Influence of soaking temperature time on the ability prepared liquefaction of wood from cashew nut shell waste

h D Q, Minh H N, Nhi N V U, Kien K D T. Influence of soaking temperature time on
the ability prepared liquefaction ofwood from cashewnut shell waste. Sci. Tech. Dev. J. – Engineering
and Technology; 4(1):713-720.
713
Copyright
© VNU-HCM Press. This is an open-
access article distributed under the
terms of the Creative Commons
Attribution 4.0 International license.
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
In Vietnam, cashew is one of the important indus-
trial trees. Due to exporting cashew nuts only, cashew
nut shell has become one of the waste items in the
cashew industry. Cashew nut shell is often pressed to
get cashew oil. However, the cashew nut shell after
pressing (often called the cashew nut shell waste) is
still a waste to be treated. There have been some stud-
ies using cashew shell waste to fabricate ceramic17,18.
Other studies have also used cashew shell waste to
make wood liquefaction19,20. This research will study
the influence of soaking temperature time on the abil-
ity to prepared wood liquefaction from cashew nut
shell waste.
EXPERIMENTALMETHODS
Rawmaterials
CNSW was taken from Binh Phuoc. Chemical com-
position was shown in Table 1 and Table 2. CNSW
was washed and crushed to a size of less than 500
mm. Phenol (1.07 g/cm3, Merck) and 98% sulfuric
acid (1.84 g/cm3, Merck) were also used to fabricate
wood liquefaction from CNSW.
Phenol, CNSW were mixed with the ratio of 2/1 (wt.)
and 5% sulfuric acid According to the amount of phe-
nol used. Themixed mixtures were placed in the dry-
ing oven and soaked at 150 C for different time peri-
ods to make wood liquefaction. The soaking temper-
ature times are shown in Table 3.
Optimum soaking time was determined by analyz-
ing properties such as vibrational units of functional
groups by FT-IR method; Wood liquefaction reaction
efficiency through assessment of residual CNSW ra-
tio; The number average molecular weight (Mn) and
the weight average molecular weight (Mw) by Gel
chromatography (GPC) method.
Methods
Fourier-transform infrared spectroscopy (FT-
IR):
The vibration of the functional groups of wood liq-
uefaction was analyzed by Fourier-transform infrared
spectroscopy (FT-IR – Model Nicolet 6700, Thermo,
USA). The scanning step was 0.9642 with a scanning
angle of 500 to 4000cm1. The binder was KBr. The
test method was a transmittance spectrum.
Determine a residual CNSW:
Phenolic resin is crushed, filtered, and washed to re-
move residual phenol in the resin. The washed resin
is dried at 70oC. The sample was then weighed 2,00
 0.01 gram, contained in Erlen, added about 40 ml
of ethanol, and swirled well. The sample is filtered
slowly through the filter paper and weighed to deter-
mine the mass of the filtered sample. After filtration
is complete, the filter paper containing the residue is
placed in a drying cup and dried to constant weight.
The residual CNSW is determined from the following
formula:
%mgd =
msmgl
mo
(1)
mgd – the percentage of residual CNSW (%)
ms – the weight of filter paper and insoluble residue
(gram)
mgl – the weight of dry filter paper (gram)
mo – the weight of the original phenolic resin (gram)
Gel permeation chromatography (GPC):
The number average molecular weight (Mn) and the
weight average molecular weight (Mw) were deter-
mined by Gel permeation chromatography method
(GPC - Model PL-GPC 50, POLYMERLAB, USA).
The used soluble solvent is Dimethyl - Formamide
(DMF). The wood liquefaction samples were dis-
solved in DMF solvent at a concentration of 0.10
mg/ml. The dosage for each sample injection was
50m l.
THE RESULTS ANDDISCUSSIONS
Vibrational units of functional groups by
FT-IR spectrum
Wood liquefaction samples at different soaking times
were determined functional groups by FT-IRmethod.
FT-IR spectrums of samples were presented in Fig-
ure 1. FT-IR spectrum showed that the samples all
had functional groups such as: CHn (2929, 2850
cm1), C=O (1700cm1), C=C (1598 cm1), C-C
(1513 cm1), CH2 (1452 cm1), CH (1371 cm1),
OH (1257 cm1), C-H (1092, 815, 754 cm1) (Ta-
ble 4)2,3,21,22.
The results of the FTIR spectrum of the samples were
similar. Comparison with the FTIR spectrum of pre-
vious studies showed that therewaswood liquefaction
formation in all samples2,3,21,22. In this case, it is dif-
ficult to estimate the optimal retention time for wood
liquefaction generation at 150C. Therefore, the de-
termination of residual CNSW and the GPC method
was used to evaluate this factor.
