Pathway to Truly Sustainable Geotextiles

By GNA Editor

Introduction

For several geotextile applications longevity and durability are important factors in order to fulfill their function in soil reinforcement and protection. However, geotextiles with a much shorter life-span are in demand, which are designed to degrade after a certain time period.Biodegradable geotextiles are perfect for applications where once they have completed their task they biodegrade and disappear from view without the generation of persistent microplastics.

These materials are used for preventing soil erosion until the seeded vegetation can take over this function or the floor is sufficiently consolidated. Thus, the geotextile should degrade after a couple of months or years into environmentally compatible components, which obviates the need of material re-collection and recovery. It also overcomes the emerging environmental issues with PP and PET geotextiles concerning soil pollution and accumulation of microplastics.

For these sort of geotextiles, natural fibres are an option. Most of these utilize natural fibres such as jute, coir or sisal. However natural fibres with high cellulose contents initially exhibit high mechanical strength but early aging effects significantly decrease in the textile's integrity and efficiency.Together with natural variations in fibre properties, difficulties during the spinning process and varying environmental influences, lifetime prediction of natural fibre geotextiles becomes challenging and hence they are still rarely used in commercial products.

The field of biodegradable geotextiles is rapidly gaining attention due to its potential environmental benefits and solution to the formation of microplastics from PP and PET geotextiles. A relative newcomer to this space is PBS which can solve the above problems.PBS is attracting increased attention for geotextiles due to the potential for bio-based production, as well as its balanced properties, enhanced processability, and excellent biodegradability.

What is PBS?

PBS is a biodegradable aliphatic polyester with excellent biodegradability, as well as thermal/UV and mechanical properties, which makes it suitable for the textile industry usage as a filament and a split yarn.

The monomers can either be derived from petrochemical or bio-based chemicals (bacterial fermentation) and the latter is called bio-based poly(butylene succinate) (Bio-PBS).PBS is a white crystalline thermoplastic polymer with a density of 1.25 g/cm3, a melting point (Tm) in the range of 90–120 °C, and a low glass transition temperature (Tg) of about −45 to −10 °C.PBS has properties that are comparable to PP and PET thus making it ideal for geotextiles.

PBS can be used to make 100% biodegradable, mechanically bonded nonwoven geotextiles. Due to its certified biodegradability, residues of the product do not harm the environment also PBS can be made UV-resistant and therefore be used in uncovered applications.PBS geotextiles’ excellent mechanical properties allow them to resist mechanical stresses during installation and construction.

How is PBS Made

Basically, PBS is synthesised through a polycondensation reaction between 1,4-butanediol and succinic acid. For bio-based monomers, succinic acid could be derived from glucose, which can be obtained from various sources of bio-feedstock through bacterial fermentation, while hydrogenation of succinic acid will produce 1,4-butandiol, which is required for PBS synthesis.

The synthesis of PBS requires two steps, which are esterification between diacid (succinic acid) and diol (1,4-butanediol), forming oligomers, followed by polycondensation at high temperature to form high MW PBS. The high MW PBS is better suited to geotextile applications. By blending PBS with its adipic acid-derived version PBSA the biodegradation rate can be adjusted. Precise control of biodegradation time can be achieved by selection of specific blend ratios of PBS:PBSA.

Potential Applications of PBS Geotextiles

PBS geotextiles can find wide-ranging applications in various fields, including:

1. Separation, Filtration, and Protection Layers: PBS geotextiles can be used as separation, filtration, and protection layers in road construction and geotechnical projects. They provide stability, prevent intermixing of different soil layers, and enhance filtration and drainage capabilities.
2. Landscaping and Vegetative Embankments: PBS geotextiles can play a vital role in landscaping projects and the construction of vegetative embankments. They help in soil stabilization, erosion control, and the establishment of healthy vegetation.
3. Temporary Paths, Access, and Road Construction: PBS geotextiles can be utilized for creating temporary paths, access roads, and in road construction projects where temporary stabilization is required. They provide temporary reinforcement and prevent soil displacement.
4. Embankment Protection and Natural-Related Waterway Construction: PBS geotextiles can be used as protective layers for embankments and contribute to the construction of waterways with a natural appearance. They offer erosion control, slope stability, and protection against water-induced damage.
5. Coastal Protection: In coastal areas, PBS geotextiles can be employed for coastal protection purposes. They can be used as single nonwoven geotextile layers or in combination with sand containers to prevent erosion, stabilize coastlines, and maintain beach integrity.
6. Scour Protection: PBS geotextiles in the form of geotextile sand containers can be utilized for scour protection. They act as a barrier to prevent soil erosion and protect structures such as bridge abutments, piers, and embankments from the effects of water currents.

Where do you Get PBS?

PBS can be sourced from the Mitsubishi Chemicals JV called PTTMCC in Thailand: https://www.pttmcc.com/PTTMMC have a PBS fibre business segment and a production plant in Rayong Thailand. https://www.pttmcc.com/fiber-and-nonwovenPTTMCC PBS Compostable Grade namely FZ78TM has the following attributes that make itideal for geotextiles:

• Good processability and wide process window
• Using conventional fiber spinning machine
• High speed spin continuity of low denier fibres
• Uniform viscosity or melt flow rate
• Low gels hence low fiber breakage rates
• OK compost INDUSTRIAL certified by TÜV Austria in European Union
• Renewable content certified by DIN CERTCO, JBPA and USDA

Contacts at PTTMCC: info@pttmcc.com | sales@pttmcc.com

Who to Ask for Technical Assistance Regarding Processing PBS into Fibres?

Should you require technical assistance to use PBS for your geotextile application these PBSindustry experts would be happy to assist:Dr. Anita Haider (Project Manager) at RUBIO anita.haider@exipnos.deDr.-Ing. Joachim Venus (Head) ATB Potsdam jvenus@atbpostdam.deDr. Martina Prambauer at TCKT Martina.prambauer@tckt.at

How to Acquire IP for PBS Geotextiles?

PBS has recently emerged as a promising material for biodegradable geotextiles due to its unique properties such as biodegradability, mechanical strength, and compatibility with various forms of geotextiles.

The patent landscape for PBS geotextiles is relatively sparse, presenting a significant opportunity for inventors and geosynthetic companies to secure intellectual property (IP) protection for their innovations in this field.

Patent Landscape Reports (PLRs) offer a comprehensive analysis of the patent situation in specific technology areas, guiding policy discussions, informing research strategies, and facilitating technology transfer.

The scarcity of existing patents in PBS geotextiles suggests ample room for novel and inventive applications of PBS in geotextile manufacturing.

Securing patents for PBS geotextiles enables inventors and companies to protect their innovations, establish barriers to entry for competitors, and explore licensing opportunities to generate revenue.

Collaboration among industry players, research institutions, and inventors can further propel advancements in PBS geotextiles, fostering a robust IP landscape and meeting the increasing demand for sustainable geotextile solutions.

Comprehensive research and analysis are crucial for inventors and organizations to capitalize on the patent and IP potential in PBS geotextiles, including identifying areas of limited prior art and developing innovative applications and manufacturing processes.

A broader IP strategy, including protecting trade secrets, trademarks, and copyrights associated with PBS geotextiles, can enhance market presence and safeguard valuable knowledge and expertise.

Collaboration and knowledge sharing with research institutions are essential for maximizing the patent and IP potential in PBS geotextiles, driving innovation and industry growth.

Further reading

https://www.mdpi.com/2073-4360/15/10/2399/pdf?version=1684736567https://www.mdpi.com/2073-4360/14/4/844/pdf?version=1645516495