Development of Plywood Binder by Partial Replacement of Phenol-Formaldehyde Resins with Birch Outer Bark Components

2021 ◽  
Vol 903 ◽  
pp. 229-234
Author(s):  
Aigars Paze ◽  
Janis Rizhikovs ◽  
Daniela Godiņa ◽  
Raimonds Makars ◽  
Rudolfs Berzins

The apparent shift in climate has resulted in the pursuit of environmentally friendly bio-based products to reduce the carbon footprint. In the scientific literature, there are many attempts to make phenol-formaldehyde resins (PFR) more sustainable by using bio-based phenolics in the synthesis instead of petroleum-based phenol. However, it is also important to reduce the content of formaldehyde in the binder, the vapours of which are toxic and even carcinogenic to the human body. One of the technologically simplest solutions could be the incorporation of another bio-based wood composite binder into the completed industrial PFR. In turn, birch outer bark suberinic acids are an effective, ecological, thermosetting binder to produce mechanically durable and moisture-resistant wood composites. The aim of the study was to adapt the components of birch outer bark (suberinic acids and betulin-based extractives) for their incorporation into industrial PFR and to find the optimal degree of resins replacement in practical experiments. At the same time, to keep a similar level of the bending strength and moisture resistance (shear strength) of the plywood bonded with the modified binder compared to pure industrial PFR. As a result, it was found that it was possible to replace up to 30 wt% (dry basis) of the industrial PFR with birch outer bark components to obtain birch plywood without significant loss of the bending strength and moisture resistance. In this way, it would be possible to significantly reduce the carbon footprint of the synthetic PFR binder in the birch plywood industry by using birch processing residues.

2014 ◽  
Vol 1035 ◽  
pp. 77-82 ◽  
Author(s):  
Eva Vejmelková ◽  
Monika Čáchová ◽  
Dana Koňáková ◽  
Pavel Reiterman ◽  
Robert Černý

Waste materials are utilized with an increasing frequency in the building industry, during the last decades. The motivation is both environmental and economical. In this paper, waste ceramic powder produced at the grinding of hollow brick blocks used in precise-walling technologies, is applied as a partial replacement of siliceous aggregates of lime plasters. The designed plaster mixes are analyzed from the point of view of their basic physical, mechanical, hygric and thermal properties. The bulk density, matrix density, open porosity, compressive strength, bending strength, water vapor diffusion permeability, water vapor diffusion coefficient, water vapor diffusion resistance factor, thermal conductivity and specific heat capacity are the investigated parameters. A reference lime plaster is analyzed as well, for the sake of comparison. Experimental results show a remarkable enhancement of mechanical properties of the plasters with the increasing dosage of ceramic powder. Moreover, the thermal insulation properties are improved and the water vapor diffusion capability of the plasters with ceramic powder increases.


2020 ◽  
Vol 175 ◽  
pp. 11008
Author(s):  
Marat Asamatdinov ◽  
Аlexey Zhukov ◽  
Andrey Medvedev ◽  
Vitaly Mukhametzyanov

The article substantiates using a modified binder based on clay-gypsum as the main component of dispersed reinforced and plasters mixtures. The rheological properties of such mixtures and the performance characteristics of plaster coatings have been studied. It is proved that the use of clay-gypsum as part of a modified dispersed reinforced binder contributes to the creation of favorable environmental conditions and the formation of a comfortable climate inside the agricultural premises, as well as increases the degree of protection of structures in fire conditions. It is established that the technological properties of dispersed reinforced plaster mixtures depend primarily on the composition of the modified clay-gypsum binder and the consumption of mineral fiber and its length. The fiber diameter within 3.2-3.4 microns does not significantly affect the properties of mixtures. Dispersed reinforcement in the range from 1 to 5% slightly affects the average density of clay-gypsum mixtures and plaster coatings based on them. Dispersed reinforcement has the greatest effect on the mobility of the mortar plaster mixture and, to a lesser extent, on its thixotropy. The introduction of mineral fibers has a significant impact on the strength characteristics of plaster coatings, and, to the greatest extent, on the strength of bending, the compressive strength is most affected by the content of semi-aqueous gypsum in the composite binder. An increase in bending strength by 20% determines the greater resistance of plaster coatings to temperature influence and this allows us to state an increase in the duration of the functioning of clay plaster barriers when protecting load-bearing structures and insulation systems from the effects of high temperatures.