Determine residual CNSW
Results from the graph in Figure 2 showed that the
residual CNSW of liquefied wood decreased as the
soaking time increases. When the retention time in-
creased, the reaction time for creating wood liquefac-
tion was prolonged, the reaction performance also in-
creased. The residue of CNSW was reduced rapidly
714
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
Table 1: The composition of the chemical elements (%wt.) of CNSW 20
Sample C N H O Others
CSNW 53.6 9.5 8.8 26.8 1.2
Table 2: The composition of chemical compounds (%wt.) of CNSW
Sample Cellulose Hemi
cellulose
Lignin Anacardic
acid
Cardanol Cardol 2-Methyl
Cardol
CSNW 53-56 11-12 16-17 10-15 1-2 2-4 <1
Table 3: The soaking temperature times
Sample Ratio (wt.) Temperature Soaking time
Phenol CNSW Sulfuric acid(*) (oC) (minutes)
ST90 2 1 5% 150 90
ST120 2 1 150 120
ST150 2 1 150 150
ST180 2 1 150 180
ST210 2 1 150 210
* According to the amount of phenol used
Table 4: Vibration of functional groups
Wavenumbers (cm1) Function groups Ref.
3351 Vibrate of OH group of phenolic and methylol 21
2929, 2850 Vibrate of CH2 group of aliphatic 2,21
1700 Vibrate of C=O group of carboxylic 3
1598 Vibrate of C=C group of benzen 22
1513 Vibrate of C-C in aromatic ring 3
1452 Vibrate of -CH2 group 1
1371 Vibrate of -CH group 21
1257 Vibrate of OH group 1
1092 Vibrate of C-H group inside the aromatic ring 1,21
815 Vibrate of C-H group of benzen 1
754 Vibrate of C-H group outside the aromatic plane 1
when extending the retention time from 90 to 180
minutes corresponding to the model ST90 to ST180
(from 29.68% to 9.44%). If the soaking time was pro-
longed, the residue of CNSWwould be difficult to re-
duce further (from 9.44% to 9.02%).
When the heat retention time was prolonged, the
chemical reactions between phenol, CNSW, and the
acid catalyst would take place more thoroughly. As
a result of this process, the amount of CNSW in-
volved in the reaction to create the resin was more,
the amount of CNSW remaining after the reaction
also was less. However, besides the resin-forming re-
action, there was also the thermal decomposition of
CNSW23. Therefore, when the heat retention time
was longer than 180 minutes, the result of CNSW
residue decreases very little. The CNSW residue re-
sult showed that at 150oC the optimal soaking time
was 180 minutes.
DetermineMn andMw by GPC
The results of the GPC analysis of the samples were
presented in Table 5 and Figure 3. According to the
715
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
Figure 1: FTIR ofwood liquefaction at 150oC for different soaking time
Table 5: Effect of soaking time to residual CNSW ratio
Sample Temperature (oC) Soaking time (minute) Residual CNSW ratio (% .wt)
ST90 150 90 29.68 1.45
ST120 150 120 15.25 1.36
ST150 150 150 11.95 0.91
ST180 150 180 9.44 1.15
ST210 150 210 9.02 1.24
data in Table 5 and Figure 3, the samples all had the
presence of two characteristic distribution areas. The
first region (region 1) had the number average molec-
ular weight (Mn) in the range of 6997 - 7552 and the
weight average molecular weight (Mw) in the range
10152 - 10849. The second region (region 2) had Mn
index in the range 1275 - 1325 and Mw in the range
of 1545 – 1755. This region was the distribution of
oligomers.
Kensuke Naka pointed out that polymer had a molec-
ular weight of more than ten thousand and oligomer
had a molecular weight of several thousand or less23.
GPC results showed that region 1 with Mw value over
10000 was the distribution region of the polymer and
region 2 with Mw value from 1545 to 1755 was the
distribution region of the oligomer. TheWn was used
to determine the formation of the liquefied wood at
different thermal retention time. When holding the
heat at 150oC from 90 minutes to 180 minutes (ST90
– ST180 samples), the oligomers linked together to
form polymers. The Wn value of the polymer region
would increase and the oligomer region would de-
crease. Conversely, if the holding time was too long
(ST210 sample), the Wn value of the polymer region
would decrease and the oligomer region would in-
crease. This result demonstrated that prolonging the
soaking time also would sever themolecular circuit of
the newly formed polymer.
