Preparation of Three Dimensional Products Using Flow Deformability of Wood Treated by Small Molecular Resins

2013 ◽  
Vol 856 ◽  
pp. 79-86 ◽  
Author(s):  
Tsunehisa Miki ◽  
Masako Seki ◽  
Ichinori Shigematsu ◽  
Kozo Kanayama
Keyword(s):  
Molecular Weight ◽  
Phenol Formaldehyde ◽  
Flow Behavior ◽  
Maximum Flow ◽  
Solid Wood ◽  
Formaldehyde Resin ◽  
Compression Tests ◽  
Softening Effect ◽  
Water Steam ◽  
Similar Molecular Weight

To investigate the effect of the additive agents such as polyethylene glycols (PEGs), melamine formaldehyde resin (MF-resin) and phenol formaldehyde resin (PF-resin) on the flow deformability of solid wood, free compression tests during heating were performed. Various molecular weights ranging from 200 to 20,000 for PEGs and almost similar molecular weight around 380 for MF-resin and PF-resin were applied. It was found from the compression tests that the yield stress indicating wood cell deformation resistance was drastically decreased with smaller molecular PEGs in wood, whereas the initiation of flow behavior, which is derived from detachment/slippage between cells, occurred at lower pressure with larger molecular PEGs. For generating the flow behaviors of solid wood, smaller molecular resin/substance was not always suitable. Thermosetting agents also act as a plasticizer during heating and especially the PF-resin showed better softening effect as well as a promoter of flow behavior than the MF-resin with almost similar molecular weight. This indicates that it is important for generating flow behavior to consider affinity/compatibility of resin to wood constituents. A maximum flow deformation ratio in the tangential direction of wood reached 180 % when using PEG 20,000 and MF-resin as an additive agent. It was also demonstrated that using PF-resin and MF-resin deep cup products shaped by a backward extrusion process had a better size stability against water, steam, and acetone.

The Chemistry of Phenol-Formaldehyde Resin Vulcanization of EPDM: Part I. Evidence for Methylene Crosslinks

1995 ◽  
Vol 68 (5) ◽  
pp. 717-727 ◽  
Author(s):  
Martin van Duin ◽  
Aniko Souphanthong
Keyword(s):  
Molecular Weight ◽  
Phenol Formaldehyde ◽  
Polymer System ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Low Molecular Weight ◽  
Hydroxyl Groups ◽  
Reaction Products ◽  
Cure Reaction ◽  
Weight Model

Abstract The application of phenol-formaldehyde resins as crosslinking agents is increasing in importance due to the good high temperature properties of the corresponding vulcanizate and the use in thermoplastic vulcanizates. With respect to the chemistry of phenol-formaldehyde cure (reaction mechanism and structure of crosslink) there are still problems that have to be resolved. The reaction products of the phenol-formaldehyde resin curing of EPDM, contain 2-ethylidene norbornene (ENB) as the third monomer, have been studied. Since such an investigation is rather difficult to perform for the polymer system, a low molecular weight model for EPDM was used: 2-ethylidene norbornane (ENBH). Reaction of ENBH and a resole results in scission of the dimethylene ether bridges, i.e. in degradation of the resole into mono-, bis- and terisooctylphenol units. These are consequently converted into products, consisting of two ENBH molecules linked by mono-, bis- and terisooctylphenol units. The solid resole seems to be a technological solution for storing phenol in combination with formaldehyde. These results support the use of 2-hydroxymethylphenol (HMP) as a low molecular weight model for the resole. At low temperatures and/or short reaction times HMP oligomers (= resoles) and HMP oligomers linked to one ENBH molecule are formed, which are converted into ENBH/HMP (1:1) condensation products. The reaction products of ENBH with both the resole and HMP are shown to contain methylene linked structures, as demonstrated by the formation of monisooctylphenol crosslinks and the presence of residual unsaturation and hydroxyl groups, besides chroman linked structures. This is the first experimental evidence that during phenol-formaldehyde resin cure of rubber, formation of methylene bridges occurs.

scholarly journals A comparison between the properties of low and medium molecular weight phenol formaldehyde resin-treated laminated compreg oil palm wood

