Investigation of strength recovery of recycled heat treated glass fibres through chemical treatments

The strength loss of thermally treated glass fibre (GF) at elevated temperature is well reported in literature. This phenomenon even occurs at short period of time such as 25 minutes. In the recycling technologies for composites, GFs are usually recovered by degradation of polymeric matrix with thermal and/or chemical treatments. Therefore thermal effect on the strength of GF is a significant factor when restricting the possibilities of recycling this material for a second life. This study reports on the strength of thermally treated commercial GF after acid treatment and silanization of the fibre surface to achieve a proper combination of treatments which may provide us with the ability to recover the mechanical properties of the heat treated GFs. It is thought that silane coupling agents can directly increase and recover the strength of GFs. Two factors associated with this recovery are the possibility of the sizing repairing the damage on the surface of the heat treated GFs and the reduction of the fibre-fibre friction in the bundle through lubricating effect. GF samples were heat treated at 4500C for 25 minutes and coated with silanes, applying different combinations of hydrochloric acid (HCl) and the two silanes used in this study, γ-Aminopropyltrimethoxy Silane (APS) and γ- Methacryloxypropyltrimethoxy Silane (MPS); these fibres were characterized by single fibre testing for strength. The results obtained demonstrated that the fibre strength improves slightly after combination of HCl and MPS treatment, and has a negative effect when the combination of HCl and APS was used. The surface deposition of silane on the surface of the fibre is also discussed using a Scanning Electron Microscope (SEM)

Regeneration of thermally recycled glass fibre for cost-effective composite recycling : Performance of composites based on PP and Recovered glass fibre

Due to economic and technical reasons, no recycling process for glass fibre composites has been commercialized on a large scale. Thermal recycling processes are promising in terms of potential for commercialization but the reinforcement potential of thermally recycled fibres is too low for the application in composites. In the present study, glass fibres were exposed to elevated temperatures prior to composite processing to imitate a thermal recycling process. The exposure of the fibres to elevated temperatures prior to composite processing caused a significant reduction of the mechanical properties of the composites. The heat treated fibres were regenerated with a post treatment. The regeneration of the glass fibres recovered the mechanical properties of the composites almost completely. Thus, this study shows that composites based on thermally recycled glass fibres have the potential to compete with composites based on ‘new’ glass fibres

Recover : Regenerating the strength of glass fibres thermally recycled from end-of-life

Global production of composite materials in 2015 will significantly exceed 10 million tons. Glass fibre reinforced composites account for more than 90% of all the fibre-reinforced composites currently produced. Development of economically viable processes for recycling end-of-life glass fibre composites would have major beneficial economic and environmental impacts for the glass fibre composites industry. This paper reports a study on regenerating the performance of thermally recycled glass fibres. The effectiveness of the ReCoVeR treatments on the single fibre strength of glass fibres thermally treated to imitate the conditions of composite recycling technology is presented. The regenerated strength levels of these ReCoVeRed fibres must be further protected and maintained by the use of fibre sizing technology similar to standard glass fibre products. Consequently the effect on fibre strength of the combination of the ReCoVeR treatment with a standard silane coating was also studied. Significant increase of fibre strength was obtained through the regeneration treatments, achieving greater than triple the fibre strength in comparison with the thermally treated glass fibre. Furthermore the same treatments have also been applied to glass fibres recovered from model composites using laboratory thermal recycling. Fibre strengths have been achieved which makes reusing these fibres as a composite reinforcement a viable option. Results on the mechanical performance of composites containing ReCoVeRed glass fibres are presented and discussed in support of this assertion

