Transparent polymers and methods for making the same

Abstract

A novel copolymer is made from a thiol terminated hydrocarbon monomer and at least one additional monomer chosen from the compounds of i) a terminally unsaturated hydrocarbon monomer, ii) an isocyanate functionalized hydrocarbon monomer and iii) a silane monomer substituted with two or more C.sub.2 to C.sub.8 terminally unsaturated alkenyl groups or C.sub.2 to C.sub.8 terminally unsaturated alkynyl groups, wherein the copolymer is a linear polymer, branched polymer or crosslinked polymer network, with the following provisos: if the at least one additional monomer is either a) a terminally unsaturated hydrocarbon monomer that is not a polymer having 12 carbon atoms or more, or b) a silane monomer, then the thiol terminated hydrocarbon monomer includes a saturated hydrocarbon ring with two or more terminal thiol groups attached to the hydrocarbon ring; if the terminally unsaturated hydrocarbon monomer is polybutadiene, the polybutadiene contains from about 0 mol % to about 30 mol % of polymer units in the cis-1,4-butadiene form; and if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then a ratio of the molecular mass of the thiol terminated hydrocarbon monomer to the number of sulfur atoms in the thiol terminated hydrocarbon monomer ranges from 65 to 500.

Claims

1. A copolymer made from a thiol terminated hydrocarbon monomer and a terminally unsaturated hydrocarbon monomer, the terminally unsaturated hydrocarbon monomer being a polymer having 12 carbon atoms or more and comprising a plurality of unsaturated groups and the thiol terminated hydrocarbon monomer being a substituted or unsubstituted, linear, branched or cyclic C.sub.3 to C.sub.36 saturated hydrocarbon having two or more terminal thiol groups, wherein the copolymer is a linear polymer, branched polymer or crosslinked polymer network and is transparent to radiation in the visual spectrum and the infrared (IR) wavelength range of about 4 microns to about 12 microns, wherein the thiol terminated hydrocarbon monomer and the terminally unsaturated hydrocarbon monomer react to form A.sub.xB.sub.y, where A is the polymer units formed from the thiol terminated hydrocarbon monomer, B is the polymer units formed from the terminally unsaturated hydrocarbon monomer and x and y each range from 0.3 to 0.7, where x+y=1; and with the proviso that if the terminally unsaturated hydrocarbon monomer is polybutadiene, the polybutadiene is a compound of formula 6: ##STR00016## where: m ranges from about 70 mol % to about 90 mol %; and n and o each range from 0 mol % to about 30 mol %, where n+o ranges from about 10 mol % to about 30 mol %.

2. The copolymer of claim 1, wherein the thiol terminated hydrocarbon monomer is chosen from compounds of formulas 1 and 2: ##STR00017## where: R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from hydrogen, SH and RSH, where R is a C.sup.1 to C.sup.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen; and R.sup.7 is a C.sub.2 to C.sub.10 hydrocarbon bridge.

3. The copolymer of claim 1, wherein the terminally unsaturated hydrocarbon monomer is the compound of formula 6.

4. The copolymer of claim 3, wherein the thiol terminated hydrocarbon monomer is a compound of formula 2:
HSR.sup.7SH 2, where R.sup.7 is a C.sub.2 to C.sub.10 hydrocarbon bridge.

5. A method of forming a copolymer, the method comprising: combining a thiol terminated hydrocarbon monomer and at least one additional monomer to form a mixture, the at least one additional monomer being chosen from compounds of (i) a terminally unsaturated hydrocarbon monomer and (ii) an isocyanate functionalized hydrocarbon monomer; and reacting the thiol terminated hydrocarbon monomer and the at least one additional monomer to form the copolymer, the copolymer being transparent to radiation in at least one of the visual spectrum or the infrared (IR) wavelength range of about 4 microns to about 12 microns, with the following provisos: if the at least one additional monomer is a terminally unsaturated hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is a compound of formula 1: ##STR00018## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from hydrogen and RSH, where R is a C.sub.2 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen; if the terminally unsaturated hydrocarbon monomer is polybutadiene, the polybutadiene contains from about 10 mol % to about 30 mol % of polymer units in a cis-1,4-butadiene form; and if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then a ratio of the molecular mass of the thiol terminated hydrocarbon monomer to the number of sulfur atoms in the thiol terminated hydrocarbon monomer ranges from 65 to 500, if the at least one additional monomer is a terminally unsaturated hydrocarbon monomer then the thiol terminated hydrocarbon monomer and the terminally unsaturated hydrocarbon monomer react to form A.sub.xB.sub.y, where A is the polymer units formed from the thiol terminated hydrocarbon monomer, B is the polymer units formed from the terminally unsaturated hydrocarbon monomer and x and y each range from 0.3 to 0.7, where x+y=1; and if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is the compound of formula 1 above, where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from H, SH and RSH, where R is a C.sub.1 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen.

