Pulverized materials su
ch as metalli
c or polymer powders play a
considerable role in many industrial pro
cesses. Their use requires the introdu
ction of preventive safeguards to
control the plant's safety.PA12 polymer powder pro
cessing by laser sintering is
chara
cteristi
c of this tenden
cy. The present work
con
cerns PA12 powder (bimodal parti
cle size distribution: 10 μm and 55 μm) and relates to explosion sensitivity and the thermal degradation of this powder, whi
ch
can o
ccur during laser sintering. Minimum Ignition Energy is determined using a modified Hartmann tube
combined with the Langlie method developed in the PRISME Laboratory. This study shows the influen
ce of parameters su
ch as distan
ce between the ele
ctrodes, powder
con
centration and ar
c power on MIE values. Theses parameters vary in the range of 3–6 A for the
current intensity of the spark and the ele
ctrode gap in the range of 2.5–4 mm. The MIE is obtained for a spark gap of 3 mm and
current intensity of the 4 A spark in our devi
ce. It shows that the MIE is less than 40 mJ for
con
centrations approa
ching 1000 g/m
3. At lower
con
centrations (under 150 g/m
3) the MIE in
creases but dis
crepan
cies in measurements appear, probably be
cause of the stati
c ele
ctri
city that
creates strong irregularities in dust dispersion. The se
cond part of this study
con
cerns the thermal degradation of the PA12 whi
ch is performed by thermogravimetri
c experiments
coupled with mass spe
ctrometri
c (MS) analysis for gas investigation. The mass loss measurement
combined with the gas analysis allows the prin
cipal stages of degradation to be determined so as to
cal
culate the kineti
cs parameter PA12. Experiments have been performed for different heating rates between 1 and 30 K min
?1 and the reprodu
cibility of experiments has been verified. The a
ctivation energy is determined using two methods: Freidman and KAS. For a rea
ction rate of between 0.2 and 0.6, the a
ctivation energy is nearly
constant. The KAS method gives a value of
Ea = 250 kJ mol
?1 and the Friedman method gives
Ea = 300 kJ mol
?1. The gas analysis by MS shows that oxidation begins at over 350 °C and finishes at under 650 °C with the formation of CO
2 and H
2O. Other major peaks with an
m/
z ratio of 29, 28 and 30 are noti
ced in this range of temperature. They show the presen
ce of intermediate spe
cies su
ch as C
2H
6, NO or CH
2O. The presen
ce of HCN is also dete
cted (
m/
z ratio of 27).
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