Investigation of the strength of thermally conditioned basalt and e-glass fibres

It is projected that the total global production of composite materials will significantly exceed 10 million tons by 2015 of which over 90% will contain glass fibre reinforcement. Traditionally most of this composite material would be directed to landfill at end of life. Thus, recycling composites has started to gain great importance due to environmental and commercial aspects. The development of an efficient process to enable cost-effective regeneration of the mechanical properties of fibre for recycling, could result in a huge decrease of landfill disposal as well as the attenuation in CO2 emissions. There are several processes available for recycling composites but the most technologically advanced is thermal recycling. However, during the recycling process glass fibres that are treated at temperatures in a range between 300 up to 600 °C exhibit a huge drop in strength and as a result sometimes are considered as not reusable or unsuitable for reprocessing [1]. Although basalt fibre has been available for some time, recent development in the processing and production of basalt has resulted in the availability of continuous basalt fibre in similar form to traditional glass fibre. It is often stated that basalt has better high temperature resistance compared to E-glass fibre [2,3]. If this were true then basalt fibre may show better prospects to survive an end-of-life composite thermal recycling process as a useful reinforcement. The present work investigates and compares the changes in the mechanical properties of basalt fibres and E-Glass fibres when heat-treated to between 300 – 600 °C. Since the fibre surface plays an important role in the retained strength of brittle fibres, the investigation used fibre with similar epoxy compatible sizings in order to maximise the quality of the comparison. Results of single fibre testing of tensile strength and modulus are presented and discussed

The ReCoVer Project : regeneration of thermally recycled glass fibre for cost-effective composite recycling

Global production of composite materials in 2015 will significantly exceed 10 million tons. Glass fibre reinforced composites account for more than 90 % of all the fibre-reinforced composites currently produced. Development of economically viable processes for recycling end-of-life glass fibre composites would have major economic and environmental impacts. This paper introduces and reviews the initial results of the ReCoVeR projects on enabling cost-effective performance regeneration of glass-fibres from thermal recycling of end-of-life automotive and wind energy composites. ReCoVeR technology targets treating glass fibre thermally reclaimed from GRP waste in order to regenerate a performance level which is equivalent to new fibres. Composite materials reinforced with ReCoVeR glass fibres can currently attain over 80 % of the reinforcement performance of composites produced with pristine glass fibres

Towards a new generation of glass fiber products based on regenerated fiber thermally recycled from end-of-life GRP and GRP manufacturing waste

The recovery and reuse of glass fiber from waste glass fiber and end-of-life GRP in an environmentally friendly, cost-effective manner is one of the most important challenges facing the composites industry. The annual global consumption of reinforcement grade E-glass fiber (GF) now exceeds 5 million tons. Associated with this global GF consumption was the production of 0.5-1 million tons of GF manufacturing waste most of which is landfilled. Furthermore, approximately 70% of reinforcement GF is used to manufacture thermoset based composites (GRP) which also produces approximately 15% manufacturing waste. Consequently it can be shown that there is actually sufficient GF available in current manufacturing waste and end-of-life GRP to meet approximately 50% of the global demand for GF reinforcements. Although a number of processes for recycling GRP are available or under development, the most likely methods to be cost-effective are based on thermal recycling where temperatures in the range 450-600 °C are used to remove the polymer matrix and allow extraction of the glass fiber reinforcement. One of the key barriers to reuse of such thermally recycled glass fibers (RGF) in second-life composite materials is their drastically reduced strength. A breakthrough in the regeneration of RGF performance has the potential to totally transform the economics of recycling GRP waste and end-of-life composites. In this presentation we will review the outputs from two EPSRC funded research projects focussed on the cost effective recycling of end-of-life glass fiber composites from automotive (TARF-LCV: Towards Affordable, Closed-Loop Recyclable Future Low Carbon Vehicle Structures) and wind energy applications (ReCoVeR: Regenerated Composite Value Reinforcement). The mission of the ReCoVeR team is to research and grow the knowledge to enable the development of cost-effective, drop-in, glass fiber and composite products based on recycled glass fibers with regenerated mechanical performance. The Research Goals for the project are threefold - • Generate fundamental understanding of the changes in glass fibers caused by thermo-mechanical conditioning • Develop cost effective treatments to regenerate the performance of thermo-mechanically recycled glass fibers • Produce examples of glass fiber and composite products using regenerated glass fibers The presentation will provide an overview of the research results from all three areas of the project

