Advances in Urethane

Science & Technology, Volume XIII

Kurt C. Frisch, Daniel Klempner

• Publisher: CRC Press
• Year: 2021
• eBook ISBN: 9781000448467
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

This book presents the reports on the developments in the field of urethane. It includes information on polyurethane automotive carpet composites, pentane blown polyurethane foams, and applications of polyols derived from renewable resources in polyurethanes and liquid crystalline polyurethanes.

Synthesis and Structure-Property Relationships of Polyurethane Hydrogels

E. HASCHKE

Busak+Shamban, Inc.
2531 Bremer Drive
Fort Wayne, IN 46803, U.S.A.

G. HILL

Vistakon-Johnson & Johnson Vision Products, Inc.
5985 Richard Street
Jacksonville, FL 32216, U.S.A.

V. SENDIJAREVIC, S. WONG, AND K. C. FRISCH

Polymer Institute, College of Engineering and Science
University of Detroit Mercy
4001 West McNichols Road
Detroit, MI 48221, U.S.A.

ABSTRACT

Polyurethane hydrogels are utilized in a variety of applications including soft contact lenses, controlled release devices, semi-permeable membranes, and hydrophilic coatings. In order to prepare hydrophilic polyurethane materials of specific water absorption, light transparency, and mechanical properties, the formulation parameters of the polyurethane elastomers which control these properties must be understood. Polyurethane hydrogels based on polyether polyols, cycloaliphatic diisocyanates, and trifunctional, hydroxy-terminated crosslinkers were prepared using both solution and bulk polymerization methods. The effects of the chemical structure of the glycol, diisocyanate, cross-linker, and chain extender on the water absorption, mechanical properties, and optical clarity of the hydrogels were investigated. The crosslink density of the polyurethanes was varied by changing the molecular weight and concentration of the crosslinker, as well as the molecular weight of the poly(oxyethylene) and poly(oxypropylene) soft segments. The theoretical $${\overline{M}}_c$$

values were calculated from the polyurethane formulation. The experimental values of the $${\overline{M}}_c$$

were determined by compression modulus measurements of the polyurethane hydrogels. The interaction parameter, χ and solubility parameter, δ, for the different structures of polyurethanes with water were determined using the experimental values of the $${\overline{M}}_c$$

. The experimental values for δ were confirmed by swelling of the hydrogels in formamide and in methanol.

INTRODUCTION

Hydrogel Types and Applications

HYDROGELS ARE POLYMERS CHARACTERIZED BY THEIR HYDROPHILICITY and insolubility in water. Hydrogels swell to an equilibrium state in water, but retain their shape due to the elastic restoring force of the polymer network.

Although the term “hydrogel” usually refers to a synthetic, water-swelling polymer, there also exist many natural hydrogels...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• PU Automotive Carpet Composites for Vehicle Interior Noise Control: Physical Basis of Behaviour
• Pentane Blown Polyurethane Foams
• Applications of Polyols Derived from Renewable Resources in Polyurethanes
• p-Phenylene Diisocyanate Based Polyurethane Elastomers
• Urethane Elastomers/Liquid Crystalline Polyurethane Blends
• Liquid Crystalline Polyurethanes
• Synthesis and Structure-Property Relationships of Polyurethane Hydrogels
• Recycling of Polyurethane Polymers