6. The method of claim 5, wherein the at least one additional monomer is the terminally unsaturated hydrocarbon monomer, and further wherein the reacting comprises exposing the mixture to ultraviolet light.

7. The method of claim 6, wherein the terminally unsaturated hydrocarbon monomer is a compound of formulas of 3, 4, 5, or 6: ##STR00019## where: R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.13 are independently chosen from H and alkenyl substituents having a terminal vinyl group, where at least two of R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.13 are not hydrogen; R is a C.sub.2 to C.sub.10 hydrocarbon bridge; r is an integer ranging from 1 to 10; m ranges from about 70 mol % to about 90 mol %, and n and o each range from 0 mol % to about 30 mol %, where n+o ranges from about 10 mol % to about 30 mol %.

8. The method of claim 5, wherein the at least one additional monomer is the isocyanate functionalized hydrocarbon monomer, and further wherein the reacting comprises adding a catalyst to the mixture.

9. The method of claim 8, wherein the catalyst is an amine.

10. The method of claim 8, wherein the isocyanate functionalized hydrocarbon monomer is a compound of formula 7 or 8: ##STR00020## where R.sup.14 is a C.sub.3 to C.sub.12 n-alkyl bridge.

11. The method of claim 5, wherein if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is the compound of formula 1 above, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from H and RSH, where R is a C.sub.1 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen.

12. A copolymer made from a thiol terminated hydrocarbon monomer and at least one additional monomer chosen from compounds of i) a terminally unsaturated hydrocarbon monomer and ii) an isocyanate functionalized hydrocarbon monomer, wherein the copolymer is a crosslinked polymer network and is transparent to radiation in at least one of the visual spectrum or the infrared (IR) wavelength range of about 4 microns to about 12 microns, with the following provisos: if the at least one additional monomer is a terminally unsaturated hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is a compound of formula 1: ##STR00021## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from hydrogen and RSH, where R is a C.sub.2 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen; if the terminally unsaturated hydrocarbon monomer is polybutadiene, the polybutadiene contains from about 0 mol % to about 30 mol % of polymer units in a cis-1,4-butadiene form; if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then a ratio of the molecular mass of the thiol terminated hydrocarbon monomer to the number of sulfur atoms in the thiol terminated hydrocarbon monomer ranges from 65 to about 500; and if the at least one additional monomer is a terminally unsaturated hydrocarbon monomer then the thiol terminated hydrocarbon monomer and the terminally unsaturated hydrocarbon monomer react to form A.sub.xB.sub.y, where A is the polymer units formed from the thiol terminated hydrocarbon monomer, B is the polymer units formed from the terminally unsaturated hydrocarbon monomer and x and y each range from 0.3 to 0.7, where x+y=1; and if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is a compound of formula 1 above, where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from H, SH and RSH, where R is a C.sub.1 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen.

13. The copolymer of claim 12, wherein the at least one additional monomer is the terminally unsaturated hydrocarbon monomer.

14. The copolymer of claim 12, wherein the terminally unsaturated hydrocarbon monomer is a substituted or unsubstituted, linear, branched or cyclic C.sub.3 to C.sub.36 hydrocarbon that is internally saturated and has two or more terminal vinyl or alkynyl groups.

15. The copolymer of claim 12, wherein the terminally unsaturated hydrocarbon monomer is a compound of formulas of 3, 4, or 5: ##STR00022## where: R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.13 are independently chosen from hydrogen and alkenyl substituents having a terminal vinyl group, where at least two of R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.13 are not hydrogen; R is a C.sub.2 to C.sub.10 hydrocarbon bridge; and r is an integer ranging from 1 to 10.

16. The copolymer of claim 12, wherein the at least one additional monomer is the isocyanate functionalized hydrocarbon monomer.

17. The copolymer of claim 16, wherein the isocyanate functionalized hydrocarbon monomer is a substituted or unsubstituted, linear, branched or cyclic C.sub.3 to C.sub.36 saturated hydrocarbon monomer having two or more terminal isocyanate groups.

18. The copolymer of claim 16, wherein the isocyanate functionalized hydrocarbon monomer is a compound of formula 7 or 8: ##STR00023## where R.sup.14 is a C.sub.3 to C.sub.12 n-alkyl bridge.

