scholarly journals Sustainable Wood Nanotechnologies for Wood Composites Processed by In-Situ Polymerization

2021 ◽  
Vol 9 ◽  
Author(s):  
Céline Montanari ◽  
Peter Olsén ◽  
Lars A. Berglund
Keyword(s):  
Cell Wall ◽  
Green Chemistry ◽  
Structural Control ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
Inorganic Nanoparticles ◽  
Wood Composites ◽  
Cumulative Energy ◽  
Materials Development ◽  
Green Processing

The development of large, multifunctional structures from sustainable wood nanomaterials is challenging. The need to improve mechanical performance, reduce moisture sensitivity, and add new functionalities, provides motivation for nanostructural tailoring. Although existing wood composites are commercially successful, materials development has not targeted nano-structural control of the wood cell wall, which could extend the property range. For sustainable development, non-toxic reactants, green chemistry and processing, lowered cumulative energy requirements, and lowered CO2-emissions are important targets. Here, modified wood substrates in the form of veneer are suggested as nanomaterial components for large, load-bearing structures. Examples include polymerization of bio-based monomers inside the cell wall, green chemistry wood modification, and addition of functional inorganic nanoparticles inside the cell wall. The perspective aims to describe bio-based polymers and green processing concepts for this purpose, along with wood nanoscience challenges.

Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Stefanie Stanzl-Tschegg ◽  
Wilfried Beikircher ◽  
Dieter Loidl
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Thermal Treatment ◽  
Mechanical Performance ◽  
Growth Ring ◽  
Beech Wood ◽  
Thermal Modification ◽  
Wood Structure ◽  
Instrumented Indentation ◽  
Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

scholarly journals Chlorination Treatment of Meta-Aramid Fibrids and Its Effects on Mechanical Properties of Polytetramethylene Ether Glycol/Toluene Diisocyanate (PTMEG/TDI)-Based Polyurethane Composites

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1794 ◽  
Author(s):  
Lu ◽  
Yi ◽  
Ning ◽  
Ge ◽  
S.M.
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Toluene Diisocyanate ◽  
Sodium Dichloroisocyanurate ◽  
Polyurethane Composites ◽  
Chemical Groups

Meta-aramid fibrids (MAF) have attracted much attention. However, it is difficult for this high mechanical performance fiber to form sufficient interface adhesion between the MAF and polyurethane (PU) matrix due to the chemical inertness of its surface. Thus, the surface activity of MAF should be improved to obtain a high-performance MAF/PU composite. A novel methodology to modify the surface of MAF with a sodium dichloroisocyanurate solution (DCCNa) was developed to obtain chlorinated MAF (MAFC) in this study. A series of MAFC/PU composites was prepared by in situ polymerization processes. The results of Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated that the chlorine-contained chemical groups were introduced onto the MAF surfaces after chlorination. Dynamic contact angle analysis (DCAA) revealed that the surface wettability and the surface free energy of the MAFC were significantly improved, which allowed for strong chemical bonding to PU. Scanning electron microscopy (SEM) showed a uniform distribution of MAFC and good interfacing bonding between the MAFC and PU. With the incorporation of 1.5 wt% MAFC into the polyurethane matrix, the tensile and tear strength values of MAFC/PU were 36.4 MPa and 80.1 kN·m−1 respectively, corresponding to improvements of approximately 43.3% and 21.1%, as compared to those of virgin PU as 25.4 MPa and 66.1 kN·m−1, respectively.

Evaluation of moisture diffusion as a threat to polymer/inorganic nanoparticles composites properties: Polystyrene/calcium sulfate nanocomposite as a case study

2020 ◽  
pp. 096739112095686
Author(s):  
Farzaneh Besharat ◽  
Mehrdad Manteghian ◽  
Mahdi Abdollahi
Keyword(s):  
Calcium Sulfate ◽  
In Situ Polymerization ◽  
Effective Diffusion ◽  
Moisture Diffusion ◽  
Sem Analysis ◽  
Inorganic Nanoparticles ◽  
Tem Analysis ◽  
Water Diffusivity ◽  
Calculation Results