This result combined with the residual CNSW ra-
tio (Figure 1) and the relative intensity ratio of the
peaks on the FT-IR spectra (Figure 2) showed that the
formed wood liquefaction at different soaking times
716
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
Figure 2: Effect of soaking time to residual CNSW ratio
Table 6: Gel permeation chromatography of wood liquefaction samples
Sample Soaking time (minutes) Region Mn Mw
ST90 90 1 7056 10152
2 1325 1679
ST120 120 1 7141 10845
2 1295 1610
ST150 150 1 7410 10401
2 1282 1755
ST180 180 1 7552 10640
2 1275 1545
ST210 210 1 6997 10509
2 1323 1629
had a similar structure and 180 minutes was the opti-
mal time to fabricate wood liquefaction from CNSW
at 150oC.
CONCLUSIONS
In this study, the effect of soaking time at 150oC
on the ability to prepared wood liquefaction was in-
vestigated. The FTIR results showed that there was
LW formation in all samples at different soaking
times. When increasing the soaking time, the resid-
ual CNSW ratio in resin decreased. However, when
increasing the retention time of more than 180 min-
utes, the residual CNSW ratio did not decrease signif-
icantly. Mw andMn values in the GPC results showed
that the samples had coexistence of the polymer and
oligomer and 180 minutes was the optimal time to
fabricate wood liquefaction from CNSW at 150oC.
The ST180 sample had the residual CNSW ratio of
717
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
Figure 3: GPC result of wood liquefactionat 150oC for different soaking time
9.44%, the number average molecular weight (Mn) of
7552, and the weight average molecular weight (Mw)
of 10640.
ACKNOWLEDGEMENTS
This research is funded by Vietnam National Uni-
versity Ho Chi Minh City (VNU-HCM) under grant
number: C2019-20-27. We acknowledge the support
of time and facilities from Ho Chi Minh City Uni-
versity of Technology (HCMUT), VNU-HCM for this
study.
CONFLICT OF INTEREST
The authors declare that there is no conflict of interest
regarding the publication of this article.
AUTHOR’S CONTRIBUTION
The authors confirm contribution to the paper as
follows: study conception and design: Do Quang
Minh, Kieu Do Trung Kien; data collection: Nguyen
Vu Uyen Nhi; analysis and interpretation of results:
Huynh Ngoc Minh; draft manuscript preparation:
Kieu Do Trung Kien. All authors reviewed the results
and approved the final version of the manuscript.
REFERENCES
1. Jiang H, et al. The pyrolysis mechanism of phenol
formaldehyde resin, Polymer Degradation and Stability.
2012;97(8):1527–1533. Available from: https://doi.org/10.
1016/j.polymdegradstab.2012.04.016.
2. Huang Y, et al. Thermal and structure analysis on reaction
mechanismsduring thepreparationof activatedcarbonfibers
by KOH activation from liquefied wood-based fibers, Indus-
trial Crops and Products. 2015;69:447–455. Available from:
https://doi.org/10.1016/j.indcrop.2015.03.002.
3. KobayashiM, et al. Analysis on residue formationduringwood
liquefactionwithpolyhydric alcohol. Journal ofWoodScience.
2004;50(5):407–414. Available from: https://doi.org/10.1007/
s10086-003-0596-9.
4. Seljak T, et al. Wood, liquefied in polyhydroxy alcohols as a
fuel for gas turbines. Applied Energy. 2012;99:40–49. Avail-
able from: https://doi.org/10.1016/j.apenergy.2012.04.043.
5. Kurimoto Y. Wood species effects on the characteristics
of liquefied wood and the properties of polyurethane films
prepared from the liquefied wood. Biomass and Bioenergy.
2001;21(5):381–390. Available from: https://doi.org/10.1016/
S0961-9534(01)00041-1.
6. Jin Y. Liquefaction of lignin by polyethyleneglycol and glyc-
erol. Bioresource Technology. 2011;102(3):3581–3583. PMID:
21050748. Available from: https://doi.org/10.1016/j.biortech.
2010.10.050.
718
Science & Technology Development Journal – Engineering and Technology, 4(1):713-720
7. Yamada T, Ono H. Characterization of the products result-
ing from ethylene glycol liquefaction of cellulose. Journal of
Wood Science. 2001;47(6):458–464. Available from: https:
//doi.org/10.1007/BF00767898.
8. Tohmura SI, et al. Preparation and characterization of wood
polyalcohol-based isocyanate adhesives. Journal of Applied
Polymer Science. 2005;98(2):791–795. Available from: https:
//doi.org/10.1002/app.22072.
