Lars Lundquist

Life Cycle Assessment of Biofibres Replacing Glass Fibres as Reinforcement in Plastics

This article aims to determine the environmental performance of China reed fibre used as a substitute for glass fibre as reinforcement in plastics and to identify key environmental parameters. A life cycle assessment (LCA) is performed on these two materials for an application to plastic transport pallets. Transport pallets reinforced with China reed fibre prove to be ecologically advantageous if they have a minimal lifetime of 3 years compared with the 5-year lifetime of the conventional pallet. The energy consumption and other environmental impacts are strongly reduced by the use of raw renewable fibres, due to three important factors: (a) the substitution of glass fibre production by the natural fibre production; (b) the indirect reduction in the use of polypropylene linked to the higher proportion of China reed fibre used and (c) the reduced pallet weight, which reduces fuel consumption during transport. Considering the whole life cycle, the polypropylene production process and the transport cause the strongest environmental impacts during the use phase of the life cycle. Since thermoplastic composites are hardly biodegradable, incineration has to be preferred to discharge on landfills at the end of its useful life cycle. The potential advantages of the renewable fibres will be effective only if a purer fibre extraction is obtained to ensure an optimal material stiffness, a topic for further research. China reed biofibres are finally compared with other usages of biomass, biomaterials, in general, can enable a three to ten times more efficient valorisation of biomass than mere heat production or biofuels for transport.

Novel pulp fibre reinforced thermoplastic composites

The reinforcement potential of pulp fibres is presently not fully explored in thermoplastic composites. One of the reasons is that currently used processing methods comprise several severe thermomechanical steps inducing premature degradation of the fibres. Three pre-forming techniques were developed to prepare pulp fibre reinforced cellulose diacetate (CDA) pre-forms, namely filtration-forming, solvent impregnation, and commingling with polymer fibres. These techniques eliminate all thermomechanical steps, prior to final processing. The CDA polymer was nevertheless found to be very sensitive to the specific process histories relevant to each technique, contrary to the pulp fibres, whose size, shape, and mechanical properties were not affected by neither of the pre-forming processes. The tensile properties of composites compression moulded from solvent impregnated pre-forms were compared to those of ground china reed reinforced CDA. Whereas ground china reed particles were found to act merely as fillers increasing composite stiffness, a remarkable reinforcement effect was observed for the pulp fibre reinforced impregnated pre-forms. A combination of a stiffness increase by a factor 5.2 and a strength increase by a factor of 2.3 relative to the pure polymer was achieved, whereas in typical pulp fibre reinforced thermoplastics, the stiffness increase is frequently obtained at the expense of loss in strength. This work highlights the key factors which control the mechanical performance of pulp fibre reinforcements previously neglected in literature, and demonstrates the remarkable reinforcement potential of such renewable material. Furthermore, the properties achieved by optimising the extraction and processing steps indicate that pulp fibre reinforced thermoplastics composites are appropriate materials for load bearing applications.

The Polymer Life Cycle

This chapter introduces the basic features of polymers and their additives. The main ageing and degradation phenomena, which relate to the reliability and durability of polymers, from manufacture and service, to final disposal or recovery, are reviewed. The prediction of the long-term performance of polymers is discussed. Polymers are giant molecules, or macromolecules, constructed from smaller repeating chemical units, or monomers. They are divided in two main classes: thermoplastics and thermosets. Upon heating, the properties of any polymer undergo marked changes at certain temperatures. At very low temperatures, the polymer is frozen in its glassy state, as no part of the molecules can move. For industrial purposes, where material reliability and durability is required, a large variety of substances called additives have been developed to limit the effect of processing and service conditions on the polymer. The combination of a polymer with appropriate additives creates a plastic. These additives not only prolong the life of the material in its application, but also prevent the material from degrading under the high temperatures and mechanical loads induced by processing. It has been shown that polymer properties change over time, as a result of the combined action of numerous external factors. The microscopic structure of polymers also changes over time, even in the absence of external factors. Competitive knowledge of material behavior and characterization and predictive skills for long-term performance are vital for the fulfillment of life cycle engineering strategies.

