Spiro(benzoxasilole) catalyzed polymerization of oxetane derivatives

Xu, Baopei; Lillya, C. Peter; Chien, James C. W.

doi:10.1002/pola.1992.080300912

Cited by 17 publications

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“…a,w-Dihydroxy terminated polymers were synthesized using the spiro (benzoxasilole ) catalyst ( 1 ) . 4 The molecular weight of the polymer could be calculated by the amount of diol used as coinitiator. Table I1 illustrates the method for the synthesis of a,w-dihydroxy PNMMO ( 5 ) .…”

Section: Telechelic Polymers Of Oxetane Derivativesmentioning

confidence: 99%

Energetic ABA and (AB)_n thermoplastic elastomers

Lin

Chien

1992

J of Applied Polymer Sci

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SYNOPSISLinear ABA triblock and ( AB ), segmented block copolymers of energetic monomers have been synthesized. The rigid and soft blocks are prepared from 3,3-bis( azidomethyl) oxetane (BAMO) and 3-nitratomethyl-3-methyloxetane (NMMO) , respectively. Polymerization of BAMO initiated by triethyloxonium tetrafluoroborate and by spiro (benzoxasilole) /propanediol produced a-monohydroxy-PBAMO ( 3) and a,w-dihydroxy-PBAMO ( 4 ) of @" 16,000 and 2,000, respectively, and a,w-dihydroxy-PNMMO ( 5 ) of M,, = 13,000 was synthesized by the latter method. The block copolymers were prepared from the appropriate telechelic polymers and toluene diisocyanate. The PBAMO-PNMMO-PBAMO copolymer 6 has T , = 8Z°C, T, = -3"C, and is strongly phase separated even in the melt. It decomposes sharply within 1°C a t 224OC evolving 0.69 kJ/g of heat. Copolymer 6 has excellent mechanical properties with elongation of 683% at break, 5.25 MPa stress, and 82% recovery.The ( PBAMO-PNMMO ), , copolymer 7 has similar thermal properties and spectroscopic characteristic, but is inferior to copolymer 6 in all rheological and mechanical properties. INTRODUCTIONThermoplastic elastomers (TPE) are useful materials.' They can be prepared from any combination of low Tg building block with high Tg or crystalline ones. Segmented TPE is prepared by coupling the appropriate telechelic prepolymer in equal molar ratio. Linear ABA triblock copolymer can be elegantly synthesized by sequential polymerization if living propagation of all the constituent monomers can be achieved. It is more readily prepared by coupling telechelic low Tg prepolymer with monofunctional high Tg/ crystalline prepolymer as the terminal hard blocks. The synthesis of these functional prepolymers are prerequisite for this route. TPE containing energetic groups have been considered to be binder for propellent. The central purpose of this research is to synthesize both segmented and ABA TPE's from energetic monomers.It has been reported that 3,3,3',3'-tetrakis- Though living polymerization was not achieved for these oxetanes, a,w-dihydroxypolymer was obtained with 1 /propandiol. Furthermore, a-monohydroxypolyoxetanes was synthesized using either the 1 / benzyl alcohol catalyst or the Et30+BF; initiator.We present here the synthesis of TPE from these prepolymers and their properties.* To whom correspondence should be addressed. Polymerization and block coupling reactions were performed using dry argon purged Schlenk type apparatus. The crystalline block 3 was synthesized by BAMO, catalyst 2, and methylene chloride in the desired ratios were mixed and stirred at 25°C. The polymerization was quenched with water and the white powdery polymer 3 was precipitated with tenfold excess of aqueous NH3 in methanol. a,w-Dihydroxy PoIy(NMM0) (5)The telechelic amorphous block 5 was also prepared using catalyst 1 and propanediol: NMMO (9.9 g, 67 mmol), propanediol (0.5 g, 7 mmol), and 1 (0.3 g, 0.59 mmol) were combined and reacted for 3 days. The product was washed with an equal volume of aqueous methanol th...

