A series of tetrapolyesters were obtained by polymerizing phloretic acid, hydroquinone, p‐hydroxybenzoic acid, or its derivatives, that is, vanillic acid or syringic acid, and dodecanedioic acid. Each monomer was polymerized in its acetylated form, except for the diacid to undergo polymerization by acidolysis. Initial polymerizations had shown that the use of phloretic acid resulted in better polymer properties than with p‐coumaric acid. The predominantly renewable polymers were obtained by melt polymerization using a two‐stage condensation process whereby antimony(III) oxide was applied as catalyst. Monomer conversions were typically close to 90%. 1H and 13C NMR, DSC, TGA, solution viscometry, and GPC were applied, as well as polarized microscopy to determine polymer microstructure and composition, transition temperatures, decomposition temperatures, intrinsic viscosities, and other molecular weight properties, and when applicable the liquid crystalline behavior of the polymers. All peaks, including end group peaks in the 13C NMR spectra were assigned, the monomer sequence distribution was verified to be random, and a complete dyad analysis involving nine dyads and eight peaks was performed. By using p‐hydroxybenzoic acid and its derivatives without any, one or two methoxy groups and varying the copolymer compositions, melting temperatures could be tuned between 106 and 181 °C. The tetrapolyesters, which included residues of p‐hydroxybenzoic acid, formed nematic liquid crystals. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1498–1507

Full encirclement repair sleeves with fillet-welded ends are used as a permanent repair on pipelines to reinforce areas with defects such as cracks or corrosion which may penetrate the pipe wall subsequent to the installation of the repair. CSA standards require that these sleeves be tapped to relieve the stress field surrounding the defect unless an engineering assessment indicates that the defect will not extend beyond the ends of the sleeve during future operation of the pipeline. This paper describes an engineering assessment recently completed to establish the relative performance of a sleeved pipe with and without a pressurized annulus. Finite element analysis (FEA) was used to relate changes in stresses in the weld region to internal pressure fluctuations. The FEA included an estimate of the effects of circumferential fillet weld shrinkage on local stiffness due to residual stress fields. Relationships between stress and internal pressure were used to convert the line pressure history to local weld stress fluctuations. This stress history was then used to assess the potential for fatigue crack propagation of possible circumferentially-oriented weld flaws using a fatigue crack growth algorithm. The results showed that the highest stresses were developed in the weld toe and root regions. The operating conditions of the line, as well as the pipe and sleeve dimensions, were considered when making recommendations concerning sleeve tapping.