ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 6, pp. 1009−1018. © Pleiades Publishing, Ltd., 2016.
The text was submitted by the authors in English.
Red phosphorus (RP) is an important ingredient for
the manufacture of pyrotech nic smokes and is likely to
be in service for many years . It has been widely used
in screening applications where obscuration is achieved
in various portions of the electromagnetic spectrum,
including the visible range and in several IR bands .
However, the main disadvantages of RP are the evolution
of highly toxic phosphine through reaction with moisture
and the poor thermos tability.
Accordingly, RP used as a pyrotechnic material
needs surface treatments and inorganic and polymeric
microencapsulation is the most often used technique .
Due to better properties of polymeric microencapsulated
RP, various thermosetting resins e.g., epoxy resin,
melamine formaldehyde, urea formaldehyde, and
phenolic formaldehyde resins are preferably adopted to
encapsulated RP . However, it is noticeable the MRP
are used as ﬁ re retardants, the mass fraction of coating
materials is more than 10%, and it must have negative
effects on the pyrotechnic smokes. In the present work,
aluminium hydroxide/melamine–formaldehyde resin
microcapsulated red phosphorus was successfully
prepared. And it not only has a high resistance to moisture,
high thermostability but also reduces the mass fraction
of coating layer.
Moreover, the pyrolysis and combustion of MRP
have a close relationship with their thermo-o xidative
degradation process. Therefore, it is very important
to evaluate the thermal stability and thermo-o xidative
degradation of MRP. Several ways have been developed
to evaluate the pyrolysis behaviors of polymer composites
[5–7]. In this regard, to understand the thermo-oxidative
degradation mechanism of MRP, some thermal analysis
methods (TG/DTG, DTA) were used to evaluate the
kinetic parameters. The mechanism is described by a
Preparation and Characterization of Microcapsulated Red
Phosphorus and Its Multi-Step Thermal Oxidation Processes
Based on Kinetic Approach
Jie Liu, Dongming Song*, and Hua Guan
Laboratory of Military Chemistry and Pyrotechnics, School of Chemical Engineering, Nanjing, China 210094
University of Science and Technology, Xiaolinwei str. 200, Nanjing, China 210094
Received May 18, 2016
Abstract—Aluminium hydroxide/melamine–formaldehyde resin microcapsulated red phosphorus (MRP) was
successfully prepared by two-step processes. The microcapsulated red phosphorus was characterized with Fourier-
transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Meanwhile its water absorp-
tion, thermostability were also determined. The results show that the MRP exhibited lower water absorption and
higher thermostability compared with red phosphorus (RP) itself. Moreover, the thermal oxidative decomposition
kinetics of MRP was investigated by TG/DTG and DTA in air atmosphere using non-isothermal experiments. The
results show that the MRP’s decomposition consisted of two steps. And the apparent activation energies E
determined by applying both the Ozawa–Flynn–Wall (OFW) and Kissinger, Akahira and Sunose (KAS) methods.
It was found that the dependence of E
on α is complex. Both of the steps in this study ﬁ tted Sestak–Berggren (SB)
model in overall reaction controlled kinetics and the corresponding model parameters, n, m, A were obtained. The
simulated curves were ﬁ tted to experimental curves by plotting dα/dt vs. temperature at different heating rates.