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Section: Telechelic Polymers Of Oxetane Derivativesmentioning

confidence: 99%

Energetic ABA and (AB)_n thermoplastic elastomers

Lin

Chien

1992

J of Applied Polymer Sci

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“…The detailed thermal and spectroscopic characterization was performed 14 . In addition to GAP, aiming to develope less sensetive and highly energetic propellant formulations, various energetic azido polymers such as 3,3,bis(azidomethy1)oxetane polymer (BAMO), 3-azidomethyl 3-methyl oxetane polymer (AMMO) and their copolymers have been synthesized [15][16][17][18][19][20] .…”

Section: Synthesis Of Gapmentioning

confidence: 99%

Untitled

2017

Org. Commun.

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:In preparation of energetic composite formulations, functionally terminated pre-polymers have been used as binder. After physically mixing the pre-polymers with oxidizing components, metallic fuel, burning rate modifier and other minor ingredients, they are cured with a suitable curing agent to provide physical and chemical stability. These pre-polymers could be functionalized with carboxyl, epoxide or hydroxyl groups at varying average chain functionalities. For carboxyl-terminated pre-polymers, an epoxy functional curing agents could be used. If the prepolymer possesses hydroxyl groups, isocyanate functional curing agents are the most suitable curing agents in terms of easy and efficient processing. Glycidyl azide polymer (GAP) is one of the well-known low-molecular weight energetic liquid pre-polymer, which was developed to use as energetic binder, high performance additive and gas generator for high performance smokeless composite propellant and explosive formulations. Linear or branched GAP can be synthesized by nucleophilic substitution reaction of corresponding poly(epichlorohydrin) (PECH) with sodium azide through replacement of chloromethyl groups of PECH with pendant energetic azido-methyl groups on the polyether main chain. Positive heat of formation (+957 kJ/kg) enables exothermic and rapid decomposition of GAP producing fuel rich gases. Its polyether main chain provides GAP with relatively low glass transition temperature o C) and presence of hydroxyl functional groups allows it to have easy processing in curing with isocyanate curing agents to form covalently crosslinked polyurethane structure. These outstanding properties of GAP enable it to be used as energetic polymeric binder and high performance additive in preparation of energetic materials and low vulnerable explosives.

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Polyethers, Tetrahydrofuran and Oxetane Polymers

Pruckmayr

Dreyfuss²,

Dreyfuss³

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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This article reviews tetrahydrofuran and oxetane polymers and polymerization. The physical and chemical properties of polytetrahydrofurans and polyoxetanes are discussed, as well as the polymerization mechanism, including initiation, propagation, termination, chain transfer, kinetics, and copolymerization to give block, graft, and star copolymers. The most important commercial product is poly(tetramethylene ether) glycol (PTMEG), sold under the trade names Terathane (Du Pont), PolyTHF (BASF), and Polymeg (QO Chemicals). The manufacture of PTMEG is described in some detail, including the most recent industrial processes. Storage and handling of PTMEG, as well as specifications and standards of commercial products, are given. Test methods used in the 1990s are referenced, such as hydroxyl number, polymer molecular weight, and molecular weight distribution. Health and safety factors are discussed, as well as the economic aspects of PTMEG production. Most important uses of PTMEG are in elastomeric polyurethanes and polyesters. The same type of information is given for oxetane polymers, although no oxetane polymer has found any practical application and is thus not available commercially as of 1995.

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Spiro(benzoxasilole) catalyzed polymerization of oxetane derivatives

Cited by 17 publications

References 15 publications

Energetic ABA and (AB)_n thermoplastic elastomers

Energetic ABA and (AB)_n thermoplastic elastomers

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Polyethers, Tetrahydrofuran and Oxetane Polymers

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Spiro(benzoxasilole) catalyzed polymerization of oxetane derivatives

Cited by 17 publications

References 15 publications

Energetic ABA and (AB)n thermoplastic elastomers

Energetic ABA and (AB)n thermoplastic elastomers

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Polyethers, Tetrahydrofuran and Oxetane Polymers

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Energetic ABA and (AB)_n thermoplastic elastomers

Energetic ABA and (AB)_n thermoplastic elastomers