A Breakdown is in the Works

To start off the research institute, I (Ty Balduf) was to spend the first few weeks finding related research to my topic of polystyrene photodegradation in the presence of a sensitizer. This research was meant to assist me in developing my proposal, which is a full description of the chemistry involved in the project, the potential applications, and the intended methodology. I came across a lot of useful articles and ideas for how I could develop my research.

One of the early problems I encountered in piecing together a method was how to best irradiate the samples. There was the option of just leaving them in the windowsill and allowing the sunlight to be my UV source, but this could have led to inconsistent results due to the varying amounts of light the samples would get. Thankfully, I was directed by Dr. Gierlus to an article that offered a convenient, albeit unusual, method for irradiating samples. The article demonstrated that one could get consistent photoreactions by using a UV light nail dryer as the light source.

UV irradiation of polystyrene via a commercial gel nail "dryer"

UV irradiation of polystyrene via a commercial gel nail “dryer”

Now that I have preliminary proposal ready, I’ve begun testing to see if my procedure will really work or if some further modifications have to be made. As of right now, my current methodology involves dissolving polystyrene in dichloromethane (DCM), a volatile substance which should evaporate on a flat surface leaving only a thin film of polystyrene. A thin film is needed so I can examine the sample using ATR/FTIR (Attenuated Total Reflectance/Fourier Transform Infrared) spectroscopy. Keeping the description relatively basic, this involves placing a sample on a reflective crystal and bouncing infrared light between it and a mirror until it reaches a detector. The detector can measure how much light of different frequencies the sample absorbed. These wavelengths of absorbed light are distinct to certain chemical groups and so allow one to identify types of chemicals present. For my experiment, there are two particular frequencies I’m looking at. If the samples absorb more light at those frequencies after having been irradiated, it suggests that the polystyrene has begun to break down.

Ty analyzing the FTIR spectrum of a polystyrene/benzophenone film

Ty analyzing the FTIR spectrum of a polystyrene/benzophenone film

 

In the time since I’ve started testing, I’ve encountered a few issues that I’ll need to address, namely that our current ATR crystal is not designed for this type of sample. Fortunately, USRI has provided funding to purchase a new flat plate ZnSe ATR crystal that should allow for more consistent sample prep and analysis. With these tweaks to the method and the new equipment, I’m looking forward to making further progress as I continue the project during the fall semester.

Ty Balduf

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