Preface

**Thermosoftening Plastics** are polymers that can be manipulated into different shapes when they are hot, and the shape sets when it cools. If we were to reheat the polymer again, we could re-shape it once again. Modern thermosoftening plastics soften at temperatures anywhere between 65°C and 200°C. In this state, they can be moulded in a number of ways. They differ from thermoset plastics in that they can be returned to this plastic state by reheating. They are then fully recyclable because thermosoftening plastics do not have covalent bonds between neighbouring polymer molecules. Methods of shaping the softened plastic include: ınjection moulding, rotational moulding, extrusion, vacuum forming, and compression moulding.

Additionally, the large amount of plastics produced and consumed in several areas of everyday life, together with their low biodegradability and short use have resulted in enormous waste amounts of these materials. Thus, **polymer recycling** is more than imperative. Several recycling methods have been presented in literature, aiming for the recovery of monomers or other secondary value-added materials as well as for converting polymeric wastes into fuels or energy. Therefore, in this book, methods for recycling of thermoplastic polymers are included, together with potential uses of the recycled materials.

This book shows three areas of thermosoftening plastics, thermoplastic materials, and the characterization of them, as well as some elements of recycling thermoplastics, together with their applications.

This book comprises six chapters. First chapter covers composition and processing conditions of plastic lumber and their characterizations. The second chapter shows a new screw design to facilitate phase to phase thermal and molecular mobility for polymer plasticization. The third chapter describes the controlled radical polymerization for cellulose based thermoplastics and elastomers. The fourth chapter presents the properties, modifications, and applications of thermoplastic recycling. The fifth chapter highlights thermal resistance properties of polyurethanes and its composites. The final chapter shows the morphological, mechanical, thermal and environmental studies of recycled polypropylene-coffee husk and coir coconut biocomposites.

We would like to take this opportunity to thank all the researchers who have made direct contributions to the writing of this book. Also, we would like to thank all the editorial members of IntechOpen, in particular, Mrs. Dajana Pemac, author service manager, for her effective editing and support during different stages of the production of this book.
