https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 12 Apr 2026 19:25:44 GMT 2026-04-12T19:25:44Z http://hdl.handle.net/10985/8276 Crosslink Density Changes during the Hydrolysis of Tridimensional Polyesters GILORMINI, Pierre; COQUILLAT, Marie; VERDU, Jacques; RICHAUD, Emmanuel The hydrolysis of almost ideal networks based on macrodiols of average molar mass about 2 kg mol 1, with L¼18 ester groups per chain is studied. Tensile testing is used to evaluate the crosslink density through the statistical theory of rubber elasticity at two temperatures and three values of relative humidity. A kinetic model for ester consumption including an autocatalysis term is proposed and combined with two original approaches for modeling the crosslink density changes. This allows kinetic parameters of hydrolysis to be determined, and very good predictions are obtained for the variations of crosslink density (or elastic modulus) in the three aging conditions considered. The initial curvature of elastic modulus versus time is predicted positive for weak autocatalysis and negative for strong autocatalysis. The obtained conversion ratio at degelation is found to decrease sharply with the number of esters per elastically active chain Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8276 2014-01-01T00:00:00Z GILORMINI, Pierre COQUILLAT, Marie VERDU, Jacques RICHAUD, Emmanuel The hydrolysis of almost ideal networks based on macrodiols of average molar mass about 2 kg mol 1, with L¼18 ester groups per chain is studied. Tensile testing is used to evaluate the crosslink density through the statistical theory of rubber elasticity at two temperatures and three values of relative humidity. A kinetic model for ester consumption including an autocatalysis term is proposed and combined with two original approaches for modeling the crosslink density changes. This allows kinetic parameters of hydrolysis to be determined, and very good predictions are obtained for the variations of crosslink density (or elastic modulus) in the three aging conditions considered. The initial curvature of elastic modulus versus time is predicted positive for weak autocatalysis and negative for strong autocatalysis. The obtained conversion ratio at degelation is found to decrease sharply with the number of esters per elastically active chain http://hdl.handle.net/10985/9634 Platicizer effect on network structure and hydrolytic degradation DERUE, Isabelle; GILORMINI, Pierre; VERDU, Jacques; VAULOT, Cyril; COQUILLAT, Marie; DESGARDIN, Nancy; VANDENBROUKE, Aude; RICHAUD, Emmanuel The hydrolytic degradation of fully cured polyester-urethane networks polymerized in the presence of several weight ratios of triacetin was monitored by the residual concentration in elastically active chains obtained from modulus and equilibrium solvent swelling measurements. The presence of triacetin does not change the water uptake but induces a lower rate of degradation. Comparisons were performed with networks in which triacetin was removed before ageing, and with networks in which polyester-urethane was first polymerized and then impregnated by triacetin. Data suggest that the presence of triacetin during polymerization induces the presence of elastically inactive chains such as dangling chains, loops… the hydrolysis of which does not change the elastic properties of the network. This explanation was checked from relaxation measurements by n.m.r and d.m.a, and by the analysis of the soluble fraction generated by hydrolysis. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9634 2015-01-01T00:00:00Z DERUE, Isabelle GILORMINI, Pierre VERDU, Jacques VAULOT, Cyril COQUILLAT, Marie DESGARDIN, Nancy VANDENBROUKE, Aude RICHAUD, Emmanuel The hydrolytic degradation of fully cured polyester-urethane networks polymerized in the presence of several weight ratios of triacetin was monitored by the residual concentration in elastically active chains obtained from modulus and equilibrium solvent swelling measurements. The presence of triacetin does not change the water uptake but induces a lower rate of degradation. Comparisons were performed with networks in which triacetin was removed before ageing, and with networks in which polyester-urethane was first polymerized and then impregnated by triacetin. Data suggest that the presence of triacetin during polymerization induces the presence of elastically inactive chains such as dangling chains, loops… the hydrolysis of which does not change the elastic properties of the network. This explanation was checked from relaxation measurements by n.m.r and d.m.a, and by the analysis of the soluble fraction generated by hydrolysis.