Technological breakthroughs

A comprehensive review published in RSC Sustainability (2025) systematizes the latest advances in sustainable materials for tire manufacturing worldwide. From bio-based rubber to recycled carbon black, and from vegetable oils to natural fibers, the tire industry is entering a new era of comprehensive green transformation.

KEY FIGURES

1. BIO-BASED RUBBER — DIVERSIFYING RAW MATERIAL SOURCES

Next-generation natural rubber

For decades, Hevea brasiliensis (Brazilian rubber tree) has almost monopolized natural rubber supply, accounting for more than 98% of global production. However, growing supply–demand imbalance is driving research into alternative crops:

• Taraxacum koksaghyz (Russian dandelion): Produces high-quality poly(cis-1,4-isoprene) with durability comparable to Hevea rubber. Over 10 major corporations, including Bridgestone, Continental, and Goodyear, are investing in its commercial development.
• Parthenium argentatum (guayule): Latex-allergen-free rubber with advantages in medical and automotive applications. The first guayule tire appeared in 2017, with 16.4% lower life-cycle energy consumption compared to conventional rubber.
• Solidago altissima (goldenrod): Potential latex yield of about 12%, already applied experimentally in tire production.
• Lettuce (Lactuca sativa): Rubber molecular weight exceeding 1 million Da, promising for research and genetic engineering approaches.

Da – Dalton: a unit of molecular mass used in chemistry and biology; 1 Dalton equals 1/12 the mass of a carbon-12 atom, approximately the mass of one proton or neutron.

Bio-based synthetic rubber

In 2014, synthetic rubber production consumed 35.5 million tons of crude oil, prompting the search for renewable alternatives:

• Elastomers from itaconic acid: Weiwei Lei and colleagues developed silica/poly(di-n-butyl itaconate-co-butadiene) nanocomposite tires meeting premium commercial standards for rolling resistance and wet traction.
• Poly(dimethyl itaconate-co-butadiene) (PDMIB): Tensile strength 10.2 MPa, elongation 1146%, toughness 37.6 MJ/m³, outperforming many conventional rubbers.
• β-myrcene (a terpene from pine leaves): Sarkar and Bhowmick synthesized diverse bio-elastomers, enabling customizable material design.
• Trans-β-farnesene from sugar fermentation: Microbial fermentation produces low-molecular-weight polymers with unique structure–property relationships.

2. REGENERATIVE FILLERS — FROM AGRICULTURAL WASTE TO NANO-SILICON

Green silica from agricultural residues

Traditional precipitated silica production consumes 1,194–1,955 kg of coal per ton and emits 10–18 tons of CO₂ equivalent. In contrast, rice-husk silica offers:

• 238 kg coal per ton — an 80% reduction
• 0.85 tons CO₂ per ton product — 92% lower emissions
• Raw materials: rice husks, bamboo leaves, bagasse, corn stalks, abundant in Vietnam and Southeast Asia
• Better dispersion, higher reinforcement index, and lower Mooney viscosity than conventional silica

→ This represents a significant opportunity for Vietnam, given its abundant agricultural by-products.

Cellulose and lignin — bio-reinforcing agents

Cellulose nanocrystals (CNC) and lignin derived from wood, straw, and bagasse are being studied to replace traditional carbon black:

• Maleic-anhydride-modified CNC (M-CNC) significantly improves the mechanical performance of epoxidized natural rubber.
• Hybrid CBp/nanocellulose composites provide low hysteresis and excellent wear resistance in natural rubber — ideal for truck tires.
• Rubber containing 50 phr lignin achieves tensile strength of about 10 MPa and elongation of ~276%, suitable for industrial applications.

Next-generation carbon nanomaterials

Multi-walled carbon nanotubes (MWCNT), carbon nanohorns, and graphene are expanding the range of high-performance fillers:

• MWCNT increases tensile strength of SBR by 600%, tear resistance by 250%, and hardness by 70%.
• Graphene derived from recycled tire carbon powder (CBp) simultaneously recycles waste and creates high-value materials.
• The MWCNT market is projected to exceed 50,000 tons per year by 2035, with product value reaching USD 60–100 billion.

3. BIO-BASED PROCESSING OILS — REDUCING TOXIC CHEMICALS

Traditional distilled aromatic extract (DAE) oils contain carcinogenic compounds and are being replaced by vegetable oils:

• Palm oil: Comparable performance to DAE, improves rubber–filler interaction and reduces crosslink density. Successfully tested in pneumatic tires with good traction and durability.
• Modified soybean oil (MSO): Enhances crosslink density, aging resistance, and abrasion resistance. MSO-6% shows the best plasticizing effect in tire rubber.
• Cashew shell oil (cardanol): Acts both as a plasticizer and a co-vulcanization activator — promising for off-road tire applications.
• Coconut shell extract (CSE): A dual bio-coupling agent capable of replacing traditional silane in silica dispersion.

