Effect of wood acidity and catalyst on UF resin gel time

Holzforschung ◽  
2004 ◽  
Vol 58 (4) ◽  
pp. 408-412 ◽  
Author(s):  
C. Xing ◽  
S.Y. Zhang ◽  
J. Deng
Keyword(s):  
Ph Value ◽  
Raw Materials ◽  
Urea Formaldehyde ◽  
Acid Catalyst ◽  
Buffering Capacity ◽  
Raw Material ◽  
Gel Time ◽  
Uf Resin ◽  
Effects Of Ph ◽  
Fiber Materials

Abstract Knowledge of pH and buffering capacity of raw fiber materials is important for understanding the effects of raw material on the curing rate of urea formaldehyde (UF) resin, used for panel manufacturing, especially with some less-desirable wood materials such as bark, top, and commercial thinnings. The effects of pH and buffering capacity as well as catalyst content on the gel time of UF resin were investigated. The results obtained from this study indicate that bark has a lower pH value as well as higher acid and alkaline buffering capacities than wood of the same species due to their extractives. The pH values of the raw fiber materials studied decrease with increased absolute and relative acid buffering capacity due to the increased absolute acidity mass in the solution. At lower levels of added catalyst, the effect of raw material pH on UF resin gel time is significant, while it is insignificant at higher catalyst contents. This may be due to the acidity of wood, which is the main acid catalyst source of the mixture at lower levels of added catalyst, while at higher levels, catalyst is the main source. With higher catalyst contents, all studied raw materials mixed with UF resin result in a longer gel time than does UF resin alone.

scholarly journals Improving Thermal Conductivity Coefficient in Oriented Strand Lumber (OSL) Using Sepiolite

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 599 ◽  
Author(s):  
Hamid R. Taghiyari ◽  
Abolfazl Soltani ◽  
Ayoub Esmailpour ◽  
Vahid Hassani ◽  
Hamed Gholipour ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Core Temperature ◽  
Thermal Conductivity Coefficient ◽  
Urea Formaldehyde ◽  
Wood Products ◽  
Raw Material ◽  
Formaldehyde Resin ◽  
The Core ◽  
Uf Resin ◽  
Hardness Values

An issue in engineered wood products, like oriented strand lumber (OSL), is the low thermal conductivity coefficient of raw material, preventing the fast transfer of heat into the core of composite mats. The aim of this paper is to investigate the effect of sepiolite at nanoscale with aspect ratio of 1:15, in mixture with urea-formaldehyde resin (UF), and its effect on thermal conductivity coefficient of the final panel. Sepiolite was mixed with UF resin for 20 min prior to being sprayed onto wood strips in a rotary drum. Ten percent of sepiolite was mixed with the resin, based on the dry weight of UF resin. OSL panels with two resin contents, namely 8% and 10%, were manufactured. Temperature was measured at the core section of the mat at 5-second intervals, using a digital thermometer. The thermal conductivity coefficient of OSL specimens was calculated based on Fourier’s Law for heat conduction. With regard to the fact that an improved thermal conductivity would ultimately be translated into a more effective polymerization of the resin, hardness of the panel was measured, at different depths of penetration of the Janka ball, to find out how the improved conductivity affected the hardness of the produced composite panels. The measurement of core temperature in OSL panels revealed that sepiolite-treated panels with 10% resin content had a higher core temperature in comparison to the ones containing 8% resin. Furthermore, it was revealed that the addition of sepiolite increased thermal conductivity in OSL panels made with 8% and 10% resin contents, by 36% and 40%, respectively. The addition of sepiolite significantly increased hardness values in all penetration depths. Hardness increased as sepiolite content increased. Considering the fact that the amount of sepiolite content was very low, and therefore it could not physically impact hardness increase, the significant increase in hardness values was attributed to the improvement in the thermal conductivity of panels and subsequent, more complete, curing of resin.

Potential of pulp and paper sludge as a formaldehyde scavenger agent in MDF resins

Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Sébastien Migneault ◽  
Ahmed Koubaa ◽  
Bernard Riedl ◽  
Hamid Nadji ◽  
James Deng ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Length Distribution ◽  
Formaldehyde Emission ◽  
Buffering Capacity ◽  
Pulp And Paper ◽  
Adhesive Properties ◽  
Bending Performance ◽  
Fiber Length Distribution ◽  
Uf Resin

