The synthesis, chemical and physical characterisation of selected energetic binder systems
Date
2009-03
Authors
Alkaabi, Khalifa
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Due to numerous accidents involving munitions, recent interest has focused on the
development and use of insensitive munitions (IM). Polymeric materials are used in
insensitive munitions as binders or plasticizers. Most of the polymeric binders used
are based on polycondensation reaction via using urethane linkages.
The main aim of this study was the synthesis and characterization of selected
energetic thermoplastic elastomers binder based on utilizing controlled free radical
polymerization. This was achieved by using hydroxyl terminated poly
(epichlorohydrin) (PECH-diol) and hydroxyl terminated glycidyl azide polymer
(GAP-diol) as starting materials, and the subsequent synthesis of different macroinitiators.
These macro-initiators were used to polymerize methyl methacrylate
(MMA) to obtain thermoplastic elastomers.
PECH-diol was prepared by cationic ring-opening polymerization (CROP) based on
using borontrifluoride etherate (BF3-etherate) as catalyst and a low molecular weight
diol as initiator. GAP-diol was synthesized by the reaction of PECH-diol with sodium
azide in organic solvent..
Poly(epichlorohydrin-methyl methacrylate) (PECH-PMMA) and poly(glycidyl azidemethyl
methacrylate) (GAP-PMMA) block copolymers were prepared by free radical
polymerization of MMA monomer in presence of PECH and GAP macro-azoinitiator
(MAI). The MAIs were prepared by the polycondensation reaction of
hydroxyl terminated groups of elastomer with 4,4' azobis (4-cyanopentanoyl chloride)
(ACPC). The phase behavior of blends of amorphous PMMA/PECH-diol and
PMMA/GAP-diol was also investigated.
Poly(epichlorohydrin-methyl methacrylate) (PECH-PMMA) and poly(glycidyl azidemethyl
methacrylate) (GAP-PMMA) graft copolymers were synthesized by
photopolymerization of MMA in presence of PECH and GAP with pendant N,Ndiethyldithiocarbamate
groups as macro-photoiniferters. . Photopolymerization of
MMA proceeded in a controlled fashion.
A macro RAFT agent, based on the reaction of PECH with pendent dithiobenzoate
was prepared. The macro-RAFT agent was used in the controlled thermal bulk
polymerization of methyl methacrylate. Finally, living/controlled radical polymerization of MMA with four different photoiniferters, namely benzyl diethyl
dithiocarbamate (BDC), 2-(N,N-diethyldithiocarbamyl) propionic acid (PDC), 2-(N,Ndiethyldithiocarbamyl)
isobutyric acid (DTCA), and diethyl dithiocarbamateepichlorohydrin
was achieved.
Description
Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2009.
Keywords
Binders (Materials), Polymerization, Polymers, Elastomers, Dissertations -- Chemistry, Theses -- Chemistry