Insight into the Surface Properties of Wood Fiber-Polymer Composites

Abstract

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.

Kraft Lignin/Tannin as a Potential Accelerator of Antioxidant and Antibacterial Properties in an Active Thermoplastic Polyester-Based Multifunctional Material

“…Both PLA and the KL and TANN structures consist of COOH and OH groups. The interfacial interaction of PLA with KL and TANN, namely by the carbonyl group reported in our previous work, does not affect the charges and consequently yields a constant IEP value [48].…”

“…Streaming potential measurements were performed using an aqueous 0.001 mol/L KCl solution as the background electrolyte. The pH dependence of the surface zeta potential was determined by adjusting an initial pH 10, using 0.05 mol/L KOH as reported elsewhere [48].…”

“…The radical scavenging activity of neat PLA, PLA-KL, and PLA-TANN composites was evaluated using DPPH• (2,2 -diphenyl-1-picrylhydrazyl) (Sigma-Aldrich, France). The method of antiradical activities is based on the reduction of the DPPH• radical, which is analyzed spectrophotometrically at a wavelength of 517 nm (Spectrophotometer (UV-VIS) UV-1800 Shimadzu) as it was clearly introduced in our previously published paper [48]. The antioxidant capacity can be determined by the decrease of absorption at wavelength 517 nm.…”

Long-Term Creep Compliance of Wood Polymer Composites: Using Untreated Wood Fibers as a Filler in Recycled and Neat Polypropylene Matrix

“…The complete materials and samples preparation procedure is described elsewhere [36,37]. The overview of investigated materials is given in Table 1.…”

Carbon Fiber Reinforced Recycled Polypropylene/Polyolefin Elastomer Composites with High Mechanical Properties

“…AlMaadeed et al mainly improved the mechanical strength of R-PP by mixing wood powder/glass fiber; this especially improved the tensile strength and Young's modulus of R-PP [13]. Črešnar et al [14] discussed the surface properties of composites filled with R-PP and wood fiber (WF) and proposed that the distribution and orientation of wood fiber filler in the R-PP matrix were the key factors affecting the overall surface properties of materials. Sascha Stanic et al [15] mainly studied composites made of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) and the relevant dynamic rheological mechanisms.…”