19. The copolymer of claim 12, wherein if the at least one additional monomer is an isocyanate functionalized hydrocarbon monomer, then the thiol terminated hydrocarbon monomer is the compound of formula 1 above, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently chosen from H and RSH, where R is a C.sub.1 to C.sub.10 hydrocarbon bridge and at least two of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are not hydrogen.

Description

EXAMPLES

Example 1Synthesis of Thiolene Film Composed of 1,2,4-trivinylcyclohexane and 1,6-hexanedithiol

(1) 1,2,4-Trivinylcyclohexane (0.2 g, 1.23 mmol) and 1,6-hexandithiol (0.28 g, 1.85 mmol) were combined and vortexed well. A photoinitiator such as 2,2-Dimethoxy-2-phenylacetophenone (DMPA) was added in a small amount (0.025 wt %) for faster curing of the film. The thiolene mixture was placed between two glass slides (75 mm50 mm; thickness 1 mm) with a Teflon spacer (0.13 mm thick) and fastened with clips. The film was exposed to UV (H bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(2) ##STR00007##

Example 2Synthesis of Thiocarbamate Film Composed of 4,4-methylenebis(4-cyclohexylisocyanate) (HMDI) and 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanthiol

(3) 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanthiol (0.150 g, 0.57 mmol; synthesized previously) and 4,4-methylenebis(4-cyclohexylisocyanate) (0.225 g, 0.86 mmol, Sigma Aldrich) were combined and vortexed well. To the mixture, tetrahydrofuran (937 L) was added and the mixture vortexed again. For the reaction to proceed, triethylamine dispersed in tetrahydrofuran was added to the vial (187 L, 1% triethylamine in tetrahydrofuran). The film was prepared by drop casting the solution onto a glass substrate and covering the substrate with a glass dish slowly allowing the solvent to evaporate leaving a clear film.

(4) ##STR00008##

Example 3Synthesis of Thiocarbamate Film Composed of 1,6-diisocyanatohexane (HDI) and 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol

(5) 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol (0.100 g, 0.38 mmol; synthesized previously) and 1,6-diisocyanatohexane (0.095 g, 0.57 mmol, Sigma Aldrich) were combined and vortexed well. To the mixture, tetrahydrofuran (565 L) was added and the mixture was vortexed again. The catalyst, triethylamine, dispersed in tetrahydrofuran was added to the vial (20 L, 1% triethylamine in THF). The film was prepared by drop casting the solution onto a glass substrate and allowing the solvent to evaporate leaving a clear film.

(6) ##STR00009##

Example 4Synthesis of Thiocarbamate Film Composed of 1,6-diisocyanatohexane (HDI), 4,4-methylenebis(4-cyclohexylisocyanate) (HMDI) and 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol

(7) 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol (0.35 g, 1.33 mmol; synthesized previously), 1,6-diisocyanatohexane (0.150 g, 0.89 mmol, Sigma Aldrich) and 4,4-methylenebis(4-cyclohexylisocyanate) (0.234 g, 0.89 mmol, Sigma Aldrich) were combined and vortexed well. To the mixture, 2-butanone (2.02 mL) was added and the mixture was vortexed again. Triethylamine dispersed in 2-butanone was added to the vial (180 L, 1% triethylamine in 2-butanone) to catalyze the reaction. The film was prepared by drop casting the solution onto a glass substrate and allowing the solvent to evaporate leaving a clear film.

(8) ##STR00010##

Example 5Synthesis of Thiolene Film Composed of 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol and tetravinylsilane

(9) In a scintillation vial, 2-[2,4-bis(2-mercaptoethyl) cyclohexyl]ethanethiol (0.5 g, 1.89 mmol; synthesized previously) and tetravinylsilane (0.19 g, 1.39 mmol, Sigma Aldrich) were combined and mixed using a vortex. A photoinitiator such as 2,2-Dimethoxy-2-phenylacetophenone (DMPA) can be added in a small amount (0.025 wt %) for faster curing of the film. The thiolene mixture is placed between two glass slides (75 mm50 mm; thickness 1 mm) with a Teflon spacer (0.13 mm thick) and fastened with clips. The film was exposed to UV (H bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(10) ##STR00011##

Example 6Synthesis of Thiolene Film Composed of 1,6-hexanedithiol and 1,6-heptadiyne

