Properties of compression‐molded plates made from wood powders impregnated with liquefied wood‐based novolak‐type phenol‐formaldehyde resins

Abstract

Novolak-type phenol-formaldehyde (PF) resins with solution form were prepared by reacting phenol-liquefied Cryptomeria japonica (Japanese cedar) wood with formalin in the presence of methanol. Wood powders of Albizzia falcate (Malacca albizzia) impregnated with these resins were air dried followed by an oven-dried at 60 C. DSC analysis showed the PF resin existing in wood powders could be melted, and could be cured if hexamine was mixed and heated at high temperature. Compressionmolded plates made with PF resin impregnated woods had a high degree of curing reaction. However, compressionmolded plates hot-pressed at 180 C for 8 min or 200 C for 5 min had better internal bonding strength and dimensional stability than others. Premixing hexamine with PF resin and impregnating into wood powders simultaneously could enhance the reactivity of PF resin, but it was not useful for improving the properties of compression-molded plates.

New Approach to Oil Palm Trunk Core Lumber Material Properties Enhancement via Resin Impregnation

“…Comparing the microwave dried impregnated OPTCL to Rubber wood still a large gap for impact strength is observed. 24 This big gap is attributed to the brittleness of the PF resin which has been fully loaded in the OPTCL.…”

Synthesis and Characterization of Phenol Formaldehyde Novolac Resin Derived from Liquefied Mountain Pine Beetle Infested Lodgepole Pine Barks

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22] The liquefied wood-based novolac resins were reported to have a higher viscosity, a higher flow temperature than the commercial novolac resins. [9][10][11][12][13][14][15][16] The novolac resin made from oxalic acid-catalyzed phenol liquefied wood was found to follow an autocatalytic mechanism in the curing process. [11,12] However, there were few systematic studies on the effects of the type of acid catalysts on the properties of the liquefied biomass and the resulting liquefied biomass-based novolac resins.…”

“…The phenolated biomass material with molecular structures highly resembling novolac (Figure ) could be used directly as a novolac resin or it could be further reacted with formaldehyde under acidic condition to form thermoplastic resins without hydroxymethyl group in the molecular structure . Previous studies have shown that the molding products made from novolac resins containing phenol liquefied biomass materials including wood, bark, waste paper, lignin, and so on had comparable mechanical properties to those made from the commercial novolac resins. The liquefaction conditions, such as catalyst type and catalyst loading level, affected the liquefaction yield and properties of the liquefied products .…”

“…The liquefaction conditions, such as catalyst type and catalyst loading level, affected the liquefaction yield and properties of the liquefied products . Molecular characteristics and end‐use properties of the resulting novolac resins such as curing behavior, thermal stability, and melting temperature could be significantly affected . The liquefied wood‐based novolac resins were reported to have a higher viscosity, a higher flow temperature than the commercial novolac resins .…”

“…Molecular characteristics and end‐use properties of the resulting novolac resins such as curing behavior, thermal stability, and melting temperature could be significantly affected . The liquefied wood‐based novolac resins were reported to have a higher viscosity, a higher flow temperature than the commercial novolac resins . The novolac resin made from oxalic acid‐catalyzed phenol liquefied wood was found to follow an autocatalytic mechanism in the curing process .…”