Thermoplastic elastomers having alternate crystalline structure for us as high energy binders
OwnerGerald E. Manser, Richard S. Millerinventors
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Abstract
Novel block polymers which are thermoplastic elastomers which are thermoplastic elastomers are provided for use as binders in high-energy compositions such as propellants, explosives, gasifiers or the like. The block polymers have an ABA structure wherein the A blocks are crystalline at temperatures below 60.degree. C. and the B blocks are amorphous at temperatures above -20.degree. C. Both the A and B blocks are polyethers formed from monomers of oxetanes and/or tetrahydrofuran. The block polymers melt in the range of 60.degree. C. to 120.degree. C. and have low viscosities above their melting points due to mutual miscibility of the A and B blocks.
Claims7
A process of forming a thermoplastic, elastomeric ABA triblock polymer with low melt viscosity, comprising,
- forming a polymer that is crystalline in structure and has a melting temperature of between about 60.degree. C. and 120.degree. C. to serve as the A blocks;
- forming a polymer having a glass transition temperature below about -20.degree. C. to serve as the B block;
- and
- forming an ABA block polymer from the A blocks and B block by cationic polymerization;
- wherein the A block is a polymer obtained from polymerizing derivatives of oxetane having the general formula:
- ##STR4## wherein n and n' can be 0 to 10 and X and X' are selected from the group consisting of --H, --NO.sub.2, --CH, --Cl, --F, --OR, --OH, --I, --ONO.sub.2, --N(NO.sub.2)R, --C.tbd.CH, --Br, --CH.dbd.CHZ, --O--CO--Z, --CO.sub.2 --Z, --N(H or R).sub.2 and --O--(CH.sub.2).sub.1-5 --O--(CH.sub.2).sub.0-8 --CH.sub.3, where R is an alkyl group and Z is H or R, and
- wherein the B block is a homopolymer obtained from polymerizing a compound chosen from the group consisting of oxetane, tetrahydrofuran, derivatives of oxetane and derivatives of tetrahydrofuran monomers.
Dependencies are inferred from the claim text.