Effect Of Organic Solvent On The Entrapment Of 25 Mole Percent Epoxidized Natural Rubber In Preformed Cyclomatrix Poly (1,3-Dioxybenzene) Cyclotriphosphazenes
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Date
2009-11
Authors
Oh, Cheng Cheow
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Blending of 25 mole percent epoxidized natural rubber (ENR-25) with preformed
cyclomatrix poly(1,3-dioxybenzene)cyclotriphosphazene (P5) was carried out in toluene,
methylene chloride, tetrahydrofuran, cyclohexane and 1,4-dioxane. Entrapment studies
with the aid of Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis
(TGA) revealed that P5 can trap ENR-25 chains. The DSC and TGA data for [P5/ENR-25]b
synthesized in all the studied solvents except toluene, revealed the presence of untrapped
ENR-25. No untrapped ENR-25 is obtained in the DSC and TGA analysis results of the
product synthesized in toluene, [P5/ENR-25]b-Toluene. As such, it can be concluded that
synthesis in toluene lead to complete entrapment of ENR-25 in P5. The swelling of P5 in
toluene facilitates the effective entrapment of ENR-25 chains into P5. The results of DSC
analysis revealed the improvement in thermal properties of [P5/ENR-25]b-Toluene, with
higher melting temperature (Tm) of 125 oC, as compared to that of the starting materials
(with Tm of 117 oC for P5 and Tg of -44 oC for ENR-25). The results of FTIR analysis of
the different products revealed no change in the functional groups of the ENR-25 entrapped
in P5, as indicated by the insignificant shift of the absorption frequencies. Therefore it is likely that there is no chemical reaction involve in the entrapment of the ENR-25 chains in
P5.
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Keywords
Organic solvents