WOOD ADHESIVE EMULSIONS FROM THERMOSETTING POLYKETONE
Chemical Product Design and Engineering (CPD&E)
Chemical Product Design & Engineering - III (CPD&E - 3)
Keywords: wood adhesive, product design, polyketone
WOOD ADHESIVE EMULSIONS FROM THERMOSETTING POLYKETONE
Youchun Zhang , F.Picchioni, A.A.Broekhuis
Department of Chemical Engineering/Chemical Product Engineering,
University of Groningen, the Netherlands
Water based polymeric emulsions have found wide applications in recent years, especially in the wood adhesive industry due to the environmental restrictions on solvent based systems. Thermosetting polyketones, low molecular weight alternating CO-ethylene/propylene co-and terpolymers have been developed to non-toxic (formaldehyde-free) water based emulsions by the following steps (scheme 1.). The polymeric surfactants that have N-substituted 2,5-pyrrolediyl groups incorporated in the backbone were first synthesized by the Paal-Knorr reaction of the starting polyketone(Pk-I) with a diamine having a sterically hindered primary amino group. Next the newly synthesized surfactants were easily protonated with weak acid and dissolved into water for resin emulsification of a second quantity of polyketone(Pk-II). All these different processing steps can be carried out by a single one-pot process. The factors, influencing the stability and structure of the final emulsions (e.g. temperature, mixing speed, protonation level of the surfactants, the Pk-I/Pk-II ratio and the molecular weight of the Pk-II for emulsification), were thoroughly studied by determining the particle size and viscosity of the emulsions with respect to the storage time at room temperature (20°C). It was found that the emulsions showed extremely long pot life at room temperature and remained stable for at least 1 year. According to the European Standard (EN-314) for wood glue testing, the quality of the emulsions as glue for wood was evaluated by measuring the shear strengths on the applied maple substrates. Average shear strengths 2.7 MPa could be achieved, which far exceeded the requirement (1MPa) of the EN-314.
Presented Thursday 20, 09:33 to 09:52, in session Chemical Product Design & Engineering - III (CPD&E - 3).
