复配改性工业木质素/木纤维复合材料的制备与表征

Preparation and characterization of hybrid modified industrial lignin/wood fiber composites

  • 摘要: 以H2O2为氧化剂对工业木质素进行改性,将H2O2氧化改性工业木质素(OMIL)与聚乙烯亚胺(PEI)复配制得复配改性工业木质素(OMIL-PEI)。以木纤维(WF)为基体,OMIL-PEI为黏结相,采用高速混合-平板热压工艺制备了环保型OMIL-PEI/WF复合材料。采用正交试验设计方法研究了H2O2用量、氧化时间、OMIL与PEI质量比及复配剂OMIL-PEI用量对该复合材料物理力学性能的影响,探索了复合材料的最优制备工艺参数,并采用FTIR、XRD、DMA和SEM对复合材料的结构和性能进行了表征。结果表明:最优工艺条件为,H2O2用量20wt%,氧化时间120 min,OMIL与PEI质量比7:1,OMIL-PEI用量20wt%,所制备的复合材料各项理化性能满足GB/T 11718-2009干燥状态下使用的承重型中密度纤维板的性能要求;OMIL-PEI能够与WF在热压过程中形成良好的化学键;优化工艺条件下的OMIL-PEI/WF复合材料的木质纤维素的晶形结构保持不变,相对结晶度从60.24%(纯WF)升高到72.91%;OMIL-PEI提高了OMIL-PEI/WF复合材料的动态储能模量,对材料的热稳定性影响不大,且各组分之间分布均匀,交织致密,界面粘结性能良好。

     

    Abstract: The hybrid modified industrial lignin (OMIL-PEI) consisting of industrial lignin oxidatively modified by H2O2 (OMIL) and polyethylenimine (PEI) was prepared. Using wood fiber (WF) as the matrix and OMIL-PEI as natural binder, the green OMIL-PEI/WF composites were prepared by the method of high speed mixed-flat of hot pressing. The orthogonal theories were used to analyze the effect of H2O2 dosage, oxidative time, mass ratio of OMIL to PEI and OMIL-PEI dosage on the mechanical properties and optimize the process parameters. The structure and property of the composites were analyzed by FTIR, XRD, DMA and SEM. Results show the optimum conditions are as follows: H2O2 dosage is 20wt%, oxidative time is 120 min, mass ratio of OMIL to PEI is 7:1 and OMIL-PEI dosage is 20wt%. The mechanical properties of OMIL-PEI/WF composites meet the mechanical property requirements of load bearing medium density fiberboard in dry state according to GB/T 11718-2009. The wood fiber gets a good chemical bond with OMIL-PEI. The crystalline structure of lignocellulose is not changed in OMIL-PEI/WF composites under the optimum conditions. The relative crystallinity increases from 60.24% for pure wood fiber to 72.91% for OMIL-PEI/WF composites. OMIL-PEI improves the dynamic storage modulus of OMIL-PEI/WF composites, but has not much effect on the thermostability of OMIL-PEI/WF composites. OMIL-PEI/WF composites has a good interfacial bondability with uniform mixtures.

     

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