Albany, California – Cooper Tire & Rubber Co. scientists have reached a key milestone toward the goal of producing, by mid-2017, a concept tire that will be based 100-percent on guayule-based polymers.

At its recent annual meeting in Albany, the public-private consortium behind the Biomass Research and Development Initiative (BRDI) grant, “Securing the Future of Natural Rubber – an American Tire and Bioenergy Platform from Guayule,” reported several key advancements emerging from the group’s work over the past year.

Guayule is a shrub that is grown primarily in the southwestern US and contains latex that can be processed into rubber for use in tires.

The 100-percent guayule-based concept tire will undergo extensive technical evaluation following its production. Concurrently, Cooper will continue studies on potential commercialisation of guayule-based tires for the future.

To date, Cooper – the lead agency in a research grant project – has completed a number of tire builds, iterative work that includes the replacement of both Hevea and synthetic rubber with guayule in various components, and then testing each build for overall performance, the Findlay-based tire maker said.

“We have nearly finished our work on developing guayule-based tire components and have tested these tires to assure a full performance evaluation,” said Chuck Yurkovich, Cooper’s senior vice president of global research & development.

“The results are highly promising. We have proven that we can replace traditional polymers with guayule in certain components, and that tires made from these components perform equal to conventional tires. We are optimising the use of guayule formulations to develop not only a full guayule tire, but we will also evaluate guayule blends in certain components where an advantage has been shown to exist.”

Another grant consortium partner, the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA-ARS), announced at the BRDI meeting that it has completed the most extensive irrigation study ever done on guayule. Growing guayule in desert regions requires judicious management of irrigation water for maximising yields while minimising water usage.

The study, which began in 2012 and involved two guayule fields in Maricopa, Arizona, compared surface irrigation and subsurface drip irrigation to determine the most effective method to drive higher rubber yield per acre.

The final harvest was completed in March 2015 and ARS concluded that drip irrigation provided an “enormous benefit” over other irrigation techniques and led to improved yields. The information obtained is critical to developing optimum guayule farming techniques to support a potential future guayule industry, the agency said.

ARS said it is developing a Web-based application that will allow farmers to use the data to maximise their yields.

The service also is sequencing the guayule genome so the crop can benefit from modern breeding and genetics tools. The molecular efforts are designed to advance improvements in terms of yield, resistance to disease and pests, cold tolerance and other factors, laying the foundation for molecular breeding of the plant.

ARS announced that this work has resulted in three patent disclosures on the genome, which will be submitted to the US Patent Office, significantly advancing the understanding of the plant and how to engineer it moving forward to maximise its potential in the production of rubber for the tire industry.

"We now have the first-ever assembly of the guayule plant genome,” said Colleen McMahan, PhD, research chemist, ARS, Western Regional Research Laboratory. “This resource, and the advanced breeding tools from Cornell (University), will benefit breeders for decades to come through agricultural innovations.”

The BRDI annual meeting also included a report from Clemson University, which is responsible for studying the environmental impacts of the entire tire life cycle using guayule vs. traditional Hevea rubber in tire production. Clemson said it has completed early work on the development of a computer-based Life Cycle Analysis programme for guayule-based tires that will help quantify the sustainability of the effort from genome to tire production and through the service life and disposal of tires.

“A comprehensive sustainability analysis encompasses all three pillars of sustainability: economics, environment and society. Our work shows that a domestic source of rubber can be sustainable; we have to minimise water consumption in agriculture and optimise energy usage and co-products throughout the supply chain,” said Clemson University’s Amy Landis.

Meanwhile, grant partner PanAridus has developed varieties of guayule with increased rubber content and has pioneered direct seeding methods, agronomics and co-product markets. At the BRDI annual meeting, PanAridus provided an update on its role in production of rubber for use in the tire industry. PanAridus and Cooper have developed a proprietary solvent-based process to extract rubber from guayule plants.

Under its work on the grant, PanAridus claimed to have produced rubber in quantities never before achieved for use in modern tires. This rubber has been supplied to Cooper for its work in the tire builds and testing.

“It has been our mission at PanAridus to commercialise guayule from the farm gate to market development of raw materials produced from the plant. Hevea is currently the only commercial source of natural rubber available. The tire industry needs another source and the United States needs an economic, sustainable and stable alternative. With the dedicated research efforts of Cooper, it is unprecedented to see that guayule has been demonstrated to meet requirements for the very vibrant tire industry,” said Mike Fraley, CEO of PanAridus.

The BRDI Consortium received the five-year grant in 2012 from the USDA and the US Department of Energy (DOE) to conduct research aimed at developing enhanced manufacturing processes for the production of solid rubber from the guayule plant as a biomaterial for tire applications, as well as evaluating the plant’s residual biomass for potential fuel applications. The grant period ends in the second quarter of 2017.