A chemistry approach to environmentally friendly yoga mats… NBR, NR, TPE, PER I'm currently seeking your expertise while creating a line of environmentally friendly yoga mats, and I apologize in advance if any chemistry knowledge of mine has been absent since college and I lack the technical capability of this forum. I typically have a scientific approach to problem solving, and I'm hoping I can apply the same methodology to finalizing the material composition of my product. 

Instead of blindly accepting the industry suggestions of natural rubber, NBR, TPE, and PER, I wanted to start with the physical characteristics required and work backwards to determine the ideal (perhaps innovative) material that would work best. My requirements are: 1) Eco-Friendly, 2) high fidelity printing compatibility via heat transfer

1) Environmentally friendly: PVC is not an option for the reasons I'm sure you would know. One would assume natural rubber would be the obvious choice, however if it degrades and has to be replaced every 2 years or so, I'd think the long term production effects might actually be more harmful then something more sustainable. From reading an article on PER it seems like it is essentially phthalate free PVC, and although processed different to be phthalate free the vinyl chloride monomer still exists and could be viewed as toxic, although to a lesser degree then PVC. Nitrile Rubber (NBR) is another option but it sounds like although it might be more heat resistant then natural rubber, it degrades similar to natural rubber. Various types of TPEs are also an option, but I've found minimum answers towards their actual eco-friendliness.

2) Heat resistant printing - Sublimation printing has typical been used on polyester, but from what I've researched should be compatible with any polymer. Unfortunately it requires a heat transfer of about 400 deg F, which I believe would scorch/melt natural rubber. 

I know its a stretch, but I would love to get your input on the above materials or any other polymer that might be an option. I don't want to blindly commit to an "eco-friendly" material without fully investigating their chemical properties.

Thank you in advance for your help, and I'm definitely open to all of your respected critiques and suggestions.
Regards,
Shane
You will need a natural woven fiber. Any film will not help the skin in contact with it.