Book review: Specialty Thermoplastics

This book, Specialty Thermoplastics, is particularly timely given the ever-increasing demand for improved performance in so many new and existing applications throughout industry. These demands are often being driven by the need to save weight or withstand various environmental factors.

The work pulls together in one convenient volume a wealth of information on four main types of specialty plastics. These four polymer types are defined by the author as amorphous or semi-crystalline polymers that can withstand high temperatures, usually higher than 150 °C. The four are polyarylether sulfones (PAES), polyether imides (PEI), polyphenylene sulfide (PPS) and polyaryl ether ketones (PAEK). By the definition given, the four are also considered to be “high-temperature plastics”.

A chapter is dedicated to each of these polymer groups covering their producers and capacity, followed by their manufacture, processing, properties and applications. These are preceded by a very useful introduction, in which it is pointed out that at 220–240 ktpa the total usage is small compared to that of the commodity plastics (e.g. PE, PP, PS, PVC), and also to the engineering plastics (PA, PC, POM, PBT). However, they are much higher priced than both these two groups of products resulting in a market size of approximately USD 3bn.

Moreover, they are used in the automotive industry, aerospace, electrical and electronic, medical and many other industries in applications that cannot be met by other plastics or conventional materials. The introduction also describes the market volume of each of the four groups and details the producers, their location and capacity. 

In common with other parts of the plastics industry, theownership of some of these products, their plants and business have changed hands through acquisitions and divestitures. These changes are also described in the introduction.

The chapter on the PAES (polysulfone (PSU), polyether sulfone (PES) and polyphenylene sulfone (PPSU)) is the second most extensive (after that on the PAEK). It outlines the chemical structures of the monomers and subsequent polymers, followed by a description of the production methods. After outlining the processing techniques and conditions used, there is an extensive section on the properties of the polymers and their compounds. Much of the data relates to polymers made by Gharda Chemicals, the author having led the Gharda business in these products.

This section is followed by one showing typical applications for PSU, PES and PPSU. A number of these demonstrate the important property of transparency available with these amorphous materials.

This same format is used in the chapters on PEI, PPS and PAEK. Interestingly, as pointed out, while PEI was commercialized in 1982, there has until now been only one source, viz, Sabic (previously GEP). As reported in the book, this is about to change with Gharda Chemicals’ PEI plant coming on stream in India. 

After describing the chemistry of PEI and its manufacture, there is an extensive section on its properties. Under processing, there is a striking picture of a part manufactured by AM (3D printing) which demonstrates the complexity that can be achieved. In fact, throughout the book, while the main manufacturing processes of injection moulding and extrusion are well covered, other processes like AM, film production and fiber spinning are also described where appropriate.

PPS, described as having the largest sales volume at about 90–110 ktpa, is also the lowest priced polymer of those covered by this work. As pointed out, it differs from the other polymers in that for most uses it needs to be reinforced or filled to have useful mechanical and thermal properties. It is suggested that, including the filled compositions, the total volume might be as high as 150 160 ktpa.

The most extensive chapter is devoted to the PAEK group of polymers covering PEEK, PEK, PEKEKK and PEKK, and some other less commercially important polymers. The introduction gives an insight into the history of the development of these polymers by various companies. It outlines the early work carried out by Union Carbide and DuPont and the crucial part played by ICI in the development and commercialization of PEEK. This section also shows the present line up of PAEK products by today’s producers (and some discontinued ones) together with their key thermal properties. The chemistry of the manufacture of the PAEK products is well covered in the following section.

 Blends of PAEK products with each other are described, together with novel blends of PEEK with PBI and PEK with ABPBI. The more conventional, and more significantly commercial, blends with PTFE are also described, highlighting the enhanced wear and friction properties of these compounds.

The processing section for PAEK materials includes compounding, which for these semi-crystalline products is highly important, as the enhancement of mechanical and thermal properties is significant and a large proportion of the volume used is made up of compounds. 

The methods of 3D printing applicable to PAEK products are described with a number of examples including the remarkable cranial implant in PEKK (also shown on the cover).The properties of PAEK products is extensively covered as are the diverse applications.

The author is uniquely qualified for presenting this work as he has been instrumental in establishing the Gharda PAES and PEEK plants and managing the business (now part of Solvay). He now leads the Gharda polymer business, in establishing a PEK and PEKK plant and most recently doing the same for their PEIplant.

Technologists, whether with a polymer producer, compounder, OEM, or in academia concerned with these specialty thermoplastics, will find this book pulls together in one volume a wealth of data and information. Processors, for example, moulders, extruders, AM users and other convertors, currently handling these materials, or considering using them, will find this book very helpful.It will appeal to sales and marketing people with an interest in this sector of theplastics industry. This work is also applicable as a textbook for special courses on polymer science and engineering for graduate and undergraduate students.