Abstract Sludge of pulp and paper mills have natural adhesive properties. The primary sludge (PS, contains fibers) and secondary sludge (SS, contains proteins) could also be suitable for manufacturing medium-density fiberboard (MDF). Protein in SS can react with formaldehyde (HCHO), and as an additive in urea-formaldehyde (UF) resins it can reduce formaldehyde emission. Thus, SS was investigated in the present study. PS and SS were collected from two mills and characterized in terms of chemical composition, fiber length distribution, pH, and buffering capacity. MDF samples were processed according to an experimental design, in which UF resin content was reduced from 12% to 8% and replaced by SS in the range of 5%–15%. Gel time measurement showed high SS reactivity with UF resin. The SS reduced HCHO emissions by up to 68% compared to control panels, without compromising internal bond strength. The bonding effect of SS was lower than expected due to the high pH, thus the buffering capacity reduced UF performance. Moreover, sludge reduced bending performance. Dimensional stability was the greatest disadvantage of sludge panels.

scholarly journals Process modification involving strong-acid step in urea-formaldehyde resin preparation

2020 ◽  
Vol 16 (2) ◽  
pp. 212-217
Author(s):  
Dicky Dermawan ◽  
Lucky William Kusnadi ◽  
Jemmy Lesmana
Keyword(s):  
Urea Formaldehyde ◽  
Gelation Time ◽  
Strong Acid ◽  
Raw Material ◽  
Molar Ratio ◽  
Formaldehyde Resin ◽  
Formaldehyde Concentration ◽  
Formaldehyde Content ◽  
Process Modification ◽  
Uf Resin

Urea-formaldehyde (UF) resin adhesive for wood-based panel industries are commonly manufactured using conventional alkaline-acid process. This paper reports a process modification of a conventional UF resin preparation by incorporating a strong-acid step, involving simultaneous methylolation and condensation reactions at very low pH at the beginning of the processing step. The experiment showed that this additional step should be carried out at short duration and at high enough temperature in order to avoid gelation or separation problems. In order to control temperature rise caused by the exothermic nature of the reactions, the modified process requires a higher initial formaldehyde-to-urea (F/U) molar ratio compared to the original. For the same reason, the first urea should be fed incrementally to ensure high F/U ratio at any time during the strong acid step. Using regular formalin concentration as raw material at the same F/U molar ratio, the modified resin showed lower free formaldehyde content thus have lower reactivity in comparison to those of the original. However, when the same procedure was applied using higher formaldehyde concentration at higher solid content, the produced resin showed comparable free formaldehyde content and shorter gelation time. Application test for making plywood showed that the modified process gave a very significant improvement in both the internal bonding strength and formaldehyde emission.

scholarly journals STUDY ON THE GRINDING TIME DURATION IMPACT ON THE PROPERTIES OF PAPER FROM ALTERNATIVE RAW MATERIALS

2020 ◽  
Vol 2020 (3) ◽  
pp. 24-31
Author(s):  
Z Galimova ◽  
◽  
H Babakhanova ◽  
M Abdunazarov ◽  
I Ismoilov ◽  
...  
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Milling Process ◽  
Raw Material ◽  
Time Duration ◽  
Paper Production ◽  
Fiber Materials ◽  
The Impact

Both raw and recycled fiber materials are used for paper production. The increase in percentage use of the latter is due to their paper-forming properties, availability and low cost. The article explores the possibility of using pulp from the inner layer of mulberry twig bark. Mulberry twigs, after removing leaves, which are the main raw material in silk production, have no practical industrial application. Recycling waste - mulberry branches - for the production of pulp is therefore relevant as it is aimed at solving raw material and environmental problems. The purpose of this work is to use local raw materials for paper production, study the impact of processing method of the grinding process on paper forming properties. During grinding the mechanical processes of changes of fibers determine mainly structure of a paper sheet, and colloidal-physical processes - bind and ability of fibers to form strong, homogenous and smooth structure of paper. The structure of the sheet of paper facilitates excessive or "selective" ink absorption into the pores of the paper and thus predetermines the quality of reproduction during the printing process. Methods for determining the physical and mechanical properties of papers were used in this work, and changes in the surface structure of samples cast at various technological modes of the milling process were studied. The results of the study revealed that the addition of cellulose mass from the inner layer of mulberry twig bark helps to obtain a strong paper. The optical properties of the paper, which contains cotton and cellulose from the inner layer of mulberry branch bark, are explained by the whiteness of the added fibers themselves. The strength properties of the paper at a weight grinding degree of 300 CWR are explained by the bond between the split and strongly interwoven fibers of the cellulose fibers. It has been established that the addition of more than 30% cellulose from the inner layer of the mulberry branch bark to the paper pulp mass is undesirable, as this adversely affects the whiteness of the paper

scholarly journals Optimization of Pyrolysis Operating Condition for Deriving Corn Starch Heterogeneous Acid Catalyst for Biodiesel Production

