This invention relates to blends containing two or more polyhydroxyalkanoates (PHAs), and related methods and articles.
1. A blend comprising a first PHA and a second PHA, wherein:
the first PHA is a copolymer consisting of a comonomer I-A and a comonomer I-B;
the second PHA is a copolymer consisting of a comonomer 2-A and a comonomer 2-B;
the first PHA copolymer and the second PHA copolymer are the same copolymer, in which the ratio of comonomer 1-A:comonomer I-B in the first PHA is different from the ratio of comonomer 2-A:comonomer 2-B in the second PHA;
comonomer I-A and comonomer 2-A are both 3-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
2. The blend of claim 1 , wherein comonomer I-B and comonomer 2-B both are 3-hydroxypropionate, 4-hydroxybutyrate, 3-hydroxyhexanoate, or 3-hydroxyoctanoate, 3-hydroxypropionate, 6-hydroxyhexanoate, 3-hydroxydecanoate, 3-hydroxydodecanoate, or 3-hydroxydodecenoate.
3. The blend of claim 2 , wherein comonomer I-B and comonomer 2-B both are 4-hydroxybutyrate.
4. The blend of claim 1 additionally comprising a third PHA.
5. The blend of claim 1 , wherein when the first PHA and the second PHA are blended and the blend is molded, the blend has a deformation angle tolerance of at least about 5°.
6. The blend of claim 1 , wherein when the first PHA and the second PHA are blended and the blend is molded, the blend has a thermal deformation resistance temperature of at least 80° C.
7. The blend of claim 1 , wherein the first PHA has a first glass transition temperature and the second PHA has a second glass transition, wherein the difference between the first and second glass transition temperature is at least about 1° C.
8. A method of preparing a PHA blend comprising blending a first PHA with a second PHA; wherein:
the first PHA is a copolymer consisting of a comonomer I-A and a comonomer I-B;
the second PHA is a copolymer consisting of a comonomer 2-A and a comonomer 2-B;
the first PHA copolymer and the second PHA copolymer are the same copolymer, in which the ratio of comonomer 1-A:comonomer I-B in the first PHA is different from the ratio of comonomer 2-A:comonomer 2-B in the second PHA;
comonomer I-A and comonomer 2-A are both 3-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
9. The method of claim 8 , wherein the blending is by solvent blending, emulsion blending or melt blending.
10. The method of claim 8 , wherein the blending is by solvent blending.
11. The method of claim 10 , wherein the solvent blending comprises:
(i) dissolving the first PHA and the second PHA in a solvent or solvent mixture; or dissolving the first PHA and the second PHA separately in a solvent or solvent mixture and combining; to form a blended PHA solution containing at most about 50 weight percent of the first PHA and the second PHA;
(ii) applying the PHA solution to a surface to form a PHA blend solution layer on the surface; and
(iii) removing some or all of the solvent to form a PHA blend layer on the surface.
12. An article comprising at least about 1 percent by weight of a PHA blend comprising a first PHA and a second PHA,
wherein:
the first PHA is a copolymer consisting of a comonomer I-A and a comonomer I-B;
the second PHA is a copolymer consisting of a comonomer 2-A and a comonomer 2-B;
the first PHA copolymer and the second PHA copolymer are the same copolymer, in which the ratio of comonomer 1-A:comonomer I-B in the first PHA is different from the ratio of comonomer 2-A:comonomer 2-B in the second PHA;
comonomer I-A and comonomer 2-A are both 3-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
13. A method of making an article comprising:
molding a PHA blend prepared by a method comprising:
blending a first PHA with a second PHA comprising;
(i) dissolving the first PHA and the second PHA in a solvent or solvent mixture; or dissolving the first PHA and the second PHA separately in a solvent or solvent mixture; and combining to form a blended PHA solution containing at most about 50 weight percent of the first PHA and the second PHA;
(ii) applying the PHA solution to a surface to form a PHA blend solution layer on the surface; and
(iii) removing some or all of the solvent to form a PHA blend layer on the surface;
wherein:
the first PHA is a copolymer consisting of a comonomer I-A and a comonomer I-B;
the second PHA is a copolymer consisting of a comonomer 2-A and a comonomer 2-B;
the first PHA copolymer and the second PHA copolymer are the same copolymer, in which the ratio of comonomer 1-A:comonomer I-B in the first PHA is different from the ratio of comonomer 2-A:comonomer 2-B in the second PHA;
comonomer I-A and comonomer 2-A are both 3-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
14. A blend comprising a first PHA and a second PHA, wherein:
the first PHA is a poly(3-hydroxybutyrate) homopolymer;
the second PHA is a copolymer having a first and a second comonomer;
the first co-monomer is 3-hydroxybutyrate;
the second comonomer is 4-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
15. The blend of claim 14 , wherein the copolymer has at most about 3 weight percent, or at most about 15 weight percent of one comonomer.
