Manufacturing and Novel Applications of Multilayer Polymer Films

Deepak Langhe, Michael Ponting

• Publisher: William Andrew
• Year: 2016
• Print ISBN: 9780323371254
• eBook ISBN: 9780323374668
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Manufacturing and Novel Applications of Multilayer Polymer Films discusses the advancements in multilayer technology, including its capability to produce hundreds of layers in a single film by a melt coextrusion process. These engineered films can have significantly enhanced performance properties, allowing films to be made thinner, stronger, and with better sealing properties. As recent developments in feedblocks and materials have opened up a range of new possibilities, this book discusses different feedblocks, and viscosity and material considerations. It is the first comprehensive summary of the latest technology in multilayer film processing and related applications, and is written from a practical perspective, translating research into commercial production and real world products. The book provides fundamental knowledge on microlayer coextrusion processing technology, how to fabricate such structures, structure and properties of such microlayers, and potential applications, thus helping research scientists and engineers develop products which not only fulfill their primary function, but can also be manufactured reliably, safely, and economically. - Provides a fundamental knowledge of microlayer coextrusion processing, including how to fabricate microlayer structures, the properties of microlayers, and potential applications, including optics, polymer film capacitors, and semiconductors - Includes an in-depth analysis of all technologies used for producing multilayered films and structures by coextrusion processing - Thoroughly assesses potential future trends in multilayer coextrusion technology, thus enabling engineers and scientists to stay ahead of the curve in this rapidly advancing area

1

Introduction to Multilayered Films

Abstract

Coextrusion process was developed to combine two or more polymers to achieve synergistic effects in the composite products. This chapter introduces the summary of various coextrusion-processing techniques for manufacturing multilayered films, sheets, or annular profiles. Many early feedblock designs were focused on producing layered composites primarily for packaging applications. The tubular and cast film coextrusion techniques, feedblocks, and die designs are discussed briefly in this chapter. The coextrusion technology progress toward multilayered films with hundreds or thousands of layers is also reviewed. In addition, different property enhancements and novel applications are also summarized.

Keywords

coextrusion

multilayered films

feedblock technology

layer multiplication

nanolayer films

microlayer films

1.1. Introduction

Development of polymer blends and composites rely on the synergistic combination of two or more materials to achieve enhanced properties. Frequently, it is necessary to use blend or composite structures because single polymer components may not meet the end use requirements. The final product properties are strongly dependent on several blend and material parameters including formulation, morphology, processing history, interactions between the components, and other intrinsic properties of the individual components. Structure–property relationships for polymer blends and composites have been reviewed and discussed previously [1]. Other approaches such as copolymerization, formulations with processing aids, compatibilizers, impact modifiers, and fillers have been employed to combine the polymers more effectively. One approach to combine the two or more polymers is coextrusion process that combines two or more polymers as a layered structure to achieve wide range of property improvements. Similar to blending, the coextrusion process also relies on achieving synergistic effects by combining polymers at different scales, however, adds an additional structural design freedom that offers control over the size and location of the constituent material domains.

For more than six decades, layered composites have demonstrated their importance in the commercial marketplace. Unlike many earlier technologies, which required multiple manufacturing steps to create multicomponent polymer-layered composites, the coextrusion process produces multilayer films using a single continuous processing step. This advantage reduces manufacturing complexities associated with other processing techniques such as multistep lamination and coating, which require separate handling of individual layers or plies. In contrast, the coextrusion processing allows simultaneous combinations of two or more polymer materials inside a die or feedblock to produce layered structures, thus eliminating the need for any postprocessing or repeated fabrication steps. In 1950s, many thermoplastic film applications were developed with only a few layers. The emergence of an advanced coextrusion processing technique enabling the fabrication of hundreds of thousands of multilayers in coextruded articles has recently led to capabilities and new breakthroughs in material properties and development. The ability to order multiple polymer materials on the micro- or nanometer size scale have led to improvements in many properties and the discovery of novel material properties that comprise the discussed technology and case studies of this text.

Many conventional packaging applications may contain only a few polymer layers (typically between two and seventeen) with diverse properties. Typical layered structure can contain as many as five to seven different polymers with varied material properties such as barrier improvement, chemical resistance, and sealability properties. In these applications, the individual layer thicknesses ranged from the millimeter size scale down to few hundreds of micrometers. In 1960s, the Dow Chemical Company developed the technology to c...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Preface
• 1: Introduction to Multilayered Films
• 2: Coextrusion Processing of Multilayered Films
• 3: Gas Transport, Mechanical, Interphase, and Interdiffusion Properties in Coextruded-Multilayered Films
• 4: Optical Properties of Multilayered Films
• 5: Dielectric and Electrical Properties of Multilayered Films
• 6: Novel Multilayered Structures and Applications
• 7: Future Trends
• Index