Thermoplastic polymers and method to make them
Polymer powders useful for additive manufacturing may be made by contacting carbon dioxide and a crystallizable polymer having at least one carbonyl, sulfur oxide or sulfone group; permeating the carbon dioxide into the polymer for a crystallizing time sufficient to induce crystallization forming an induced crystalized polymer; removing the carbon dioxide; and forming induced crystalized polymer particles having a D90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 100 micrometers equivalent spherical diameter. The carbon dioxide is desirably supercritical carbon dioxide for at least a portion of the crystallizing time. The polymer powders upon heating during additive manufacturing may result in a polymer having less crystallinity or become amorphous.
1. A polymer comprised of a semi-crystalline polymer having: (i) an undetectable amount of a volatile organic compound, (ii) at least one carbonyl, sulfur oxide or sulfone group, wherein, upon heating the semi-crystalline polymer above its melt temperature it forms an amorphous polymer upon cooling below its glass transition temperature, wherein the semi-crystalline polymer has an amount of crystallinity of at least 10% by volume.
2. The polymer of claim 1 , wherein the semi-crystalline polymer is comprised of a blend of two or more different semi-crystalline polymers, wherein upon heating above their melt temperatures and cooling below their glass transition temperatures they form amorphous polymers.
3. The polymer of claim 1 , wherein the semi-crystalline polymer is comprised of particles having a median particle size of 1 micrometer to 100 micrometers by volume.
4. The polymer of claim 3 , wherein the particles have D 90 of at most 300 μm, and a D 10 of at least 0.1 μm by volume.
5. The polymer of claim 3 , wherein the semicrystalline polymer has an operating window of at least 10° C.
6. The polymer of claim 3 , wherein at least 65% of the particles by number have a circularity of at least 0.75.
7. The polymer of claim 6 , wherein the particles have a flowability of at least 0.5 g/s.
8. The polymer of claim 7 , wherein the particles are further comprised of an insoluble additive.
9. The polymer of claim 1 , wherein the semi-crystalline polymer is comprised of one or more of a polyketone, polyetherketone, polyetherketoneketone, polyamide, polyimide, polysulfone, polyarylate and polysulfoxide.
10. The polymer of claim 1 , wherein the semi-crystalline polymer is further comprised of a dissoluble additive.
11. The polymer of claim 10 , wherein the dissoluble additive is comprised of one or more of a monomer, prepolymer, UV stabilizer, lubricant, plasticizer, pigment, flow aid, and flame retardant.
12. The polymer of claim 11 , wherein the dissoluble additive is present in an amount of 0.1% to 10% by weight of the semi-crystalline polymer.
13. The polymer of claim 11 , wherein the amount of crystallinity is at least 20% to essentially crystalline.
14. A polymer comprised of a semi-crystalline polymer having: (i) an undetectable amount of a volatile organic compound, (ii) at least one carbonyl, sulfur oxide or sulfone group, wherein, upon heating the semi-crystalline polymer above its melt temperature it forms an amorphous polymer upon cooling below its glass transition temperature, wherein the semi-crystalline polymer is comprised of particles having a median particle size of 1 micrometer to 100 micrometers by volume.
15. The polymer of claim 14 , wherein the semi-crystalline polymer is further comprised of a dissoluble additive.
16. The polymer of claim 15 , wherein the semi-crystalline polymer is further comprised of an insoluble additive.
17. A polymer comprised of a semi-crystalline polymer having: (i) an undetectable amount of a volatile organic compound, (ii) at least one carbonyl, sulfur oxide or sulfone group, wherein, upon heating the semi-crystalline polymer above its melt temperature it forms an amorphous polymer upon cooling below its glass transition temperature, wherein the semi-crystalline polymer is comprised of one or more of a polyketone, polyetherketone, polyetherketoneketone, polyamide, polyimide, polysulfone, polyarylate and polysulfoxide.
18. The polymer of claim 17 , wherein the semicrystalline polymer has an operating window of at least 10° C.