Črešnar Klementina Pušnik, Bek Marko, Luxbacher Thomas, Brunčko Mihael, Zemljič Lidija Fras
Faculty of Mechanical Engineering, University of Maribor, 2000 Maribor, Slovenia.
Faculty of Mechanical Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia.
Polymers (Basel). 2021 May 11;13(10):1535. doi: 10.3390/polym13101535.
The surface properties of wood fiber (WF) filled polymer composites depend on the filler loading and are closely related to the distribution and orientation in the polymer matrix. In this study, wood fibers (WF) were incorporated into thermoplastic composites based on non-recycled polypropylene (PP) and recycled (R-PP) composites by melt compounding and injection moulding. ATR-FTIR (attenuated total reflection Fourier transform infrared spectroscopy) measurements clearly showed the propagation of WF functional groups at the surface layer of WF-PP/WF-R-PP composites preferentially with WF loading up to 30%. Optical microscopy and nanoindentation method confirmed the alignment of thinner skin layer of WF-PP/WF-R-PP composites with increasing WF addition. The thickness of the skin layer was mainly influenced by the WF loading. The effect of the addition of WF on modulus and hardness, at least at 30 and 40 wt.%, varies for PP and R-PP matrix. On the other hand, surface zeta potential measurements show increased hydrophilicity with increasing amounts of WF. Moreover, WF in PP/R-PP matrix is also responsible for the antioxidant properties of these composites as measured by DPPH (2,2'-diphenyl-1-picrylhydrazyl) assay.
木纤维（WF）填充聚合物复合材料的表面性能取决于填料含量，并且与聚合物基体中的分布和取向密切相关。在本研究中，通过熔融共混和注塑成型将木纤维（WF）加入到基于非回收聚丙烯（PP）的热塑性复合材料以及回收（R-PP）复合材料中。衰减全反射傅里叶变换红外光谱（ATR-FTIR）测量清楚地表明，在WF-PP/WF-R-PP复合材料的表面层，WF官能团优先随着WF含量增加至30%而传播。光学显微镜和纳米压痕法证实，随着WF添加量增加，WF-PP/WF-R-PP复合材料较薄表层的排列情况。表层厚度主要受WF含量影响。添加WF对模量和硬度的影响，至少在30%和40%重量百分比时，对于PP和R-PP基体有所不同。另一方面，表面zeta电位测量表明，随着WF量的增加亲水性增强。此外，通过2,2'-二苯基-1-苦基肼（DPPH）测定法测量可知，PP/R-PP基体中的WF也是这些复合材料抗氧化性能的原因。
