Today's KNOWLEDGE Share:
Plastic fork
I was travelling a few weeks ago and between flights grabbed some dinner at the Atlanta airport. I got my food and along with it came a plastic fork – nothing unusual there. As I looked around from my table, I noticed that there were signs indicating that the utensils were made from compostable material and that they were environmentally friendly. Cool, I thought. As I was eating, I noticed molded-in writing on my fork. On the top surface the fork was labelled as “Compostable Commercially*”. I thought it was funny that there was an asterisk. What could that be about I wondered, until I noticed even smaller molded-in printing on the reverse side. The reverse side markings indicated “*Facilities may not exist in your area.” Ahh – the asterisk is explained.
My curiosity was peaked - what is this *compostable* fork made from? I took the fork and when I returned to the office, I analyzed it. The first test I ran was Fourier transform infrared spectroscopy (FTIR). This identified the fork material as polylactic acid (PLA). This made sense because I found that PLA is compostable under controlled conditions.
Next, the material was analyzed using differential scanning calorimetry (DSC). This thermal analysis technique identified a glass transition temperature (Tg) of 65 °C and a melting point (Tm) of 177 °C. Both of these were consistent with a PLA resin.
Finally, thermogravimetric analysis was utilized, and this indicated that the base polymer underwent thermal degradation at 349 °C. Further, the composition was characterized with a nominal filler content of 15%.
On the non-technical side, I noticed that there were no special receptacles at the airport to collect these compostable utensils, and that people were throwing them into the garbage. From the little I know; I do not think that these PLA forks will compost in a landfill.
Source:The Madison Group
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#plastics #polymerengineering #polymerscience #materialsscience #forks #pla #compostable #ftir #dsc #tga #analysis #biobased #molded #food #printing #utensils
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