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

Abstract

Silica/montmorillonite hybrid nanoparticles were prepared to modify high‐density polyethylene which was used to fabricate wood/polymer composites (WPC). Surface modification of hybrids with γ‐methacryloxypropyltrimethoxysilane (MPTS) increased water contact angles from 10.7°to 88.1°and decreased the content of hydroxyl groups (42% relative OH content), indicating the successful grafting of MPTS. Compared with silica, the layered structure of montmorillonite (MMT) provided a better barrier (tortuous paths) for water penetration, and the incorporation of silica in hybrids provided more sites for MPTS grafting. Both of them resulted in the improvement on hydrophobicity for hybrids and WPCs. In the WPC system, some silicas in modified hybrids were not only dispersed in the polymer matrix but also penetrated into the cell wall of wood flours (WF) owing to the extruded process. The MMT in hybrids could mainly cover the WF surface. This distribution of hybrids could improve the WF mechanical strength and interfacial compatibility between the WF and polymer with the help of MPTS, resulting in enhanced mechanical properties of the composites. Compared with control (without nanoparticles), the tensile strength, impact strength, modulus of rupture and modulus of elasticity of the WPC with modified hybrids incorporation increased by 31%, 47%, 18%, and 28%, respectively.

Effect of silica nanoparticles on physical, mechanical, and wear properties of natural fiber reinforced polymer composites

“…[22] Polymer composite prepared by silica nanoparticles and natural fibers were also reported to enhance mechanical properties of polymer composites. [23][24][25][26][27] Incorporation of silica nanoparticles with montmorillonite nanoparticles and wood flour was reported to improve the tensile strength, modulus of rupture, impact strength, and modulus of elasticity of high-density polyethylene composites by J. Jiang et al. [23] T. Buddi et al [24] studied the mechanical properties of 5 wt% wood powder reinforced and 3, 5, and 7 wt% silica nanoparticles filled highdensity polyethylene composites.…”

“…[23][24][25][26][27] Incorporation of silica nanoparticles with montmorillonite nanoparticles and wood flour was reported to improve the tensile strength, modulus of rupture, impact strength, and modulus of elasticity of high-density polyethylene composites by J. Jiang et al. [23] T. Buddi et al [24] studied the mechanical properties of 5 wt% wood powder reinforced and 3, 5, and 7 wt% silica nanoparticles filled highdensity polyethylene composites. The authors concluded that the evaluated flexural and tensile strength remained maximum for 5 wt% silica nanoparticles composites while the composite with 3 wt.% silica nanoparticles displays the highest impact strength.…”

Functionalization of molten polyethylene by ozonization and its application in wood fiber reinforced polyethylene composites

“…[ 42–44 ] However, when the interfacial interaction of WPCs was improved, WF would be dispersed more homogeneous, and the stress concentration can be diminished under the external force, which was facilitated to promote the tensile properties of WPCs. [ 45–46 ] Due to the formation of oxygen‐containing groups in OPE surface, the interfacial interaction between WF and OPE was greatly enhanced, confirmed by SEM. Therefore, the tensile properties of OPE/WF composites were improved compared to those of PE/WF composites.…”

Comparative study on the effects of silica size and dispersion mode on the fire retardancy of extruded wood fiber/HDPE composites

“…[1][2][3] The incorporation of WF in polymer results in wood-polymer composites (WPCs), which are environmentally friendly materials that have been widely used in building materials, logistics packaging, and decorative materials. [4,5] However, both the WF and polymer in WPCs are flammable, thus posing a fire risk that extremely limits its application. [6,7] Many efforts have been implemented to reduce the flammability of WPCs.…”