Polyester hydrolytically aged

Crystallinity in Hydrolytically Aged Polyester Polyurethane Elastomers... 

V. Bellenger, M. Ganem, B. Mortaigne, and J. Verdu, Lifetime prediction in the hydrolytic ageing of polyesters. Polymer Degradation and Stability, 49(l) 91-97,1995. 

Pinel, B. A methodology to predict the Ufe duration of polymers used in nuclear power stations. Industrial needs and their approach. Nucl. Instrum. Methods B 151,471-476 (1999) Bellenger, V., Ganem, M., Moitaigne, B., Verdu, J. Lifetime prediction in the hydrolytic ageing of polyesters. Polym. Degrad. Stab. 49, 91-97 (1995)... 

Van Schoors, L.V., 2007. Hydrolytic aging of polyester (polyethylene terephthalate) geotextiles state of the art assessment. Bulletin des Laboratoires des Fonts et Chaussdes 270, 271. 

Foams prepared from phenol—formaldehyde and urea—formaldehyde resins are the only commercial foams that are significantly affected by water (22). Polyurethane foams exhibit a deterioration of properties when subjected to a combination of light, moisture, and heat aging polyester-based foam shows much less hydrolytic stabUity than polyether-based foam (50,199). 

Furthermore, while being hydrophobic, polyester when subjected to high humidity for long periods loses strength through the hydrolytic degradation of its polymer backbone whereas the hydrophilic nylons do not suffer from this property and so have superior ageing characteristics. 

Due to the hydrophobic nature of the cyclohexylene unit, the polyesters based on 1,4-CHDM are more hydrolytically stable than those others made from aliphatic glycols as neopentyl glycol or 2-butyl-2-ethy 1-1,3-propanediol (115). The effect of annealing and aging in water on the properties of amorphous PE CjuT were studied by Golovoy et al. (116). The annealing treatment induced... 

Table 5.111 shows the compression strength for PUR foams as a measure of aging under the influence of temperature and humidity. Humidity at increased temperatures leads to a reduction in compression strength of polyester foams caused by hydrolytic processes. Polyether-based PURs are largely resistant. 

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