Making progress in polymers

Materials World magazine
10 May 2019

Polymers are changing, with developments focused on meeting our high demands while also addressing major global challenges in waste and recycling. IOM3 Polymer Society Divisional Board Chair, Stuart Patrick, discusses some ongoing projects.

With roots going back to 1921 for rubber and 1931 for plastics, the Plastics and Rubber Institute (PRI) came together in 1975 and subsequently joined the Institute of Materials in 1993.

Now called the Polymer Society, it exists to support the plastics and rubber/elastomer supply chain by providing a focus for improving knowledge exchange around education, production, processing, applications and end-of-life.

Externally, we are the polymer face of the Institute, linking with industry, trade associations, government, UK innovation and learning infrastructure, media and conference organisations and other relevant national and international bodies, to encourage and support professional membership of the Institute.

The core of the society is built around three long-standing and successful groups – PVC, Rubber in Engineering (RIEG) and Polymer Processing and Engineering (PPEC).

Polyvinyl chloride

The PVC Committee organises the triennial PVC Conference and Education Initiatives, which educate people on, and promote, particular aspects of polymers and materials.

Polyvinyl chloride (PVC) is composed of two simple building blocks – chlorine, based on common salt, and ethylene from natural gas. By employing further chemistry based on many different additives, PVC can be made flexible, rigid or semi-rigid, clear or pigmented, and thick or thin. Formulations of this highly versatile plastic material can be adapted to satisfy standards and regulations for specific applications, such as building codes, food contact, medical and fire resistance.

Combining durability and strength with being lightweight and low maintenance, rigid applications cover water and sewage pipes, window frames, guttering and ducting. In a flexible format the sheer range of applications spans blood and intravenous fluid bags, tubing and surgical gloves for medical use, to flooring, and insulation and sheathing for low-voltage power supplies, telecommunications, and automotive applications. Further, it can be used as a coating for materials such as tarpaulins and leisure products like garden hoses and footwear.

PVC is incredibly useful but the main issue for the sector has been achieving closed-loop recycling at end-of-life through Vinyl 2010 – the Voluntary Commitment by the European PVC Industry, which was set out in 2002. The target for PVC recycling has grown since its initial proposal and currently stands at 800,000 tonnes a year, according to the latest 2011 version. Other targets include reducing organochlorine emissions, safe transportation of vinyl chloride monomer and reducing emissions from resin production plants, the sustainable use of additives, energy and raw materials, and improving sustainability awareness. Balancing the production of PVCs while meeting these targets requires ongoing efforts from the sector.

A current project supported by the British Plastics Federation’s (BPF) VinylPlus UK group and facilitated through the Materials and Design Exchange (MaDE) is the design competition PVC Reuse, which encourages the community to create innovative ideas for reuse of PVC construction products. By bridging the gap between the design and construction industries, it aims to ensure products are installed with intelligent design, so that at end-of-life they can be extracted and reused.

Educational projects have included a partnership with the Royal Institution of British Architects (RIBA), contributing to a lecture series around UK universities and colleges entitled Design through Production by highlighting Polymers for Architectural Design – a partnership with the BPF for a unique new online PVC resource for students of architecture and building industries through RIBA’s President’s Medal Student Awards, setting up a resource at the Thackray Medical Museum in Leeds, UK. The exhibit, Fantastic Plastics, aims to increase public understanding of the role of medical plastics, in particular PVC, and the issues surrounding them. The interactive exhibit enables users to experience first-hand use of medical plastics in a surgical context.

Industrial rubbers

RIEG was formed as part of the Institute of Rubber Industries more than 60 years ago with the principal aim to promote understanding of the behaviour of rubber from an engineering perspective. It is fitting that 2019 commemorates the 200th anniversary of Thomas Hancock’s pioneering work with natural rubber in London, UK. After his early attempts to find a suitable solvent failed, he used his knowledge of machines and experience as a skilled toolmaker to develop a mechanical method of processing rubber.

