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 ◽  
...  

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.

2019 ◽  
Vol 770 (5) ◽  
pp. 62-66
Author(s):  
A.A. ASKADSKII ◽  
◽  
T.A. MATSEEVICH ◽  
V.I. KONDRASHCHENKO ◽  
◽  
...  

2021 ◽  
Vol 5 (6) ◽  
pp. 141
Author(s):  
Imen Elloumi ◽  
Ahmed Koubaa ◽  
Wassim Kharrat ◽  
Chedly Bradai ◽  
Ahmed Elloumi

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.


2006 ◽  
Vol 102 (6) ◽  
pp. 5085-5094 ◽  
Author(s):  
Yaolin Zhang ◽  
S. Y. Zhang ◽  
Dian Qing Yang ◽  
Hui Wan

2020 ◽  
Vol 54 (5) ◽  
pp. 1091-1119 ◽  
Author(s):  
Aleksander Hejna ◽  
Marta Przybysz-Romatowska ◽  
Paulina Kosmela ◽  
Łukasz Zedler ◽  
Jerzy Korol ◽  
...  

Abstract Wood-polymer composites technologies are gaining more and more attention in the scientific community, positively affecting the increase in their industrial applications, for example, automotive, building, 3D printing, etc. Many research works are focused on the improvement in matrix–lignocellulosic filler interactions to produce highly filled composites with satisfying performance properties. In this field of research, using isocyanates due to their versatile structure and functionality seems to be a very promising approach. This paper aims at reporting on recent advances in compatibilization strategies of wood-polymer composites by isocyanates. Particular attention is focused on the correlation between isocyanate structure, as well as modification conditions on the matrix–lignocellulosic filler interactions and their impact on the structure–property relationships of wood-polymer composites. Furthermore, limitations and future research trends related to applications of isocyanate to wood-polymer composites technologies are also discussed.


Measurement ◽  
2018 ◽  
Vol 115 ◽  
pp. 197-203 ◽  
Author(s):  
Hatem Mrad ◽  
Sébastien Alix ◽  
Sébastien Migneault ◽  
Ahmed Koubaa ◽  
Patrick Perré

2021 ◽  
Vol 12 (2) ◽  
pp. 33-39
Author(s):  
N. V. Buiskykh

One of the areas of wood waste processing is their use in the production of wood-polymer composites (WPC). The relevance of wood-polymer products is due to the wide range of applications and qualities of this material. WPC does not rot, is not damaged by insects and fungi, does not contain harmful binders. Products from the duodenum do not crack, do not gouge, are waterproof, which makes them an excellent material for manufacturing a terrace board. However, the terrace board must have certain mechanical qualities, which will allow it to be used in fairly harsh conditions - under the action of humidity, UV radiation and under a certain load. This study aimed to determine the main physical and mechanical properties (density, strength at static bending, modulus of elasticity, water absorption, hardness, abrasion resistance, changes in linear dimensions with changing atmospheric environment) samples of terrace board manufacturing from duodenum with different fillers. Samples from a hollow terrace board, which were filled with polyethylene (PE) and polyvinyl chloride (PVC), were used for the study. Based on experimental studies, it was found that the density of both samples is quite high, close to the maximum; the difference is not significant, but when examining microslices under a microscope in samples with PE as a binder, a larger number of voids is observed, indicating the presence of excess moisture or lack of mineral fillers. It may also indicate the destruction of the polymer. It was determined that a number of other important indicators such as strength at static bending, modulus of elasticity, water absorption, abrasion resistance were the best in the samples with a filler of polyvinylchloride. The greatest difference was in the bending strength index and was 35%. It was also found that the hardness of both samples were equivalent. However, the modulus of elasticity of the sample with a filler with PE exceeded the performance of the sample with a filler with PVC by almost 2.5 times. Thus, based on the research, it is possible to identify a number of clear relationships that indicate that theuse of polyvinylchlorideas a binder significantly improves the physical and mechanical properties of the terrace board based on wood-polymer composite. The results of the research will solve the problem of improving the strength characteristics of wood-composite material to expand the range based on wood waste Keywords: density, hardness, modulus of elasticity, water absorption, abrasion resistance.


2019 ◽  
Vol 97 ◽  
pp. 02043
Author(s):  
Tatyana Matseevich ◽  
Andrey Matseevich ◽  
Andrey Askadskii

The materials based on wood-polymer composites (WPC) in the form of decking boards are produced, in which wood filler is partially replaced by mineral one. WPC materials manufactured by Savewood using a matrix polymer of polyvinyl chloride (PVC) have good mechanical properties, low abrasion and satisfactory resistance to climatic influences. However, they have relatively high water absorption, the task of reducing which is relevant not only in Russia, but also in other countries where there are constructions of facilities operating in outdoor environmental conditions. The modification of such materials in this work was carried out by replacing part of the wood filler with the mineral filler, which is CaCO3 (chalk). Partial replacement of wood flour with mineral filler resulted in a marked reduction in swelling from 1.25 to 0.01%. In this case, the modulus of elasticity is increased from 2260 to 2880 MPa, tensile strength from 30.5 to values of 16.7 ÷ 32 MPa. The specific impact strength varies from 8.90 to 7.74 kJ/m2. The optimal ratio of wood and mineral fillers is 60/40%.


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