Synthesis and characterization of energetic GAP‐b‐PAEMA block copolymer

Abstract

Energetic block copolymer of polyglycidylazide‐b‐poly (azidoethyl methacrylate) (GAP‐b‐PAEMA) was synthesized and characterized. Macroinitiator PECH‐Br prepared via the reaction of 2‐bromoisobutyryl bromide with hydroxyl‐terminated polyepichlorohydrin (PECH‐OH) was used to initiate the atom transfer radical polymerization (ATRP) of chloroethyl methacrylate (CEMA). After azidation of the resulting copolymer, energetic copolymer GAP‐b‐PAEMA was obtained. Increase in the molecular weight determined by gel permeation chromatograph (GPC) is in agreement with the formation of block copolymer. Fourier transform infrared spectroscopy (FTIR) shows that the chlorine groups in the block copolymer can be substituted by azide group easily. Thermogravimetric analysis (TGA) shows that degradation of GAP‐b‐PAEMA involves two steps: the instantaneous decomposition of the azide groups followed by progressive scission of the polymer backbone. From differential scanning calorimetry (DSC) analysis, the GAP‐b‐PAEMA copolymer exhibits two glass transition temperatures (Tg) at −18 and 36°C, suggesting that the synthesized copolymer is a thermoplastic elastomer. This research provides a new method for the synthesis of energetic polymer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Synthesis, spectroscopic characterization, thermal stability and compatibility properties of energetic PVB-g-GAP copolymers

“…Thermodynamic incompatibility of the so-called soft and hard segments leads to microphase separation. The second T g values of the PVB-g-1 # GAP, PVB-g-2 # GAP and PVB-g-3 # GAP were probably due to the interaction of incompatible segments of the blocks [21]. However, interaction of incompatible segments of the blocks of 4 # GAP was likely weaker Fig.…”

“…The inclusion of soft segments within the hard microphase can decreases the hard microphase glass transition temperature [33]. So the minimum and maximum glass transition temperature could be attributed to movements of the GAP and PVB chains, respectively [5,21]. Thermodynamic incompatibility of the so-called soft and hard segments leads to microphase separation.…”

“…Glycidyl azide polymer (GAP) is an azide energetic material. It is a wellrecognized energetic polymer suitable for energetic materials, such as propellants and composite explosives, because of its high energy, higher density, higher nitrogen content and lower mechanical sensitivity [17][18][19][20][21][22][23][24]. Moreover, the terminal hydroxyl group of GAP can also be easily modified through various reactions [23,24].…”

Synthesis and Characterization of Poly(3‐azidomethyl‐3‐methyl oxetane) by the Azidation of Poly(3‐mesyloxymethyl‐3‐methyl oxetane)

“…As an important raw material for synthesis of P(BAMO/ AMMO), PAMMO is synthesized by livingc ationic polymerization of its corresponding monomer AMMO [7][8][9].H owever the main disadvantages of this synthetic route are the synthesisa nd storage of energetic monomer AMMO, which has ah igh mechanical sensitivity (impact test 19.6 J, friction test 6kg) [4].I ti st hus necessary to seek as afe processf or synthesiso fP AMMO. Indirect synthesis can avoid the preparation of energetic monomer,a nd various methods to obtain PAMMO by indirect synthesis methodh ave been tested [10,11]. Since tosyli sabetter leaving group than ahalogena tom, Polacco has reported the indirectsynthesis of PAMMO by the azidation of poly(3-tosyloxymethyl-3-methyl oxetane)( PTMMO) [ 4].P AMMOc ould be prepared, but the polymerization time was too long (115 h) for further applicationi nt he field of energetic materials.…”

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“…The succesful synthesis and characterization of GAP-PMMA-GAP type block copolymer by redox polymerization was reported. 27 . Regarding the unique thermal properties of GAP-diol and physico-chemical properties of HTPB at relatively low temperatures, a HTPB-g-PGA copoymer was prepred and characterized.…”