Polymer networks
Polymer mixtures containing a first long-chain polymer and a second short-chain polymer. The structural parameters of the two polymers are coordinated in such a way that a polymeric material is obtained which is easier to process while being provided with improved mechanical properties and in part also improved thermal properties compared with the first polymer at suitable conditions for producing the polymer mixture as a result of networks being formed and heterocrystallization taking place.
1. A polymer mixture consisting of:
at least one synthetic first polymer P(i) and between 3% to 14% by weight of at least one second polymer P(j),
wherein the first polymer P(i) has a degree of polymerisation DP(P(i))>500 and at least one type of crystallisable sequences A having a degree of polymerisation DPs(P(i)) of these sequences >20,
wherein the second polymer P(j) is made up of the same monomer units as the sequences A of P(i) and the degree of polymerisation DP(P(j)) of P(j) is 20<DP(P(j))<500,
wherein the polymer mixture comprises a molecularly dispersed mixture containing P(i) and P(j) that forms a network by heterocrystallisation,
wherein P(i), or the sequences A of P(i), comprises a polyethylene,
wherein P(j) has a polydispersivity <30 and is a polyethylene wax; and
wherein P(i) has a degree of branching <3×10 −2 , and P(j) has a degree of branching <5×10 −2 , wherein the first polymer P(i) and the second polymer P(j) have been mixed together using a twin screw extruder, and wherein the polymer mixture of the first polymer P(i) and the second polymer P(j) has an elongation at break greater than an elongation at break of the first polymer P(i) alone.
2. The polymer mixture according to claim 1 , wherein under comparable processing conditions of P(i) and of P(i)+P(j) the quotient of the yield stress sy(i, j) of P(i)+P(j) and the yield stress sy(i) of P(i), sy(i, j)/sy(i) is >1.1 and <3.0.
3. The polymer mixtures according to claim 2 , wherein E(i,j) is >1.3, sy(i, j) is >1.2 and eb (i,j) is >1.03.
4. The polymer mixtures according to claim 2 , wherein E(i,j) is >1.5, sy(i, j) is >1.3 and eb (i,j) is >1.05.
5. The polymer mixtures according to claim 2 , wherein E(i,j) is >2.0, sy(i, j) is >1.5 and eb (i,j) is >1.10.
6. The polymer mixture according to claim 1 , wherein a quotient of the MFI(i, j) of the mixture of P(i)+P(j) and the MFI(i) of P(i), MFI(i, j)/MFI(i) is >1.2 and <500.
7. The polymer mixture according to claim 6 , wherein the quotient of MFI(i, j) and MFI(i) is >1.5.
8. The polymer mixture according to claim 6 , wherein the quotient of MFI(i, j) and MFI(i) is >2.0.
9. The polymer mixture according to claim 6 , wherein the quotient of MFI(i, j) and MFI(i) is >3.0.
10. The polymer mixture according to claim 1 , wherein under comparable processing conditions of P(i) and of P(i)+P(j), the quotient of the crystallinity K(i, j) of P(i)+P(j) and the crystallinity K(i) of P(i), K(i, j)/K(i) is >1.03 and <3.
11. The polymer mixture according to claim 10 , wherein the quotient of K(i, j) and K(i) is >1.05.
12. The polymer mixture according to claim 10 , wherein the quotient of K(i, j) and K(i) is >1.1.
13. The polymer mixture according to claim 10 , wherein the quotient of K(i, j) and K(i) is >1.2.
14. The polymer mixture according to claim 1 , wherein P(i) has a degree of branching <1×10 −2 , and P(j) has a degree of branching <1×10 −3 .
15. The polymer mixture according to claim 1 , wherein P(i) has a degree of branching <5×10 −3 , and P(j) has a degree of branching <1×10 −3 .
16. The polymer mixture according to claim 1 , wherein P(i) has a degree of branching <1×10 −3 , and P(j) has a degree of branching <1×10 −4 .
17. The polymer mixture according to claim 1 , wherein P(j) has a polydispersivity <20.
18. The polymer mixture according to claim 1 , wherein P(j) has a polydispersivity <10.
19. The polymer mixture according to claim 1 , wherein P(j) has a polydispersivity <5.
20. The polymer mixture according to claim 1 , wherein P(i) and/or P(j) have long-chain branchings which have a degree of polymerisation >20.
21. The polymer mixture according to claim 1 , wherein P(i) and/or P(j) have long-chain branchings which have a degree of polymerisation >30.
22. The polymer mixture according to claim 1 , wherein P(i) and/or P(j) have long-chain branchings which have a degree of polymerisation >40.
23. The polymer mixture according to claim 1 , wherein P(i) and/or P(j) have long-chain branchings which have a degree of polymerisation >50.
24. The polymer mixture according to claim 1 , wherein P(j) has a density in g/cm 3 of >0.9, and a melting or dropping point in ° C. of >80.
25. The polymer mixture according to claim 1 , wherein P(j) has a density in g/cm 3 of >0.925, and a melting or dropping point in ° C. of >100.
26. The polymer mixture according to claim 1 , wherein P(j) has a density in g/cm 3 of >0.950, and a melting or dropping point in ° C. of >110.
27. The polymer mixture according to claim 1 , wherein P(j) has a density in g/cm 3 of >0.970, and a melting or dropping point in ° C. of >120.
28. The polymer mixture according to claim 1 , wherein P(j) has a density in g/cm 3 of >0.980, and a melting or dropping point in ° C. of >125.
29. The polymer mixture according to claim 1 , wherein the polymer mixture after preparation is present in the form selected from the group consisting of granules, pellets, powder, macro- or micro-fibres, films, continuous casting, casting, extrudate, thermo-shaped part and combinations thereof.
30. The polymer mixture according to claim 2 , wherein, if there is a fraction A(j) of P(j) relative to P(i)+P(j) in wt.% within the range 1 <A(j)<15, the quotient of the elongation at break eb(i, j) of P(i)+P(j) and the elongation at break eb(i) of P(i), eb(i, j)/eb(i) is >1.01 and <1.5.
31. The polymer mixture according to claim 1 , wherein 0.5×DP(P(j))<DPs(P(i))<5×DP(P(j)).
32. The polymer mixture according to claim 1 , wherein 0.3×DP(P(j))<DPs(P(i))<7×DP(P(j)).
33. A polymer mixture consisting of:
at least one synthetic first polymer P(i) and between 3% to 14% by weight of at least one second polymer P(j),
wherein the first polymer P(i) has a degree of polymerisation DP(P(i))>500 and at least one type of crystallisable sequences A having a degree of polymerisation DPs(P(i)) of these sequences >20,
wherein the second polymer P(j) is made up of the same monomer units as the sequences A of P(i) and the degree of polymerisation DP(P(j)) of P(j) is 20<DP(P(j))<500,
wherein the polymer mixture comprises a molecularly dispersed mixture containing P(i) and P(j) that forms a network by heterocrystallisation,
wherein P(i), or the sequences A of P(i), comprises a polypropylene,
wherein P(j) has a polydispersivity <30 and is a polypropylene wax; and
wherein P(i) has a degree of branching <3×10 −2 , and P(j) has a degree of branching <5×10 −2 , wherein the first polymer P(i) and the second polymer P(j) have been mixed together using a twin screw extruder, and wherein the polymer mixture of the first polymer P(i) and the second polymer P(j) has an elongation at break greater than an elongation at break of the first polymer P(i) alone.