Phenol-formaldehyde resin mechanical strength

The impregnation of PF (phenol-formaldehyde) resin into wood was studied in the early part of the twentieth century. PF resin wood composites have been commercialized as Impreg and Compreg for their high mechanical strength and dimensional stability. Although the enhancement of decay resistance by PF resin treatment was also found earlier [1], it has not been applied to wood preservation techniques for the prevention of biodeterioration. 

The enzyme-catalysed isomerization of D-glucose to D-fructose has attracted a good deal of attention, particularly with the availability of immobilized forms of D-glucose isomerase. The properties of D-glucose isomerase attached to a phenol-formaldehyde resin have been carefully studied the immobilized enzyme possesses sufficient mechanical strength to stand up to the pressures of column flow, is active over broad ranges of temperature and pH, and is not so dependent on Mg + and 00 + ions for activity. An active immobilized form of D-glucose oxidase is also produced by precipitation of the enzyme with concanavalin A this form could be reused without appreciable loss of enzymic activity. ... 

The leading expert on the mechanical properties of bulk polymers, R. Houwink of Phillips, presented a paper on Strength and Modulus of Elasticity of Some Amorphous Materials. Houwink also published a series of books on mechanical properties of polymers. The interchange in the discussion between Mark and Houwink emphasized the need for polymer scientists to be at the forefront of thinking in their area of expertise. Even if the experiments were well done, there is a need for a consistent conceptual scheme to interpret them. The discussion also heralded the appearance of N.J.L. Megson of the British Government Laboratory at Teddington. He discussed the stmcture and properties of phenol-formaldehyde resins. 

Surface oxidation processes have also been used as pretreatments for improving the bonding strength of adhesives. Brink et al. [9] reported that the wet bonding strength of plywoods or particleboards manufactured using phenol formaldehyde increased after pretreatment of wood with nitric acid. Mari et al. [10] also reported that nitric acid oxidation reduced the amount of isocyanate resin adhesive required to manufacture particleboard and improved the mechanical properties and biological resistance of boards. 

The first realised kind of fibre-reinforced composites was in form of preforms where fibres, unidirectionally aligned or weaved or processed in one or another way, were impregnated by epoxide, phenol formaldehyde or imide resins. As mechanical strength of materials in fibrous form is usually one order of magnitude higher than... 

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