2017 ◽  
Vol 19 (3) ◽  
pp. 1-11 ◽  
Author(s):  
G. Aizat ◽  
A. Zaidon ◽  
S. H. Lee ◽  
S. B. Edi ◽  
B. Paiman
Keyword(s):  
Molecular Weight ◽  
Oil Palm ◽  
Phenolic Resin ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Low Molecular Weight ◽  
Hot Press ◽  
Plastic Bag ◽  
Better Than

In order to improve the inherently poor properties of oil palm wood (OPW), this study examines the effects of resin molecular weight, diffusion time and compression ratio on the properties of laminated compreg OPW. Treating solutions used were medium molecular weight phenol formaldehyde (MmwPF) and low molecular weight phenol formaldehyde (LmwPF). OPW strips were soaked in the treating solutions for 24 h before wrapping in a plastic bag and leaving them for diffusion for 2, 4 and 6 days, respectively. Then, three-layer laminated compreg OPW were fabricated and compressed in hot press at 150°C for 20 minutes to achieve compression ratios of 55%, 70% and 80%. Results indicated that dimensional stability and mechanical properties of the phenolic resin treated laminated compreg OPW were significantly better than the untreated laminates. MmwPF-treated laminates exhibited inferior properties in comparison to that of LmwPF-treated laminates. Nevertheless, MmwPF-treated laminated compreg OPW emitted significantly lesser formaldehyde.

scholarly journals Phenol-Furfural Resin/Montmorillonite Based High-Pressure Green Composite from Renewable Feedstock (Saccharum munja) with Improved Thermo-Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1562 ◽  
Author(s):  
Muhammad Zeeshan Asad ◽  
Azhar Mahmood ◽  
Syed Tasweer Hussain Shah
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Phenol Formaldehyde ◽  
Testing Machine ◽  
Montmorillonite Clay ◽  
Plant Residue ◽  
Formaldehyde Resin ◽  
Compression Tests ◽  
Green Composite ◽  
Saccharum Munja

This research endeavour aimed to explore the potential of a native, nonedible and low market value plant feedstock, i.e., Saccharum munja for green synthesis of woodware materials and improve its features by incorporating an economical blending material. A significant amount of furfural, i.e., 58%, was extracted from Saccharum munja through the modified acid digestion method. Extracted furfural was reacted with phenol to prepare phenol-furfural resin, an alternative to phenol-formaldehyde resin but with no harmful effects for humans. The synthesized resin was also blended with montmorillonite clay after modification via Dimethyl Sulfoxide (DMSO) treatment for improved thermo-mechanical properties. These resins and composites were characterized by XRD, SEM, and FTIR spectroscopy. Resultant resins and composites were further employed as a binding agent to make high-pressure composite from leftover plant residue by hot-press method. The resultant product was subjected to TGA analysis and furnished high value of degradation temperature (Tdeg), i.e., 607 °C. Prepared high-pressure composite samples were mechanically tested through compression tests by Tinius Olsen Testing Machine and hardness tests by Rockwell Hardness Tester. Its tensile strength value was 58.3 MPa while hardness value was found to be 64 RHB which was greater than mild copper with hardness value 48.9 RHB. Thus, green high-pressure composite material was successfully developed by employing Saccharum munja and montmorillonite clay while no toxic resin was used, nor was any residue left over.

New Strategy toward Novel Hyperbranched Phenol-Formaldehyde Resin: Synthesis, Characterization and Curing Study

2007 ◽  
Vol 29-30 ◽  
pp. 177-180
Author(s):  
Samaresh Ghosh
Keyword(s):  
Phenol Formaldehyde ◽  
Flow Behavior ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
New Strategy ◽  
Ft Ir ◽  
First Time ◽  
Tof Ms

Novel hyperbranched phenol-formaldehyde (HBPF) resin 1 has been prepared for the first time. Thorough characterizations (FT-IR, NMR, HPLC, MALDI-TOF MS and elemental analyses and rheological flow behavior) were performed to ascertain the structure of HBPF 1. The condensationcuring event of HBPF with diglycidylether of bisphenol-A (DGEBA) has been studied by differential scanning calorimetry (DSC) technique.

scholarly journals Tensile and Impact Bending Properties of Chemically Modified Scots Pine

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 84 ◽  
Author(s):  
Susanne Bollmus ◽  
Cara Beeretz ◽  
Holger Militz
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Maximum Load ◽  
Solution Concentration ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Chemically Modified ◽  
Impact Bending

