Interactions of Polymers with Bioactive and Corrosive Media

Description

Natural polymers have always been used in medicine. However, the development of synthetic polymers for use in medicine has occurred only in the last few decades. The successful applications of these synthetic polymers in medicine depend mainly on their physico-chemical and special characteristics such as biological compatibility with tissues, stability, durability and elasticity. This book deals mainly with the kinetic and structural aspects which are essential for the realization of these characteristics. The authors have examined in detail the processes of diffusion, chemical and biological diintegration, changes in various structural levels induced by chemical and biological media, and the problems of simultaneous influence of these media and mechanical strains on polymers used in medicine. Researchers in the field of polymer physics and chemistry, as well as those who are working with applications of polymers in medicine and biology should find this book useful Cover Half Title New Concepts in Polymer Science Interactions of Polymers with Bioactive and Corrosive Media Copyright Contents Introduction Preface Foreword 1. Kinetic Aspects of Polymer Interaction With Components of Aggressive Media 1.1 Introduction 1.2. Macrokinetic Correlations of The Chemical Degradation Processes 1.2.1. Internal Diffusion-Kinetic Zone 1.2.2. Internal Kinetic Zone 1.2.3. External Diffusion-Kinetic Zone 1.3. Degradation of Polymeric Materials of Inhomogeneous Structure 1.3.1. The Accessibility of Chemically Unstable Bonds in Polymeric Articles 1.3.2. The Reaction Capability of Chemically Unstable Bonds in Polymeric Articles 1.4. Physical Model of Polymeric Articles Degradation Process References 2. Water Diffusion in Polymer Systems of Different Hydrophilicity 2.1 Introduction 2.2. Water Sorption in Hydrophobic Polymers 2.2.1. The Condition of Henry’s Law Fulfillment 2.2.2. The Condition of Positive Deflection of the Sorption Isotherm From Henry’s Law 2.3. Water Diffusion in Hydrophobic Polymers 2.3.1. Diffusion With Cluster Formation Calculation. Formulation and Solution of the General Problem 2.3.2. Diffusion in Fluoroplasts. Partial Immobilization Model 2.3.3. Diffusional Transport, Complicated By Continuous Distribution of Sizes of Water Associates 2.4. Equilibrium Water Sorption in Hydrophilic Polymers 2.5. Water Diffusion in Hydrophilic Polymers 2.6. Water Diffusion in Moderately Hydrophilic Polymers References 3. Transport Processes in the System Polymer-Chemical (Biological) Medium 3.1 Introduction 3.2. Diffusion Features of Ionized Low-Molecular Compounds in Polymer Systems 3.2.1. The Henderson-Planck Approach 3.2.2. Constant Field Approach 3.3. Description of Multicomponent Diffusion in Polymers Through Thermodynamics of Irreversible Processes 3.4. Theories Describing the Connection of Diffusion Coefficients of Medium Components With Volume Contents in Polymers 3.5. Electrolyte State in Polymer 3.5.1. Ions Hydration 3.5.2. Electrolyte Dissociation 3.5.3. Electrolyte Influence on Conformational Behaviour of Macromolecules 3.5.4. Influence of Macromolecular Chemical Structure on Diffusion 3.5.5. Electrolyte Action on Polymer Morphology 3.5.6. Acid Sorption Causing Structural Transition in the Crystalline Phase 3.5.6.1. Version A 3.5.6.2. Version B 3.5.6.3. Version C 3.5.7. Crosslinking Influence on Diffusion 3.6. Surface Phenomena Complicating Diffusion Process 3.6.1. External Mass Transfer Influence on Diffusion in Polymers 3.6.2. Influence of Features of Polymer Structural Organization 3.6.3. Dependence of Surface Concentration on Time 3.6.4. Equilibrium Electrolyte Sorption References 4. The Role of Diffusion Processes Under Controlled Release of Biologically Active Substances From Polymer Therapeutic Systems 4.1 Diffusion Controlled Therapeutic Systems 4.2. The Influence of Solvent Diffusion on the Rate of Release of Medicinal Substance 4.3. Diffusion Polymer Systems of Special Purpose 4.3.1. Flow Regulation by Changing the Distance Between Macrochains 4.3.2. Permeability Regulation Through Liquid Crystal Structure Formation 4.4. Erosive Therapeutic Systems 4.4.1.1. Metabolite Formation 4.4.1.2. Capsule Formation 4.4.1.3. Enzyme Activity Influence References 5. Diffusion and Adsorption of Plasma Proteins — the Processes, Characterizing