The present study aims to investigate the water diffusivity into polystyrene/ calcium sulfate (PS/CaSO4) nanocomposite samples as a threat to the intended reinforcing properties. For this purpose, CaSO4 nanoparticles were synthesized through a chemical reaction using polyethylene glycol as the stabilizing agent. The polystyrene/calcium sulfate nanocomposites were fabricated through in situ polymerization of styrene monomer and stearic acid coated CaSO4 nanoparticles. SEM analysis was applied to determine the size and shape of the produced nanoparticles. In addition, TEM analysis was applied to study the general morphology and structure of the nanocomposites in order to confirm the PS/CaSO4 nanocomposites formation. FTIR analysis was employed to study the surface functions and bonds formation in both the surface treatment and nanocomposite preparation steps. Water diffusivity into the nanocomposites was evaluated through samples water exposure followed by calculation of the effective diffusion coefficients (Deff) using the diffusion equation given by Fick’s 2nd law. The calculation results have revealed that the obtained Deff values for water diffusivity in PS/CaSO4 (1.5 wt.%) and pure PS samples were 8.73 × 10−20 and 11.1 × 10−20 m2/s, respectively.

Study of the Proper Sintering Conditions of Anionically-Polymerized Polyamide 6 Matrices for the Fabrication of Greencomposites

2012 ◽  
Vol 713 ◽  
pp. 121-126
Author(s):  
A. Alfonso ◽  
J. Andrés ◽  
J.A. García
Keyword(s):  
Material Characterization ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
Research Work ◽  
Polyamide 6 ◽  
Liquid Composite Molding ◽  
Thermoplastic Matrix ◽  
Composite Molding ◽  
Long Fiber Thermoplastic

The present research work assesses the manufacture of long fiber thermoplastic matrix composite materials (GreenComposites). Thermoplastic matrices are too viscous to be injected into the conventional LCM (Liquid Composite Molding) molds, and then epoxy, polyester or vinylester resins are used. Nevertheless, the groundbreaking anionic polymerization of caprolactam allows such a synthesis of a thermoplastic APA6 matrix inside the mold. This matrix is sintered from the starting monomers, and presents high mechanical performance and recyclability. In order to do the reactive injection in a LCM mold, it is necessary to control the polymerization mechanism of such a thermoplastic matrix. This paper puts special emphasis on detecting and solving all problems which arose during synthesis. For instance, moisture values were assessed for all starting reactants, since humidity keeps polymerization from occurring. It is thought that once the synthesis and the resulting material characterization are well controlled, the manufacture of GreenComposites through in situ polymerization, as well as addition of state-of-the-art fabrics such as basalt, can proceed successfully.

Experimental study on in-plane compressive response of irregular honeycombs

2017 ◽  
Vol 52 (8) ◽  
pp. 1121-1135
Author(s):  
Youming Chen ◽  
Raj Das ◽  
Mark Battley
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Compressive Load ◽  
Neighbouring Cell ◽  
Deformation And Failure ◽  
Compressive Response ◽  
A Cell ◽  
Foam Mechanics

Compared with regular honeycombs, irregular honeycombs are more representative of real foams, and thus more suitable for the study of foam mechanics. In this paper, the deformation and failure progression in the irregular honeycombs are investigated by analysing the images captured in order to gain an improved understanding on foam failure. Irregular honeycombs with varying cell wall thickness, cell size and cell shape were manufactured using a three-dimensional printer and tested under compression. The behaviour of irregular honeycombs is found to be different from that of regular honeycombs. In irregular honeycombs, cell walls start to fracture at some point, initially at a low speed from multiple locations. The global stress reaches its maximum value shortly after the first fracture of cell walls. Only a few cell walls buckle in the specimens with cells of irregular shape. Fracture is more likely to occur to thin and long cell walls aligned within a medium angle (around 30 to 60°) to the compressive load. However, the susceptibility of a cell wall is to fracture is also affected by its neighbouring cell walls. Strong and stiff neighbouring cell walls could shield load away and protect it from breaking. Because of this, it is better to think of a weak spot as a region, rather than an individual cell or cell wall. Overall, the more uniform cell wall size and thickness are, the better the mechanical performance of cellular solids is.

