Mylène Falardeau

[Mylène Falardeau @FalardeauMylene]

Du 15 au 18 juin, #UQTR s’invite dans ton salon https://t.co/zvZY9JGmXj

[Mylène Falardeau @FalardeauMylene]

Du 15 au 18 juin, l’UQTR s’invite dans ton salon https://t.co/zvZY9JGmXj

[Mylène Falardeau @FalardeauMylene]

@csfs1953 Indeed, there are polymer residues on the projectiles. One of the next steps of the project is to analyze these residues!

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[Mylène Falardeau @FalardeauMylene]

It is with pride that I present to you today at #CSFSPoster2020 my master project in forensic chemistry realized at #LRC_UQTR #UQTR and in partnership with #LSJML. My project focuses on the analysis of the degradation of polymers used for 3D printing of firearms.

[Mylène Falardeau @FalardeauMylene]

@csfs1953 Hi,

Official data have not yet been published, as there were not yet many cases identified.Most studies have focused on different types of ABS, as it is one of the polymers whose characteristics are well suited for 3D printed firearms (impact resistance and elasticity).
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[Mylène Falardeau @FalardeauMylene]

@csfs1953 However, I can tell you that the majority of cases at present were 3D printed firearms made of ABS, but there have been recent new cases with other types of polymers (this is confidential for the moment).

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[Mylène Falardeau @FalardeauMylene]

@csfs1953 During my experimental firing, it was precisely the ABS barrel that best withstood the shooting.

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[Mylène Falardeau @FalardeauMylene]

@GarneauBeatrice @UQTR @LRC_UQTR Very interesting, Thank you !!!

[Mylène Falardeau @FalardeauMylene]

@SamuelDaviau I use the example of polylactic acid (PLA) barrel. The degradation temperature of PLA is about 360 C, which is considerably lower than the temperature reached when shooting. For this reason, I believe that the polymer has probably been degraded during the firing process.

[Mylène Falardeau @FalardeauMylene]

@SamuelDaviau During the combustion, the pressure varies thus between 400 and 1000 MPa and the temperature can reach a little more than 3000°C. However, the chamber undergoes these stresses only for a fraction of a second, because the gases are directed towards the muzzle of the gun.

[Mylène Falardeau @FalardeauMylene]

@SamuelDaviau This depends, among other things, on the type of ammunition used. In my case, this is Winchester Super-X .22LR subsonic, 40 gr.

[Mylène Falardeau @FalardeauMylene]

@SamuelDaviau Oh yes, I understand better now why this can be an advantage but also a disadvantage. Thank you!

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan Thanks for the suggestion, I'll find out more about these kinds of tools!

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan Otherwise, it will be difficult to evaluate which deformations come from the shooting and which ones come from the cutting.

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan Lilian, I'm just thinking about this part of the project which is a bit problematic. Indeed, I have to find a way to slice my barrel lengthwise but without creating any additional deformation to the material.

[Mylène Falardeau @FalardeauMylene]

@SamuelDaviau Hi Samuel,
Small question for you: In the advantages and disadvantages you have listed "substrate dependence" as an advantage but also as a disadvantage. What is the reason for this?

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan @Nanophotonics_ ok thanks a lot !

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan @Nanophotonics_ A few questions: 1) What color are your polymer samples, 2) If there are black ones, what happens with the Raman analysis, you must have trouble getting a good signal and 3) Considering that the majority of firearms are made of black polymer, what do you plan to do with that?

[Mylène Falardeau @FalardeauMylene]

@LilianSkokan @Nanophotonics_ Very interesting project Lilian !!!