2015 ◽  
Vol 9 (7) ◽  
pp. 61 ◽  
Author(s):  
Herry Santoso ◽  
Christ Michael ◽  
Hillman Wira ◽  
Maria Inggrid
Keyword(s):  
Oleic Acid ◽  
Pyrolysis Temperature ◽  
Corn Starch ◽  
Edible Oils ◽  
Raw Materials ◽  
Acid Catalyst ◽  
Raw Material ◽  
Biodiesel Production ◽  
Fatty Oil ◽  
Heterogeneous Acid Catalyst

Biodiesel can be produced from various oils and fats. Due to possibility of diversion of edible oils from feedstocks to raw materials for biodiesel production, which may lead to food crisis, it is preferable to choosenon-edible oils as raw material for biodiesel production. As a country rich in natural resources, Indonesia has avast amount and variety of non-edible fatty-oil production plants. However, non-edible oils usually have highfree fatty acid (FFA) contents. Oils with high FFA contents cannot be converted directly to biodiesel using aconventional alkaline catalyzed process due to saponification problem. To avoid this problem, the high FFAcontents in the oils must be reduced via esterification process using acid catalyst. The use of homogeneous acidcatalyst in this process can be very corrosive and not environmentally friendly while the use of commerciallyavailable heterogeneous acid catalyst can be very expensive. In this research, a heterogeneous acid catalystsuitable for biodiesel production will be derived from corn starch through pyrolysis followed by sulphonationprocesses. The purpose of this research is to study the effects of pyrolysis temperature and time to the aciddensity of the catalyst and the activity of the catalyst in the esterification of oleic acid using a 22 factorial designwith 3 center points experimental design. It is found that the catalyst obtained from pyrolysis at 400°C for 15hours has the optimum–HSO3 content of 5.9% which corresponds to the highest average conversion of theesterification of oleic acid of 97.45%.

scholarly journals Comparison of Methodologies for Acid Buffering Capacity Determination—Empirical Verification of Models

2019 ◽  
Vol 9 (11) ◽  
pp. 2345
Author(s):  
Patryk Król ◽  
Piotr Borysiuk ◽  
Mariusz Mamiński
Keyword(s):  
Raw Materials ◽  
Chemical Properties ◽  
Bond Line ◽  
Buffering Capacity ◽  
Raw Material ◽  
Optimal Amount ◽  
Acid Buffering ◽  
Materials Used ◽  
Different Origins

Raw materials used in particleboard production may have different chemical properties as they have different origins, nature, and storage histories. One of the most important factors is the acidity of the wood which affects the process of bond line formation. Thus, determination of the acid buffering capacity (ABC) of a raw material helps to adjust the optimal amount of hardener in the adhesive. In the present study, three methods for pH-metric ABC determination in the presence of lignocellulosic material were compared. Models that correlate the hardener amount with the internal bonding of particleboards were built from the ABC results. The approach was tested on three materials of different acidity—pine, oak, and ammonia-treated oak. The developed models allowed the prediction of the optimal amount of hardener for the maximized internal bond of the boards. The experimental verification of the models showed a high convergence of the calculated and empirical results.

scholarly journals An effect of the recipe composition on minced meat properties

2021 ◽  
Vol 6 (2) ◽  
pp. 174-182
Author(s):  
E. V. Tsaregorodtseva
Keyword(s):  
Milk Fat ◽  
Ph Value ◽  
Raw Materials ◽  
Binding Capacity ◽  
Raw Material ◽  
Chicken Breast ◽  
Technological Parameters ◽  
Water Binding ◽  
Minced Meat ◽  
By Products

The paper describes an experiment on the development of minced meat recipes for poultry-based semi-prepared products. The design principle included a search for optimal compatibility of recipe ingredients to develop a balanced meat system. The model recipes included meat from different animal and poultry species, by-products and dairy products. White and red turkey meat and chicken breast fillet provided recipes with complete animal proteins. Fat meat raw materials were partly replaced with milk fat. A semi-prepared product filled into an intestinal casing was named “sausages for grilling”. A technology of sausages for grilling was developed with the indication of the main control technological parameters for the production process and thermal treatment up to product readiness. The incoming control of raw material quality was carried out: dairy cream was assessed by acidity and pasteurization effectiveness; cheese by sensory indicators; meat raw materials by the pH value. The functional-technological properties of raw minced meat for sausages for grilling were compared before and after cooking by the pH level, moisture mass fraction, water binding capacity. The rheological properties of minced meat (adhesion, viscosity, shearing structural-mechanical properties) were studied. The expedience of introducing meat by-products and dairy ingredients into recipes of sausages for grilling to stabilize protein and fat in the meat system was substantiated. It was proved that replacement of the main raw materials in recipes with pork heart, ginger, cheese and chicken liver allows obtaining sausages for grilling with preservation of high quality indicators. Sausage sensory properties after grilling were analyzed.

