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transcript
Synthesis and Characterization of Phenol
Formaldehyde Resol Resins from Bark
Extractives by Autoclave
Yong Zhao+, Ning Yan+, Martin Feng++
+ University of Toronto ++ FPInnovation
Introduction
Objectives
Methodologies
Key Results
Conclusions
Outline
2
• PF resin industry valued at
approx. $ 2.3 billion in North
America, $10 billion in the
world (in 2010).
• PF resins has been widely
used in molding, insulation,
construction, electronic
devices.
Phenol Formaldehyde Resin
Introduction
3
Resol: pH>7, F/P>1.5
OH-
3D structure after curing
• Depletion of fossil fuel
• Carbon footprint
• Rising price of petroleum -
based phenol
Introduction (cont’d)
Environmental Concerns
Using renewable biomass materials as feedstock could
be a solution. 5
Introduction (cont’d)
Bark is rich in phenolic compounds.
Bark Materials
6
Introduction (cont’d)
Mountain Pine Beetle Infestation (MPB, Dendroctonus
ponderosae Hopkins)
• MPB affected approximately 10 million hectares of pine
forests in 2007 in western Canada
• Lodgepole pine (Pinus contorta)
Value-added applications of beetle infested lodgepole pine bark is highly
advantageous for the forest industry. 7
8
• Reactivity of phenolic compounds from biomass materials
towards formaldehyde and their adhesive application have
been demonstrated in previous studies.
• Phenol liquefaction or alkaline extraction: moderate
conditions, high yield...
• Autoclave extraction: chemical elements in soil, water
soluble vitamin in milk, autoclave/water to extract tannins
from bark……
…However,
• Very few studies on alkaline extraction of MPB bark with
autoclave.
• Resin performance (Curing, thermal stability and bonding
strength)
Adhesive Application of Biomass
Objectives
1. To obtain phenol substitutes from mountain pine beetle
infested lodgepole pine (MPB) bark through autoclave
extraction in alkaline solution.
2. To formulate bio-based bark extractive-PF resol resins
and to investigate the resin properties.
9
Mountain pine beetle infested lodgepole pine Bark
Bark Extractives
(Dried under either alkaline or neutral
condition)
Resin formulation (BEA-PF, BEA-PF(N),
30%, 50% and 70% phenol replacement)
and characterization (Curing behavior
& Bond Strength)
Bark Extraction (Autoclave, 120°C, 30min,
solvent/bark ratio = 5:1 (V/m))
Separation
O
OH
OHHO
OH
O
OH
OHHO
OH
O
OHOH
HO
OH
O
OH
OHHO
OH
Methodologies
Key results
Mn (Da) Mw (Da) Mw/Mn Stiasny number
(%)
Alkaline Extractives (wet) 1.46×103 2.45×103 1.67 -
Alkaline Extractives (dry) 1.07×103 1.96×103 1.83 43.11 (37.93)
Neutralized Extractives
(wet) 1.66×103 3.01×103 1.81 -
Neutralized Extractives
(dry) 2.53×103 5.85×103 2.31 42.96 (37.50)
Properties of bark alkaline extractives
Bark alkaline extraction by autoclave
Neutralization affected molecular weight of the extractives , but did not
affect extractives’ reactivity towards formaldehyde.
Average yield of extractives = 55.32%
Extraction condition: Autoclave 120°C, 30min, solvent/bark ratio = 5:1 (V/m), 1% NaOH
Bark alkaline extractives from autoclave extraction
Extraction condition: 100°C, 120min, solvent/bark ratio = 5:1 (V/m), 1% NaOH
13
• Bark alkaline extractives obtained using or without
using autoclave extraction contained tannin,
degraded lignin and degraded hemicellulose in their
composition.
• The tannin structures of the bark extractives were
mainly procyanidin type, consisted of phloroglucinol
A-ring, catechol B-ring and pyrogallol B-ring.
• Less C4-C8 and C4-C6 interflavonoid bonds, more
degraded lignin fragments and degraded
hemicellulose were found in the bark extractives
obtained using autoclave.
pH
Solids
content
(%)
Viscosity
at
25℃(cps)
Gel
time at
120℃
(s)
Mn (Da) Mw (Da) Mw/M
n
30% BEA-PF 12.42 50.91 440 78 481.6 960.5 1.99
50% BEA-PF 11.74 48.53 370 89 452.8 1132.2 2.50
70% BEA-PF 11.25 50.84 325 105 557.8 1243.8 2.23
30% BEA-PF (N) 12.11 48.81 580 59 801.2 1261.4 1.57
50% BEA-PF (N) 11.90 48.72 520 67 905.1 1385.9 1.53
70% BEA-PF (N) 10.91 47.98 495 88 698.4 1337.4 1.91
Lab PF 11.93 48.87 25 173 258.95 327.27 1.25
Com PF 11.16 59.00 200 172 212.09 386.48 1.82
Properties of the bark extractive-PF resins
Key results
Bark extractive-PF resin had a higher viscosity, shorter gel time, and higher Mw.
Dynamic DSC of bark extractive-PF resin (30% phenol
substitution rate)
Two exothermic peaks were observed in bark extractive-PF resins with 30%
phenol substitution rate.
