Preparing method of aliphatic polycarbonate

Abstract

A preparing method of an aliphatic polycarbonate is provided to synthesize oligomer monomers by a transesterification reaction of carbonic acid dialkyl esters and aliphatic diols with accelerants in an atmosphere of a protective gas, and generate an aliphatic polycarbonate polymer by a polycondensation reaction of the oligomer monomers in a condition of high temperature and low pressure. According to the disclosure, environmentally friendly compounds with low boiling points and low costs are utilized as the accelerants to substitute the enzyme or acid-base catalysts to prepare aliphatic polycarbonate polymers in the prior art, and the cost is reduced; meanwhile, in the process of generating the aliphatic polycarbonate polymers, the accelerants can be removed from the reaction system along with the pressure reduced in the reaction system. The synthesis system is simple; moreover, the aliphatic polycarbonate obtained by the preparing method provided by the disclosure has merits such as superior colors.

Claims

1. A preparing method of an aliphatic polycarbonate comprising following steps: in an atmosphere of a protective gas, synthesizing oligomer monomers by a transesterification reaction of carbonic acid dialkyl esters and aliphatic diols with accelerants; generating an aliphatic polycarbonate polymer by a polycondensation reaction of the oligomer monomers in a predefined temperature and under a predefined pressure; wherein the carbonic acid dialkyl ester is diphenyl carbonates, the aliphatic diols is 1,4-butyleneglycols, the accelerant is distilled water, and a mole ratio of diphenyl carbonates, 1, 4-butyleneglycols, and distilled water is 0.96:1:3; wherein a mixture of diphenyl carbonates, 1, 4-butyleneglycols, and distilled water is added in a reactor and stirred in N.sub.2 at 90 C. for 1 h, and then is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out, a pressure of the reaction system is reduced to below 300 Pa, after the reaction at the temperature for 2 h, a weight-average molecular weight M.sub.w of the obtained aliphatic polycarbonate polymer is 9.810.sup.5.

2. A preparing method of an aliphatic polycarbonate comprising following steps: in an atmosphere of a protective gas, synthesizing oligomer monomers by a transesterification reaction of carbonic acid dialkyl esters and aliphatic diols with accelerants; generating an aliphatic polycarbonate polymer by a polycondensation reaction of the oligomer monomers in a predefined temperature and under a predefined pressure; wherein the carbonic acid dialkyl ester is diphenyl carbonates, the aliphatic diols is 1,4-butyleneglycols, the accelerant is distilled water, and a mole ratio of diphenyl carbonates, 1, 4-butyleneglycols, and distilled water is 1:1:1; wherein a mixture of diphenyl carbonates, 1, 4-butyleneglycols, and distilled water is added in a reactor and stirred in N.sub.2 at 90 C. for 1 h, and then is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out, a pressure of the reaction system is reduced to below 300 Pa, after the reaction at the temperature for 2 h, a weight-average molecular weight M.sub.w of the obtained aliphatic polycarbonate polymer is 1.2210.sup.5.

3. A preparing method of an aliphatic polycarbonate comprising following steps: in an atmosphere of a protective gas, synthesizing oligomer monomers by a transesterification reaction of carbonic acid dialkyl esters and aliphatic diols with accelerants; generating an aliphatic polycarbonate polymer by a polycondensation reaction of the oligomer monomers in a predefined temperature and under a predefined pressure; wherein the carbonic acid dialkyl ester is diphenyl carbonates, the aliphatic diols is 1,4-butyleneglycols, the accelerants is phenols, and a mole ratio of diphenyl carbonates, 1, 4-butyleneglycols, and phenols is 1:1:3; wherein a mixture of diphenyl carbonates, 1, 4-butyleneglycols, and phenols is added in a reactor and stirred in N.sub.2 at 90 C. for 1 h, and then is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out, a pressure of the reaction system is reduced to below 300 Pa, after the reaction at the temperature for 2 h, a weight-average molecular weight M.sub.w of the obtained aliphatic polycarbonate polymer is 1.1510.sup.5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flowchart of steps of a preparing method of an aliphatic polycarbonate provided by the disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) In order to better clarify the objective, embodiments and technical effects of the disclosure, concrete embodiments of the disclosure will be illustrated with reference to accompanying drawings as follows. The described concrete embodiments are for explaining the disclosure instead of limiting the disclosure.

(3) In the disclosure, relational terms such as first and second are merely for the purpose of distinguishing one object or process from another object or process, which do not request or imply any practical relation or sequence between the objects or processes. Moreover, terms include, contain or the like tends to indicate non-exclusive inclusion to make processes, methods, objects or devices with a series of factors to include the factors and other factors that are not clearly listed, or including inherent factors of the processes, methods, objects or devices. Without further limitation, a factor restricted by a sentence include a does not exclude other identical factors included in the processes, methods, objects or devices with the factors.

(4) Referring to FIG. 1, FIG. 1 is a flowchart 100 of steps of a preparing method of an aliphatic polycarbonate provided by the disclosure, including following steps.

(5) Step S110: in an atmosphere of a protective gas, synthesizing oligomer monomers by a transesterification reaction of carbonic acid dialkyl esters and aliphatic diols with accelerants.

(6) Preferably, the protective gas is nitrogen.

(7) Preferably, the carbonic acid dialkyl esters are one or a combination of some of dimethyl carbonates, diethyl carbonates and diphenyl carbonates.

