Effect of Absorbed Water

As nylons absorb water, their electrical properties deteriorate. Their performance as insulators declines and they become more susceptible to energy dissipation in alternating fields. 

An undesirable effect of the hygroscopic nature of nylons is that we must take care that they are dry before trying to process them in the molten state. If we were to attempt to extrude wet nylon, the water would vaporize within the extruder, creating bubbles in the melt. The result would be a non-uniform extrudate containing voids and exhibiting an uneven surface texture. 

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Table 4. Effect of Absorbed Water on the Mechanical Properties of the TGMDA—DDS System ...

Figure 19.9. Effect of absorbed water on the dimensions of acetal homopolymer resins ( Delrin ). (Du...

Weinhold, S., The Effect of absorbed water on the crystallization rate of PET from the glass, presentation given at the Polyester 97 World Congress, Maack Business Services, 8804 Au/near Zurich, 3-5 November, 1997. 

Shamblin, Sh.L., Zografi, G. The effect of absorbed water on the properties of amorphous mixtures containing sucrose. Pharm. Res. 16,1119-1124,1999... 

K. B. Armstrong, Effect of absorbed water in CFRP composites on adhesive bonding. Int. J. Adhes. Adhes., 16(1), 21-28 (1996). 

K. Mazur. Effect of absorbed water on same properties of PMMA. ZN WSI Zielona Gdra 94 69(1992). 

The rate of diffusion of water in an adhesive is important if water can displace the adhesive from its substrate, or if there is appreciable solubility, for this determines its rate and pattern of saturation. Where the adherend itself absorbs moisture, as does wood, the rate of diffusion through the adhesive from one adherend to the other may be of importance in minimizing stresses arising from incipient dimensional changes. A full account of the method for calcidating the pattern of distribution of water in an adhesive joint is given by Althof (1981) and also by Comyn (1981). Both these authors also consider the effect of absorbed water and the pattern of its distribution on the properties of the joint. The maximum stresses in a lap-shear joint are at the ends of the overlaps and, of course, since here in one of the boundary surfaces for the entry of moisture the moisture first attains moisture equilibrium at the position of maximum stress. This results in a reduction of the... 

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