16. The blend of claim 14 , wherein the blend comprises poly 3-hydroxybutyrate blended with poly 3-hydroxybutyrate-co-11 wt %-4-hydroxybutyrate; or poly 3-hydroxybutyrate blended with poly 3-hydroxybutyrate-co-33 wt %-4-hydroxybutyrate.
17. The blend of claim 16 , wherein the blend comprises at most about 20 wt % poly 3-hydroxybutyrate.
18. The blend of claim 16 , wherein the blend comprises at most about 60 wt % poly 3-hydroxybutyrate.
19. The blend of claim 14 additionally comprising a third PHA.
20. The blend of claim 14 , wherein when the first PHA and the second PHA are blended and the blend is molded, the blend has a deformation angle tolerance of at least about 5°.
21. The blend of claim 14 , wherein the first PHA and the second PHA are blended and the blend is molded, the blend has a thermal deformation resistance temperature of at least 80° C.
22. A method of preparing a PHA blend comprising blending a first PHA with a second PHA wherein:
the PHA blend comprises the first PHA and the second PHA;
the first PHA is a poly(3-hydroxybutyrate) homopolymer;
the second PHA is a copolymer having a first and a second comonomer;
wherein the first co-monomer is 3-hydroxybutyrate and the second comonomer is 4-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
23. The method of claim 22 , wherein the blending of the first PHS, and the second PHA is by solvent blending, emulsion blending or melt blending.
24. The method of claim 22 , wherein the blending is by solvent blending.
25. The method of claim 22 , wherein the blending comprises:
(i) dissolving the first PHA and the second PHA in a solvent or solvent mixture; or dissolving the first PHA and the second PHA separately in a solvent or solvent mixture; and combining to form a blended PHA solution containing at most about 50 weight percent of the first PHA and the second PHA;
(ii) applying the PHA solution to a surface to form a PHA blend solution layer on the surface; and
(iii) removing some or all of the solvent to form a PHA blend layer on the surface.
26. An article comprising at least about 1 percent by weight of a PHA blend comprising a first PHA and a second PHA, wherein:
the first PHA is a poly(3-hydroxybutyrate) homopolymer;
the second PHA is a copolymer having a first and a second comonomer;
wherein the first co-monomer is 3-hydroxybutyrate and the second co-monomer is 4-hydroxybutyrate; and
the first PHA and the second PHA are miscible.
27. A method of making an article comprising:
molding a PHA blend prepared by a method comprising:
blending a first PHA with a second PHA comprising:
(i) dissolving the first PHA and the second PHA in a solvent or solvent mixture; or dissolving the first PHA and the second PHA separately in a solvent or solvent mixture; and combining to form a blended PHA solution containing at most about 50 weight percent of the first PHA and the second PHA;
(ii) applying the PHA solution to a surface to form a PHA blend solution layer on the surface; and
(iii) removing some or all of the solvent to form a PHA blend layer on the surface;
wherein:
the PHA blend comprises the first PHA and the second PHA;
the first PHA is a poly(3-hydroxybutyrate) homopolymer;
the second PHA is a copolymer having a first and a second comonomer;
wherein the first co-monomer is 3-hydroxybutyrate and the second comonomer is 4-hydroxybutyrate; and
the first PHA and the second PHA are miscible.