibiaxial flexure testing.The results indicated that the addition of starch did not have side effect on the sintering process and ceramic composition.It was found that the main phase of the woodceramic was β?SiC and the ceramic texture was isotropous.The pore?forming trend of different kinds of starch was the same.At the low starch addition level(5wt%-10wt%),the dissipated starch pore former particles could form regular?shaped pores with diameters around 10μm.While with the increasing addition level,starch pore former particles could aggregate,causing large pores with diameters around 30-40μm.With the increasing starch content,the open porosity of the woodceramic increased from 68%to 80%,while the flexural strength decreased from 5 MPa to around 3 MPa.From a practical point of view,the optimum pore former choice should be sweet potato starch and the addition level should be 10wt%-15wt%.Under this condition,the porosity could be around 71%-77%and the flexural strength could be around 4.0-4.7 MPa.

关 键 词：碳化硅木陶瓷 多孔陶瓷 淀粉造孔剂 微观结构 力学性能 

分 类 号：S781.7[农业科学—木材科学与技术] TQ174.75[农业科学—林学]