scholarly journals A Branched Polyelectrolyte Complex Enables Efficient Flame Retardant and Excellent Robustness for Wood/Polymer Composites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2438
Author(s):  
Yanping Huang ◽  
Shuai Zhang ◽  
He Chen ◽  
Chunxiang Ding ◽  
Yan Xuan ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Polymer Composites ◽  
Polyelectrolyte Complex ◽  
Electrical Equipment ◽  
Interfacial Bonding ◽  
Thermoplastic Composites ◽  
Wood Fibers ◽  
Bonding Performance ◽  
Fiber Reinforced Polymer Composites ◽  
Wood Polymer

Wood/thermoplastic composites (WPCs) have been restricted in some fields of building construction and electrical equipment because of their inherent high flammability and lower toughness. In this work, a branched crosslinking network polyelectrolyte complex (PEC) has been designed by incorporation of polyethyleneimine (PEI), a cation polyelectrolyte end capped amine groups, into cellulose nanocrystals (CNC), and ammonium polyphosphate (APP) via self-assembling. The hydrogen bonding interactions, penetration, and mechanical interlock provided by PEC effectively enhance the interfacial bonding within matrix, wood fibers, and flame retardant. Interestingly, it generates abundant micropores on the inner structure of WPC. The excellent interfacial bonding performance and easy-to-move molecular chain successfully transfer the stress and induce energy dissipation, simultaneously giving rise to higher strength and toughness for WPC. As well as the PEC endows WPC with a promotion in both smoke suppression and UL-94 V-0 rate. Additionally, the peak heat release rate and total smoke release for WPC obviously reduce by 36.9% and 50.0% respectively in presence of 25% PEC. A simple, eco-friendly, and concise strategy exhibits prospects for fiber-reinforced polymer composites with effective flame retardancy and mechanical robust properties.

scholarly journals Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition

2021 ◽  
Vol 5 (6) ◽  
pp. 141
Author(s):  
Imen Elloumi ◽  
Ahmed Koubaa ◽  
Wassim Kharrat ◽  
Chedly Bradai ◽  
Ahmed Elloumi
Keyword(s):  
Dielectric Properties ◽  
Polymer Composites ◽  
Wide Frequency Range ◽  
Dielectric Constants ◽  
Cellulose Content ◽  
Wood Fibers ◽  
Low Frequencies ◽  
Wood Polymer ◽  
Wood Polymer Composites ◽  
New Applications

The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose content show higher dielectric constants.

scholarly journals Effects of Coating on the Dimensional Stability of Wood-Polymer Composites

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 711
Author(s):  
Marouan Rejeb ◽  
Ahmed Koubaa ◽  
Fayez Elleuch ◽  
François Godard ◽  
Sébastien Migneault ◽  
...  
Keyword(s):  
Water Absorption ◽  
Polymer Composites ◽  
Dimensional Stability ◽  
Thickness Swell ◽  
Wood Fibers ◽  
Pulp Fibers ◽  
Wood Polymer ◽  
Hydrophilic Nature ◽  
The Matrix ◽  
Wood Polymer Composites

Wood polymer composites (WPC) are sensitive to moisture because of the hydrophilic nature of the wood fibers. The main objective of this study was to improve the dimensional stability of WPCs by coating. Polypropylene and polylactic acid were reinforced by three pulp fibers (kraft, thermomechanical (TMP), and chemothermomechanical (CTMP)) at three fiber contents (50, 60, and 70% w/w). The resulting WPCs were coated using two commercial coatings, epoxy and acrylic. Kraft fiber WPCs were less sensitive to moisture than TMP and CTMP WPCs. These differences were explained by the crystallinity of the kraft fibers and their better interfacial adhesion to the polymers. The epoxy coating proved to be more effective than the acrylic coating and significantly reduced the water absorption and the thickness swell for all formulations. Negative relationships between the contact angle and water absorption were obtained. These relationships depend on the fiber content and type, the matrix nature, and the coating.

scholarly journals Insight into the Surface Properties of Wood Fiber-Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1535
Author(s):  
Klementina Pušnik Črešnar ◽  
Marko Bek ◽  
Thomas Luxbacher ◽  
Mihael Brunčko ◽  
Lidija Fras Zemljič
Keyword(s):  
Polymer Composites ◽  
Surface Properties ◽  
Wood Fiber ◽  
Antioxidant Properties ◽  
Skin Layer ◽  
Filler Loading ◽  
Attenuated Total Reflection ◽  
Thermoplastic Composites ◽  
Wood Fibers ◽  
Pp Composites

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.

Water Absorption of Wood-Polymer Composites Based on PVC with Partial Replacement of Wood Filler by Mineral One

2019 ◽  
Vol 770 (5) ◽  
pp. 62-66
Author(s):  
A.A. ASKADSKII ◽  
◽  
T.A. MATSEEVICH ◽  
V.I. KONDRASHCHENKO ◽  
◽  
...  
Keyword(s):  
Water Absorption ◽  
Polymer Composites ◽  
Partial Replacement ◽  
Wood Polymer ◽  
Wood Polymer Composites
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