Suresh C. Ameta

An Overview of Rubber Recycling

Since the discovery of vulcanisation, rubber has become an indispensable material for the technological development of civilisation, starting from a simple balloon to complex rocket propellant. Rubber Industry worldwide is using on an average 50% of raw materials. These materials are mostly petroleum-based, except natural rubber (NR), steel cord and bead wire. Use of these petroleum-based raw materials not only depletes natural resources, but also produces more extreme environmental hazards. Escalation of petroleum prices, greater awareness of the environment has resulted in different recycling and environmental friendly technologies. Furthermore, the new concept of ‘Cradle to Grave’ has created a significant concern to the manufacturer about present use of petroleum-based raw materials in the rubber industry worldwide. For both environmental and economic reasons, there is also a continuing broad-based interest in the recycling of scrap rubber and rubber recycled materials and therefore in the development of recycling technologies.

Effect of Ozone, Thermo, and Thermo-oxidative Aging on the Physical Property of Styrene Butadiene Rubber-Organoclay Nanocomposites

The present study describes the effect of thermo, thermo-oxidative, and ozone exposure on the retention of physical property of organoclay nanocomposites. Accelerated thermal aging is carried out at 130°C for 30 h. Accelerated thermo-oxidative aging is carried out at 105°C for 7 days. Samples are exposed to 50 pphm ozone atmosphere for 24 and 48 h. The result indicates that the retention of physical property is better in nanocomposites compared to carbon black-filled compounds under thermal and thermo-oxidative aging. Besides, ozone resistance is also relatively superior for nanocomposites. The superior barrier property of the nanocomposites is attributed to the better retention of the physical property after aging.

Use of recycled lyre material in natural rubber based tyre tread cap compound Part I: (with ground crumb rubber)

For both environmental and economic reasons, there is a continuing broad-based interest in the recycling of scrap rubber and therefore in the development of recycling technologies. In the present work three different sizes of mechanically ground Indian crumb rubbers were used in a natural rubber (NR) based tyre tread cap compound. Varying doses of crumb rubber were used as an additional compounding ingredient. The minimum torque and Mooney viscosity values were marginally increased with increasing dose and mesh size of crumb rubber. In a Rubber Process Analyser (RPA) study, the Payne effect before curing was marginally higher for compounds containing crumb rubber, while, after curing a comparable Payne effect was observed with respect to the control compound without having crumb rubber. A marginal deterioration in tensile strength, fatigue to failure and abrasion properties was observed. At all levels of usage, the 100 mesh size ground crumb rubber retained the properties better than other lower mesh size crumb rubbers.

Use of recycled tyre material in natural rubber-based tyre tread cap compound: Part I

For both environmental and economic reasons, there is a continuing broad-based interest in recycling of scrap rubber and in the development of recycling technologies. Among all the polymeric materials, the reuse of rubber vulcanisate is the most difficult, being thermosetting in nature the crosslinks formed are not easily broken down. In the present work, three different types of recycled materials (coarse reclaim, superfine reclaim and de-vulcanised rubber) were used in a natural rubber (NR) based bias tyre tread cap compound. Various quantities of the above ingredients were used as a replacement for virgin natural rubber. Chemical characterisation of the recycled material, the mixed rubber compound rheometric properties, unaged and air-aged stress strain properties, hardness, fatigue to failure, Demattia crack initiation, crack propagation, abrasion loss, volume fraction, rebound resilience, elastic modulus and dynamic mechanical properties were performed. In all levels of usage, the superfine reclaim rubber retained the properties to a greater extent when compared to the other recycled materials used in the study.

Use of recycled tyre material in NR/BR blend based tyre tread compound: Part II (with ground crumb rubber)

For both the environment and basic economic reasons, there is a continual interest in the recycling of scrap rubber and therefore in the development of recycling technologies. In the present work three different sizes of mechanically ground Indian crumb rubbers were characterised using different chemical and analytical methods and were used in a NR/BR blend based light commercial vehicle (LCV) tyre tread compound. Varying doses of crumb rubber were used as an additional ingredient. The minimum torque and Mooney viscosity values were marginally increased with increasing dose and mesh size of crumb rubber. A marginal deterioration in tensile strength, fatigue to failure and abrasion properties was observed. At all levels of usage, the 100 mesh size mechanically ground Indian crumb rubber retained the properties better than other lower mesh size crumb rubbers.

Improved Polymer–Filler Interaction with an Ecofriendly Processing Aid. Part 1

Internationally there is a trend towards the use of ecofriendly materials in view of the environmental benefit and the improvement in properties. In the present work, the chemical and analytical properties of an eco processing aid and a soluble-zinc-soap-based processing aid (Zincolet PN60) were assessed. The two processing aids were also analysed in a styrene butadiene rubber/natural rubber/butadiene rubber blend based on tyre tread compounds. Compounds mixed with the eco processing aid exhibited better mixing properties, better polymer–filler interaction, marginally better filler dispersion and flow behaviour, and better heat build-up and fatigue-to-failure properties.

Research on the Application of Recycled Waste RFL (Resorcinol-Formaldehyde-Latex) Dip Solid in Styrene Butadiene Rubber Based Compounds

Waste resorcinol-formaldehyde-latex (RFL) dip solid was collected from the suction chamber of a typical tyre industry dip unit. The physico-chemical characterization of the material was carried out, along with a fresh RFL dip solid obtained by drying a fresh dip solution. The effect of the waste material was studied in a styrene butadiene rubber (SBR) based compound in both gum and filled state. The waste material was treated with boiled water and dilute hydrochloric acid and the effect of the treated material was further studied in the SBR based filled compound. The filler dispersion, polymer-filler interaction and dynamic mechanical properties was also studied.

Recycling of waste RFL (Resorcinol-Formaldehyde Latex) dip solid in natural rubber-based ply skim compound

Waste resorcinol – formaldehyde – latex (RFL) dip solid was collected from the suction chamber of a typical tyre industry dip unit. The cure acceleration effect of the waste material was studied in a natural rubber (NR) based filled compound. The effect of the waste material was examined in a natural rubber (NR) based ply skim compound of a bias tyre with cure package modification. Rheological, tack index, stress-strain properties, swell index, dynamic mechanical properties, H-adhesion before and after anaerobic aging was also studied.

Effect of regenerated carbon-black on a bias tyre tread cap compound

Carbon black, which is an important ingredient in a tyre, was regenerated from waste automobile tyre tread component. The regenerated black was characterised by different chemical and analytical methods and the properties were compared with a virgin N330 black. The regenerated black was also evaluated in a bias lug type tyre tread cap compound. It was observed that compared to the virgin black the regenerated black exhibited marginal inferior physico-mechanical properties. A linear trend of decrease in properties on increasing the dosage of the regenerated black was also observed.