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.

scholarly journals Furan resin as potential substitute for phenol-formaldehyde resin in plywood manufacturing

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 2727-2739
Author(s):  
Anca Maria Varodi ◽  
Emanuela Beldean ◽  
Maria Cristina Timar
Keyword(s):  
Mechanical Properties ◽  
Water Resistance ◽  
Bending Strength ◽  
Reference Product ◽  
Phenol Formaldehyde ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Furan Resin

Replacement of phenol-formaldehyde with a mixed furan resin is considered in this work as a means to improving plywood properties made with urea-formaldehyde-based adhesive currently made with an addition of phenol-formaldehyde resin. Previous research showed that the furan resins can improve water resistance and can provide long stability for the glue line. Plywood was manufactured with modified adhesives and characterized in comparison with a reference product. Thickness, physical properties (moisture content, density, and total water absorption), mechanical properties (shearing strength, bending strength, and elasticity modulus in bending), and formaldehyde emission were determined according to standardized methods. The results indicated that the addition of furan resin enhanced the water resistance by 43% and formaldehyde emission is according to E1 class. Also, the mechanical properties were improved; the shear strength for the adhesive composition with furan resin was increased by 14 to 30% compared with the reference product, depending on the testing conditions.

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.

The possible reduction of phenol-formaldehyde resin spread rate by its nanocellulose-reinforcement in plywood manufacturing process

2020 ◽  
Vol 111 ◽  
pp. 21-26
Author(s):  
Jakub Kawalerczyk ◽  
Dorota Dziurka ◽  
Radosław Mirski
Keyword(s):  
Manufacturing Process ◽  
Quality Evaluation ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Spread Rate ◽  
Bonding Quality ◽  
Adhesive Application ◽  
Reference Samples

The possible reduction of phenol-formaldehyde resin spread rate by its nanocellulose-reinforcement in plywood manufacturing process. The aim of the study was to investigate the possibility of phenol-formaldehyde (PF) resin consumption in plywood by its reinforcement with cellulosic nanoparticles (NCC). In order to determine the possible reduction of resin spread rate bonding quality was assessed both after boiling in water for 24h and after ageing test including i.e. boiling in water. Studies have shown that the addition of nanocellulose made it possible to significantly reduce the amount of the applied adhesive. Reference samples were characterized by similar shear strength values to experimental plywood manufactured with the adhesive application of 140 g/m2. NCC-reinforcement resulted also in the increase of mechanical properties such as modulus of elasticity and bending strength. The analysis of the data confirmed the tendency observed during bonding quality evaluation and it was concluded that resin modification allowed to reduce its spread rate by 30 g/m2.

Novolak Type Phenol Formaldehyde Resin from Waste Brown-Rotted Wood

2011 ◽  
Vol 217-218 ◽  
pp. 490-494
Author(s):  
Gai Yun Li ◽  
Te Fu Qin
Keyword(s):  
Mechanical Properties ◽  
Phosphoric Acid ◽  
Thermal Property ◽  
Significant Influence ◽  
Phenol Formaldehyde ◽  
Product Yield ◽  
Flow Property ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Liquefied Wood

The waste brown-rotted wood was liquefied in phenol with phosphoric acid as a catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood-based phenol formaldehyde resin (LWF). The results showed that brown-rotted wood could be almost completely liquefied within 0.5 h at phenol to wood (P/W) ratio 2. An increase in P/W ratio from 2 to 3 slightly improved the flow property of LWF, but accompanied by decreasing the product yield from approximately 140 to 120 %. The increase of liquefaction time from 30 min to 60 min did not have a significant influence on the resulting LWF. The thermofluidity of LWF were compared to that of the commercial novolak PF resin, and could be used to make moldings with similar thermal property and mechanical properties to those obtained from the conventional novolak PF resin.

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 Self-adhesion X-ray Shielding Composite Material of EPDM Rubber with Barite: Mechanical Properties

2020 ◽  
Vol 57 (1) ◽  
pp. 28-36
Author(s):  
Vasiliy Cherkasov ◽  
Yuiy Yurkin ◽  
Valeriy Avdonin ◽  
Dmitriy Suntsov
Keyword(s):  
Mechanical Properties ◽  
Phenol Formaldehyde ◽  
Peel Strength ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Adhesion Properties ◽  
X Ray ◽  
Industrial Oil ◽  
Oil Concentration ◽  
Free Material

It is actual now to work out new radiation protecting sheeting on the basis of non-curing polymeric composition which possess self-adhesion properties, are easily mounted and dismantled and provide high tightness and low permeability. Mechanical properties of non-curing composites consisting of ethylene propylene diene monomer (EPDM), industrial oil (IO), alkyl phenol-formaldehyde resin (PF) with addition of barite (52 %) to the total material volume were investigated in this article. The aim of investigation is to find optimal content of the above mentioned components at which it would be possible to get the following properties: composite would be sticky enough (peel strength not less than 4 N/cm); character of a separation would be cohesive (on a material) and thus there would be no migration of softener and satisfactory resistance of fluidity. The results showed that PF addition till 20 % in the system EPDM/PF leads to the increasing of adhesive strength, in this case optimal oil concentration in the system EPDM/PF/IO is in the interval from 45 till 55 %. New self-adhesion lead-free material, exhibited higher X-ray-shielding properties, is also received in the result of investigation.

scholarly journals Bending Strength and Porous Structure of Carbonized Panels Made from Waste Phenol-formaldehyde Resin and Magazine Paper

2003 ◽  
Vol 14 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Kensuke Kawarada ◽  
Hirotaka Nakanami ◽  
Takahiko Iida ◽  
Takayuki Okayama ◽  
Toshio Waku ◽  
...  
Keyword(s):  
Porous Structure ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin

Physico-mechanical characteristics and phase composition of unburned periclase-carbon refractories on modified phenol-formaldehyde resin

2019 ◽  
pp. 29-33
Author(s):  
D. A. Brazhnik ◽  
G. D. Semchenko ◽  
G. N. Shabanova ◽  
E. E. Starolat ◽  
I. N. Rozhko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Phase Composition ◽  
Mechanical Characteristics ◽  
Carbon Materials ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Ethyl Silicate ◽  
Ammonium Citrate ◽  
Formaldehyde Resin

The possibilities of improving the physico-mechanical properties of periclase-carbon materials by modifying the phenol-formaldehyde resin (PFR) with organoinorganic complexes are described. The composition of the modifying additives, the phase composition of the materials after the PFR hardening are given, the influence of modifiers on the formation of the structure of materials is established. It is shown that the introduction of ethyl silicate or hydrolyzed ethyl silicate into liquid PFR during preparation of the charge contributes to the formation of SiC in the phase composition. The conclusion is made about the rationality of the introduction of ethyl silicate in an amount of from 0,66 to 1 wt. % and the prospects of introducing nickel oxalate into a liquid PFR together with ammonium citrate to increase the compressive strength of periclase-carbon materials up to 60 MPa. Ill. 7. Ref. 9.

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