Synthesis and Characterization of

Sucrose - Melamine - Formaldehyde Adhesive

Professor: Weixing Gan

Gangxi University, China

Outlet

Acknowledgments & Next work

Conclusions

Results and discussion

Materials and Methods

Background

SMF

Background

MF is common adhesive used in wood industries

(paper laminates); maybe replace of PF . Advantages:

high bonding strength, good boiling-water resistance and

low curing temperature ; Defects: the short shelf-life and

higher cost than UF ; Therefore, MF is modified .

Sucrose is a renewable, biodegradable, abundant with

low cost, and readily available. It is a good modifier for

MF because of rich hydroxyl groups (hydroxymethyl

groups specially).

The objective of this paper is to

investigate the synthesis process on

the sucrose modified MF (SMF)

resin, and to evaluate the

performance of the SMF resin as

affected by the sucrose content.

Background

Materials and Methods

Sucrose, Melamine and Formaldehyde

Characterizations of FT-IR and MS

Bonding Strength Test

Shelf-Life of Adhesive

Formaldehyde Emission

Materials and Methods

The preparation of the SMF resin

178 g of formaldehyde solution (37% wt %) and 1.3 g of

borax (0.3 wt %) were put into a reactor. The pH of

mixture was adjusted to 8.5 by sodium hydroxide

solution (0.1 mol/L). Then, 126 g of melamine and 138 g

of sucrose were added into the mixture. The temperature

was increased to 90℃, and kept for 150 min. When

water tolerance was 2 ,the solution was cooled to room

temperature and 192 g of water was added. Finally,

sodium hydroxide solution (0.1mol/L) was added to

adjust the pH to 7.5-8.5.

Results and Discussion

1.Fourier Transform-Infrared Spectroscopy Analysis

4000 3500 3000 2500 2000 1500 1000 50084

86

88

90

92

94

96

98

100

T/%

Wavenumbers/cm-1

MF

SMF

the SMF shows enhanced characteristic peaks at

3349cm-1 and 1160cm-1, compared to MF, indicating

the effect of sucrose groups on the structure of SMF

resin.

Fig. 1

2. Mass Spectrum Analysis

LCW-HZF-SMF # 92-96 RT: 2.56-2.67 AV: 5 SB: 8 2.26-2.45 NL: 3.30E6

T: - c Full ms [ 50.00-2000.00]

150 200 250 300 350 400 450 500 550 600 650 700 750 800

m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

377.2

379.2

719.0

455.0

720.9404.1

215.2421.2

332.8176.0 264.1 278.1506.1 676.7590.5524.7

367.1 668.4 722.1621.8486.1 576.4 770.3

Fig. 2

Results and Discussion

O

HO O

OHHO

HOH2COH

CH2OH

HOH2C

OH

OH

O

The fragment from 719(m/z) to 377(m/z)

NH2

H2N NH2

The fragment from 234(m/z) to 108(m/z)

NH2

H2N NH

The fragment from 206(m/z) to 79(m/z)

N N

N

N

N

N

H2N

NH2

NH

NH

H2N

NH2

H2C

The fragment from 719 (m/z) to 455 (m/z)

O

HO

OHHO

-OH2CCH2O-

OH

O

HOH2C

OH

OH

O

The fragment from 719(m/z) to 379(m/z)

N

NN

NH

NH2

NH2

H2C

The fragment from 218 (m/z) to 79(m/z)

Fig. 3

Results and Discussion

The above analysis suggested that the SMF resin was

synthesized by the chemical condensation of melamine,

formaldehyde and sucrose. In addition, the main

covalent linkages between the monomers were ether

group and methylene group.

Results and Discussion

3. Bonding Strength Test

Fig. 4

Results and Discussion

Wood Failure Percentage (%) of SMF bonded Plywood in Bonding Strength Test

Mole ratio of S/M

0 0.2 0.4 0.6 0.8

F/M

1.8 80 60 60 30 10

2.0 80 50 60 40 10

2.2 100 80 70 40 20

The mole ratio of F/M is 1.8, 2.0, 2.2 and the wood failure

percentage is speculated according to Chinese standard of GB/T

17657-2013.

Results and Discussion

The bonding strength of the resins was reduced. As the S/M

ratio increases, the bonding strength of plywood decreases. A

turning point which meet the requirement of Chinese

standard of GB/T 17657-2013 (≥0.7MPa) of 0.4 S/M mole

ratio, 0.80 MPa, 0.86 MPa and 0.90 MPa, is shown in Fig. 4.

The incorporation of sucrose reduced the water resistant

(especially in boiling water) of the resin because of the

hydroxyl group of sucrose.

Results and Discussion

4. Shelf-Life test

0.0 0.2 0.4 0.6 0.80

10

20

30

40

50

60

70

80

90S

hel

f-li

fe/d

Mole Ratio of S/M

F/M=2.0

Fig. 5

Results and Discussion

0.0 0.2 0.4 0.6 0.80

10

20

30

40

50

60

70

80

90

Sh

elf-

life

/d

Mole Ratio of S/M

F/M=2.0

As the sucrose content increases, the shelf life increases

when the mole ratio of sucrose and melamine is

between 0 and 0.6. The longer shelf life of SMF may be

due to the efficient reaction of hydroxyl of sucrose and

the active groups-methylol of resin, so that the

crosslinking reaction of active groups of resin is

reduced.

Results and Discussion

5. Formaldehyde Emission test

0.0 0.2 0.4 0.6 0.80.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00F

orm

ald

ehy

de

Em

issi

on

/mg/L

Mole Ratio of S/M

F/M=2.0

F/M=1.8

Fig. 6

Results and Discussion

It is shown that different trends on the formaldehyde

emission vs. S/M ratios between the F/M 2.0 and F/M 1.8.

For the both F/M ratios, when the S/M ratio bellows 0.4,

increasing the sucrose content is beneficial to reducing

the formaldehyde emission. As the sucrose content

continues to increase, the formaldehyde emission

increases.

Results and Discussion

0.0 0.2 0.4 0.6 0.80.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

Fo

rmal

deh

yd

e E

mis

sio

n/m

g/L

Mole Ratio of S/M

F/M=2.0

F/M=1.8

It is equivalent to acknowledge an efficient reaction can be

coming true as the mole ratio of sucrose and melamine, 0.4.

Increased sucrose content could promote reaction of MF

resin and sucrose which will enhance the stability of chemical

bond of SMF resin to reduce the formaldehyde emission from

the degradation of ether.

Results and Discussion

A SMF adhesive that can be used indoor was synthesized by

the condensation of sucrose, melamine and formaldehyde.

An optimum sucrose to melamine mole ratio was found as

0.4:1, with a wet bonding strength of 0.90 MPa, formaldehyde

emission of 0.49 mg/L.

Compared with the MF adhesive, an improved performance

of shelf life was achieved.

SMF adhesives can be a potential alternative for environment-

friendly wood adhesive.

Conclusions

This work was financially supported by Natural Science

Foundation of China （ 31360158 ） , National Forestry

Industry Research Special Funds for Public Welfare

Projects(201004070) and Scientific and Technological

Development Projects of Guangxi Province(10100022-26,

1298025-11).

Acknowledgments

Investigating the synthesis mechanism of SMF resin by

building kinetic model of synthesis process

Investigating thermostability of SMF resin

Investigating the curing kinetics of SMF resin

Researching MMF (Maltose-Melamine-Formaldehyde) resin

Next work

蔗糖(左) 和麦芽糖（右）结构式The Structure of sucrose (left)and maltose (right)

2015-6-8