Borax Modify Phenol-Formaldehyde Resin as Wood Adhesives

2012 ◽  
Vol 610-613 ◽  
pp. 507-513 ◽  
Author(s):  
Rui Hang Lin ◽  
Xiao Feng Zhu ◽  
Xiao Bo Wang ◽  
Zhen Zhong Gao

A modified phenol-formaldehyde (PF) resin was synthesized under alkaline condition in varying proportion of borax up to 21% (w/w). All the prepared resin were characterized by free phenol content, free formaldehyde content as well as hydroxymethyl content. It was proved by Fourier transform infrared spectrometer (FTIR) that B-O bond had been successfully introduced into the structure of PF resin. Thermo gravimetric analyzer (TGA) and different scanning calorimetry (DSC) were used to characterize the thermodynamic characteristics of the PF resin. The result showed that when the mass fraction of borax was 9wt.% of PF resin, the heat resistance was the best and the curing temperature of the modified PF resin was higher than that of the unmodified PF resin.

2013 ◽  
Vol 467 ◽  
pp. 185-191
Author(s):  
Min Zhen Bao ◽  
Hong Wei Yu ◽  
Bin Fu Bao ◽  
Yuan Cao

This paper aimed to produce the alkaline phenolic resin by the addition of diallyl phthalate into traditional phenolformaldehyde resin. Then the modified resin was characterized using dynamic mechanical analyzer (DMA), differential scanning calorimetry (DSC), fourier transform infrared spectrometer (FTIR) and simultaneous thermal analyzer (STA). The results indicated that: the increase of the diallyl phthalate contributed to the rise of the storage modulus (E) and loss modulus (E), the decrease of the loss factor. Curing temperature also showed a decline trend and was decreased by 5°Cwhen the amount of modifider was 2.5% of the phenol. The improvemnt of Organic ester on curing of alkaline phenolic resin achieved by rapidly promoting resin molecular to generate reactive intermediate quinone methide. The amount of the modifier had little effect on the thermostability of resin, but it reduced the bonding strength of plywood.


2012 ◽  
Vol 184-185 ◽  
pp. 1198-1206
Author(s):  
Jin Sun ◽  
Rui Hang Lin ◽  
Xiao Bo Wang ◽  
Xiao Feng Zhu ◽  
Zhen Zhong Gao

The novel adhesives were prepared using PF resin as matrix and sodium silicate as modification additive. It was proved by Fourier transform infrared spectrometer (FTIR) that silicon-oxygen bonds had been successfully introduced to the structure of PF resin. Boiling water extraction (BWE),scanning electron microscopy (SEM),thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC) were used to characterize the structure of PF resin modified with sodium silicate (Na2SiO3-PF). The test results show that sodium silicate is an effective modifier to PF resin which lessen the brittleness, accelerate the cure rate and enhance the boiling water resistance of PF resin as well. The FTIR,TGA and DSC test results also show that the structure of PF resin has been changed by sodium silicate.


2011 ◽  
Vol 396-398 ◽  
pp. 1640-1644 ◽  
Author(s):  
Shi Hong Shen ◽  
Yan Zhang ◽  
Yu Jian Liu

A Titanium-modified phenol-formaldehyde resin (Ti-PF) was prepared. FT-IR was adopted to characterize the molecular structure of the modified resin. And the curing behavior and curing kinetic characteristics were studied by differential scanning calorimetry (DSC). The initial curing temperature Ti, the exothermic peak temperature Tp and the end curing temperature Td of Ti-PF are 153.1°C, 172.5°C and 193.9°C, respectively, all about 10°C higher than that of the unmodified phenolic resin. The Kissinger and Crane equations were applied to establish the curing kinetic parameters of Ti-PF. The kinetic analysis indicates the activation energy for the Ti-PF is 79.9kJ•mol-1, lower than that of the unmodified phenolic resin(87.6kJ•mol-1). In addition, the thermal degradation behavior of the cured Ti-PF was studied by thermal gravimetric (TG) method. TG results show that the char yield of Ti-PF is 73.3% at 850°C, while that of the unmodified phenolic resin is only 62.3%. It demonstrated that titanium-modified phenolic resin has much better thermal stability compared with the unmodified one.


