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13
Biodegradable Polyester-Based Blends and Composites:
Manufacturing, Properties, and Applications
Raj Das and Kariappa M. Karumbaiah

13.1
Introduction

Sustainability, eco-efficiency, and green chemistry are controlling the devel-
opment of the next generation of materials. With a strong emphasis on
environmental awareness, the development of biodegradable composite mate-
rials has received considerable attention in the past two decades. Consumer
demands, as well as environmental legislation in many countries, are guiding
manufacturing processes to develop environmental-friendly products. The eco-
logical impact of a product is not only determined by the materials opted but also
by the in-service usage and disposal/recyclability of the product itself. Composite
materials have become a vital part of modern material systems. Significant
research and development efforts are underway to incorporate biodegradable
materials into novel composites. This blends traditional advantages of composites
(e.g., lightweight, high specific mechanical, and functional properties) with
biodegradability and sustainability. In a specific instance, when fiber-reinforced
composites are used in vehicles as a replacement for metals, the ecological impact
in the use phase will be reduced owing to lower energy consumption as a result
of lower car weight. The impact on the environment in the disposal phase of
the composites, however, has highlighted the hazardous nature of some of the
composite constituents, leading to an adverse influence on the environment. In
addressing this problem, biodegradable polymers play a vital role in realizing
either partially or fully biodegradable composite materials.
The degradation of polymer composites occurs mostly through scission of the
side chains or main chains of polymer molecules, caused by their oxidation, ther-
mal activation, radiolysis, photolysis, or hydrolysis. Several polymer composites
undergo degradation in organic environments when living cells or bacteria are
present around the polymers, and such atmospheres include soils, rivers, seas,
and lakes on the earth as well as within the body of animals and human beings.
In this context, biodegradable polymers are defined as those which are degradable
in these biological environments through enzymatic or nonenzymatic hydrolysis
(rather than through photolysis, thermal oxidation, or radiolysis). Polymers that

Biodegradable Polyesters, First Edition. Edited by Stoyko Fakirov.
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2015 by Wiley-VCH Verlag GmbH & Co. KGaA.