19
$\begingroup$

To give this question context, I work in a restaurant and sometimes I'm in charge of getting all of the gum off of the tables at work. Don't mind the work, but I'd be interested in hearing what makes gum so sticky and if there is any chemical I can use to make the cleaning a bit easier and why that chemical works.

I guess another backwards question is: Is there any chemical I can apply to the underside of tables that will prevent the gum from sticking? Would be awesome if I could fix the problem at the source and would be super interested in the chemistry behind it.

$\endgroup$
14
$\begingroup$

The International Chewing Gum Association tells us:

Gum base is what gives chewing gum its “chew.” It is made of a combination of food-grade polymers, waxes, and softeners that give it the texture desired by consumers and enable it to effectively deliver sweetness, flavor, and various other benefits, including dental benefits.

A more complete description of what makes chewing gum sticky states:

Terence Cosgrove, Professor of Chemistry at the University of Bristol and Chief Scientific Officer of Revolymer, explains that the chemical bonds between the molecules in a polymer-based chewing gum make it difficult to remove from a surface. When you pull a piece of used gum off a surface, most of the energy goes into stretching the polymer bonds in the gum, rather than actually breaking the bonds between the surface and the gum. Since polymers are long chains of covalently bonded molecules that give the gum its elasticity and "chewiness," the attractive forces between the atoms are formed by the sharing of electrons [8]. Thus, the bonds between the repeating units tend to remain intact as they lengthen and contract from an applied external force.

The temperature at which the polymer base is exposed to the air also affects both the elasticity and adhesiveness of the chewing gum. When a piece of gum is heated by saliva and deformed by the grinding of human teeth, its polymer chains align in the direction of these forces. The degree of alignment is a function of the magnitude of applied stress, which explains why the gum becomes tougher and less elastic the longer or more rigorously you chew [8]. After the gum is removed from your mouth and placed in a cooler environment, the drop in temperature causes the orientation of the polymer chain to freeze, resulting in a hardened piece of used gum.

Most commercial polymer gum bases are hydrophobic (water-insoluble), which is the reason they stick easily to oily surfaces and are difficult to remove, even with the help of household cleaning solutions. A hydrophobic substance tends to repel polarized molecules like water and attract non-polar compounds, such as the grease and grime on streets. A hydrophilic substance, on the other hand, behaves in the opposite manner by attracting water and repelling fats and oils [8]. A compound that exhibits both hydrophobic and hydrophilic traits is known as "amphiphilic" [9]. These substances, which attract both water and oil to some degree, can be used to create synthetic polymers that could help eliminate the sticky mess of chewing gum pollution.

Note: The numbered references in the above block quote can be pulled from the linked article. The article also details efforts aimed at producing a new type of chewing gum that doesn't stick to things as much as normal/currently-manufactured ones seem to. It's a good read.

But to your main point, I've linked the MSDS for a popular product for removing gum and related compounds (it's called Goof Off), which consists almost entirely of acetone (also commonly found in nail polish remover). Given the deleterious health effects of acetone (and its high vapor pressure), it's not a good candidate for your needs.

Something non-stick and more permanent, such as a Teflon spray might be ideal for your needs.

$\endgroup$
  • $\begingroup$ Judging from Wikipedia, Acetone really is not bad. It is pretty much entirely nontoxic, as far as I know. Short of ingesting it, what deleterious effects are you talking about? I mess with it a lot, and am worried if that is not a good idea. $\endgroup$ – ChemBird Dec 3 '16 at 18:39
  • $\begingroup$ Wikipedia - or, more accurately, your interpretation of the information given there - is incorrect. I refer you to the SDS for acetone. You should always consult the SDS (Safety Data Sheet) for any chemical you work with: these are standardized forms that communicate the hazards of the substance in question (find out more at OSHA). $\endgroup$ – Todd Minehardt Dec 3 '16 at 19:50

protected by orthocresol May 9 '17 at 11:18

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.