CN117820614A

CN117820614A - 2, 5-furandimethanol modified polyethylene naphthalate and preparation method and application thereof

Info

Publication number: CN117820614A
Application number: CN202311583969.1A
Authority: CN
Inventors: 孙中华; 周兴; 陈圣春; 钱俊峰; 何明阳; 陈群; 韦梅峻
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2023-11-24
Filing date: 2023-11-24
Publication date: 2024-04-05

Abstract

The invention discloses 2, 5-furandimethanol modified polyethylene naphthalate and a preparation method and application thereof, and relates to the technical field of copolymerization modification of polyethylene naphthalate, and the preparation method comprises the following steps: 2, 5-furandimethanol, glycol, 2, 6-naphthalic acid dimethyl ester and catalyst are put into a 50mL reaction kettle, and under the nitrogen atmosphere, the temperature is raised to 260-330 ℃ after esterification reaction for 1-12 hours, and the polyethylene naphthalate-2, 5-furandimethanol copolyester is obtained after polycondensation reaction for 1-12 hours under the condition that the vacuum degree is 5-100 Pa. The preparation method provided by the invention is convenient to operate, efficient, controllable, simple and feasible; the prepared copolyester has the intrinsic viscosity of 0.50-0.70 dL/g, the glass transition temperature of 127.2 ℃, excellent thermal stability, hydrophobicity and physical and mechanical properties, and has very wide application prospect in the fields of automobiles, films, food packaging and the like.

Description

2, 5-furandimethanol modified polyethylene naphthalate and preparation method and application thereof

Technical Field

The invention belongs to the technical field of polyethylene naphthalate modification, and particularly relates to 2, 5-furandimethanol modified polyethylene naphthalate and a preparation method and application thereof.

Background

Polyethylene naphthalate (polyethylene naphthalate, PEN for short) is semi-crystalline aromatic polyester prepared by polycondensation of 2, 6-dimethyl naphthalate or 2, 6-naphthalene dicarboxylic acid and ethylene glycol, has excellent physical and mechanical properties, thermal stability, gas barrier property, chemical stability, radiation resistance and other properties, and has good application prospects in the fields of battery films, packaging materials, aerospace and the like. However, PEN also has drawbacks such as high heat processing temperatures, poor toughness and poor heat resistance, and is necessary for its modification. The PEN is modified mainly by two modes of physical modification and chemical modification, the former is convenient and simple to operate, carbon nano tubes, titanium dioxide or nylon are added in the melt processing process to improve the physical and mechanical properties, dielectric properties or processability of the PEN, but the compatibility is poor; the latter is usually to add terephthalic acid, pyromellitic dianhydride and cardanol in the polymerization reaction to reduce the synthesis cost, improve the hot workability and the heat resistance, and make the PEN performance more stable and the modification effect better.

The polyester material prepared by taking the furan ring as the framework has excellent performance and is widely focused on the market in the fields of films and packaging application. Wu Linbo and the like melt-polycondensate 2, 5-furandicarboxylic acid with ethylene glycol and 1, 3-propanediol under the catalysis of acetate, wherein the tensile strength of the synthesized polyethylene2, 5-furandicarboxylic acid (PEF for short) is 70-83 Mpa, the elongation at break is 115-256%, the physical and mechanical properties are excellent, and the barrier property to oxygen and carbon dioxide is obviously improved (CN 108659209A). On the other hand, 2, 5-furandimethanol may also be an important comonomer; however, the copolymerization of polyester materials by using 2, 5-furandimethanol is not reported in the related literature.

Disclosure of Invention

This section is intended to outline some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description summary and in the title of the application, to avoid obscuring the purpose of this section, the description summary and the title of the invention, which should not be used to limit the scope of the invention.

The present invention has been made in view of the above and/or problems occurring in the prior art.

Therefore, the invention aims to overcome the defects in the prior art, provide 2, 5-furandimethanol modified polyethylene naphthalate, and in particular relates to the technical field of copolymerization modification of the polyethylene naphthalate; the preparation method provided by the invention is convenient to operate, efficient, controllable, simple and feasible; the prepared polyethylene naphthalate-2, 5-furandimethanol copolyester has the intrinsic viscosity stabilized at 0.50-0.70 dL/g, excellent thermal stability, hydrophobicity and physical and mechanical properties, and has good application prospect in the fields of automobiles, household appliances and clothing materials.

In order to solve the technical problems, the invention provides the following technical scheme: 2, 5-furandimethanol modified polyethylene naphthalate, wherein the structural formula of the 2, 5-furandimethanol modified polyethylene naphthalate is shown as (I):

wherein m and n are arbitrary positive integers.

The invention also aims to overcome the defects in the prior art and provide a preparation method of the 2, 5-furandimethanol modified polyethylene naphthalate, which comprises the steps of putting 2, 5-furandimethanol, glycol, dimethyl 2, 6-naphthalate and a catalyst into a reaction kettle, and heating to 160-230 ℃ at one time under nitrogen atmosphere;

and raising the temperature to 260-330 ℃ for the second time, and carrying out polycondensation reaction under the vacuum condition to obtain the polyethylene naphthalate-2, 5-furan dimethanol copolyester.

As a preferred embodiment of the preparation process according to the invention, there is provided: the molar ratio of the 2, 5-furandimethanol to the glycol is 0.05-0.3:1.

As a preferred embodiment of the preparation process according to the invention, there is provided: the molar ratio of the ethylene glycol to the dosage of the 2, 6-naphthalic acid dimethyl ester is 2-4:1.

As a preferred embodiment of the preparation process according to the invention, there is provided: the catalyst comprises one or more of manganese acetate, antimony acetate, zinc acetate, calcium acetate, cobalt acetate or stannous octoate.

