Showing papers in "Transactions of The Faraday Society in 1944"

Stress-strain data for vulcanised rubber under various types of deformation

Abstract: Stress-strain data are given for two types of vulcanized rubber: (1) an 8% S rubber, and (2) a latex rubber. The types of deformation studied were simple elongation, 2-dimensional extension (or compression), pure shear, and combined elongation and shear. Comparison with the theoretical relations based on the molecular-network model shows the agreement to be good for the 2-dimensional extension, but less good for simple elongation and shear. The effect of combined elongation and shear is satisfactorily accounted for. It is concluded that the theory provides a satisfactory explanation of rubberlike elasticity, and forms a useful basis for the description of the mechanical properties of rubber subjected to large deformations of any type.

The melting of crystalline polymers

Abstract: The thermodynamic equilibrium which exists between crystalline and amorphous polymeric phases is discussed in terms of a fringed micelle model, as indicated by x-ray data. An expression derived for the melting point of a crystalline polymer is found to depend on the proportion θ of amorphous material in the structure: this unsharp melting point depends ultimately on a nonlinear relationship between θ and the free energy of the system. Calculated values of the crystalline amorphous equilibrium ratio over a range of temperature are in good agreement with experimental data. An attempt has been made to extend the calculations to the case of stretched polymers and a qualitative agreement has been found. This work has been carried out in the Department of Colloid Science, Cambridge, and we should like to thank Professor E. K. Rideal for much stimulating criticism. This paper arose out of discussions with Professor Sir R. H. Fowler: his advice and encouragement during its development have been invaluabl...

The interaction between rubber and liquids. V. The osmotic pressures of polymer solutions in mixed solvents

Abstract: An expression is obtained for the free energy of dilution of a ternary mixture of polymers + two liquids by one of the liquids. This is used to consider the osmotic equilibrium between a solution of a polymer in a mixture of two liquids, and a second phase containing only the two liquids. It is shown that the osmotic behavior of the ternary solution is very similar to that of a polymer in a single liquid, and in particular that van't Hoff's law holds at infinite dilution. The distribution of the two liquids between solvent and solution is also calculated. The experimental difficulties involved in the use of mixed solvents are discussed.