Emerging Science Journal
|
Vol. 3, No. 2
Page | 105
Table 1.
Characterization of phenol-formaldehyde resoles modified by boric acid
Properties of the resin
Amount of modifiers (mol)
0
0.3
0.5
0.8
Solid mass content, (wt. %)
62.0
95.0
92.0
89.0
Free formaldehyde content, (wt. %)
2.50
0.25
0.20
0.16
Free phenol content,(% )
6.3
1.5
1.8
2.1
Curing temperature, (°C)
160
172
130
130
According to the Figure 2,
the typical absorption band of Ar-CH
2
-OH observed at 1039 cm
-1
, modified resin shortened
the peak compare to virgin. B-O absorption peak was appeared at 1362 cm
-1.
. The main bands are in agreement with the
bands coming from boron and the alcohol. The region at 3381 cm
-1
shows characteristic bands for-OH group of alcohol
and acid. Boric acid (B-OH) has a strong and characteristic band at 1515 cm
-1
.
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