2 research outputs found
Synthesis and Characterization of Biobased Melamine Formaldehyde Resins from Bark Extractives
In this study, bark alkaline extractives
from the mountain pine
beetle (<i>Dendroctonus ponderosae</i> Hopkins) infested
lodgepole pine (<i>Pinus contorta</i> Dougl.) was used to
partially replace 30 wt % of melamine in formulating the biobased
bark extractive–melamine formaldehyde (MF) resin. Results showed
that the addition of the bark extractives and the type of solvent
system used for resin formulation significantly affected the initial
molecular weight, molecular structure, viscosity, curing behavior,
postcuring thermal stability, and bonding performance of the resulting
resins. The bark extractive–MF resins exhibited similar dry
and wet bonding strengths to the laboratory made control MF resins
formulated in the same type of solvent system. The liquid-state <sup>13</sup>C NMR study showed that bark extractives were reactants and
incorporated into the resulting biobased MF resin structures. Bark
extractives obtained from the mountain pine beetle infested lodgepole
pine showed promise as a suitable partial replacement for melamine
in MF resin formulations
Characterization of Modified Phenol Formaldehyde Resole Resins Synthesized in Situ with Various Boron Compounds
In this study, three
different boron compounds were used together
with alkaline catalyst to synthesize phenol formaldehyde (PF) resole
resins in situ. The resin curing behavior, molecular structure, bonding
performance, and properties of resin-impregnated wood were investigated.
Results showed that boron compound-modified PF resins had a lower
degree of polymerization than the control PF resin made in the laboratory.
The curing kinetics, molecular structure, and functional groups of
the modified resins varied depending on the type of boron compounds
used. The thermal stability of cured modified PF resins was slightly
lower than that of laboratory-made control PF resin. Boron compound-modified
PF resins exhibited dry and wet bonding strengths comparable to the
those of the laboratory-made control PF resin. Wood impregnated using
modified PF resins had comparable dimensional stability, mechanical
properties and improved fire resistance than the wood impregnated
using lab made control PF resin regardless the type of boron compounds
used