Molecular weight influence, cohesion

The constant F also called the parachor by S.Sudgen (1924) is essentially a molecular volume modified to eliminate some of the influence of the cohesive forces which are different for different liquids. Parachor may be defined as the molar volume of a liquid at a temperature at which the surface tension is unity. Two liquids of molecular weight M, and having densities... 

It is unlikely that this branching analysis can be reliably applied to graft or to block copolymers because chain dimensions—from which branching indices are determined—are influenced by polymer-polymer and polymer-solvent interactions. The magnitude of the problem is indicated by published data that indicate that graft copolymers can exhibit an intrinsic viscosity, for the same molecular weight, which is not even intermediate between the two homopolymers [6, 7]. A fortuitous match of cohesive energy densities... 

Adhesion and cohesion of polyacrylate dispersions can be varied over a broad range and matched to many appHcations through the type and combination of low Tg ( soft ) and high Tg ( hard ) monomers, the choice of auxiharies, and the control of the molecular weight and process parameters [26-29]. Some examples are given below. The influence of glass transition temperature (Tg) of acrylic homopolymers on tack (according to A. Zosel [30, 31]) at various temperatures is shown in Fig. 8-2. 

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