以熔融沉积增材制造技术为依据，研究了聚乳酸与杨木木粉熔融复合混合工艺，探索了原料混合比例、挤出条件等，并对挤出的复合材料进行了力学性能和微观性能检测。结果表明，杨木木粉添加量对复合材料有显著性影响，随着木粉添加量的增加，复合材料力学性能降低，当普通杨木粉原料添加量为40%时，弯曲强度降低30.3%，拉伸强度降低26.4%，冲击强度降低82.2%；当特殊杨木粉原料添加量为40%时，弯曲强度降低14.5%，拉伸强度降低22.9%，冲击强度降低72.9%；从材料的流变性能可见，添加杨木木粉后，弹性模量和损耗模量均增加，并且与木粉的添加量呈现正相关；复合材料流体的黏度降低，表明添加木粉后，复合材料的流动性变差，流体阻力增大；应用DSC检测复合材料时发现，复合材料基体的玻璃化转变温度、结晶温度和熔融温度与聚乳酸单体相比没有改变，加入木粉后只改变了熔体的流动性，对熔点没有影响；通过SEM观察，无论原料为何种比例，聚乳酸与木粉结合均比较紧密，混合也很均匀；同时傅里叶变换红外光谱显示，各主要基团没有变化。
Currently, the constraints of the 3D printing technology is in the materials. The paper studies how to add the material by the technology of the fused deposition and the melt mixing process of the polylactic acid and the poplar wood powder composites are experimentally studied, focusing on the mixing ratio of the raw materials, the extrusion conditions and the testing mechanical properties, as well as the microstructure and the performance of the extruded composites. The results show that the amount of poplar wood powders has a significant impact on the composites. With the increasing amount of powders, the mechanical properties of the composites deteriorate. When the added amount of the ordinary poplar powders is 40%, the flexure strength, the tensile strength and the impact strength are decreased by 30.3%, 26.5% and 82.2%. When the added amount of the special poplar powders is 40%, the flexure strength, the tensile strength and the impact strength are decreased by 14.5%, 22.9% and 72.9%. From the rheological properties of the materials, it is seen that the elastic modulus and the loss modulus increase with the increase of the wood powders in a positive correlation. The viscosity of the composites fluid reduces, which suggests that the mobility gets worse and the fluid resistance increases after adding the powders. DSC detection finds that the glass-transition temperature, the crystallization temperature and the melting temperature of composites see no difference as compared to the pure PLA. The addition of wood powders only changes the melt flow but has no effect on the melting point. From the SEM, it is seen that the polylactic acid and the wood powders combine closely and mix uniformly no matter what the proportion of the raw material is. The FT-IR shows that the major groups do not change.
[1] 卢秉恒.3D打印正进入发展期[J].信息技术与信息化,2014(9):6.Lu Bingheng.3D Printing and development[J].Information Technology and Informatization,2014(9):6.
[2] 王雪莹.3D打印技术与产业的发展及前景分析[J].中国高新技术企业,2012(26):3-5.Wang Xueying.3D Printing technology and the analysis of industry development and prospect[J].China High Technology Enterprises,2012(26):3-5.
[3] 陈新伟.三维喷绘机器人喷墨机理研究[D].天津:南开大学,2009.Chen Xinwei.Three-dimensional printing robot system[D].Tianjin:Nankai University,2009.
[4] 李青,王青.3D打印:一种新兴的学习技术[J].远程教育杂志,2013(4):29-35.Li Qing,Wang Qing.3D printing:A new technology for learning[J].Journal of Distance Education,2013(4):29-35.
[5] 李坚,许民,包文慧.影响未来的颠覆性技术:多元材料混合智造的3D打印[J].东北林业大学学报,2015(6):1-9.Li Jian,Xu Min,Bao Wenhui.Impact of future disruptive technologies:Mixed multi-material 3D printing technology[J].Journal of Northeast Forestry University,2015(6):1-9.
[6] Zhou Z F,Xu M,Yang Z Z,et al.Effect of maleic anhydride grafted polyethylene on the properties of chopped carbon fiber/wood plastic composites[J].Journal of Reinforced Plastics and Composites,2014,33(13):1216-1225.
[7] Wu G,Xu M.Effects of boron compounds on the mechanical and fire properties of wood-chitosan and high-density polyethylene composites[J].Bioresources,2014,9(3):4173-4193.
[8] 姜洪丽.木粉含量对木粉/PE-HD复合材料力学性能的影响[J].泰山医学院学报,2007(4):256-259.Jiang Hongli.Effect of wood floor content on mechanical properties of wood flour/PE-HD composites[J].Journal of Taishan Medical College,2007(4):256-259.
[9] 李东方.聚乙烯木塑复合材料性能影响因子与界面特性研究[D].北京:北京林业大学,2013.Li Dongfang.Study on performance Influence factors and interfacial characteristic of PE wood plastic composite[D].Beijing:Beijing Forestry University,2013.
[10] Pötschke P,Villmow T,Krause B.Melt mixed PCL/MWCNT compos-ites prepared at different rotation speeds:Characterization of rheologi-cal,thermal,and electrical properties,molecular weight,MWCNT macrodispersion,and MWCNT length distribution[J].Polymer,2013,54(12):3071-3078.
[11] Marcovich N E,Reboredo M M,Kenny J,et al.Rheology of particle suspensions in viscoelastic media.Wood flour-polypropylene melt[J].Rheologica Acta,2004,43(3):293-303.
[12] Li T Q,Wolcott M P.Rheology of wood plastics melt.Part 1.Capil-lary rheometry of HDPE filled with maple[J].Polymer Engineering & Science,2005,45(4):549-559.
[13] Nayak S K,Mohanty S,Samal S K.Influence of short bamboo/glass fi-ber on the thermal,dynamic mechanical and rheological properties of polypropylene hybrid composites[J].Materials Science and Engineer-ing:A,2009,523(1):32-38.
