Preparation method of branched polyamide (PA) copolymer with ultra-high toughness, PA copolymer prepared using the method, and use of the PA copolymer
A preparation method of a branched polyamide copolymer with ultra-high toughness is disclosed. The preparation method includes: (1) dissolving a linear dibasic acid in a solvent A to obtain a linear dibasic acid solution, dissolving a diamine B in a solvent B to obtain a diamine solution B, and dissolving a diamine C in a solvent C to obtain a diamine solution C; (2) adding the diamine solution B to the linear dibasic acid solution to obtain an amide salt solution B; and adding the diamine solution C to the linear dibasic acid solution, and collecting a precipitate to obtain an amide salt C; and (3) mixing the amide salt solution B with the amide salt C, adding a catalyst, and conducting melt polycondensation. The prepared branched copolymer has excellent mechanical performance and is suitable for melt blending toughening, melt extrusion spinning, blow-extruded films, hot melt adhesives, and other fields.
1 . A preparation method of a branched polyamide (PA) copolymer with an ultra-high toughness comprising the following steps:
(1) dissolving a linear dibasic acid in a first solvent to obtain a linear dibasic acid solution, dissolving a first diamine in a second solvent to obtain a first diamine solution, and dissolving a second diamine in a third solvent to obtain a second diamine solution,
wherein the first diamine comprises
(i) a linear diamine selected from ethylenediamine (EDA), 1,3-propanediamine, 1,4-diaminobutane, 1,5-pentanediamine, 1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, cis-1,4-cyclohexanediamine, trans-1,4-cyclohexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, cyclohexanediamine, methylcyclohexanediamine, p-phenylenediamine, m-phenylenediamine, and dimethyldiamine; or
(ii) a mixture of the linear diamine and a diamine with an unreactive side group selected from 2-methylpentanediamine, 1,2-propanediamine, 1,3-diaminopentane, 2,2-dimethyl-1,3-propanediamine, and 4-fluoro-1,3-diaminobenzene, and
the second diamine comprises a diamine with a reactive hydroxyl side group selected from 1,3-diamino-2-propanol and 2,4-diaminophenol;
(2) in separate preparations, adding the first diamine solution to a first portion of the linear dibasic acid solution, and mixing to obtain an amide salt solution B; and
adding the second diamine solution to a second portion of the linear dibasic acid solution, mixing, and collecting a precipitate to obtain a solid amide salt C; and
(3) adding the amide salt solution B and the solid amide salt C to a reactor, adding a catalyst, and after removing solvent and water by heating, conducting a melt polycondensation by heating to 150° C. to 170° C. to allow prepolymerization and then heating to 200° C. to 280° C. under vacuum to effect amide formation between amino and carboxyl groups and an esterification reaction between hydroxyl side groups of the second diamine and carboxyl groups to obtain the branched PA copolymer with the ultra-high toughness.
2 . The preparation method of the branched PA copolymer with the ultra-high toughness according to claim 1 , wherein in step (2), a pH of the amide salt solution B is adjusted to 6.5 to 7.5, and then the amide salt solution B is heated for a solvent evaporation and a concentration to obtain the amide salt solution B with a solute mass fraction of 60% to 80%.
3 . The preparation method of the branched PA copolymer with the ultra-high toughness according to claim 1 , wherein in step (2), the linear dibasic acid solution and the first diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt solution B, and the linear dibasic acid solution and the second diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt C.
4 . A branched PA copolymer with an ultra-high toughness prepared by the preparation method according to claim 1 , wherein the branched PA copolymer with an ultra-high toughness comprises a branched part and an unbranched part, and there are ester bonds in the branched part resulting from esterification between hydroxyl side groups of the second diamine and carboxyl groups.
5 . The branched PA copolymer with the ultra-high toughness according to claim 4 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), a pH of the amide salt solution B is adjusted to 6.5 to 7.5, and then the amide salt solution B is heated for a solvent evaporation and a concentration to obtain the amide salt solution B with a solute mass fraction of 60% to 80%.
6 . The branched PA copolymer with the ultra-high toughness according to claim 4 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), the linear dibasic acid solution and the first diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt solution, B and the linear dibasic acid solution and the second diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt C.