9. Ugovšek A, Sernek M. Characterisation of the curing of liq-
uefied wood by rheometry. DEA and DSC, Wood Science and
Technology. 2013;47(5):1099–1111. Available from: https://
doi.org/10.1007/s00226-013-0565-4.
10. Pan H. Wood Liquefaction in the Presence of Phenol with a
Weak Acid Catalyst and Its Potential for Novolac Type Wood
Adhesives. Doctor of Philosophy, Graduate Faculty of the
Louisiana State, The School of Renewable Natural Resources
Graduate Faculty of the Louisiana State. 2007;.
11. Lin L, et al. Liquefaction of wood in the presence of phe-
nol using phosphoric acid as a catalyst and the flow proper-
ties of the liquefied wood, Journal of Applied Polymer Sci-
ence. 1994;52(11):1629–1636. Available from: https://doi.org/
10.1002/app.1994.070521111.
12. Ahmadzadeh A, Zakaria S. Preparation of Novolak Resin by
Liquefaction of Oil Palm Empty Fruit Bunches (EFB) and Char-
acterization of EFB Residue. Polymer-Plastics Technology and
Engineering. 2008;48(1):10–16. Available from: https://doi.
org/10.1080/03602550802497776.
13. Lee WJ, Chen YC. Novolak PF resins prepared from phenol
liquefied Cryptomeria japonica and used in manufacturing
moldings, Bioresour Technol. 2008;99(15):7247–7254. PMID:
18243689. Available from: https://doi.org/10.1016/j.biortech.
2007.12.060.
14. Lee SH, Teramoto Y, Shiraishi N. Acid-catalyzed liquefaction of
waste paper in the presence of phenol and its application to
Novolak-type phenolic resin, Journal of Applied Polymer Sci-
ence. 2002;83(7):1473 –1481.
15. Xie T, Chen F. Fast liquefaction of bagasse in ethylene carbon-
ate and preparation of epoxy resin from the liquefied prod-
uct. Applied Polymer Science. 2005;98(5):1961–1968. Avail-
able from: https://doi.org/10.1002/app.10039.
16. Yu F, et al. Liquefaction of corn stover and preparation of
polyester from the liquefied polyol. Appl Biochem Biotech-
nol. 2006;130(1-3):574–585. Available from: https://doi.org/
10.1385/ABAB:130:1:574.
17. Kien KDT, et al. Study on Sintering Process of Woodceram-
ics from The Cashew nut shell waste, Ceramic Processing Re-
search. 2018;19(6):472–478.
18. Kien KDT, Minh DQ. Nghiên cứu chế tạo vật liệu gốm
gỗ từ bã thải vỏ điều. Vietnam Journal of Chemistry.
2017;55(4E23):147–152.
19. Minh DQ, et al. The Influence of Composition of Raw Mate-
rials on Formation of Phenolic Resin from Cashew Nut Shell
Waste (CNSW). Defect and Diffusion Forum. 2019;394(1):103–
108. Available from: https://doi.org/10.4028/www.scientific.
net/DDF.394.103.
20. Kien KDT, et al. Ảnh hưởng của nhiệt độ đến khả năng tạo
nhựaphenolic từ nguyên liệu bã thải vỏ điều, Vietnam Journal
of Chemistry. 2019;57(6E1,2):403–407.
21. e EJ, et al. Cellulose liquefaction in acidified ethylene glycol.
Cellulose. 2009;16(3):393–405. Available from: https://doi.org/
10.1007/s10570-009-9288-y.
22. Alma MH, Basturk MA. Liquefaction of grapevine cane (Vitis
vinisera L.) waste and its application to phenol-formaldehyde
type adhesive. Industrial Crops and Products. 2006;24(2):171–
176. Available from: https://doi.org/10.1016/j.indcrop.2006.03.
010.
23. Naka K. Monomers, Oligomers, Polymers, and Macro-
molecules (Overiew). Encyclopedia of Polymeric Nanomate-
rials. 2014;p. 1–6. PMID: 25533776. Available from: https:
//doi.org/10.1007/978-3-642-36199-9_237-1.
719
Tạp chí Phát triển Khoa học và Công nghệ – Kĩ thuật và Công nghệ, 4(1):713-720
Open Access Full Text Article Bài nghiên cứu
1Bộ môn Vật liệu Silicat, Khoa Công
nghệ Vật liệu, Trường Đại học Bách
KhoaThành phố Hồ Chí Minh
(HCMUT), 268 Lý Thường Kiệt, quận
10, thành phố Hồ Chí Minh, Việt Nam
2Đại học Quốc Gia Thành phố Hồ Chí
Minh (ĐHQG-HCM), phường Linh
Trung, quậnThủ Đức, thành phố Hồ
Chí Minh, Việt Nam.
