A method of rapid determination of thermal expansion and apparent second-order transition temperature of polymer films

1966 ◽  
Vol 6 (2) ◽  
pp. 112-116 ◽  
Author(s):  
Edwin C. Rothstein ◽  
Daniel Spechler
Keyword(s):  
Thermal Expansion ◽  
Transition Temperature ◽  
Polymer Films ◽  
Rapid Determination ◽  
Second Order ◽  
Order Transition ◽  
Second Order Transition

Ideal Copolymers and the Second-Order Transitions of Synthetic Rubbers. I. Noncrystalline Copolymers

1953 ◽  
Vol 26 (2) ◽  
pp. 323-335 ◽  
Author(s):  
Manfred Gordon ◽  
James S. Taylor
Keyword(s):  
Thermal Expansion ◽  
Transition Temperature ◽  
Small Molecules ◽  
Second Order ◽  
Order Transition ◽  
Kinetic Measurements ◽  
Practical Applications ◽  
Second Order Transition ◽  
Binary Copolymers ◽  
General Reduction

Abstract Theoretical and practical evidence is put forward to show that copolymers can be treated like solutions of small molecules in the interpretation of packing phenomena, and that ideal volume-additivity of the repeating units in copolymers is frequently realized. On this basis equations are derived for predicting θ, the second-order transition temperature, of binary copolymers from the two second-order transition temperatures of the pure polymers and their coefficients of expansion in the glassy and rubbery states. Previous mechanistic theories of the second-order transition temperature of such copolymers are thus superseded by a general reduction of the problem to the mechanism of thermal expansion. Practical applications to the choice of monomers in producing synthetic rubbers are outlined, and attention is drawn to the importance of second-order transitions in kinetic measurements on the reactions of polymers.

Thermal Expansion Measurements and Transition Temperatures, First and Second Order

1959 ◽  
Vol 32 (4) ◽  
pp. 1005-1015
Author(s):  
Mark L. Dannis
Keyword(s):  
Thermal Expansion ◽  
Transition Temperature ◽  
Physical Properties ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Second Order ◽  
Rate Of Change ◽  
Order Transition ◽  
Abrupt Changes ◽  
Second Order Transition

Abstract When any pure material goes through a change in state, its physical properties change greatly. In each phase the physical properties are relatively constant or change slowly enough with temperature that the rate of change of a property such as volume is a constant. This rate of change of volume is the thermal expansion coefficient, (∂V/V)/∂T. The thermal expansion coefficient is almost constant, experimentally, as long as the temperature range over which measurements are made does not include a phase transition. At the transition temperature, abrupt changes in volume are found as illustrated in Figure 1. Polymeric materials often show changes in physical properties not necessarily accompanied by abrupt changes in volume, even though the expansion coefficient does change. Since the expansion coefficient changes, some change in internal structure is suspected, and the name second-order transition (Tg) has been adopted. This kind of change is roughly diagrammed in Figure 2. This latter change at the second-order transition temperature can be found in every known polymer, even though many polymers possess clear, first-order, crystalline transitions as well. Hevea rubber, for example, has a crystalline melting point of 28° C, compared to its Tg about −70°. These data are shown, copied from Boyer and Spencer, as Figure 3.

Refractometric Determination of Second-Order Transition Temperatures in Polymers. IV. Butadiene-Acrylo-Nitrile Copolymers

1949 ◽  
Vol 22 (2) ◽  
pp. 402-404 ◽  
Author(s):  
Richard H. Wiley ◽  
G. M. Brauer
Keyword(s):  
Low Temperature ◽  
Linear Relation ◽  
Second Order ◽  
Order Transition ◽  
Copolymer Composition ◽  
Transition Temperatures ◽  
Second Order Transition ◽  
Refractometric Determination ◽  
Acrylonitrile Copolymers

Abstract A previous study of the low-temperature properties of a series of vulcanized butadiene-acrylonitrile copolymers indicated an approximately linear relation between composition and brittle temperature. This study provides information relating low-temperature properties to copolymer composition for a series of industrially available butadiene-acrylonitrile copolymers of varying acrylonitrile content. The refractometric technique for determining second-order transition temperatures (Tm) as previously described was used to determine Tm.

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