Thermoelasticity of Acrylic Copolymers in Simple Shear

A New Analytical and Experimental Approach To Rubber Thermodynamics

“…In the vast majority of these efforts, the authors start with the statistical theory of rubber elasticity, which is based on the assumption of ideal rubber behavior (i.e., pure entropy). Yet when the same relations are manipulated according to thermodynamics, an energetic term is revealed. − …”

“…Yet when the same relations are manipulated according to thermodynamics, an energetic term is revealed. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] The Maxwell relations can be manipulated to yield an expression for the relative energy contribution, f e /f, resulting from isothermal deformation as where f e ) (∂U/∂L h (T)) T,V h (T) , U is the internal energy, L h (T) is the deformed length of the sample, and f is the force. 30 One can rewrite eqs 13 and 14 in terms of the force as 14) which is the same as our result when m ) 1.…”

“…Considerable effort has been devoted to using the statistical theory to establish the entropic and energetic contributions resulting from thermomechanical deformation, and several reviews on these results have been written. − By using a thermodynamic approach, several researchers have used this theory to calculate a nonzero term for the internal energy contribution to the stress resulting from isothermal deformation. ,,− ,, This result violates one of the basic assumptions of the statistical theory. One purpose of this paper to establish that this nonzero term is merely an artifact of an improper temperature reference state.…”

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] By using a thermodynamic approach, several researchers have used this theory to calculate a nonzero term for the internal energy contribution to the stress resulting from isothermal deformation. 6,10,[13][14][15][16]18,19 This result violates one of the basic assumptions of the statistical theory. One purpose of this paper to establish that this nonzero term is merely an artifact of an improper temperature reference state.…”

Thermoelastic properties of chemical copolymers

“…(l), there are a number of errors in both sign and magnitude apparently introduced elsewhere in their analyses. 5 The value of fe/fT = d In(rz),/dT resulting from their own study8 of an ethylene-propylene copolymer should be 0.13 X lov3 deg-1, and not the cited6 value, -0.13 X deg-1. The result obtained for polyethylene from the thermoelastic study by Flory and co-workers' is -1.1 X deg-1, and not 0.11 X deg-1.…”