Phenolic resins chemical aspects

This chapter reports work on two aspects of this adhesive system 1) tests on the strength of panels bonded with phenol/carbohydrate/urea/formaldehyde (P/C/U/F) adhesive compositions outside the ranges previously reported (9,10) and 2) analysis of chemical reactions in this resin system. 

The overall objective of this and a companion paper (22) is to define the extent to which board formaldehyde emission is controlled by resin hydrolysis or other processes. In the companion paper I have critically reviewed the literature and presented original Forest Products Laboratory (FPL) data in three related aspects of the formaldehyde emission phenomenon the chemistry of and formaldehyde liberation from formaldehyde-urea and formaldehyde-phenol states the chemistry of and formaldehyde liberation from formaldehyde-cellulose and resin-cellulose states and our knowledge of the board emission mechanism derived from actual board and wood systems. Whereas my oral presentation at the American Chemical Society (ACS) Symposium made use of information from all three of those parts, this written paper, in the interest of saving space, is limited to literature and FPL data dealing with actual wood-containing systems. The Conclusions section of this paper, however, makes use of the results from all three parts of the companion paper. Experimental details of the... 

As is the case with phenol-formaldehyde-type resins, the lack of detailed understanding of the reaction mechanisms and complete characterization of the complex polymeric products did not prevent the large scale utilization of furan based network polymers. In both instances, the synthetic chemistry and chemical technology aspects are far better understood than the physical and topological aspects of the solid systems [446, 464-466]. 

This area of adhesives technology is obviously where the polymer chemist plays a crucial role but a review of the basic chemistry of adhesives and of the formulation of adhesives is well beyond the scope of the present book. For such information the reader should consult references, such as Skeist s excellent Handbook of Adhesives [1] where these aspects are reviewed in detail for every imaginable chemical type of adhesive. There are also many specialized articles and chapters devoted to particular adhesive types such as those available on natural materials [2], solutions and latices [3], hot-melts [4], polyurethanes [5,6], phenolics [7], epoxies [8,9], acrylics [10,11], imide resins [12,13] and pressure-sensitive adhesives [14,15]. To translate from a particular chemical type of adhesive into a commercially available product reference may be made to the technical data sheets provided by the adhesives companies and to adhesive product directories, such as that produced by Shields [16]. 

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