scholarly journals Karakteristik Minuman Probiotik Sari Ubi Kayu dari Kultur Bakteri Lactobacillus acidophilus dan Streptococcus thermophilus

2020 ◽  
pp. 87-94
Author(s):  
Nunung Yulia ◽  
Adi Wibowo ◽  
Eva Dania Kosasih
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Acidophilus ◽  
Functional Foods ◽  
Ph Value ◽  
Raw Materials ◽  
Streptococcus Thermophilus ◽  
Physiological Effect ◽  
Raw Material ◽  
Experiment Method ◽  
The Cost

Functional foods are food that consumed, as usual, has a physiological effect and can reduce the effect of chronic disease. One of them is probiotic beverages. Probiotic beverages that have been widely known overtime was produced by a dairy house. This product could have been expensive due to the cost of raw materials. The alternative raw material such as the use of extracted cassava juice may reduce the price of the final product. The aims of this research were to study the effects of culture comparison between characteristics of the probiotic beverage from cassava juice, and get the best culture comparison that produces the best probiotic characteristics of the lactic beverage fermentation from cassava juice. This research applied qualitative experiment method in Lactobacillus acidophilus and Streptococcus thermophiles as an inoculum evaluated. Serial in culture ratio respectively 20:50; 30:50; 40:50; and 50:50. The observed research were pH value, viscosity, total lactic acid bacteria (LAB) and activities test against bacteria Escherichia coli. The result showed that the best culture comparison qualified as probiotics criteria was 50:50. It was having pH value 4,1; viscosity 0,706 g/mL; total LAB 2,1x106 cfu/mL and activity bacteria Escherichia coli was 5,3 mm.

Effects of pH Value and Water Content of Sol on TiO2 Photocatalytic Activity Prepared by SAS

2013 ◽  
Vol 774-776 ◽  
pp. 864-867
Author(s):  
Zai Feng Shi ◽  
Su Min Zhang ◽  
Su Guo
Keyword(s):  
Methylene Blue ◽  
Particle Size ◽  
Photocatalytic Activity ◽  
Citric Acid ◽  
Water Content ◽  
Mass Fraction ◽  
Ph Value ◽  
Sol Gel ◽  
Raw Material ◽  
Effects Of Ph

To investigate the effects of sol pH value and water content on photocatalytic activity of TiO2 prepared with sol-gel auto-igniting synthesis (SAS) method, TiO(NO3)2 was prepared with TiCl4 as raw material and used as precursor of TiO2. By changing sol pH value and water content, different TiO2 powders were prepared and characterized with XRD, SEM and photodegradation of methylene blue (MB). Results indicated that TiO2 presented the highest photocatalytic activity while sol pH value and mass fraction of water were adjusted to 7 and 50% respectively while the mole ratio of n (TiCl4): n (citric acid): n (ammonium nitrate) was fixed as 1: 1: 3. The TiO2 powders were confirmed as loose and porous anatase type with particle size of 15 nm by SEM and XRD.

Feasibility of Using MDP Panels, Compared to Conventional Particleboards

2015 ◽  
Vol 668 ◽  
pp. 145-149
Author(s):  
Bárbara Maria Ribeiro Guimarães ◽  
José Benedito Guimarães Jr. ◽  
Jefferson Barbosa Campomori ◽  
Rafael Farinassi Mendes ◽  
Lourival Marin Mendes
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Urea Formaldehyde ◽  
Raw Material ◽  
Thickness Swelling ◽  
Gel Time ◽  
Pressing Cycle ◽  
Base Resin ◽  
Solids Content

The objective of this study was to investigate, by physical properties, the efficiency of MDP panels, compared to conventional particleboards, since MDP was considered as a raw material for the manufacture of these panels. MDP panels had the following composition: 20/60/20 face/core; a urea-formaldehyde adhesive was used, with a solids content of 55%; pH 8.42; viscosity of 420 Cp and gel time of 51 seconds. 12% of dry base resin were applied to the particles. The pressing cycle was 4 MPa, with a temperature of 160°C for a period of 8 minutes. The panels were produced with a density of 0.70g/cm3. We observed that with the exception of the physical properties of water absorption after 2 hours, the MDP showed lower physical properties (water absorption after 24 hours and thickness swelling after 2 hours and 24 hours of immersion in water) in relation to the panels conventional clusters. Thus demonstrating its superiority in relation to the physical properties of MDP compared to conventional agglomerated panels, emphasizing their use in this way.

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