# Reaction of PLA plastic with methane or carbon dioxide

PLA (polylactic acid) plastic is commonly used for 3D printing, and I would like to create a 3D printed part that can be used in an experiment with methane ($\ce{CH4}$) and carbon dioxide ($\ce{CO2}$) gas sensors. Does $\ce{CH4}$ or $\ce{CO2}$ gas react with PLA plastic? What are the long-term effects of these gases in contact with PLA plastic?

Anaerobic biodegradation can break down PLA, producing $\ce{CH4}$ under some environmental conditions (DOI: 10.3390/ijms10093824). But is PLA resilient to $\ce{CH4}$, or is there a chemical reaction? I can't seem to find any reference to such an effect in the literature.

The experiment that I am conducting involves the measurement of environmental sources of $\ce{CH4}$ and $\ce{CO2}$ gas. A hose needs to be passed into a 3D printed chamber that encapsulates the sensors. A molecular sieve material blocks water and sources of moisture before the gas enters the chamber. The chamber will not be heated in any fashion (room temperature or colder), and detection of the gas by the sensors is by diffusion.

• Do you intend just to place PLA altogether with $\ce{CH4}$ or/and $\ce{CO2}$ alone in a dry, closed container, at room temperature? Then the occurrence of a degradation / decomposition reaction is unlikely. Or do you add some other chemicals? Or do you intend to warm / heat PLA and $\ce{CH4}$, or even ignite the methane in presence of PLA? Please add some details of the intended experiment. – Buttonwood Jun 28 '17 at 20:51
• @Buttonwood: Thanks, I've added some text to the description above. – Nicholas Kinar Jun 29 '17 at 0:29