The industry is facing ever-increasing performance requirements for engineered rubber products such as tyres, anti-vibration mountings, hoses and seals. As simple examples, the trend of weight reduction in transportation applications or the trend for increasingly demanding higher and lower operating temperatures for seals in the oil and gas sector have made it ever more difficult to meet service life requirements. At the same time, elastomeric components are required to last longer because of increased warranty periods offered for vehicles and engineered devices. In the tyre industry, the conflicting demands of weight reduction and reduced rolling resistance coupled with increased abrasion resistance and wet and dry friction performance also make the tyre designer’s role more difficult.

RIEG continues to bring practicing engineers together to explore how best to exploit the extraordinary properties of rubber materials effectively. RIEG also allows industry and academia to showcase the latest developments in materials and their uses to promote discussion and cross fertilisation of ideas, to ultimately expand their use across the sector.

For example, advances in curing chemistry can lead to more effective ways of processing elastomers so they can be used more efficiently, e.g. platinum cured silicones are ideal for injection moulding due to the rapid cure times. It may lead to better fluid resistances or thermal stability so it can be used in more extreme situations.

Ways of measuring changes in materials can be applied from one use to another, for example, looking at the change in electrical properties over time may be a way of condition monitoring an inaccessible component or the changes with applied load can be used to make sensors for smart applications.

Novel fillers like nanotubes and graphene convey interesting properties on polymer materials such as large changes in stiffness, strength and electrical properties. Work is exploring how they can be translated into rubber applications to produce smaller, cheaper, more durable products with better performances.

Polymer processing

PPEC is one of the original PRI Committees running since the 1970s, covering developments in polymer processing technology, in-process measurements and process flow modelling and control and provides a technical focus and networking for the processing and technology industries.

PPEC has formed a part of the Polymer Society original board, and has close links with leading edge processing technologies, modelling of process and structure, design and properties of polymer and polymer composites. It is also emphasising related pharmaceutical and biological materials in line with multidisciplinary progress in modern materials and products.

Established in 1985, Design Innovation in Plastics is now the longest running student plastics design award in Europe, set up to encourage plastics design innovation and best practice in our future product designers. Organised by IOM3 through the Polymer Society and the Worshipful Company of Horners, Design Innovation in Plastics is sponsored and supported by market leaders in the fields of design and innovation.

Over the background of the marine pollution crisis which focused attention on the disposable nature of single-use plastics that has, unfortunately, encouraged littering across the world – particularly where there is no infrastructure for collecting waste and recyclable materials – the 2019 design brief aims to redress the balance, exploring latest initiatives related to the circular economy with zero waste requirement, where everything is valued and nothing is wasted.

This will encourage the long-lasting and performance benefits from well-designed plastic products.

Another initiative, Healthy Body - Healthy World - The Benefits of Plastics in the Modern World, challenges participants to produce a design on the theme of improving health, well-being or encouraging exercise. The circular economy model will have a significant effect on the polymer and packaging sectors by encouraging the concept of reuse after the end-of-first-life, repurposing materials for reuse, improving the availability of recyclate at a lower cost than fresh material and using alternative renewable, cost-effective compostable materials.

Polymers present and future

Currently, the society’s board is active in bringing sound science and sense to the discussions around single-use plastics and ocean litter, rather than encouraging a change to alternative non-plastic materials that may not have the same performance profile nor solve the fundamental issues. We continually monitor discussions in the media around relevant issues and have experts available to comment technically on these issues supported by the depth of resources available within IOM3, e.g. the Sustainable Development Group or the Packaging Society.

In the future, we will focus on helping to develop suitable education courses, such as part-time apprenticeship-based programmes, to suit the development needs of the plastics and elastomer sectors.

In addition to continuing the existing, varied support for professional development of members, we will be prepared to anticipate issues and developments around the wider challenges involved in polymers.

These are likely to include the harmful effects, collection and minimisation of microplastics, finding cost-effective routes of tyre recycling and acceptance of materials derived from the recycling process, which would possibly require setting up and agreement of new specifications. In the longer term, we will be promoting lifecycle thinking and circular economy concepts in which we keep resources in use for as long as possible, extracting the maximum value from them while in use, then recovering and regenerating products and materials at the end of each service life.