The In-Situ Reaction of Hexachlorocyclotriphosphazene with (2- and 4- hydroxyaniline) In the Presence of 25 mole Percent Epoxidized Natural Rubber

الملخص

In this study, the entrapment of 25 mole percent epoxidized natural rubber (ENR-25)
within the matrix of organocyclotriphosphazene has been explored. Two different
matrices, tight and loose were prepared via a one-step condensation polymerization of
hexachlorocyclotriphosphazene (CTP) with 2-hydroxyaniline (o-aminophenol) or 4-
hydroxyaniline (p-aminophenol) in molar ratio (1:3) in the presence of 25-mole percent
epoxidized natural rubber resulting, PO2APC/ENR-25 and PO4APC/ENR-25,
respectively. The morphology study of PO2APC/ENR-25 showed two separated entities
present at the surface of the material, indicating that the entrapment of ENR-25 chains
within the tight matrix (1-oxy-2-minophenyl)cyclotriphosphazene (PO2APC) seized to
happen. On the other hand, the morphology of PO4APC/ENR-25 showed a very smooth
and homogenous surface texture, indicating the effective entrapment and uniform
dispersion of the ENR-25 chains within the loose matrix (1-oxy-4-
minophenyl)cyclotriphosphazene (PO4APC). The DSC analysis of pure PO4APC showed
a glass transition temperature (Tg) at 120oC while the neat ENR-25 showed Tg at about -
44oC. The DSC thermogram of PO4APC/ENR-25 reveals a soul glass transition
temperature at 76oC which is more than 120oC higher than the Tg of ENR-25 and 44oC
lower than the Tg of PO4APC. The TGA thermogram of neat ENR-25 showed one main
decomposition step at 416 oC, while that of PO4APC showed three decomposition steps at
220, 500, 645oC. The TGA thermogram of PO4APC/ENR-25 showed two decomposition
steps, the
first occurred at 213°C is attributed to partial decomposition of the cyclomatrix, PO4APC,
and the second (main) occurred at 460°C is due to decomposition of ENR-25 trapped in
PO4APC. The structural study of PO4APC/ENR-25 by FT:IR showed all the
characteristic absorptions due to PO4APC and ENR-25 without any changes or shifting,
indicating that there is no bonds braking or forming taken place between PO4APC and
ENR-25. The 1HNMR analysis of PO4APC/ENR-25 revealed that the relative integral
ratio of the epoxy proton at δ 2.70 ppm and olefinic proton at δ 5.17 ppm remains
practically similar to that observed in the 1HNMR spectrum of neat ENR-25 which is
equal to about 25%, affirming that the microstructure of ENR-25 remains intact in
PO4APC/ENR-25.