Characterization of poly(3,3‐bisethoxymethyl oxetane) and poly(3,3‐bisazidomethyl oxetane) and their block copolymers

Abstract

SynopsisThe homopolymers, poly(3,3-bisethoxymethyl oxetane) (polyBEMO), poly(3,3-bisazidomethyl oxetane) (polyBAMO), and triblock copolymers based on these homopolymers and a statistical copolymer center block composed of BAMO and 3-azidomethyl-3-methyl oxetane AMMO were synthesized and characterized by differential scanning calorimetry, modulus-temperature, optical microscopy, membrane osmometry, and solution and melt viscosity. The values of K and a for the Mark-Houwink equation were found to be 7.29 x mL/g and 0.80, respectively, for polyBEMO at 25°C Using number-average molecular weights. Glass transition temperatures were in the range -25 to -40°C and melting temperatures were between 65 and 90°C for all polymers. The melting temperature was found to increase as expected with molecular weight. Melt viscosities of triblock copolymers with polyBAMO end blocks were at least an order of magnitude lower than those with polyBEM0 end blocks and clear optically, suggesting that the polyBAM0-based triblock copolymers formed one phase in the melt, while the polyBEMO-based triblock materials (milk white) phase separated. The addition of filler raised the melt viscosity to a level between that predicted by the Guth-Smallwood and the Mooney equations.

Multiple endotherm melting behavior in relation to the morphology of poly[3,3‐ bis(ethoxymethyl) oxetane]

“…The viscoelastic behavior of polyBEMO block copolymers was investigated by Hardenstine The phenomenon of multiple melting peaks was initially observed for polyBEMO by Hardenstine et a1.21 and then by E. A. Murphy et al 24 In both studies, multiple melting phenomena were observed only for samples crystallized from the polymerization vessel, not for samples crystallized from the melt or from solution. In the present paper, the presence of multiple melting peaks in polyBEMO samples crystallized from the melt is characterized.…”

Improvement of the creep resistance of glycidyl azide polyol energetic thermoplastic elastomer-based propellant by nitrocellulose filler and its mechanism

“…1,2 In view of the inherent disadvantages of cross-linked polymers and energy, a profound interest has emerged concerning the development of energetic thermoplastic elastomers (ETPEs) as a suitable candidate for binder applications. 3,4 Hence, a considerable amount of work has been devoted to investigating ETPEs binder and ETPE-based propellant, which show good application prospects for propellant. [5][6][7][8][9] During the past decades, glycidyl azide polyol ETPE (GAP-ETPE)-based propellant is extensively studied not only because of its high energy, insensitivity and greenness, environment-friendliness and recyclability but also for its simple screw processing and high productivity.…”

Thermal decomposition of energetic thermoplastic elastomers of poly(glycidyl nitrate)

“…Conventional binders use crosslinked elastomers, in which prepolymers (e.g., HTPB) are crosslinked by chemical curing/crosslinking agents. However, the disposal of the crosslinked binder is difficult and usually accomplished by burning; this causes environmental problems . In view of the inherent disadvantages of crosslinked polymers, there has been profound interest in the development of thermoplastic elastomers (TPEs) as suitable candidates for binder applications.…”