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Emerging Science Journal-5- Mechanical Properties of Modified Resins122-386-1-PB (1)3-5- Mechanical Properties of Modified Resins
As shown in Table 3; Conductivity, the ion exchange property was observed in Sulfonated PF resin. The gelation
time of the phenolic resole decreases with increase in the F/P molar ratio. This is due to the progressive increase in the
methylol groups as the amount of formaldehyde increases. The increase in the number of methylol groups speeded up
the crosslinking reaction and resulted in an early attainment of the gel point [9].
The TSC is seen to remain almost
constant for resins with various F: P molar ratios. Variations in the TSC lead to a decrease or increase in the dimensions
of the castings. Thermal stability was analyzed by gel time. If the gel time increases, the thermal stability proportionally
increase. Boron and lignin modified PF resoles were more thermally stabilized than virgin PF resole.
Table 3.
The variation of physical properties Table for modified resins
Property
Phenol Formaldehyde
resole (PF)
Boron modified PF
resole (BPFR)
Sulfonated PF resole
(SPFR)
Lignin modified PF
resole (LPFR)
Conductivity (mS/cm)
0
0
121
0
TSC (total solid content) %
52.72
55.32
42.31
48.45
Gel time (sec.)
472
1072
2008
842
Swell percentage (%)
20
15
31
25
4- Conclusion
Modified resins were prepared for improve mechanical properties.
Acacia
sp lignin was effectively suited for the
modification of PF resin with the effective environmental control. The
Acacia
sp lignin based resin has similar
characteristics as observed for the virgin phenol-formaldehyde resin. FTIR study displays that lignin-PF resin interaction.
Lignin modified resin found to be a highly thermally stabilized than virgin PF resin as the gel time of LPFR is higher
than virgin PFR. Rather than that, the lignin based resin showed increased heavy metal adsorption capacity. PF resins
used in timber industrials as their excellent wetting and heat resistance, thus there are some limitations due to expenses
and hazardous. Hence, the modifications with biomass are essential to overcome these limitations. This could be efficient
alternative for the PF resin with the eco-friendly manner and due to bearing strength. Moreover, Lignin based phenolic
resins suggested to install in the heavy metal polluted areas to adsorb pollutants as an environmental friendly manner.
And also LPFR suggested using in wood industries as eco-friendly Bonding glue. The use of boric acid as a modifier in
Phenol Formaldehyde resin leads to decrease the free monomers and increase the solid mass, which leads to produce
smooth resin surface without causing cracks and bubbling. Boric acid modification resulted non-toxic resin compositions
and increase in thermal resistance so their flammability becomes smaller. Boron modified resins suggested to use in
burning products, electrical goods manufacturing field.
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