Liên hệ
Kiều Đỗ Trung Kiên, Bộ môn Vật liệu Silicat,
Khoa Công nghệ Vật liệu, Trường Đại học
Bách Khoa Thành phố Hồ Chí Minh (HCMUT),
268 Lý Thường Kiệt, quận 10, thành phố Hồ
Chí Minh, Việt Nam
Đại học Quốc Gia Thành phố Hồ Chí Minh
(ĐHQG-HCM), phường Linh Trung, quận Thủ
Đức, thành phố Hồ Chí Minh, Việt Nam.
Email: kieudotrungkien@hcmut.edu.vn
Lịch sử
 Ngày nhận: 25-11-2020
 Ngày chấp nhận: 16-03-2021 
 Ngày đăng: 30-03-2021
DOI : 10.32508/stdjet.v4i1.796 
Ảnh hưởng của thời gian lưu nhiệt đến khả năng tạo gỗ hoá nhựa
từ nguồn nguyên liệu bã thải vỏ điều
ĐỗQuangMinh1,2, Huỳnh NgọcMinh1,2, Nguyễn Vũ Uyên Nhi1,2, Kiều Đỗ Trung Kiên1,2,*
Use your smartphone to scan this
QR code and download this article
TÓM TẮT
Gỗ hoá nhựa là một trong những sản phẩm nhựa phenolic. Tuy nhiên, không giống như các loại
nhựaphenolic thươngphẩm thườngđược tổnghợp từphảnứnghoáhọcgiữaphenol và formalde-
hyde, gỗ hoá nhựa thường được tổng hợp từ phản ứng giữa phenol với một loại nguyên liệu gốc
gỗ và xúc tác tại nhiệt độ 120 – 180oC. Tuỳ thuộc vào xúc tác sử dụng là bazơ hoặc axít, nhựa tạo
thành có thể là nhựa nhiệt rắn hoặc nhiệt dẻo. Trong nghiên cứu này, gỗ hoá nhựa được tổng hợp
từ bã thải vỏ điều, phenol và xúc tác axít sulphuric. Bã thải vỏ điều được lấy từ tỉnh Bình Phước –
Việt Nam và được nghiền đến kích thước hạt nhỏ hơn 500 mm. Phenol và xúc tác axít sulphuric sử
dụng là các hoá chất thí nghiệm. Bột bã thải vỏ điều, phenol và axít sulphuric được trộn với nhau
và được cho phản ứng ở 150oC trong những thời gian lưu nhiệt khác nhau. Thời gian lưu nhiệt
thích hợp được xác định thông qua dư lượng bã thải vỏ điều còn lại sau phản ứng tạo nhựa. Ngoài
ra, sản phẩm gỗ hoá nhựa cũng được các định số lượng phân tử số trung bình (Mn) và phân tử khối
trung bình (Mw) bằng phương pháp sắc ký thẩm thấu gel (GPC). Nhóm chức tạo thành được xác
định bằng phổ biến đổi hồng ngoại (FTIR). Kết quả chỉ ra rằng nhựa tạo thành là nhựa nhiệt dẻo và
thời gian lưu nhiệt thích hợp để tạo gỗ hoá nhựa là 180 phút. Mẫu nhựa này có dư lượng bã thải
vỏ điều còn lại sau phản ứng là 9.44%, phân tử số trung bình là 7552, phân tử khối trung bình là
10640. Gỗ hóa nhựa từ bã thải vỏ điều có thể được sử dụng làm chất liên kết trong sản xuất tấm
ván gỗ ép (MDF) hoặc làm nguyên liệu thúc đẩy quá trình kết khối trong sản xuất vật liệu gốm gỗ.
Ngoài ra, gỗ hoá nhựa cũng có thể được nhiệt phân để tạo thành sợi cacbon. Sợi cacbon có thể
được ứng dụng làm vật liệu gia cường trong sản xuất một số loại gốm.
Từ khoá: nhựa phenolic, gỗ hoá nhựa, bã thải vỏ điều
Trích dẫn bài báo này: Minh D Q, Minh H N, Nhi N V U, Kiên K D T. Ảnh hưởng của thời gian lưu nhiệt 
đến khả năng tạo gỗ hoá nhựa từ nguồn nguyên liệu bã thải vỏ điều. Sci. Tech. Dev. J. - Eng. Tech.; 
4(1):713-720.
720