Preparation and Properties of Polydicyclopentadiene/MMt Nanocomposites Using Supported Tungsten Catalyst

2011 ◽  
Vol 52-54 ◽  
pp. 2071-2075 ◽  
Author(s):  
Yu Qing Zhang ◽  
Yan Yi Nan ◽  
Joong Hee Lee ◽  
Yu Xin He ◽  
Da Hu Yao ◽  
...  
Keyword(s):  
Ring Opening ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
Low Cost ◽  
Supported Catalyst ◽  
X Ray Diffraction ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
The Matrix ◽  
Good Catalytic Activity

Polydicyclopentadiene (PDCPD) is a kind of engineering plastic which possesses excellent mechanical performance. It can be made by dicyclopentadiene (DCPD) through Ring-opening metathesis polymerization. In this paper, a supported catalyst of WCl6-phenol on montmorillionite (MMt) was prepared, formed a high efficienct, low-cost and more stable in air, tagether with Et2AlCl as activator, to polymerize the DCPD monomer through ring-opening metathesis polymerization mechanism, and obtained a Polydicyclopentadiene/MMt Nanocomposites. The Molding of PDCPD was finally made by Gusmer-decker’s RIMcell Lt Machine, and the products were characterized by X-ray diffraction, TEM, TGA, SEM, DMA. Mechanical properties were also measured. The result showed that the supported catalyst had good catalytic activity in polymerizing DCPD. MMt was exfoliated in the matrix after the in-situ polymerization, according to the XRD and TEM, which brought about improved properties of PDCPD with small amount MMt dispersed in the matrix.

Cell wall features with regard to mechanical performance. A review COST Action E35 2004–2008: Wood machining – micromechanics and fracture

Holzforschung ◽  
2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Lennart Salmén ◽  
Ingo Burgert
Keyword(s):  
Cell Wall ◽  
Mechanical Performance ◽  
Wood Cell Wall ◽  
Wood Products ◽  
Wall Structure ◽  
Detailed Knowledge ◽  
Structure Property ◽  
Property Relations ◽  
Recent Developments ◽  
Wood Machining

Abstract The mechanical performance of wood and wood products is highly dependent on the structural arrangement and properties of the polymers within the fibre cell wall. To improve utilisation and manufacture of wood materials, there is an increasing need for a more detailed knowledge regarding structure/property relations at the micro- or nanostructural level. In this article, recent developments regarding our understanding of the wood cell wall structure and its mechanical performance are summarised. The new results are interpreted in relation to property performances of wood fibres and wood tissues. Suggestions are made for future requirements for research in this field.

scholarly journals CORROSION RESISTANCE AND MECHANICAL PROPERTIES OF TiO2 NANOTUBES / EPOXY COATING ON STEEL SPCC-JISG 3141

2018 ◽  
Vol 55 (5B) ◽  
pp. 203
Author(s):  
Duong Thi Hong Phan
Keyword(s):  
Corrosion Resistance ◽  
Titanium Dioxide ◽  
Epoxy Resin ◽  
Tio2 Nanotubes ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
Salt Spray ◽  
Epoxy Coating ◽  
Test Model ◽  
Titanium Dioxide Nanotubes

     Titanium dioxide nanotubes (TNTs) have been considered the promising nanostructures employed for many practical applications such as biomedical, photonic and optoelectronic devices. Coatings prepared from epoxy-nano-TiO2 nanotubes synthesized by in situ polymerization were found to exhibit excellent corrosion resistance much superior to epoxy resin in aggressive environments. The corrosion studies were carried out on steel SPCC JISG 3141 plates coated with 5 wt % and without of TiO2 nanotubes (TNTs). The synthesis of titanium dioxide nanotubes (TNTs) using hydrothermal method was investigated. The synthesized TNTs were characterized with Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) specific area surface test, X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) imaging. The results demonstrated a unique tubular nanostructure of TNTs shape. The mechanical performance of the nanocomposites was examined to show that the 5 wt % TNTs/epoxy coating was more impact resistance, the film hardness behavior and bending resistance than epoxy coating. The effects of TNT particles on corrosion resistance of epoxy coating were studied by salt spray test (Model SAM Y90) and compared to that of non-filler. After 144 h exposure, the corrosion resistance of epoxy resin greatly improved by using reinforcing the white pigment of TNTs. The results indicated that the coating containing TNTs shows the best protection efficiency. 

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