Holzforschung ◽  
2020 ◽  
Vol 74 (7) ◽  
pp. 663-672 ◽  
Author(s):  
Hanna Paananen ◽  
Tuula T. Pakkanen

AbstractLignin is the second most abundant biopolymer and will be an important source for carbon-containing compounds in the future. Based on their similar phenolic structures, lignin has great potential to become a valuable substitute for phenol in phenol-formaldehyde resin adhesives. To meet this aim, the sodium hydroxide (NaOH)-catalyzed reaction of kraft lignin with formaldehyde was studied by using paraformaldehyde (PFA) as a formaldehyde source. The advantage of using PFA, the solid polymer of formaldehyde, is the simple composition of the depolymerized solution. According to the results of differential scanning calorimetry (DSC), the lignin reaction was found to require a high NaOH concentration in order for the reaction with PFA to proceed at reasonably low temperatures compared to the curing temperature of phenol-formaldehyde resins (approximately 150°C). On the other hand, high alkalinity conditions are known to favor the disproportionation of formaldehyde to formic acid and methanol. Due to the moderate reactivity of lignin, the Cannizzaro reaction can compete with the methylolation reaction of lignin. Based on the results of 13C, 31P and 1H-13C heteronuclear single quantum correlation nuclear magnetic resonance (HSQC NMR), methylolation was found to be the main reaction occurring in the lignin-formaldehyde reaction.


Author(s):  
Г.С. Варанкина ◽  
Д.С. Русаков ◽  
Е.Г. Соколова ◽  
А.Н. Чубинский

В настоящее время перед отечественным производителем древесных композиционных материалов стоят задачи по увеличению объемов производства, повышению качества и конкурентоспособности, снижению токсичности выпускаемой продукции. Решение этих задач основано на разработке новых и совершенствовании имеющихся технологий современного производства клеёв и композиционных материалов на их основе. Цель исследования – повышение эффективности производства фанеры путём применения клеев на основе порошкообразных термореактивных полимеров поликонденсационного типа. Для достижения поставленной цели в работе необходимо исследовать влияние наполнителя на свойства клеевой композиции и готовой продукции. Исходными компонентами для проведения экспериментов являлись порошковая фенолоформальдегидная смола и аэросил технический. Установлено, что введение аэросила технического в клеящие составы на основе поликонденсационной порошковой фенолоформальдегидной смолы СФЖ-3013 увеличивает прочность фанеры, также с увеличением количества наполнителя уменьшается содержание свободных продуктов в смоле: содержание свободных фенола и формальдегида уменьшается до 0,05 – 0,06% и 0,02 – 0,03% соответственно. Предполагается, что при горячем способе склеивания происходит гелеобразование, частицы аэросила образуют разветвленные цепочки ~Si-O-Si~, которые целиком пронизывают объем клея, этот процесс сопровождается связыванием формальдегида в процессе структурирования. Полученные результаты исследований могут быть использованы в работе специалистов деревообрабатывающих производств при управлении технологическими процессами склеивания. Разработанные составы клеевой композиции на основе фенолоформальдегидных смол, модифицированных (наполненных) техническим аэросилом позволяют сократить расход клеевых материалов; повысить прочность и качество склеиваемой продукции; ускорить процесс отверждения связующего; сократить продолжительность склеивания; снизить энергозатраты путем уменьшения времени склеивания; уменьшить себестоимость клея, за счёт замещения основных компонентов наполнителем. At present, the domestic manufacturer of wood composite materials is faced with tasks to increase production volumes, improve quality and competitiveness, and reduce the toxicity of manufactured products. The solution to these problems is based on the development of new and improvement of existing technologies for the modern production of adhesives and composite materials based on them. The purpose of the study is to increase the efficiency of plywood production by using adhesives based on powdered thermoset polymers of the polycondensation type. To achieve this goal in the work, it is necessary to study the effect of the filler on the properties of the adhesive composition and finished products. The initial components for the experiments were powder phenol-formaldehyde resin and technical aerosil. It was found that the introduction of technical aerosil in adhesives based on polycondensation powder phenol-formaldehyde resin SFZh-3013 increases the strength of plywood, as the amount of filler increases, the content of free products in the resin decreases: the content of free phenol and formaldehyde decreases to 0.05 – 0.06% and 0.02 – 0.03%, respectively. It is assumed that during the hot bonding method, gel formation occurs, so that aerosil particles form branched chains ~ Si-O-Si ~ that completely penetrate the glue volume, this process is accompanied by formaldehyde bonding during structuring. The obtained research results can be used in the work of specialists in woodworking industries in the management of gluing processes. The developed compositions of the adhesive composition based on phenol-formaldehyde resins modified (filled) with technical aerosil allow you to: reduce the consumption of adhesive materials; to increase the strength and quality of glued products; speed up the curing process of the binder; shorten bonding time; reduce energy costs by reducing the bonding time; reduce the cost of glue, due to the replacement of the main components with filler.


