Thursday, April 09, 2015

Material Choices and Testing Protocols for Condoms

Last week Slate magazine published an in-depth article entitled "We Should Have a Better Condom by Now. Here’s Why We Don’t." Before clicking on the link, I would suggest proceeding with caution, as there numerous photographs of condoms on all manners of produce items. In other words, it may be a little bit unsafe for work. Or around children. Or your parents. But I would recommend reading it if you are interested. It provides a serious look at the many sides of something that has far too much politics involved (as you will soon see.)

My comments here will be just limited to comments. No photos or images. Not ribald jokes. Just a serious discussion about some of the issues about the mechanical testing and the polymers being explored for new condoms. At times like this, it's appropriate to pull out the middle French expression - Honi_soit_qui_mal_y_pense (May he be shamed who thinks badly of it).


When Carl Djerassi, the inventor of "the Pill", recently passed away, there was much recognition of the role that the pill has played in the lives of women around the world. While it has numerous "off-label" uses, it's most commonly used for birth control. As important as that is, a lowly piece of rubber, a condom, has to do all that and more. Not only are condoms used for birth control, but also for preventing the spread of sexually transmitted infections. And yet as important as this product is, the article points out that very few innovations have been or are being developed, despite the well-known shortcomings in existing products.

The reasons for the lack of developments are numerous. Part of it is lack of appropriate testing procedures. The testing procedures that the US Food and Drug Administration (FDA) uses are designed to mimic vaginal sex and no other sex act.
" 'It’s a little political, because I don’t think the sponsors—i.e., condom manufacturers— necessarily want their name identified in publications that they’ve done this big anal research study...The FDA would love the information, and I also think the NIH [National Institute of Health] would love the information, but they also don’t want to be known as funding the anal intercourse study.' Take a moment to imagine how Republicans in Congress might react if the NIH used taxpayer dollars to study the mechanics of anal sex."
But this does raise a legitimate question - What are the mechanical demands placed on a condom? Once they are known, then it is much easier to develop a test that can measure the material performance of interest. But current testing is well removed from reality.
"To test condom strength, the air burst test, in which randomly selected condoms are filled with air to determine the volume and pressure at which they burst, won out over the tensile strength test, which stretched condoms mechanically to determine the force required to rip them."
Air burst? Tensile testing (i.e., pulling the condom from both ends and measuring the force)? How could either of these be under consideration at all? Wouldn't some type of friction test or other shearing stress better mimic reality?

The article also discusses the materials being used and developed. The vast majority of current condoms are made from latex (natural) rubber. Some polyurethane condoms have been developed, but the author gets a raspberry from me for not knowing that there are countless numbers of polyurethane rubbers that all have different mechanical properties. As such, polyurethane condoms should not all be grouped together as one. But she quickly makes up for it when it comes to a condom that the manufacturer describes as being made from "a revolutionary material - polyisoprene". The author gets plenty of kudos from me for pointing out what many readers will already know - the macromolecule that makes up the rubber in latex rubber is polyisoprene. This "revolutionary" material is simply the synthetic equivalent of latex rubber and has been around for decades.

The discussion of materials naturally leads into a discussion of "feel", which is a large drawback for current condoms. For reasons that are well removed from condom design, I've always thought that latex would have about as good of feel as you could hope for. After all, they are the preferred choice of surgeons for whom "feel" is critical in surgical procedures. Surgeons who develop sensitivity to latex are always complaining about how the latex-free gloves have less feel to them. I would have expected the same of condoms. The article also mentioned the high cost associated with clinical evaluations that prevent smaller companies from innovating with new materials - maybe a tie-in with surgical gloves would help expand the potential market and the interest of investors.

The overall tone of the article is not optimistic. Between the snickering and political stands, it's hard to get support for the work. Having better condoms would increase their usage. It's much like PPE is for chemists - the more comfortable it is and the easier it is to use, the more likely it is to be used. If you've still had a great fitting pair of safety glasses on when you get home from work (like I have), you know what I mean.

As always, comments are welcomed below. And as always, you can comment anonymously.

Hattip to Chemjobber for bringing this article to my attention.

Previous Years

April 9, 2014 - Those Rich Petroleum Engineers

April 9, 2013 - Can We All Get Along?

April 9, 2012 - Poor Posed Concerns About Chemical Safety

April 9, 2010 - A Neat New Set of Solvents

No comments: