About 600,000 metric tons of chewing gum are manufactured yearly. Inevitably, a large percentage ends up on streets and pavements and results in a pollution issue. London spends an estimated two million pounds - over four million dollars - every year to clean gum from subway trains and stations. A new gum created by the U.K.-based company Revolymer tackles this issue, easily coming off roads, shoes, and hair.
The main ingredient in most chewing gums is a gum base: a mix of synthetic petroleum-derived polymers, natural latex, resins, and waxes. All of these components are hydrophobic, meaning they stay away from water and are attracted to oil. This is why gum traditionally sticks to the grease and grime on sidewalks. The Revolymer gum base has polymers with a hydrophobic part that's wrapped inside a hydrophilic, or water-attracting, part. So even though the gum sticks to a surface, a film of water can form around it so that it easily washes away with water.
The new gum performed well in tests. When stuck on sidewalks, rainwater or street cleaning washed it off within 24 hours. Tests also showed that when Revolymer's gum was stirred into water, it disintegrated completely in eight weeks, which means it could degrade once it goes into a drain. The gum also did well in blind taste tests, though the texture is slightly softer because the hydrophilic polymer interacts with saliva. Revolymer plans to launch the gum in three different flavors next year.