Vestnik MGSU ◽  
2019 ◽  
pp. 1132-1139
Author(s):  
Nguyen Viet Cong ◽  
Nikolay Y. Sosnovskiy ◽  
Valentin P. Yanchuk ◽  
Anastasia M. Smirnova ◽  
Larisa S. Grigorieva

Introduction. Gas-filled polymers are highly efficient building thermal insulation materials, and therefore, researching to develop technologies to create them is a promising task. Phenol-formaldehyde foamed plastic can be a high-potential material with many significant advantages. However, the high toxicity of the phenol and formaldehyde compounds it releases is a significant deterrent to its usage. Therefore, the purpose of this study was to search for ways to reduce the toxicity of foamed plastic. The research considered the method of using ferric chloride as a complexing agent that binds phenol, with simultaneous use of sodium hexafluorosilicate to reduce material consumption. Materials and methods. The studies were carried out on phenol-formaldehyde resin FRV-1A (TU 6-05-1104-78 “Resin, phenol-formaldehyde, foaming, brand FRV-1A”) and curing agent VAG-3 (TU 6-55-1116-88 “Product VAG-3”). The number of free phenol monomers was determined through gas chromatography method following GOST 11235-2017 “Phenoloformaldehyde resins. Methods for determination of free phenol”. The tests were carried out using a Tsvet-4 chromatograph. Tests on determining the foaming rate were carried out according to TU 6-05-1104-78 “Resin, phenol-formaldehyde, foaming, brand FRV-1A”. The density of the samples was measured basing on the mass-to-volume ratio of the samples. Strength was determined using samples of size 50 × 50 × 50 mm mm at 10 % compression on a test press. Results. The conducted studies showed a decrease in the content of free phenol monomers in samples modified with ferric chloride. The use of sodium hexafluorosilicate allows significantly reducing the density of the finished material and, consequently, reducing the toxicity of foamed phenolic plastic per material mass unit. Conclusions. According to the obtained results, the most effective for detoxifying a cast foamed phenolic plastic is the use of ferric chloride in an amount of 2 % of the FRV-1A oligomer mass with the addition of 0.5 % of the sodium hexafluorosilicate mass. The use of this method for modifying phenol-formaldehyde resin foam in the future may make it possible to obtain a much safer material and expand its areas of application.


2007 ◽  
Vol 29-30 ◽  
pp. 177-180
Author(s):  
Samaresh Ghosh

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.


2011 ◽  
Vol 239-242 ◽  
pp. 1022-1025
Author(s):  
Jun Gang Gao ◽  
Xue Fang Zhang ◽  
Hong Qiu Lv

In order to improve the properties of boron-containing phenol-formaldehyde resin (BPFR), the tetrabromo-bisphenol A epoxy resin (TBBPAER) was used to cure BPFR. The curing mechanism, thermal properties and the fire resistance of TBBPAER/BPFR were investigated by fourier transform infrared spectrometer (FTIR), thermal gravimetric analysis (TGA), torsional braid analysis (TBA) and the oxygen index method. The results show, -OH of -C6H4-CH2OH and -C6H4OH reacts with the epoxy group. With the increase in the amount of BPFR, the thermal properties get better. When the additive amount of TBBPAER is 10 wt%, this material has best thermal stability at high temperature and higher temperature of loss bromine. The glass transition temperature (Tg) is 223.2 °C and the LOI is 68.5.


Sign in / Sign up

Export Citation Format

Share Document