(8) Preferably, the aliphatic diols are one or more of ethylene glycols, 1,2-propylene glycols, 1,3-propylene glycols, 1,3-butyleneglycols, 1,4-butyleneglycols, 1,5-pentanediols, neopentyl glycols, 1,6-hexandiols, 1,3-hexandiols and 1,12-dodecanediols, one or a combination of some of 1,4-cyclohexanedimethanols, 1,4-cyclohexane diols, isosorbides and 2,2,4,4-tetramethyl-1,3-tetramethylene glycols.

(9) Preferably, the accelerants are one or a combination of some of phenols, water, methanol, ethanol, o-cresols, m-cresols, p-cresols, 2,4-xylenols, 2,5-xylenols and 3,5-xylenols.

(10) Preferably, a pH value of the accelerants is 2.0-10.0.

(11) Preferably, a mole ratio of the aliphatic diols to the carbonic acid dialkyl esters is 1:0.954.0; a mole ratio of the accelerants to the carbonic acid dialkyl esters is 0.110:1.

(12) Preferably, a heating process of the transesterification reaction is: first reacting at 40-110 C. for 0.5-5 h, then reflux reacting with a heating rate of 1 C./min at 160-300 C. for 1-5 h.

(13) Preferably, the oligomer monomer is

(14) ##STR00002##
where R is an alkyl.

(15) Step S120: generating an aliphatic polycarbonate polymer by a polycondensation reaction of the oligomer monomers in a condition of high temperature and low pressure.

(16) Preferably, the high temperature is in a range of 150-300 C. The low pressure is lower than 300 pa, and a reaction period is 0.5-24 h.

(17) As the accelerants are compounds with low boiling points, after the transesterification reaction, the accelerants can be removed from the reaction system in the process of reducing the pressure along with the condition of the system turned to be high temperature and low pressure.

(18) Preferably, a weight-average molecular weight M.sub.w of the aliphatic polycarbonate polymer is above 1.2210.sup.5.

(19) The disclosure will be further illustrated by the following embodiments. The embodiments are merely for an objective of illustration rather than limiting the scope of the disclosure. Except for any given note, the test methods in the embodiments are processed according to the conventional condition.

Embodiment 1

(20) Diphenyl carbonates, 1,4-butyleneglycols and phenols are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in the N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=5.510.sup.4, M.sub.n=3.610.sup.4, and PDI=1.53.

Embodiment 2

(21) Dimethyl carbonates, 1,4-butyleneglycols and phenols are added in a reactor. A mole ratio of the three materials in the mixture is 2:1:1. The mixture is fast stirred in the N.sub.2 at 90 C. for 1 h, and is heated up to 190 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=4.310.sup.4, M.sub.n=2.710.sup.4, and PDI=1.59.

Embodiment 3

(22) Diphenyl carbonates, 1,4-butyleneglycols and distilled water are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in the N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=1.2210.sup.5, M.sub.n=7.710.sup.4, and PDI=1.58.

Embodiment 4

(23) Diphenyl carbonates, 1,6-hexandiols and distilled water are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in the N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=9.910.sup.4, M.sub.n=6.310.sup.4, and PDI=1.6.

Embodiment 5

(24) Diphenyl carbonates, 1, 4-butyleneglycols and phenols are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:3. The mixture is fast stirred in the N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=1.1510.sup.5, M.sub.n=7.310.sup.4, and PDI=1.57.

Embodiment 6

(25) Diphenyl carbonates, 1,4-butyleneglycols and distilled water are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The pH value of the distilled water is adjusted to be 5 by HNO.sub.3. The mixture is fast stirred in N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=1.0310.sup.5, M.sub.n=6.510.sup.4, and PDI=1.58.

Embodiment 7

(26) Diphenyl carbonates, 1,4-butyleneglycols and distilled water are added in a reactor. A mole ratio of the three materials in the mixture is 0.96:1:3. The mixture is fast stirred in N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=9.810.sup.5, M.sub.n=6.210.sup.4, and PDI=1.6.

Embodiment 8

(27) Diphenyl carbonates, 1,4-butyleneglycols and phenols are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in N.sub.2 at 90 C. for 1 h, and is immediately heated up to 220 C. till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=8.510.sup.4, M.sub.n=5.610.sup.4, and PDI=1.52.

Embodiment 9

(28) Diphenyl carbonates, 1,4-butyleneglycols and distilled water are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at 250 C. for 6 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=1.0110.sup.5, M.sub.n=6.010.sup.4, and PDI=1.68.

Embodiment 10

(29) Diphenyl carbonates, 1,4-butyleneglycols and diphenols are added in a reactor. A mole ratio of the three materials in the mixture is 1:1:1. The mixture is fast stirred in N.sub.2 at 90 C. for 1 h, and is heated up to 220 C. with a heating ratio of 1 C./min till no fraction is steamed out. And the pressure of the reaction system is reduced to below 300 Pa. Polymers obtained after reaction at the same temperature for 2 h are aliphatic polycarbonate materials. The molecular weight of the polymers is tested by gel chromatography. The results are M.sub.w=2.810.sup.4, M.sub.n=2.110.sup.4, and PDI=1.37.

(30) The foregoing embodiments merely preferred embodiments of the disclosure rather than any limitation of the disclosure. Even though the disclosure has been disclosed by preferred embodiments above, they are not for restricting the disclosure. Equivalent embodiments obtained by modifying the embodiments disclosed previously according to the contents and spirit of the disclosure achieved by a person skilled in the art are all included in the protection scope of the disclosure.