Polymer/surface interface reaction

Penn, L.S., Tesoro, G.C. and Zhou, H.X. (1988). Some effects of surface-controlled reaction of Kevlar 29 on the interface in epoxy composites. Polym. Composites 9, 184-191. 

The basic theories of physics - classical mechanics and electromagnetism, relativity theory, quantum mechanics, statistical mechanics, quantum electrodynamics - support the theoretical apparatus which is used in molecular sciences. Quantum mechanics plays a particular role in theoretical chemistry, providing the basis for the valence theories which allow to interpret the structure of molecules and for the spectroscopic models employed in the determination of structural information from spectral patterns. Indeed, Quantum Chemistry often appears synonymous with Theoretical Chemistry it will, therefore, constitute a major part of this book series. However, the scope of the series will also include other areas of theoretical chemistry, such as mathematical chemistry (which involves the use of algebra and topology in the analysis of molecular structures and reactions) molecular mechanics, molecular dynamics and chemical thermodynamics, which play an important role in rationalizing the geometric and electronic structures of molecular assemblies and polymers, clusters and crystals surface, interface, solvent and solid-state effects excited-state dynamics, reactive collisions, and chemical reactions. 

Besides the classical Schottky contact, various surface mechanisms are known to influence polymer metal contacts. Band bending in metal/PPV interfaces is also discussed in terms of surface states or chemical reactions between the semiconductor and the metal [70-74]. An excellent review on conjugated polymer surfaces and interfaces is given by [129]. 

A method of covalently bonding heparin to a polymer substrate is presented. The synthetic route consists of coupling heparin covalently with polyisocyanatostyrene. This reaction was made possible by the fact that formamide is a room temperature solvent for sodium heparin and this allowed a liquid-solid interface reaction to take place. Lee-White clotting tests in vitro (in hydrogel tubes) showed these surfaces to be non-clotting after 24 hours whereas untreated controls and surfaces of GBH type clotted in approximately 25-35 minutes. 

The chapters in this volume present a concise overview of surface analytical techniques from the specific viewpoint of surface morphology and its modification at the polymer-metal interface. A consistent picture begins to emerge of the chemical reactions occurring on metal deposition and why this leads to metal adhesion. The coeditors hope this information will be timely and useful. 

The interface of metallized polymers has been considered from the points of view of the polymer surface, reaction during metal deposition and the effect of contaminant ions. Each is discussed in terms cf the critical factors which maintain the mechanical... 

The evolution and decomposition of metal clusters in the polysiloxanes has been quantified (49), and a diffusion-plus-reaction model for cluster growth at the surface and in the near subsurface region of a polymer film has been developed (SO). Collectively, the studies show that organometallic chemistry at the polymer/vacuum interface can have profound effects on both the dynamics of polymer chains at the surface and the evolution of low nuclearity clusters (SO, 51). 

New experimental results on specific polymer material problems are presented in the last nine chapters. Several cases involve the study of polymers from commercial sources. The topics include (1) surface chemistry as induced by (a) outdoor weathering, (b) chemical reactions, and (c) plasma exposure (2) chemical bond formation at the polymer -metal interface and (3)biomaterials characterization and relationship to blood compatibility. 

In the presence of catalysts, heterogeneous catalytic cracking occms on the surface interface of the melted polymer and solid catalysts. The main steps of reactions are as follows diffusion on the surface of catalyst, adsorption on the catalyst, chemical reaction, desorption from the catalyst, diffusion to the liquid phase. The reaction rate of catalytic reactions is always determined by the slowest elementary reaction. The dominant rate controller elementary reactions are the linking of the polymer to the active site of catalyst. But the selectivity of catalysts on raw materials and products might be important. The selectivity is affected by molecular size and shape of raw materials, intermediates and products [36]. 

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