Degradation process of an industrial thermoplastic elastomer polyurethane-coated fabric in artificial weathering conditions

Abstract

ABSTRACT:The aging of an industrial thermoplastic elastomer polyurethane (TPU)-coated fabric, based on a polyether diol and an aromatic diisocyanate, is studied in artificial weathering tests. It is noticed that the degradation of this TPU-coated fabric leads to a weight loss, to the formation of a reticulated layer in sample surface, and to a change of surface relief. The degradation layer and the surface relief have been observed by optical microscopy. The weight loss has been followed with aging time. The main degradation products causing weight loss are volatile. Therefore, they have been analyzed by gas chromatography-mass spectroscopy. The weight loss degradation takes place in the exposed part of the reticulated layer by volatile products emission, which implies the urethane and the polyether bonds. Water is involved in degradation process: without external water supply, weight loss is limited; with a permanent contact of vapor or liquid water, the weight loss rate is constant and depends on aging conditions.

Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties

“…Monte Carlo predictions and/or diffusion front advance may be incorporated into this low frequency approximation. To a first order, the loss of coating thickness (or weight per unit area) [30,31] is linear with exposure time. Thus, for the ablation film thickness loss at a rate K 1 (in units of thickness/time), we can write a simple expression for film thickness as function of exposure time.…”

Different photodegradation processes of PVC with different average degrees of polymerization

“…It is widely recognized that PVC photodegradation is a very complex process due to the coexistence of two presumably sharply inter‐related chain reactions: zip dehydrochlorination and oxidation 9. Zip dehydrochlorination leads to the formation of long, conjugated polyene sequence (CHCH) n in the polymer chains, which give the red‐brown color of degraded 12. Photoelimination creates Cl radicals that are able to initiate oxidation chains.…”

Weathering of Compounded Products

“…The two structural elements of coated fabrics [193][194][195][196][197][198] perform a variety of different roles in coated fabrics (see Table 16.2). Many coated fabrics are used outdoors, some in very demanding conditions, where they are exposed to intensive radiation, winds, and stresses.…”

“…Table 16.2 shows that there are many requirements which differ between fabric and coating. 196,198 There is a substantial increase in weight loss in the presence of water. To do this, the coating is designed either to reflect (using reflective pigments having a higher gloss) or to absorb radiation (by increasing the thickness of the layer).…”