Sustainable and thermal insulating composite materials: cements containing recycled textile microfibres

Beatrice Malchiodi, Cristina Siligardi, Paolo Pozzi
University of Modena and Reggio Emilia, Department of Engineering Enzo Ferrari

This project has been awarded by Compositi’s editorial staff and technical-scientifical Commitee!

Every year a large amount of textile waste is generated by the fashion sector. Recently this phenomenon has rapidly worsened due to the spread of the “fast fashion” concept, based on a linear economic model and mass consumption. Annual statistical reports, i.e. ISPRA Italian annual report of waste production, confirm this trend and should be regarded as warning data toward more sustainable practices and recycling solutions in all fields.

The Italian fashion sector plays an important role in national waste production; namely, it is responsible for the production of 37.4% of the total Italian non-hazardous waste [ISPRA2020].

Depending on the activities that generated it, textile waste is classified into:

• special waste: evaluated at around 490.000 ton/year in Italy [ISPRA2020], is generated by industries and collects industrial processing waste (fibres, yarns, fabrics, scraps) and unsold or old-fashioned clothes.
• urban waste: 146.000ton/years in Italy [ISPRA2020], derives from the post-consumption of families and small activities.

Actually, a part of them is reused or recycled:

• clothes, both from pre and post-consumer use, are collected and resold in the second-hand market or donated to charity
• Yarns, fabrics and scraps are selected depending on colours and materials and recycled to create new sustainable textile yarns, thermal insulating panels for buildings and as upholstery for home and transports furniture

However, all the other textile wastes and, in particular, fibres resulting from industrial processes are actually still disposed to landfill. With this in mind and aiming to contribute to the amount increase of potentially reusable and recyclable textile waste, we proposed to face this problem by considering a new application of waste textile fibre.

Invest in recycling mode

Precisely, we focused on the issue of waste textile microfibres deriving from the finishing process of fabrics. The finishing of fabrics is an industrial process involved to confer particular and desired properties to the fabric surface. For example, it might be required in the fabrics production process to promote aesthetic properties, antibacterial effect, self-cleaning capacity, anti-static properties, stain resistance, hydrophobicity, heat insulation etc.

The research work was carried out in collaboration with a consortium of four local companies of the Carpi (Modena, Italy) textile district and it was part of the project “Invest in recycling mode” aimed at promoting the eco- and social sustainability of local industrial development.

The waste microfibres from finishing were furnished directly by one of the involved companies that mainly operates in the finishing of fabrics sector and precisely in conferring aesthetics and thermal insulating properties to textile surfaces.

The surface treatment is achieved by creating a heating fluff on the fabric surface and cutting off the fibrous fluff at a desired high. As a consequence of this process, a suspension of microfibres in the air is generated, so an air filtering system is required to collect it and avoid environmental contamination. Microfibres are then mechanically compacted and disposed to landfill.

The amount of waste microfibres produced solely from the finishing phase was computed by the company at around 35ton/years and it’s estimated that 5.000ton/years are produced in Italy. The total cost of waste management, the desire to reduce process environmental impact and the objective to create new business with waste products pushed the consortium’s companies to start a research project in collaboration with the Department of Engineering Enzo Ferrari.
 

The common project issue

It  was to find a new application for this textile waste, different from the well-established and commercially available applications, in order to:

1. reduce the company’s cost due to waste disposal
2. increase the sustainability of the finishing process

On the other hand, the use of recycled raw materials is an urgent and actual issue also for the construction sector. Indeed, in the last decade, scientific research has focused on developing sustainable building materials to reduce the impact of construction on the environment. Our research group is highly involved in this area and contributed to several works focused on the use of recycled aggregates and fibres (glass waste, plastic waste, tile waste, organic waste, Construction and Building concrete waste, industrial waste etc.