Microfliuidics to measure wetting properties of untreated/chemically treated steel and wood strands substrates

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Traditionally, formaldehyde based resins were used for manufacturing of engineered wood products (EWP)however the industry is shifting to the use of polymeric diphenylmethane diisocyanate (pMDI) binding resins.This shift is due to both the safety concerns with the use of formaldehyde, but also due to the significantadvantages with the use of pMDI including: reduced concentration and cost; fast curing; increased panelperformance through the formation of strong chemical bonds; increased strength and water resistance.However, there is a drawback limiting the use of pMDI due to its superior adhesive properties which requiresthe application of effective release agents (RA). RA prevents the sticking of the produced boards to the pressplates/belts resulting in downtime, costly cleaning and production losses. Guardian has previously developed aseries of Pressguard RA for pMDI bonded composite wood products which are protected by patents. Whilesuccessful, recent industry trends such as increased press temperatures as well as competitive market pressurerequires that we renew our research efforts in this field to regain lost market share and address the changingpress operating conditions. Development of efficient RA requires in depth understanding of their physicalproperties and wetting/adhesive interactions with the involved solid substrates, including stainless/mild steeland wood strands. The main objective of this joint project is to use microfluidic channels along with real-timehigh resolution microscopy to identify and measure the key physical properties that govern the adhesion/releasebetween hot metal plate and composite wood panels manufactured with pMDI resins. The experimental schemeincludes determination of dynamic surface tension, dynamic contact angles of pMDI resins, water, silicone oiland proprietary release agent (RA) blends. Microfluidic channels will be designed and fabricated in an attemptto act as micromodels to mimic the absorption of liquids in the wood porous structure. Different coating agentswill be used to change hydrophilicity/hydrophobicity of the channels to systematically study the effects ofsubstrate wettability on dynamic contact angle and capillary flow.