Polyester damage analysis

The high frequency of stains as a manifestation of damage was mentioned in Section 8.3.2. The reasons for the occurrence of stains are very numerous. Several examples of stain analysis were described in Section 8.4.4 and the typical method of approach in Section 8.3.5. LoffeT has also described the comparative selective extraction of stains with subsequent identification, preferentially with TLC and IRS. In Section 8.4.3 details of TLC analysis of stains caused by grease and oil or polyester carriers are presented. In Section 8.4.4 information is given on the identification of silicone stains and fluorocarbon deposits using IRS. The detection of silicones with fluorescence microscopy is described in the literature. ... 

Fourier transform infrared (FTIR) analysis of the damaged epoxy suggested that phthalate linkages in the 934 epoxy resin had been disrupted, probably by nucleophilic attack by hydroxide ions in the high pH environment. (Resin 934 includes 11.2% diglycidyl orthophthalate to lower the viscosity and improve fibre wet-out). Note that most marine grade polyesters are based on phthalic acid precursors as major constituents, and thus are likely to be even more prone to this form of degradation than epoxies when within cathodically protected systems. 

Beltran J F, Williamson E B (2011) Numerical procedure for the analysis of damaged polyester ropes , Eng Struct, 33, 1698-1709. 

Norwood LS, Marchant A (1981) Recent developments in polyester matrices and reinforcements for marine applications, in particular in polyester/kevlar composites. In Marshall IH (ed) Composite structures. Applied Science Publishers, New York, pp 158-181 O Brien TK, Raju IS, Garber DP (1986) Residual thermal and moisture influences on the strain-energy release rate analysis of edge delamination. J Compos Technol Res 8 37 7 Ogi K, Takao Y (1998) Effect of moisture on stress-strain response and damage evolution in quasi-isotropic laminates. J Jpn Soc Compos Mater 24(l) 20-29 Ogi K, Kim HS, Maruyama T, Takao Y (1999) The influence of hygrothermal conditions on the damage processes in quasi-isotropic carbon/epoxy laminates. Compos Sci Technol 59 (16) 2375-2382... 

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