Cure temperature of bark extractive-PF resins with
30% phenol substitution rate
30 BEA-PF 30 BEA-PF (N)
Heating
rate
(°C/min)
Onset
(°C)
Peak 1
(°C)
Peak 2
(°C)
Onset
(°C)
Peak 1
(°C)
Peak 2
(°C)
0 100.6 104.4 132.1 99.3 104.0 131.7
5 102.1 108.3 137.6 103.3 108.7 138.6
10 111.9 118.3 151.7 110.0 117.6 151.1
15 113.8 122.9 158.1 114.0 123.9 159.8
20 114.8 126.1 162.7 118.0 127.1 165.0
Lab PF: Onset temp: 95°C, peak temperature: 136 °C
Commercial PF: Onset temp: 98°C, peak
temperature:127°C
Dynamic DSC of bark extractive-PF resin (50% phenol
substitution rate)
Single exothermic peak was observed in bark extractive-PF resins with 50%
phenol substitution rates.
Dynamic DSC of bark extractive-PF resin (70% phenol
substitution rate)
Single exothermic peak was observed in bark extractive-PF resins with 70%
phenol substitution rates.
50 BEA-PF 50 BEA-PF(N)
Heating rate
(°C/min)
Onset
(°C)
Peak
(°C)
Onset
(°C)
Peak
(°C)
0 111.5 115.8 117.4 122.2
5 117.2 121.5 121.5 126.2
10 121.9 128.4 124.0 132.5
15 129.1 134.4 127.7 136.1
20 133.2 140.0 132.3 140.5
70 BEA-PF 70 BEA-PF(N)
Heating rate
(°C/min)
Onset
(°C)
Peak
(°C)
Onset
(°C)
Peak
(°C)
0 123.7 128.6 132.4 142.3
5 127.5 133.0 135.6 145.9
10 133.5 139.8 137.1 149.1
15 137.4 146.1 139.8 152.1
20 141.1 148.5 143.5 156.2
Cure temperature of bark extractive-PF resins with
50% and 70% phenol substitution rate
Parameters of cure kinetics of different resins
E1
(kJ/mol)
A1
(/s)
E2
(kJ/mol)
A2
(/s)
30 BEA-PF 90.91 1.06X1012 74.15 7.05X108
30 BEA-PF(N) 87.76 3.76X1011 70.92 2.56X108
50 BEA-PF 95.17 1.59X1012 - -
50 BEA-PF(N) 128.44 3.29X1016 - -
70 BEA-PF 115.18 2.91X1014 - -
70 BEA-PF(N) 190.36 4.20X1023 - -
Lab PF 70.22 1.59X108 - -
Commercial PF 82.23 1.18X1010 - -
Bonding development of resins
DMA of bark extractive-PF resin (30% phenol substitution rate)
tanδ
Ttanδ
E’min
E’max
ΔE
Tgel
Tgel and T tanδ of the bark extractive-PF resins slightly decreased with
increasing phenol substitution rate in the resin formulation.
No significant difference was observed in the rigidity of resins made with 30%,
50% and 70% phenol substitution rates.
Thermal stability of cured resins
30 BEA-PF
(%)
50 BEA-PF
(%)
70 BEA-PF
(%)
Lab PF
(%)
Commercial PF
(%)
RT-200 13.12 10.17 11 11.62 13.83
200-400 17.82 23.45 28.96 10.31 22.64
400-600 13.03 11.85 9.82 14.53 15.91
600-700 2.57 2.33 1.36 2.49 2.41
Total 46.54 47.8 51.14 38.95 54.79
Bark extractive-PF resins made from autoclave bark extractives dried under
alkaline conditions
Bark extractive-PF resins made from autoclave bark extractives dried under
neutral conditions
30 BEA-PF(N)
(%)
50 BEA-PF(N)
(%)
70 BEA-PF(N)
(%)
Lab PF
(%)
Commercial PF
(%)
RT-200 17.75 8.63 12.13 11.62 13.83
200-400 17.08 27.05 26.94 10.31 22.64
400-600 11.71 11.38 10.24 14.53 15.91
600-700 3.36 2.09 1.64 2.49 2.41
Total 49.9 49.15 50.95 38.95 54.79
Bonding Strength of different resins S
he
ar
Str
en
gth
(M
pa
)
Bark extractive-PF resins with 30% phenol replacement by autoclave extractives dried
under alkaline condition and neutral condition, bark extractive-PF resin with 50% phenol
replacement by autoclave extractives dried under alkaline condition had comparable dry
and wet bonding strengths to the commercial PF.
Bark extractive-PF resins with 50% phenol replacement by autoclave extractives dried
under neutral condition exhibited similar dry and wet bonding strengths to the lab PF
resin.
Neutralization negatively affected the bonding strength of the BEPF resins when the
phenol replacement was higher than 50%.
Conclusions
• Bark alkaline extractives obtained from autoclave extraction
contained tannin, degraded lignin and degraded
hemicellulose in their composition. It had less C4-C8 and C4-
C6 interflavonoid bonds, more degraded lignin fragments
and degraded hemicellulose than that of extractives obtained
from normal alkaline extraction .
• Bark extractive-PF resins had a higher Mw, higher viscosity
shorter gel time and faster curing rate than the lab PF resin.
• Neutralization of extractives before drying process affected
the extractives’ molecular weight, curing behavior and
bonding strength of the resulting bark extractive-PF resins.
• Bark alkaline extractives obtained from autoclave extractions
is suitable to replace petroleum-based phenol for PF resin
formulation.
Prof. Ning Yan & Martin Feng.
FP Innovation Forintek Division
Lab-mates for suggestions and discussions.
Acknowledgement
Acknowledgement
• Ontario Ministry of Economic Development and Innovation
30
• Industry partners
• Participating institutions
MINISTRY OF ECONOMIC DEVELOPMENT AND
INNOVATION
Thanks!
FTIR of extractives
1000 1500 2000 2500 3000 3500
Wavenumber cm-1
Tra
nsm
itta
nce
Bark autoclave extractives
dried under alkaline condition
Bark autoclave extractives
dried under neutral condition