jedrider wrote:Just a blurb on rubber. Surprisingly, natural rubber is produced (or harvested) in equal amounts to synthetic rubber. So, it must not be obsolete by any means.
Rubber: A simple introduction.https://www.explainthatstuff.com/rubber.html
There is a world of difference between something being obsolete and something being manufacturable, for want of a better word. The only real reason I know much about rubber derives from two facts, 1) tire derived fuel is used at a power plant about 60 miles north of where I am right now. I happened to board a tour boat at a company picnic hosted by my then spouse's employer at the same dock where the TDR was unloaded and picking a piece up that had escaped the power station property I was made curious so I looked it up. It turns our shredded used rubber has about the same calorie count by volume as diesel fuel and by using it to fire the boilers in the formerly coal fired power station the city that owns it got credit from some green federal initiative for disposing of waste tires in an environmentally sound manner getting both electricity out of the burning in a tightly controlled efficient fire with pollution controls, but also for reducing the massive piles of waste tires that our culture has accumulated over many decades. 2) the second reason is plain old common rubber aka PolyButeidine, is the main fuel mass in solid rocket engines for everything from the air to air missiles our military uses to space launch vehicles like the old Scout rocket or the Space Shuttle solid rocket boosters. You take a rubber matrix that is still liquid, mix in small flakes of aluminum powder and Ammonium Perchlorate crystals and Voile' you have solid rocked fuel you can pour into a casing and allow to harden. Then you very carefully do not ignite it until you want it to go off because once it starts burning it keeps burning until 99.9% of the mass is consumed. The civilian Space Ship Two project even used tire derived fuel and Dinitrogen Tetroxide gaseous oxidizer back in 2006 to set civilian space flight records.
IMO the reason any natural rubber is still on the market is pretty basic, what of it there is is almost exclusively harvested by small scale private landholders who work in the tropics using hand labor to tend the trees and harvest the raw material for very very low wages compared to first world expectations. If these small farmers were not willing to work for such incredibly low wage scales compared to the people working in the synthetic rubber plants in industrialized nations they would never be able to compete with the economies of scale those industrial plants use.