Patent Application
20210284794
The present invention relates to bis(hydroxyalkyl) mercaptosuccinates and derivatives thereof, and methods for producing and using the same.
Dilatant materials exhibit Non-Newtonian properties. One interesting property is the ability to change from soft and moldable to hard upon impact. Because of this, they have potential as materials for body armor and sports equipment.
According to one exemplary embodiment of the invention, a series of materials that exhibit a range of dilatant properties have been synthesized. The materials show good transparency and are chemically uniform, that is, they consist of a single chemical component. The dilatant properties likely are due to the presence of both aggregated and non-aggregated forms of the oligomers. The degree of dilatancy can be modified by adjusting the monomer composition. The range of dilatant properties, good transparency, and single chemical component nature of the dilatant samples make these materials of particular interest.
The drawings illustrate the best mode currently contemplated of practicing the present invention.
In the drawings:
The following is an exemplary scheme (Scheme I) for the synthesis of some of the exemplary embodiments of the dilatant materials of the disclosure:
where each of W, X, Y and Z can vary from 0 to 1, e.g., as molar fractions or ratios of the relative amounts of the monomers present in the resulting dilatant material, with the sum of all values for W, X, Y and Z being equal to 1. For example, W=0.25, X=0.25, Y=0.25, and Z=0.25 if equimolar amounts of each of the four monomers was used at the beginning of the reaction and W=1.0 (X, Y, and Z=0) if only MSA and propylene glycol were used at the beginning of the reaction.
To a round bottom flask equipped for distillation and magnetic stirring was added 15.0395 g (0.1000 moles) of mercaptosuccinic acid and 7.6216 g (0.1000 moles) of propylene glycol. The flask was placed in an oil bath and the system was purged with nitrogen gas for about five minutes to remove excess oxygen. The gas flow was reduced to a low rate and the reaction mixture was heated for four hours at 155° C. After cooling, the system was equipped for vacuum distillation. The reaction mixture was heated for eight hours under reduced pressure (˜100 mm Hg) to give poly(1,2-propylenemercaptosuccinate) (6.4249 g, 83%). Transfer of the viscous mixture to a sample vial was facilitated by gentle heating with a heat gun. The structure was confirmed by 1HNMR spectroscopy.
To a 4-necked, two piece reaction flask equipped for simple distillation and with a stainless steel stir shaft and Teflon stir blade and vacuum bearing was added 434.1 g of 2-mercaptosuccinic acid (MSA, 2.891 mol) and 220.0 g of 1,2-propanediol (2.891 mol). The flask was purged for five minutes and then maintained under slowly flowing nitrogen gas while heated and stirred for 4 hours at 155° C. After cooling to room temperature, the flask was equipped for vacuum distillation and stirred for 4 additional hours at 155° C. under reduced pressure (˜250 Torr). To facilitate transfer, the viscous product was removed from the flask while warm giving a near quantitative yield.
The above procedure was followed except 3.8122 g (0.0500 moles) of propylene glycol, 1.4795 g (0.0125 moles) succinic acid, and 5.6429 g (0.0375 moles) mercaptosuccinic acid were used to give 6.8578 g (94%) of product.
The above procedure was followed except 3.8149 g (0.0254 moles) mercaptosuccinic acid, 3.0089 g (0.0254 moles) succinic acid, and 3.8047 g (0.0508 moles) propylene glycol were used to give 6.2859 g (91%) of product.
The above procedure was followed except 3.8192 g (0.0502 moles) propylene glycol and 5.9269 g (0.0502 moles) succinic acid were used to give 8.7573 g (91%) of product.
The above procedure was followed except 7.7052 g (0.0513 moles) mercaptosuccinic acid, 1.9248 g (0.0253 moles) propylene glycol, and 1.6165 g (0.0260 moles) ethanediol were used to give 6.5386 g (86%) of product.
The following is another exemplary scheme (Scheme II) for the synthesis of some of the exemplary embodiments of the dilatant materials of the disclosure:
where a, b, c and d can vary from 0 to 1, e.g., as ratios of the relative amounts of the monomers present in the resulting dilatant material, with the sum of all values for a, b, c and d being equal to 1. Also, R and R′ are each selected from the group of alkylene, alkenylene, heteroalkylene, heteroalkenylene, haloalkylene, haloalkenylene, cycloaklyene, cycloalkenylene, arylene or heteroarylene. Further, the total initial molar quantity of the diacids is equivalent to the total initial molar quantity of diols.