(11) Hexanedithiol (0.979 g, 6.51 mmol) was combined with 1,6-heptadiyne (0.300 g, 3.26 mmol) and vortexed well. DMPA (0.32 mg) was added and the mixture vortexed again. The mixture was placed between two glass slides (75 mm50 mm) with a telfon spacer (0.13 mm thick) and fastened by clips. The film was exposed to UV (H2 bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(12) ##STR00012##

Example 7Synthesis of Thiolene Film Composed of 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol and 1,2,4-trivinylcyclohexane

(13) 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol (0.614 g, 3.78 mmol) was combined with 1,2,4-trivinylcyclohexane (0.750 g, 3.78 mmol) and vortexed well. DMPA (0.34 mg) was added and the mixture vortexed again. The mixture was placed between two glass slides (75 mm50 mm) with a telfon spacer (0.13 mm thick) and fastened by clips. The film was exposed to UV (H2 bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(14) ##STR00013##

Example 8Synthesis of Thiolene Film Composed of 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanthiol and 1,6-heptadiyne

(15) 2-[2,4-bis(2-mercaptoethyl)cyclohexyl]ethanethiol (1.15 g, 4.34 mmol) was combined with 1,6-heptadiyne (0.300 g, 3.26 mmol) and vortexed well. DMPA (0.36 mg) was added and the mixture vortexed again. The mixture was placed between two glass slides (75 mm50 mm) with a teflon spacer (0.13 mm thick) and fastened by clips. The film was exposed to UV (H2 bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(16) ##STR00014##

Example 9Synthesis of Thiolene Film Composed of Polybutadiene and 1,6-hexanedithiol

(17) Polybutadiene (0.49 g; Mn=2900, 80% Vinyl) was combined with 1,6-hexanedithiol (0.54 g, 3.62 mmol) and vortexed well. A photoinitiator such as 2,2-Dimethoxy-2-phenylacetophenone (DMPA) can be added in a small amount (0.025 wt %) for faster curing of the film. The mixture was placed between two glass slides (75 mm50 mm) and a Teflon spacer (0.13 mm thick) and fastened by clips. The film was exposed to UV (H bulb (560 sec)) on three occasions. The film was carefully removed from the glass slides to give a clear film.

(18) ##STR00015##

(19) The copolymer material of Examples 1-9 above all gave excellent visual transmission at 5 mils thickness, and can be considered transparent in the visual spectrum. While visual transmission was not measured directly it would be estimate at >90%. The IR average absorption coefficient (alpha) of each example copolymer was:

(20) Example 1=33.3 cm.sup.1

(21) Example 2=125.6 cm.sup.1

(22) Example 3=213.9 cm.sup.1

(23) Example 4=182.2 cm.sup.1

(24) Example 5=100.6 cm.sup.1

(25) Example 6=83.2 cm.sup.1

(26) Example 7=127.7 cm.sup.1

(27) Example 8=131.6 cm.sup.1

(28) Example 9=59.1 cm.sup.1.

(29) The average absorption coefficient values reported for the materials of examples 1 to 9 were determined for wavelengths of 8000 nm to 12000 nm using the procedure as explained below. The materials with lower absorption coefficients have better transmission at the tested wavelengths. As an example, the average absorption coefficient (alpha) for the copolymer materials alone can range from 225 or less, such as about 200 to 0, about 150 to 0, about 100 to 0 or about 75 to 0. The absorption coefficient can be determined using the following relationship:

(30) $=\frac{4k}{}$$\mathrm{Complex}\mathrm{index}\mathrm{of}\mathrm{refraction}=n+\mathrm{ik}$
where is the absorption coefficient, is the wavelength, and k is the imaginary portion of the complex index of refraction (n+ik). Both reflectance and transmission values for determining absorption coefficient at infrared wavelengths of 2.5 microns to 25 microns were collected using an SOC-100 Hemispherical Directional Reflectometer. The reflection and transmission values were used to determine the complex refractive index of the material using the Kramers-Kronig relationship. From the k value of the complex refractive index, the absorption coefficient (intrinsic attenuation within the material measured in per cm) was calculated. For each wavelength measured within the SOC-100, an alpha value was determined. From these values an average alpha value was calculated for the infrared waveband of 8000 nm to 12000 nm. For example, alpha values can be determined at 1000 nm increments from 8000 nm to 12000 nm and the values averaged to arrive at an average absorption coefficient.

(31) Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein.

(32) While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the present teachings may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular function. Furthermore, to the extent that the terms including, includes, having, has, with, or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term comprising. Further, in the discussion and claims herein, the term about indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the intended purpose described herein. Finally, exemplary indicates the description is used as an example, rather than implying that it is an ideal.

(33) It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompasses by the following claims.