How does Pickering Emulsion Pre-treatment Influence the Properties of Wood Flour and its Composites with High-Density Polyethylene?

Abstract

Silica synergistically stabilized paraffin Pickering emulsion is applied to modify wood flour (WF) for preparing wood/polymer composites. The effect of Pickering emulsion on properties of the WF and its composites with high-density polyethylene (HDPE) is investigated. The impregnation of paraffin Pickering emulsion could significantly improve the WF dispersion in HDPE matrix, resulting in increased melt flow index (MFI). It increased from 1.3 g/10 min (control) to 2.1 g/10 min (Pickering treatment) due to the lubrication of paraffin and rolling friction provided by silica nanoparticles. The hydrophobicity of the WF was improved by the penetration of paraffin and silica in the cell wall, which could consume the hydroxyl groups in WFs via hydrogen bonding. Owing to the well distribution of WFs and silica, the mechanical properties and surface hardness of the composites were enhanced obviously. The optimal tensile strength and impact strength increased 23% (18.28 MPa) and 32% (14.16 KJ/m2), respectively. It also could be attributed to the improved interfacial compatibility due to the incorporation of surfactants (Span 80 and Tween 80), which acted as a coupling agent. Furthermore, the silica incorporated in the WF could compensate the negative effect of paraffin on thermal stability of the composites. A model concerning the interactions in the composites was proposed based on the research results.

Improved Hydrophobicity and Dimensional Stability of Wood Treated with Paraffin/Acrylate Compound Emulsion through Response Surface Methodology Optimization

“…Furthermore, both the photostability and decay resistance of wood could be improved by this method [3,4]. In our previous studies [5,6], paraffin Pickering emulsion was successfully prepared to treat solid wood and wood flours for composites preparation, through which the hydrophobicity, thermal stability and surface hardness in wood and composites improved obviously. Paraffin emulsion is a dispersion in which the hydrophobic paraffin is homogeneously dispersed in water in the form of small particles with the help of certain surfactants.…”

Study on the Impact of a Combination of Synthetic Wollastonite and 2-Mercaptobenzothiazole-Based Fillers on UHMWPE Polymeric Matrix

“…In the case of agglomerates of acicular particles, MBT filled the interphase layer between the filler and the polymer. The localization of MBT on the interphase border is called the Pickering effect when the interphase surface tension is decreased [59][60][61][62]. The MBT particles in the interfacial layer can act as additional "molecular clamps" according to a figurative expression [63], which explains the changes in the material's mechanical behavior.…”

Improved mechanical properties and hydrophobicity on wood flour reinforced composites: Incorporation of silica/montmorillonite nanoparticles in polymers

“…Using inorganic particles like silica, MMT, titanium dioxide, and calcium carbonate is an alternative to enhance WPC's thermal properties, mechanical properties, and water resistance. Among these particles, silica and MMT have been widely used as fillers in the WPC frication . Incorporating silica nanoparticles with wood flour (WF) and polymer could improve the flexural strength, impact strength, and surface hardness of WPCs .…”

“…Among these particles, silica and MMT have been widely used as fillers in the WPC frication. [18][19][20] Incorporating silica nanoparticles with wood flour (WF) and polymer could improve the flexural strength, impact strength, and surface hardness of WPCs. [15,21] Highly improved properties were found at 0.5 wt.% MMT concentration in the organic MMT modified WF/PLA composites.…”