4. RECYCLED MATERIALS — THE PRACTICE OF A CIRCULAR ECONOMY

Recycled rubber and devulcanization

Ground tire rubber (GTR) from used tires is being integrated into new production processes:

• Araujo-Morera and colleagues developed self-healing GTR+SBR composites with 80% healing efficiency and 300% increased tensile strength.
• Microwave devulcanization: breaks S-S bonds without damaging the main polymer chains.
• Ultrasonic and mechano-chemical devulcanization allow revulcanized rubber with properties exceeding conventional silica-NR composites.

Recovered Carbon Black (rCB) — strategic potential

Currently 65% of tire manufacturers view rCB as an ideal material for sustainability goals.

• Recovered Carbon Black (rCB): 100% recycled from used tires; capable of replacing N700–N500 carbon blacks; expected to reach industrial scale by 2024.
• Plasma methane pyrolysis carbon black: conversion efficiency >99%, hydrogen yield >95%, simultaneously producing clean hydrogen.
• Green Carbon Black (GCB) from biomass pyrolysis oil: structurally comparable to traditional carbon black and potentially capable of full replacement by 2041.

Recycled steel and textile fibers

• Steel from end-of-life tires (ELT): reduces costs by 30–70% compared to virgin steel; Bridgestone has commercialized bead wire made from recycled tire steel through a joint venture with Nippon Steel.
• Polyester fiber from PET bottles: Continental’s ContiRe.Tex uses up to 15 PET bottles per tire, converting plastic waste into high-strength polyester.
• Recycled nylon fibers from fishing nets and carpets, and aramid fibers from protective armor and old tires.

5. ADVANCED MANUFACTURING TECHNOLOGIES

Artificial intelligence in tire life-cycle management

AI is increasingly deployed across the tire industry—from selecting eco-friendly materials and optimizing design to improving manufacturing efficiency, supply-chain management, and end-of-life tire processing. AI models can predict the properties of new composite materials without requiring exhaustive physical testing.

Life Cycle Assessment (LCA)

LCA has become an essential tool in sustainable tire design, quantifying environmental impacts from raw material extraction to end-of-life disposal, guiding chemical formulation and material selection.

Triboelectric tires — energy harvesting

Tires integrated with triboelectric nanogenerators (TENG) can harvest energy from rolling friction to improve fuel efficiency and extend the driving range of electric vehicles.

3D printing and airless tires

Technologies such as Michelin Uptis (Unique Puncture-Proof Tire System) and developments by Goodyear, BigRep, Polaris, and Kenda Rubber aim to create airless tires, eliminating puncture risks, reducing vehicle weight, and significantly extending tire lifespan.

Vitrimers — self-healing and recyclable materials

Vitrimers are polymers with dynamic reversible chemical bonds that allow tire rubber to self-heal, be reprocessed, and be recycled multiple times without losing performance—offering a potential solution to tire waste at the material level.

6. CHALLENGES AND RESEARCH GAPS

Despite remarkable progress, the review identifies six major challenges:

• Long-term performance: insufficient data on durability and safety of bio-materials over long operating periods
• Full biodegradability: limited understanding of the life cycle of new nanomaterials, especially microplastic and micro-rubber emissions from tire wear
• Supply–demand balance: severe imbalance between global natural rubber demand and alternative supply sources
• Scaling and cost: many promising bio-materials remain expensive at industrial scale compared to petroleum-based materials
• Processing compatibility: hydrophilic fillers (cellulose, lignin) are difficult to disperse uniformly in hydrophobic rubber matrices
• Standardization: lack of testing standards and regulatory frameworks for sustainable materials and recycled content in tires

CONCLUSION

The global tire manufacturing industry is undergoing a materials revolution. From diversified bio-rubber sources and agricultural fillers to renewable processing oils and circular recycling technologies, the shared goal is to reduce petroleum dependence by 30% before 2030 and achieve 100% sustainable materials by 2050.

With abundant agricultural biomass, a strong natural rubber industry, and rapidly growing industrial demand, Vietnam is strategically positioned to participate in the green tire material value chain—not only as a consumer market but also as a supplier of bio-based raw materials for the region.