7 . The branched PA copolymer with the ultra-high toughness according to claim 4 , wherein in step (3) of the preparation method, a mass fraction of the amide salt solution B is 89% to 97%, a mass fraction of the solid amide salt C is 2% to 10%, and a mass fraction of the catalyst is 1% to 2%.
8 . A bio-based nylon composite prepared from the following raw materials in parts by weight: 1 to 100 parts of nylon 6, 50 to 100 parts of the branched PA copolymer with the ultra-high toughness prepared by the preparation method according to claim 1 , and 0 to 5 parts of an antioxidant.
9 . A preparation method of the bio-based nylon composite according to claim 8 , comprising the following steps:
(1) pretreating each of the nylon 6 and the branched PA copolymer with the ultra-high toughness in a vacuum oven at 40° C. to 120° C. for 4 h to 12 h to obtain pretreated materials; and
(2) adding the pretreated materials to an internal mixer, and blending for 3 min to 20 min at a temperature of 180° C. to 260° C. and a rotational speed of 40 r/min to 300 r/min to obtain the bio-based nylon composite.
10 . The bio-based nylon composite according to claim 8 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), a pH of the amide salt solution is adjusted to 6.5 to 7.5, and then the amide salt solution is heated for a solvent evaporation and a concentration to obtain the amide salt solution with a solute mass fraction of 60% to 80%.
11 . The bio-based nylon composite according to claim 8 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), the linear dibasic acid solution and the first diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt solution, and the linear dibasic acid solution and the second diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt.
12 . A PA fiber prepared from the following raw materials in parts by weight through a melt spinning: 1 to 1,000 parts of the branched PA copolymer with the ultra-high toughness prepared by the preparation method according to claim 1 and 0 to 5 parts of an antioxidant.
13 . A preparation method of the PA fiber according to claim 12 , comprising the following steps:
(1) pretreating the branched PA copolymer with the ultra-high toughness at 40° C. to 100° C. for 4 h to 12 h to obtain a pretreated PA copolymer; and
(2) mixing the pretreated PA copolymer with the antioxidant, adding a resulting mixture to a melt spinning machine, preheating at 50° C. to 120° C., conducting a melt compression at 180° C. to 250° C., extruding, and rolling out at a speed of 1 m/min to 3,000 m/min to obtain the PA fiber.
14 . The PA fiber according to claim 12 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), a pH of the amide salt solution is adjusted to 6.5 to 7.5, and then the amide salt solution is heated for a solvent evaporation and a concentration to obtain the amide salt solution with a solute mass fraction of 60% to 80%.
15 . The PA fiber according to claim 12 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), the linear dibasic acid solution and the first diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt solution, and the linear dibasic acid solution and the second diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt.
16 . A high-strength and high-toughness polylactic acid (PLA) composite prepared from the following raw materials in parts by weight: 50 to 100 parts of PLA, 1 to 50 parts of the branched PA copolymer with the ultra-high toughness prepared by the preparation method according to claim 1 , and 0 to 1 part of an antioxidant.
17 . A preparation method of the high-strength and high-toughness PLA composite according to claim 16 , comprising the following steps:
(1) pretreating each of the PLA and the branched PA copolymer with the ultra-high toughness in a vacuum oven at 40° C. to 120° C. for 4 h to 12 h to obtain pretreated materials; and
(2) adding the pretreated materials to an internal mixer, and blending for 3 min to 20 min at a temperature of 160° C. to 240° C. and a rotational speed of 40 r/min to 300 r/min to obtain the high-strength and high-toughness PLA composite.
18 . The high-strength and high-toughness PLA composite according to claim 16 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), a pH of the amide salt solution is adjusted to 6.5 to 7.5, and then the amide salt solution is heated for a solvent evaporation and a concentration to obtain the amide salt solution with a solute mass fraction of 60% to 80%.
19 . The high-strength and high-toughness PLA composite according to claim 16 , wherein in a process of preparing the branched PA copolymer with the ultra-high toughness, in step (2), the linear dibasic acid solution and the first diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt solution, and the linear dibasic acid solution and the second diamine solution are mixed in a molar ratio of 0.98:1 to 1.02:1 during a preparation of the amide salt.