Life Cycle Engineering in Product Development

This chapter discusses product and process development in the light of the Life Cycle Engineering concept. The issues of material reduction, material life extension, product life extension, process improvement and product management are addressed. Examples of products and processes designed with these issues in mind are given. Existing design methodologies already cover design for recycling, assembly and disassembly; in this chapter, the importance of including material-related life cycle performance issues, such as durability and reliability, into design strategies is emphasized. The implementation of integrated product development allows environmental and cost issues to be approached in a more systematic and innovative way, and has been proven to give product performance and cost advantages. Much development within the field of Life Cycle Engineering is still to come. It is likely that technology will be developed that will help solve problems of waste by minimizing resource use. The increased emphasis on environmental issues expressed by consumer organizations and governments not only shifts the focus onto product performance but also onto the environmental performance of entire organizations.

Introduction to Life Cycle Engineering

The preservation of non-renewable natural resources is an issue that has assumed great importance in modern society. It is now widely recognized that continued economic development should be accompanied by more appropriate use of natural resources. Just how the economy should be organized to achieve such balanced growth is at present open to a great deal of debate. Industry is under great pressure to improve its practices. The polymer industry is particularly under fire, no doubt due to the short lifespan of many plastics based consumer products, the high visibility of polymers in municipal solid waste and the rapid increase of plastics consumption. Sustainable development has been widely accepted as a viable concept for ensuring long-term survival of humankind and of other species on the planet under acceptable conditions. Sustainable growth must therefore encompass environmental, social, and economic factors and maintain a balance between them. This implies consideration of a wide range of factors in determining solutions to environmental problems. Life cycle engineering (LCE) provides a methodology of how to design, manufacture, use, maintain and recover materials and products with the aim of optimizing resource use and minimizing environmental impact. The life cycle of a product made from a polymer or from a polymer-based composite is composed of a series of distinct steps. By monitoring the value of the polymer throughout its life cycle, from the “cradle” to the “grave”, it is possible to guide improvement, the aim being to maintain the performance value of the constituent materials at as high a level as possible throughout the life cycle.

Organisational Aspects of Life Cycle Engineering

The implementation of technical solutions to environment-related problems requires organizational change. Environmental Management Systems (EMS) allows companies to systematize their approach to environmental issues by identifying environmental liabilities and by improving efficiency as well as creating business opportunities. The ICC Business Charter for Sustainable Development, the British green audit Standard BS 7750, the European Community Environmental Management and Audit Scheme and the international standard series ISO 14000 are reviewed. Adhering to these standards is not free from cost, but long-term competitive advantages such as access to markets, finance and insurance as well as improved operational efficiency are likely to compensate for initial costs. Opportunities for support in the implementation of EMS for small and medium-sized companies are discussed. The implementation of such systems is not free from cost, and they demand a certain level of commitment from their participants. There are nevertheless inherent advantages of managing environmental issues in a systematized way, in terms of access to finance and insurance, but more importantly to identify potential liabilities and avoid unnecessary expenditure on clean up and noncompliance. Other reasons for adhesion to a standardized EMS are the possibility of gaining competitive advantage in international trade. The creation of national and international standards for environmental management systems is no guarantee for environmental improvement. Neither does the existence of an EMS within a company make its activities environmentally sound. The increasing adoption of environmental management systems as a core management tool will probably create a common language between companies to aid quicker learning and progress.

Plastics Recovery and Recycling

Publisher Summary Plastics waste is receiving increased attention in the environmental debate. The technology of recovery and recycling is rapidly progressing, but there is no unique solution for treating plastics waste. The strategy to apply depends on the type of material and product and on consumption patterns. Mechanical recycling, feedstock recycling, energy recovery and environmentally degradable plastics are discussed. The importance of efficient collection and separation systems, of steady material supply and quality and of available markets for revaluated material is shown. Early recycling efforts have been plagued by the high capital costs of setting up recycling plants, an irregular supply of material and the low quality of products made from recycled material, which kept recyclers from working at full capacity. The efficiency of collection and sorting structures is measured by collection costs, capture rate and purity of generated feedstock. Automated identification and separation technology is necessary to reduce the cost of recycling and enable greater volumes of waste to be processed. Reclaiming is labor intensive. The material passes through more hands and is transported longer distances than virgin material. This greatly raises the cost of producing competitive material. Each of the described collection and sorting methods has inherent strengths and weaknesses. They will most likely have to be used in combination to achieve good sorting. It remains to be seen whether the economy and energy efficiency of such systems will be competitive compared to incineration or landfill.