This study deals with the influence of chemical modification on elasto-mechanical properties of Scots pine (Pinus sylvestris L.). The elasto-mechanical properties examined were impact bending strength, determined by impact bending test; tensile strength; and work to maximum load in traction, determined by tensile tests. The modification agents used were one melamine-formaldehyde resin (MF), one low molecular weight phenol-formaldehyde resin, one higher molecular weight phenol-formaldehyde resin, and a dimethylol dihydroxyethyleneurea (DMDHEU). Special attention was paid to the influence of the solution concentration (0.5%, 5%, and 20%). With an increase in the concentration of each modification agent, the elasto-mechanical properties decreased as compared to the control specimens. Especially impact bending strength decreased greatly by modifications with the 0.5% solutions of each agent (by 37% to 47%). Modification with DMDHEU resulted in the highest overall reduction of the elasto-mechanical properties examined (up to 81% in work to maximum load in traction at 20% solution concentration). The results indicate that embrittlement is not primarily related to the degree of modification depended on used solution concentration. It is therefore assumed that molecular size and the resulting ability to penetrate into the cell wall could be crucial. The results show that, in the application of chemically modified wood, impact and tensile loads should be avoided even after treatment with low concentrations.

Flow Behavior of Wood Treated with Melamine Formaldehyde Resin under Non-Equilibrium Thermal-Compression

2015 ◽  
Vol 1119 ◽  
pp. 278-282 ◽  
Author(s):  
Tsunehisa Miki ◽  
Rumiko Nakaya ◽  
Masako Seki ◽  
Soichi Tanaka ◽  
Nobuo Sobue ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Solid Wood ◽  
Formaldehyde Resin ◽  
Melamine Formaldehyde ◽  
Size Change ◽  
Flow Forming ◽  
Thermal Compression ◽  
Moisture Condition ◽  
Melamine Formaldehyde Resin ◽  
Non Equilibrium

A uni-axial compression test of solid wood containing a melamine formaldehyde resin and moisture at a heating condition was carried out to investigate fluidity of solid wood aiming at application of wood-flow-forming with an acceptable pressure level. Results show that there is a preferable moisture condition for initiation of flow phenomenon of the resin-treated wood. Since the decrease in the flow stress of wood generating pronounced size change in the drying process was distinguished, there might be a positive effect of the non-equilibrium state in moisture on the ease in generation of flow deformation.

Evaluation of water related properties of birch wood products modified with different molecular weight phenol-formaldehyde oligomers

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Juris Grinins ◽  
Vladimirs Biziks ◽  
Janis Rizikovs ◽  
Ilze Irbe ◽  
Holger Militz
Keyword(s):  
Molecular Weight ◽  
Dimensional Stability ◽  
Phenol Formaldehyde ◽  
Treated Wood ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Solid Wood ◽  
Wood Products ◽  
Birch Wood ◽  
Molecular Weights

Abstract This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the dimensional stability of birch solid wood and plywood. Therefore, three different low molecular weight PF resins with average molecular weights (M w ) of 292, 528, and 884 g/mol were synthesized and used for silver birch (Betula pendula) solid wood (20 × 20 × 20 mm3) and veneer (100 × 100 × 1.4 and 300 × 300 × 1.4 mm3) impregnation to produce plywood. The weight percent gain (WPG) and bulking after curing of resin treated wood specimens were determined. The leaching was performed to evaluate the PF resin fixation stability. All tested resins at all concentrations were similarly fixed in wood blocks after the leaching (1.5–2.0% WPG loss). The dimensional stability of birch wood after treatment with all tested PF resins was significantly improved. The anti-swelling efficiency (ASE) of birch wood blocks treated with PF resins after seven water soaking-drying cycles was in the range of 39–53%, 46–65% and 49–65% using 10, 15 and 20% solution concentrations, respectively. Whereas, the ASE of plywood obtained from veneers treated with 10% of PF solution was improved by 6–20%. The equilibrium moisture content (EMC) and volumetric swelling (VS) of PF treated plywood at 98% of relative humidity (RH) decreased significantly. All PF resin treated plywood surfaces were more hydrophobic compared to untreated plywood.

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