Surface energetics, polymer

For example, the increment in maximum stress over the neat polymer is 100% and 53% in the case of the unmodified- and the modified-clay-fiUed samples, respectively. The extraordinary results obtained with the unmodified clays were explained with the help of thermodynamics and surface energetics. They explained it as follows. 

The characteristics of particulate filled polymers are determined by the properties of their components, composition, structure and interactions [2]. These four factors are equally important and their effects are interconnected. The specific surface area of the filler, for example, determines the size of the contact surface between the filler and the polymer, thus the amount of the interphase formed. Surface energetics influence structure, and also the effect of composition on properties, as well as the mode of deformation. A relevant discussion of adhesion and interaction in particulate filled polymers cannot be carried out without defining the role of all factors which influence the properties of the composite and the interrelation among them. 

Although a number of filler characteristics influence composite properties, particle size, specific surface area, and surface energetics must again be mentioned here. All three also influence interfacial interactions. In the case of large particles and weak adhesion, the separation of the matrix/ filler interface is easy, debonding takes place under the effect of a small external load. Small particles form aggregates which cause a deterioration in the mechanical properties of the composites. Specific surface area, which depends on the particle size distribution of the filler, determines the size of the contact surface between the polymer and the filler. The size of this surface plays a crucial role in interfacial interactions and the formation of the interphase. 

The surface energetics that control wetting are largely related to the general chemical composition of the epoxy polymer molecule. However, the surface tension of an epoxy... 

Schonhorn, H., and Sharpe, L., Surface Energetics, Adhesion, and Adhesive Joints II, Journal of Polymer Science PartB Polymer Letters, vol. 2, no. 7, 1964, p. 719. 

Tn recent years, developing interests in surface energetics and adhesion of liquid-like polymers, or polymer liquids, have prompted both theoretical and experimental work on surface tension. Unlike low molecular weight liquids, polymer liquids have not been extensively studied. Bondi and Simkin (1) mentioned surface tension in their study on high molecular weight liquids. Roe (28) applied both the cell theory of polymer liquids and the hole theory of surface tension of simple liquids to develop an approximate theory of surface tensions of polymer liquids. His approach has met some degree of success. Notably, both Bondi s and Roes work are somewhat related to the cell theory introduced by Prigogine and... 

Paper wettability by polystyrene based toner has been studied by Lee (3). Wax/polymer coating of paper and paperboard has been investigated by Swanson and Becher (4), Glossman (5 ), and more recently by Fredholm and Westfelt (60. In the coating studies it was believed that surface energetics of the paper structure played a fundamental role in the spreading process and subsequent adhesion of polymer to the paper surface. 

Although the surf ce energy is probably not the only parameter which determines the state of adsorbed FN, it does appear to be important. An understanding of how surface energetics effect the interaction of FN with polymer surfaces would be an important contribution in the areas of cell growth and the interaction of blood proteins with synthetic polymers. 

Fracture Energetics and Surface Energetics of Polymer Wear... 

Since the first review on the effect of surface energetics on polymer friction and wear published in 197, (0 many new works have appeared. Some of these papers(2- ) are on fracture mechanics. In this paper we shall review our current knowledge about both fracture energetics and surface energetics of polymer wear. First, we discuss wear mechanisms and then emphasize these two aspects related to each wear mechanism. 

In comparison with metals, most conventional polymers are low in wear resistance. For wear control, we need to understand various wear mechanisms for each polymer system (V). As discussed in a previous paper, for adhesive wear, surface energetics can determine the extent of surface wear. Thus, a low surface energy is preferred to minimize the surface attrition. In addition, a harder polymer is desired to lower the wear rate. For abrasive wear, fracture energetics become important a harder and tougher material should be more wear resistant. 

They are capable of providing insight into the presence or absences of transfer (wear), the adhesive strength of polymer to metal, amount of transfer, bond scission, mechanical effects such as loading of surfaces together, chemical effects on bonding and surface energetics. The field ion microscope coupled with the atom probe is the ultimate tool for the study of polymer wear because it allows... 

Baler, R.E. and Meyer, A.E., "Surface Energetics and Biological Adhesion," Proceedings, International Symposium on Physlochemical Aspects of Polymer Surfaces (K. L. Mittal, ed.) Plenum Press, NY, 1982. 

Since the energetic interactions between polymer segments are very similar to those between small molecules, the statistical mechanics of a polymer surface is rather similar to that of small-molecule liquids. The role of connectivity is minor and a theory of polymer surface tension can be constructed in the spirit of van der Waals, which is rather successful at predicting the observed surface tension of polymer melts. This is at first sight slightly surprising, for it must be the case that the presence of a surface imposes a serious perturbation on the conformation of a nearby chain. Both the theory of these conformational effects and experiments to measure them are in a rather rudimentary state, but we discuss what is known, together with the even more uncertain area of the effect of surfaces on polymer dynamics. 

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