Internally-plasticized polyethers from substituted oxetanes

• US 4,764,586 A
• Filed: 10/29/1986
• Issued: 08/16/1988
• Est. Priority Date: 10/29/1986
• Status: Expired due to Fees

• Current Assignee: Morton Thiokol, Inc.
• Original Assignee: Morton Thiokol, Inc.
• Inventors: Manser, Gerald E., Shaw, Graham C. III
• Primary Examiner(s): Miller, Edward A.
• Application Number:
  US06/925,659
• Time in Patent Office: 657 Days
• Field of Search: 149/19.4, 149/19.6, 528/417, 528/362
• US Class Current: 528/362
• CPC Class Codes: C06B 45/10 the organic component containing a resin
• CPC Class Codes: C07D 305/06 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring atoms
• CPC Class Codes: C08G 65/18 Oxetanes
• CPC Class Codes: C08G 65/20 Tetrahydrofuran
• CPC Class Codes: C08G 65/223 containing halogens epihalohydrins C08G65/24

Abstract

Internally plasticized elastomeric binders for projectile propellants are cured polyethers containing THF, CYMMO plus BMEMO, BEEMO and/or OMMO mer units. The polyethers are fluid at room temperature and are miscible with nitrate ester plasticizers. Propellant binders prepared from these polyethers are curable, have low T_g '"'"'s, good mechanical properties, and I_sp '"'"'s comparable to PEG-based binders.

Claims

1. A curable polyether comprising between about 10 and about 85 molar percent tetrahydrofuran mer units, between about 10 and about 80 molar percent of a first oxetane mer unit of mixture of oxetane mer units, and between about 5 and about 70 molar percent of a second oxetane mer unit or mixture of oxetane mer units, said first and second oxetane mer units in unpolymerized from each have the formula:

##STR4## wherein in said first oxetane mer unit or mixture of mer units R¹ and/or R² is or contains moieties selected from the group consisting of cyano, azido, nitro, nitrato, nitramine and hydroxyl, and in said second oxetane mer unit or mixture of oxetane mer units R¹ plus R² contain between about 6 and about 12 carbon atoms.

2. A curable polyether in accordance with claim 1 wherein said first oxetane mer unit or mixture of oxetane mer units includes an energetic pendant group.

3. A curable polyether in accordance with claim 1 wherein said first oxetane mer unit or mixture of oxetane mer units includes a pendant group which promotes miscibility of said polyether with nitrate ester plasticizers.

4. A curable polyether in accordance with claim 1 wherein said first oxetane mer unit or mixture of mer units comprises 3-cyanomethyl-3-methyloxetane.

5. A curable polyether in accordance with claim 1 wherein said second oxetane mer unit or mixture of mer units comprises a mer unit selected from the group consisting of 3,3-bis[(2-ethoxy-ethoxy)methyl]oxetane, 3,3-bis[(2-methoxy-ethoxy)methyl]oxetane and 3-octoxymethyl-3-methyloxetane.

6. A curable polyether according to claim 1 wherein having a number average molecular weight of between about 1500 and about 6000.

7. A curable polyether in accordance with claim 5 wherein said first oxetane mer unit or mixture of oxetane mer units is selected from the group consisting of 3-cyanomethyl-3-methyl oxetane, 3-azidomethyl-3-methyloxethane, 3,3-bis(nitratomethyl) oxetane, 3-nitratomethyl-3-methyloxetane, 3,3-bis(methylnitraminomethyl) oxetane, 3-methylnitraminomethyl-3-methyloxetane, and 3,3-bis(azidomethyl) oxetane and mixtures thereof.

8. A curable polyether according to claim 1 having a weight average molecular weight of between about 4000 and about 12000.

9. A curable polyether according to claim 1 have a functionality of at least about 2.0.

10. A curable polyether according to claim 1 having a Brookfield viscosity at 22°

C. of about 7000 poise or below.

11. A curable polyether comprising between about 45 and about 85 molar percent tetrahydrofuran mer units and between about 15 and about 55 molar percent of a mixture of two or more oxetane mer units, said oxetane mer units in unpolymerized form having the formula:

##STR5## wherein R¹ and R² are selected from the group consisting of;

--H;

--O--C₂ H₄ --O--C₂ H₅ ;

--O--C₂ H₄ --O --C₂ H₄ --O --CH₃ ;

--CN and --O --(CH₂) n--CH₃, wherein n is 2-10, between about 10 and about 50 molar percent of said oxetane mer units being residues of 3-cyanomethyl-3-methyl-oxetane and between about 5 and about 50 percent of said oxetane mer units having R¹ plus R² containing between 6 and 12 carbon atoms.

12. A curable polyether according to claim 11 wherein having a number average molecular weight of between about 1500 and about 6000.

13. A curable polyether according to claim 11 having a weight average molecular weight of between about 4000 and about 12000.

14. A curable polyether according to claim 11 have a functionality of at least about 2.0.

15. A curable polyether according to claim 11 having a Brookfield viscosity at 22°

C. of about 7000 poise or below.

16. A curable polyether comprising tetrahydrofuran mers at between about 45 and about 80 molar percent, 3-cyanomethyl-3-methyloxetane mers at between about 10 and about 50 molar percent and mers selected from the group consisting of 3-octoxymethyl-3-methyloxetane, 3,3-bis[(2-methoxy-ethoxy-methyl]oxetane, 3,3-bis[(2-ethoxy-ethoxy)methyl]oxetane and mixtures thereof at between about 5 and about 20 molar percent.

17. A curable polyether according to claim 16 comprising tetrahydrofuran mers at between about 50 and about 70 molar percent, 3-cyanomethyl-3-methyloxetane, mers at between about 30 and about 45 molar percent and mers selected from the group consisting of 3-octoxymethyl-3-methyloxetane, 3,3-bis[(2-methoxy-ethoxy)methyl]oxetane, 3,3-bis[(2-ethoxy-ethoxy)methyl]oxetane and mixtures thereof at between about 5 and about 10 molar percent.