2020 ◽  
Vol 111 ◽  
pp. 21-26
Author(s):  
Jakub Kawalerczyk ◽  
Dorota Dziurka ◽  
Radosław Mirski

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.


2016 ◽  
Vol 865 ◽  
pp. 22-26
Author(s):  
Jana Zahalkova ◽  
Pavla Rovnanikova

The article is focused on study of the effect of filtering diatomite as a partial replacement of cement in an amount of 5-30%. Diatomite is used in civil engineering especially for its high content of an amorphous SiO2, chemical resistance, high porosity, and good thermal insulating properties. Diatomite can be used as a pozzolanic material due to the high content of amorphous SiO2.Cement was replaced by filtering diatomite in amount of 5, 10, 15, 20, 25 and 30% by weight. Diatomite was characterized by chemical composition, granulometry and pozzolanic activity.The specimens were tested in bulk density, bending strength and compressive strength, hydration process was investigated using thermal analysis, and microstructure was observed by scanning electron microscopy. All results were compared to reference sample.


Author(s):  
Ping Li ◽  
Yuan Zhang ◽  
Yingfeng Zuo ◽  
Jianxiong Lu ◽  
Guangming Yuan ◽  
...  

To compare The effects of organic and inorganic impregnation on the properties of unmodified, phenol formaldehyde oligomer-modified (PFOMCF), and sodium silicate-modified Chinese fir wood (SSMCF) were compared using samples prepared using the respiratory impregnation method. Impregnation and reinforcement effects and water resistance of PFOMCF and SSMCF were compared and the results was showed that the weight percentage gain, density increase rate, bending strength, and compressive strength of SSMCF were clearly higher than those of PFOMCF and had a lower water absorption rate within 60 h. The impregnation and reinforcement effects and dimensional stability of SSMCF were better than those of PFOMCF. FT-IR, XRD, CONE, and TGA examinations were used to test and analyze the chemical structure, crystalline structure, flame retardancy, and heat resistance of these modified woods. The results indicated that SSMCF possessed more hydrogen bonds than PFOMCF and that Si–O–Si chemical bonding with high bond energy was formed. Meanwhile, the weakened degree of the diffraction peak of SSMCF was much less than that of PFOMCF. These results explained that the mechanical properties and water resistance of SSMCF were better than PFOMCF. Compared with PFOMCF, SSMCF had a lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release, smoke production rate, and total smoke production as well as higher thermal decomposition temperature and residual rate. Inorganic sodium silicate was shown to be a better flame retardant, while SSMCF had good smoke suppression effects, thermal stability, and safety performance in the case of fire.


2003 ◽  
Vol 14 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Kensuke Kawarada ◽  
Hirotaka Nakanami ◽  
Takahiko Iida ◽  
Takayuki Okayama ◽  
Toshio Waku ◽  
...  

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 84 ◽  
Author(s):  
Susanne Bollmus ◽  
Cara Beeretz ◽  
Holger Militz

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.


2016 ◽  
Vol 40 (5) ◽  
pp. 949-958 ◽  
Author(s):  
Rafael Rodolfo de Melo ◽  
Eder Pereira Miguel

ABSTRACT This study aims to assess Artificial Neural Networks (ANN) in predicting particleboard quality based on its physical and mechanical properties. Particleboards were manufactured using eucalyptus (Eucalyptus grandis) and bonded with urea-formaldehyde and phenol-formaldehyde resins. To characterize quality, physical (density and water absorption and thickness swelling after 24-hour immersion) and mechanical (static bending strength and internal bond) properties were assessed. For predictions, adhesive type and particleboard density were adopted as ANN input variables. Networks of multilayer Perceptron (MLP) were adopted, training 100 networks for each assessed parameter. The results pointed out ANN as effective in predicting quality parameters of particleboards. With this technique, all the assessed properties presented models with adjustments higher than 0.90.


