SOLVENT-FREE MELT POLYCONDENSATION PROCESS OF MAKING FURAN-BASED POLYAMIDES
Disclosed herein are processes of making furan-based polyamides using solvent-free melt condensation of a diamine and an ester derivative of 2,5-furandicarboxylic acid with a C 2 to C 12 aliphatic diol or a polyol. The processes comprise a) forming a reaction mixture by mixing one or more diamines, a diester comprising an ester derivative of 2,5-furandicarboxylic acid with a C 2 to C 12 aliphatic diol or a polyol, and a catalyst, such that the diamine is present in an excess amount of at least 1 mol % with respect to the diester amount; and b) melt polycondensing the reaction mixture in the absence of a solvent at a temperature in the range of 60° C. to a maximum temperature of 250° C. under an inert atmosphere, while removing alkyl alcohol to form a furan-based polyamide, wherein the one or more diamines comprises an aliphatic diamine, an aromatic diamine, or an alkylaromatic diamine.
1 . A process comprising:
a) forming a reaction mixture by mixing one or more diamines, a diester comprising an ester derivative of 2,5-furandicarboxylic acid with a C 2 to C 12 aliphatic diol or a polyol, and a catalyst, such that the diamine is present in an excess amount of at least 1 mol % with respect to the diester amount; and
b) melt polycondensing the reaction mixture in the absence of a solvent at a temperature in the range of 60° C. to a maximum temperature of 250° C. under an inert atmosphere, while removing alkyl alcohol to form a furan-based polyamide, wherein the one or more diamines comprises an aliphatic diamine, an aromatic diamine, or an alkylaromatic diamine.
2 . The process of claim 1 , wherein the catalyst is selected from hypophosphorus acid, potassium hypophosphite, sodium hypophosphite monohydrate, phosphoric acid, 4-chlorobutyl dihydroxyzinc, n-butyltin chloride dihydroxide, titanium(IV) isopropoxide, zinc acetate, 1-hydroxybenzotriazole, and sodium carbonate.
3 . The process of claim 1 , wherein the diamine is present in the reaction mixture in an excess amount of at least 5 mol % with respect to the diester amount.
4 . The process of claim 1 , wherein the step of melt polycondensing the reaction mixture in the absence of a solvent at a temperature in the range of 60° C. to a maximum temperature of 250° C. under an inert atmosphere further comprises:
i) first heating the reaction mixture to a temperature in the range of 60° C. to 100° C. for 30 to 60 minutes
ii) ramping the temperature of the reaction mixture from 100° C. to a maximum temperature of 250° C. for an amount of time in the range of 30 to 240 minutes;
iii) holding the maximum temperature of the reaction mixture constant for an amount of time in the range of 40 to 800 minutes.
5 . The process of claim 1 , further comprising adding at least one of a heat stabilizer or an anti-foaming agent to the reaction mixture.
6 . The process of claim 1 , further comprising solid state polymerizing the furan-based polyamide at a temperature between the glass transition temperature and melting point of the polyamide.
7 . The process of claim 1 , further comprising solid state polymerizing the furan-based polyamide at a temperature in the range of 140° C. to 250° C.
8 . The process of claim 1 , wherein the aliphatic diamine comprises one or more of 1,6-diaminohexane, 1,4-diaminobutane, 1,5-diaminopentane, (6-aminohexyl)carbamic acid, 1,2-diaminoethane, 1,12-diaminododecane, 1,3-diaminopropane, 1,5-diamino-2-methylpentane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, mixtures of 1,3- and 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, (2,5 (2,6) bis(aminomethyl)bicycle(2,2,1)heptane), 1,2-diaminocyclohexane, 1,4- or 1,3-diaminocyclohexane, isophoronediamine, and isomeric mixtures of bis(4-aminocyclohexyl)methane.
9 . The process of claim 1 , wherein the aromatic diamine comprises one or more of 1,3-diaminobenzene, phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, sulfonic-p-phenylene-diamine, 2,6-diamonopyridine, naphthidine, benzidine, and o-tolidine.
10 . The process of claim 1 , wherein the alkylaromatic diamine comprises one or more of m-xylylene diamine, 1,3-bis(aminomethyl)benzene, p-xylylene diamine, and 2,5-bis-aminoethyl-p-xylene.
11 . The process of claim 1 , wherein at least one of the one or more diamines is hexamethylenediamine.
12 . The process of claim 1 , wherein at least one of the one or more diamines is trimethylenediamine.
13 . The process of claim 1 , wherein at least one of the one or more diamines is m-xylylene diamine.
14 . The process of claim 1 , wherein the furan-based polyamide comprises the following repeat unit:
wherein R is selected from an alkyl, aromatic, and alkylaromatic group.