Initial Stage of Polymer-Blood Interactions 5.1. The role of primary adsorption and diffusion of proteins in the general scheme of polymer-blood interaction 5.1.1. Diffusion-Convective Model 5.1.2. Transmission Electron Micrograph 5.1.3. Haemorheological Model 5.2. Thermodynamic Aspect of Protein Adsorption 5.3. Surface Energy of Polymers and Plasma Protein Adsorption 5.3.1. Surface Topography of Polymers 5.4. Structural Aspect of Plasmic Protein Adsorption 5.5. Medium Acidity Influence on Protein Adsorption 5.6. The Kinetic Aspect of Adsorption 5.7. The Diffusive-Kinetic Model of Protein Adsorption on Polymer Surface 5.7. The diffusive-kinetic model of protein adsorption on polymer surface References 6. Polymer Biodegradation: Kinetics and Mechanism 6.1. Primary reactions of the body to polymer objects 6.2. Medium Components Responsible for Polymer Degradation 6.3. Classification of Resolvable Polymers 6.3.1. Soluble Polymers 6.3.2. Polymers Decomposable via Non-Specific Hydrolysis 6.3.3. Enzymatically Decomposable Polymers 6.3.3.1. General Approach 6.3.3.2. Ways of Controlling Resolution Rate of Enzyme-Splitable Polymers 6.3.4. Dissociating Polymer-Polymer Complexes (PPC) 6.3.5. Resolvable Polymer Types 6.4. Uses and Resolvability Estimates 6.4.1. Surgical Sutures 6.4.2. Coats for Wounds and Burns 6.4.3. Osteosynthesis Pins 6.4.4. Resolvable Polymer Compositions for Filling Internal Canals and Cavities and For Use as Artificial Blood Vessels 6.4.5. Coats for Medical Pills and Tablets 6.4.6. Biologically Active Resolvable Polymers 6.4.7. Medical Adhesives 6.4.8. Biodegradable Materials as Medicine Depots 6.4.9. Drug Release Rate From the Resolvable Polymer Matrix 6.4.9.1. LMS Molecules in the Main Chain of the Polymers 6.4.9.2. LMS Molecules Attached to Side Chains of Dissolved Polymer 6.4.9.3. Medicine Encased in a Resolvable Polymer Shell 6.4.9.4. Drug Uniformly Distributed in the Resolvable Polymer Matrix in the Form of a Solid Solution 6.5. Rough Estimates of Resolvability and Resolution Times According to Model Experiments 6.6. Kinetic Regularities of Drug Release by Biodegradable Polymers 6.6.1. Degradation in Solid Polymers and Solutions Compared 6.6.2. Solid Polymer Degradation 6.6.3. Degradation of Drug-Containing Polymers in Solution 6.6.4. Kinetics Specialities of Drug-Delivery Polymer Degradation 6.7. Conclusion References 7. Degradation and Medico-Biological Estimation of Polymers in Biological and Model Chemical Media 7.1 Introduction 7.2. Macrokinetic Features of Degradation and Medico-Biological Estimation of Fast Destroyable Polymers 7.2.1. Degradation of Collagen Materials in Model Media 7.2.2. Physico-Chemical and Medico-Biological Estimation of Collagen Haemostatics 7.3. Regularities of Disintegration of Long Lived Polymers, and Their Effect on a Living Organism 7.3.1. Polyethyleneterephthalate in Model Media and in the Living Organism 7.3.2. Carbon Composite Materials’ Behaviour in Model Media and Living Organism References 8. Mechanical Reliability of Polymers in Physical, Chemical and Biological Media 8.1 Introduction 8.2. The Estimation of Mechanical Reliability of Polymers in Aggressive Media 8.3. Polymers in Physically Active Aggressive Media 8.3.1. Physical-Mechanical Effect 8.3.2. Mechanical-Physical Effect 8.4. Polymers in Chemically Active Media 8.4.1. Chemomechanical Effect 8.4.1.1. The Influence of the Degradation Occurring in the External Diffusive-Kinetic Zone on the Mechanical Properties of Polymers 8.4.1.2. Degradation of Bulky Polymer and Mechanical Properties 8.4.2. Mechanochemical Effect 8.4.2.1. The Influence of Mechanical Stress on Polymer Degradation Occurring in External Diffusive-Kinetic Zone 8.4.2.2. The Influence of Mechanical Stress on Reaction Rate for Degradation Occurring in a Bulky Sample 8.5. Polymers in biologically active Media 8.5.1. The Action of Biological Medium on the Mechanical Properties of Biological Tissues 8.5.2. The Influence of Biological and Model Chemical Media on Mechanical Properties of Polymer Substitutes of Biological Tissues 8.5.2.1. Kinetic Changes of Lavsan (PET) Endoprosthesis of Tendons and Cords Under the Influence of Organism Internal Medium and Biological Stresses 8.5.2.2. In Vitro and Ex Vivo Investigations of the Cords From Carbonic Fibres 8.5.2.3. Carboplastics Application in Traumatology and Orthopaedics Subject Index