2018 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Nyoman J Wistara ◽  
Wulan Starini ◽  
Fauzi Febrianto ◽  
Gustan Pari

Modified lignin with improved reactivity can be a potential alternative for synthetic phenol formaldehyde resin for the adhesive of wood composite. Direct hydroxymethylation of kenaf in the present experiments was intended to increase lignin reactivity, and therefore was expected to result in satisfying properties of binderless MDF. The stem of kenaf was refined in a disk refiner and the refined fibers were hydroxymethylated in various levels of alkalinity. The concentration of NaOH during hydroxymethylation was of 3%, 6% and 12%. Wet process was applied to produce MDF (30 cm x 30 cm x 1 cm) with target density of 0.65 g/cm³. Physical and mechanical properties of MDF were measured in accordance with the standard procedure of JIS A 5905: 2003. Chemical changes in the surface of pulp and the change of board crystallinity were evaluated by FTIR-KBr method and X-Ray Diffractometry (XRD), respectively. Density, moisture content, and screw withdrawal of the board increased with increasing of NaOH concentration. Thickness swelling, water absorption, MOE and MOR increased up to 3% concentration of NaOH. The IB and heat conductivity of MDF were not influenced by NaOH concentration. Increasing OH groups due to hydroxymethylation was thought to be the origin of high water absorption and thickness swelling of the resulting boards. Higher alkalinity during hydroxymethylation stage was likely increasing cellulose crystallinity that brought about increasing board density. However, chemical modification of the fiber was thought to be more influential to the bending strength and stiffness of the resulting fiberboard. Hydroxymethylation of kenaf pulp was successfully improved board properties. Except for the moisture content, thickness swelling and internal bonding (at 0% and 3% NaOH concentration), all properties of the MDF satisfied the requirement of JIS A 5905: 2003 (type 5) standard. MDF Tanpa Perekat dari Pulp Kenaf TerhidroksimetilasiIntisariLignin yang telah ditingkatkan reaktifitasnya dapat menjadi bahan alternatif perekat resin sintetis fenol formaldehida. Reaktivitas lignin dapat diperbaiki melalui hidroksimetilasi. Dalam penelitian ini, batang kenaf digiling menggunakan disk refiner, dan selanjutnya dilakukan hidroksimetilasi pada beragam alkalinitas. Konsentrasi NaOH yang digunakan dalam hidroksimetilasi bervariasi dari 3%, 6% dan 12%. Proses basah diterapkan untuk membuat MDF (30 cm x 30 cm x 1 cm) dengan target kerapatan 0,65 g/cm3. Sifat fisis dan mekanis MDF diukur mengikuti  prosedur standar JIS A 5905: 2003. Perubahan gugus fungsi permukaan pulp dan tingkat kristalinitas papan masing-masing dievaluasi menggunakan FTIR-metode KBr dan difraksi sinar X (XRD). Hasil penelitian menunjukkan bahwa konsentrasi NaOH tidak mempengaruhi IB dan konduktivitas panas MDF. Kerapatan, kadar air, dan kuat pegang sekrup cenderung meningkat dengan meningkatnya konsentrasi NaOH. Pengembangan tebal, daya serap air, MOE, dan MOR meningkat sampai dengan hidroksimetilasi dalam NaOH konsentrasi 3%. Peningkatan gugus OH serat akibat hidrosimetilasi diduga meningkatkan penyerapan air dan pengembangan tebal papan yang dihasilkan. Alkalinitas hidroksimetilasi yang lebih tinggi meningkatkan gugus cincin aromatik yang menunjukkan bahwa reaksi formaldehida berlangsung dengan lebih baik. Peningkatan alkalinitas dalam hidroksimetilasi meningkatkan kristalinitas selulosa. Peningkatan kristalinitas selulosa diduga berkontribusi dalam meningkatkan kerapatan, namun perubahan gugus kimia serat diduga lebih berpengaruh terhadap MOR dan MOE dari papan serat yang dihasilkan. Hidroksimetilasi pulp kenaf berhasil meningkatkan sifat papan. Kecuali untuk kadar air, pengembangan tebal dan IB (pada hidroksimetilasi dalam 0% dan 3% NaOH), semua sifat-sifat dari MDF yang dihasilkan memenuhi persyaratan standar JIS A 5905: 2003 (tipe 5).


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