Recover : regenerating the strength and value of glass fibres thermally recycled from end-of-life GRP composites

The recovery and reuse of end-of-life GRP in an environmentally friendly, cost-effective manner is one of the most important challenges facing the polymer composites industry. A number of processes for recycling GRP are available or under development. However, nearly all options deliver recycled glass fibres which are not cost-performance competitive due to the huge drop in performance of recycled glass fibre compared to its original state. A breakthrough in the regeneration of recycled glass fibre performance has the potential to totally transform the economics of recycling such GRP composites. This presentation will review the status of the ReCoVeR project which is focussed on the enabling cost-effective regeneration of the performance and value of glass fibres obtained from thermal recycling of end-of-life GRP and GRP manufacturing waste. Highlights of our latest results will be presented with emphasis on our breakthrough treatments to regenerate the properties of thermally conditioned glass fibres

Regeneration of the performance of glass fibre recycled from End-of-life composites or glass fibre waste : Presentation & Abstract

The disposal of end-of-life composite products in an environmentally friendly manner is one of the most important challenges facing the industry and community. In this presentation we will introduce two recently initiated EPSRC funded projects focussed on the cost effective recycling of end-of-life glass fibre composites from automotive and wind energy applications. The ultimate goal of these projects is to enable cost-effective regeneration of the mechanical properties of glass fibres which have been produced from thermal recycling of glass reinforced structural composites. This project has the potential to totally transform the economics of recycling GRP composites which would otherwise most likely be disposed of to landfill. A breakthrough in this field will enable such recycled fibres to compete with pristine materials in many large volume composite applications. The development of an economically viable process for regenerating the properties of thermally recycled glass fibres would have major technological, societal, economic, environmental impacts. Conservative estimates indicate that there is a potential to generate a global industry with an annual production of 1 million Tons of reusable regenerated glass fibres with a market value order of magnitude of £1,000M. The reuse of these materials could result in a huge reduction in the environmental impact of the glass-fibre industry where the replacement of pristine glass fibre products would equate to a global reduction in CO2 production of 400,000 Tons/annum from reduced melting energy requirements alone. Furthermore, such a technological development would also reduce the need for an annual landfill disposal of 2 million Tons of composite materials. These developments would clearly be in line with the growing societal and environmental pressure to reduce the use of landfill disposal, increase the reuse of valuable raw materials resources, and reduce the release of CO2 to the atmosphere. The results of a study of the properties of glass fibres after thermal conditioning will be presented. The mechanical performance of rovings and single fibres of well-defined silane sized and unsized E-glass fibre samples was investigated at room temperature after thermal conditioning at temperatures up to 600°C. Thermal conditioning for only 15 minutes led to strength degradation of greater than 80% at higher temperatures. The room temperature strength of silane coated fibres was relatively stable up to 300°C but exhibited a precipitous drop at higher conditioning temperatures. Unsized fibres exhibited an approximately linear decrease in strength with increasing conditioning temperature. The results as discussed in terms of the changes in surface coating and bulk glass structure during heat conditioning

Regeneration of thermally recycled glass fibre for cost-effective closed-loop composite recycling in automotive

RECOVER - Final Presentatio

New insights about the electrochemical production of ozone

Ozone is a rather attractive oxidant, it is very efficient in the oxidation of pollutants and in the killing of pathogens and does not generate any hazardous waste during its use. Its generation has been constantly sought in an effective way, focusing on obtaining high concentrations of ozone at the lowest possible cost. Recently, electrochemical production of ozone show advantages over conventional corona discharge generation, since this technology do not need very high voltages, feeding oxygen or pure air or dissolving the ozone into wastewater to be treated. However, it is still at early development stage and there is still a long way to reach the high technology readiness levels needed to complete its value chain. Equipment considerations and operation conditions are the key points that need to be understood in order to increase efficiently. Recent novelties in the state of the art of research are summarized in this work