Science and Technology of Polymers and Advanced Materials

Applied Research Methods

Omari V. Mukbaniani, Tamara N. Tatrishvili, Marc J. M. Abadie, Omari V. Mukbaniani, Tamara N. Tatrishvili, Marc J. M. Abadie

• Publisher: Apple Academic Press
• Year: 2019
• Print ISBN: 9781774634387
• eBook ISBN: 9780429757594
• Edition: 1
• Topic: Sciences physiques
• Subtopic: Physique

Increasing interest in lightweight and high-performance materials is leading to significant research activity in the area of polymers and composites. One recent focus is to develop multifunctional materials that have more than one property tailored as to the specified design requirements, in addition to achieving low density. The possibility of simultaneously tailoring several desired properties is attractive but very challenging, and it requires significant advancement in the science and technology of high-performance functional polymers and composites.

This volume presents a selection of new approaches in the field of composites and nanomaterials, polymer synthesis and applications, and materials and their properties. Some composites/nanocomposites and interfaces are explored as well, some with medical applications. The authors also look at simulations and modeling, synthesis involving photochemistry, self-assembled hydrogels, and sol-gel processing.

PART I
Composites and Nanomaterials

CHAPTER 1

Chemistry of the Interfaces/Interphases in Composites and Nanocomposites

MARC J. M. ABADIE

Institute Charles Gerhardt of Montpellier Aggregates, Interfaces, and Materials for Energy (ICGM-AIME, UMR CNRS 5253), University of Montpellier, Place Bataillon, 34095 Montpellier Cedex 5, France, E-mail: [email protected]

ABSTRACT

Fiber reinforced polymer composites (FRPCs) are still an emerging class of engineering materials as well as nanofiller (NF) reinforced polymer nanocomposites (NFRPNCs). In polymer composites or nanocomposites, the interface/interphase is a key issue of which depends on the performance of the materials, but not for the same reason.

For the composites, the interface/interphase is a key issue since it guarantees the necessary stress transfer from the matrix (weak part) to the reinforcement (strong part). In the nanocomposites, the main issue is the homogeneous dispersion of the NF into the matrix due to its nano size and low wt.% used (1–5 wt.%); therefore, a good control of the interface/interphase will strongly help in the homogeneity and guarantee performance of these materials.

After defining interface/interphase in such materials, we will describe the recent progress in chemical treatments of inorganic fillers (glass, clay, POSS) as well as organic fillers (aramid, GFs, CFs & NFs: CNFs, CNTs, graphite, GOs).

SEM for composites, TEM, and XRD analysis for nanocomposites will be discussed in order to control the performance properties of both composites and nanocomposites.

1.1 INTRODUCTION

Chemistry has been the driven force for the development of high-performance polymer composites and new materials [1, 2]. Polymeric materials have been developed to fulfill the requirements imposed by constraints of high tech products such as lightweight, toughness, high-temperature resistance, oxidative thermal stability, low shrinkage, high modulus, etc. [3, 4].

If polymers were developed since the beginning of last century, composites appeared to emerge in the 60s mainly for the aerospace conquest first and then applied to all sectors of advanced technologies. Since the discovery made by the engineers of the carmaker Toyota loading polyamide with nano-fillers (NFs) as clay, the drastic improvement observed in the mechanical and barrier properties. This new field is considered as emergent and so-called nanocomposites [5].

1.2 COUPLING AGENT [6–8]

Glass fibers are the only fibers that can commonly be modified on the surface by chemical treatment, so-called coupling agent. This surface treatment is done online during the process of fabrication of the fibers. Generally, it is a water emulsion of a coupling agent that is spread on the surface of the fibers.

The role of the coupling agent is to link the reinforcing agent and matrix by covalent bonds that give higher mechanical properties to the composite (Figure 1.1).

FIGURE 1.1Interface/Interphase in a composite.

It is important to underline that the coupling agent depends on the matrix used and will be different if we use unsaturated polyester (UP) or vinylester (VER) and epoxy (EPR) resins.

The coupling agent is principally constituted by two parts: one polar side (for glass fiber) in contact with reinforcement agent and having at the other end a chemical function that matches with the matrix considered. A general formula is X₃Si (CH₂)_nY, where X is a methoxy or ethoxy group and Y the chemical function adapted to the matrix used; i.e., acrylate for UP and VER, epoxy or amine for EPR (Figure 1.2).

FIGURE 1.2 (See color insert.) Interaction of the coupling agent with matrix and reinforcement agent.

Table 1.1 describes some coupling agents currently used in the industry under spray solution during manufacturing continuous filaments.

TABLE 1.1 Industrial Coupling Agents and Compatibility with Resins: Unsaturated Polyester Resins UPR, Vinylester Resins VER, and Epoxy Resins EPR

1.3 HOW TO DEFINE INTERFACES/INTERPHASES [9]

A composite is mainly constituted by three parts: the matrix which is the weak part of the composite, the reinforcement agent which is the strong part of the composite, and the interface/interphase of the composite on which depends the toughness and the integrity of the material.

For nanocomposite, the problem is the same in term of composition (nanofiller dispersed in an organic phase, interface/interphase) but due to the nanosize of the filler and its low percentage (1 to 5 wt.%) into the organic phase, the homogeneous dispersion of the nanofiller is crucial with regards to the mechanical performance.

When a composite is submitted to any force, the first part receiving that force is the matrix-envelope of the composite. As the matrix is the weak part of the composite, forces have to be transferred to the strong part of the composite ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• About the Editors
• Table of Contents
• Contributors
• Abbreviations
• Preface
• PART I: Composites and Nanomaterials
• PART II: Polymer Synthesis and Application
• PART III: Materials and Properties
• PART IV: Constitutional Systems for Medicine
• Index