Table 1 shows the compounds created using the synthesis processes I-V, and their corresponding dilatant properties:
In Table 1, the values for MSA, SA propylene glycol and ethylene glycol are molar amounts for the starting components (for example, 50 MSA=0.50 mole fraction of MSA and 50 SA=0.50 mole fraction of SA) and the resulting composition expressed in terms of the ratio of the monomers in the dilatant composition formed thereby. The amount in the table divided by 100 will give the mole fraction of each component. For Compound I, 1.00 mole fraction of SA was allowed to react with an equimolar amount of propylene glycol (mole fraction of propylene glycol also=1.00). The lengths of the polymer chains are such that they have a number-average molecular weight of about 1500 to 2000 amu.
Comparison of 1HNMR spectra of pure propylene glycol and Compound IV confirmed that propylene glycol is used up completely in the reaction. This is evidenced by the lack of peaks at 1.12, 3.37, 3.55, 3.87, and 4.44 ppm in spectra of the oligomers (
Synthesis of poly(1,2-1-methylethylene-2-mercaptosuccinate). In one particular example of a dilatant compound of the present disclosure, to a round bottom flask equipped with a condenser and with magnetic stirring, was added 3.2863 grams (0.043190 moles) of 1,2-propanediol and 6.4788 g (0.043149 moles) of mercaptosuccinic acid. The flask was purged with nitrogen and then maintained under a slowly flowing nitrogen atmosphere. The reaction mixture was heated at 150° C./hour to 155° C. and then maintained at 155° C. for 4 hours. After cooling to room temperature, the flask was equipped for vacuum distillation. The resulting resin was heated under reduced pressure (<0.075 mm Hg) at 155° C. for an additional 4 hours. The structure was confirmed by 1HNMR spectroscopy.
where n is approximately equal to 10.
Brief characterization: The resultant poly(1,2-1-methylethylene-2-mercaptosuccinate) material exhibits interesting non-newtonian dilatant properties. In particular, the material is flexible under usual conditions but it can be stretched into long fibers. For example, a small piece can be stretched out to a thin 11 foot long, free standing piece that was perfectly straight when held horizontal to the floor (i.e., straight similar to a 2×2 piece of lumber held horizontally). The stretched material readily softened as soon as it was touched.
However, upon fast stretching, the poly(1,2-1-methylethylene-2-mercaptosuccinate) material becomes very hard. A piece of the material can be readily molded into a small flexible ball. However, when thrown at a wall the material struck the wall with a solid crack, like a stone hitting the wall. After picking up the material, the material was soft again and showed no deformation at all, but was perfectly round. After subsequent trials, the material continued to exhibit this behavior but typically came back unaffected, i.e., round, but soft again. However, in one case (
Additionally, the materials typically exhibit excellent adhesive properties. For example, all samples of the dilatant materials we have made containing MSA and a diol have been shown to adhere strongly to all glass, metal, wood, and plastics tested and are only removed from the surface with difficulty, i.e., usually involving some scraping of the material off of the surface, with the least adherence observed being to silicone polymers. As a result, this dilatant material may be useful as a next generation window glass adhesive. For example, current glass windshields are multi-layer with polymer adhesives between the glass layers. Potentially, the use of the dilatant material/polymer disclosed here in place of the current polymer adhesive would afford much higher levels of protection since our dilatant polymer strengthens as pressure is rapidly applied. This could be useful on all vehicles, but may be especially important for air or spacecraft or military and police vehicles. This material also may be useful in personal body armor or even for the preparation of polymeric projectiles. Further, the materials of the present disclosure exhibit these beneficial dilatant properties without being crosslinked.
The following references are expressly incorporated herein by reference for all purposes:
The present application claims priority from U.S. Provisional Patent Application Ser. No. 62/502,013, filed on May 5, 2017, the entirety of which is expressly incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2018/031377 | 5/7/2018 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62502013 | May 2017 | US |