As a preferred embodiment of the preparation process according to the invention, there is provided: the molar ratio of the catalyst to the 2, 6-naphthalic acid dimethyl ester is 1 multiplied by 10 ^-5 ～3×10 ^-4 :1。

As a preferred embodiment of the preparation process according to the invention, there is provided: the reaction time of the primary temperature rise is 1-12 h.

As a preferred embodiment of the preparation process according to the invention, there is provided: the vacuum condition, wherein the vacuum degree is 5-100 Pa.

As a preferred embodiment of the preparation process according to the invention, there is provided: the polycondensation reaction is carried out for 1-12 h.

The invention further aims to overcome the defects in the prior art and provide an application of the 2, 5-furandimethanol modified polyethylene naphthalate in preparing food packaging materials, circuit board substrates and cosmetic packaging materials.

The invention has the beneficial effects that:

(1) According to the invention, monomer 2, 5-furandimethanol, 2, 6-naphthalate dimethyl ester and ethylene glycol are introduced for the first time to prepare the polyethylene naphthalate-2, 5-furandimethanol copolyester, the intrinsic viscosity is stabilized at 0.50-0.70 dL/g, the tensile strength is increased from 38.62MPa to 55.21MPa, the Vicat softening point is increased to 127.2 ℃, the melting point is reduced to 250 ℃, the water contact angle is increased from 64 DEG to 91 DEG, the oxygen permeability is reduced from 2050 cc/(-day) to 980 cc/(-day), the oxygen barrier property is obviously improved, the physical and mechanical properties, the thermal stability and the hydrophobic properties are excellent, the processing window is wider, and the polyethylene naphthalate-2, 5-furandimethanol copolyester can be applied to manufacturing food packages, circuit board substrates and cosmetic packages, and has wide application prospects.

(2) The preparation method provided by the invention is convenient to operate, efficient, controllable, simple and feasible.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is an infrared spectrum of the copolyester of example 1 (PECF-1);

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of the copolyester of example 1 (PECF-1);

FIG. 3 is a film pressed from the copolyester of example 1 (PECF-1).

FIG. 4 is a graph of the Vicat softening point of the PECF copolyester materials (PECF-1, PECF-6, PECF-7) prepared in examples 1, 6, and 7.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will become more apparent, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.

Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The raw materials used in the invention are all commonly and commercially available without special description.

The product prepared by the embodiment of the invention is subjected to performance test according to the following method:

(1) Determination of intrinsic viscosity of PECF copolyester material

The intrinsic viscosity of the sample was measured in a precision thermostatted bath (JWC-32C) at 30.+ -. 0.1 ℃ in a thermostatted water bath using hexafluoroisopropanol as solvent, 25 mg of PECF was taken, placed in a 25 ml volumetric flask, dissolved in 25 ml hexafluoroisopropanol solution, and after shaking dissolution, the solution was poured into a precision thermostatted viscometer, and the intrinsic viscosity was calculated by measuring three times, taking the average value.

(2) Mechanical property test of PECF copolyester material

The PECF copolyester was prepared into 50mm x 10mm dumbbell-shaped bars, which were placed in a Kai Jiang Li electronic universal tester WDT 0.2 to test tensile strength and elongation at break at a tensile rate of 10mm/min.

(3) The Vicat softening point test was performed using a VTM1300-A1 thermal deformation Vicat softening point tester.

(4) TGA test using NETZSCH/TG 209F3 thermogravimetric analyzer

Example 1

2, 5-Furanodimethanol (0.64 g,0.01 mol), ethylene glycol (12.41 g,0.20 mol), dimethyl 2, 6-naphthalenedicarboxylate (12.21 g,0.05 mol) and zinc acetate (5.50 mg,0.60 mmol) were charged into a 50mL reaction vessel equipped with a heating and temperature controlling device, a stirring device, a condensing device, and a nitrogen protecting device.

The reaction mixture is stirred and heated to 200 ℃, after reaction for 5 hours, the temperature is gradually raised to 290 ℃, and under the condition of 10Pa of vacuum degree, polycondensation is carried out for 5 hours, thus obtaining polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-1), the yield is 86%, and the intrinsic viscosity is 0.70dL/g.

The finished polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-1) prepared in example 1 was uniformly laid in a 50mm by 2mm mold, laid flat on a flat vulcanizing press, and the machine heating temperature was set at 280 ℃. And after the set temperature is reached, starting a flat vulcanizing machine to lift the heating layer and clamp the die to obtain the polyethylene naphthalate-2, 5-furandimethanol ester film with the thickness of 2 mm. The light transmittance of the ultraviolet and visible light of the film at 600nm is improved from 70.5% before being unmodified to 91.1%, and the light transmittance is obviously improved.

FIG. 1 is an infrared spectrum of polyethylene naphthalate-2, 5-furandimethanol copolyester prepared in the above example:

infrared data (cm) of PECF-1 ^–1 ): 3050w, 2960w, 1709s, 1601m, 1503m, 1451w, 1405m, 1377m, 1337w, 1274m, 1176m, 1128w, 1082m, 1041w, 963w, 915m, 878w, 822m, 761s, 640m, 522w, 474s, 963cm as can be seen from the figure ^-1 Ji 1041cm ^-1 The stretching vibration peak of furan ring appears, and the structural characteristics of the PECF-1 copolyester are clearly determined by the test result of FTIR, which shows that 2, 5-furandimethanol is successfully introduced into the molecular chain of the copolyester by the transesterification method.

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of the copolyester of example 1 (PECF-1), nuclear magnetic data 1H NMR (400 MHz, CF3COOD) of PECF: 1.21 (t, 1H), 2.2 (s, 1H), 4.9 (s, 1H), 7.9 (d, 1H), 8.5 (s, 1H), it can be seen from the figure that the molecular structure of the copolyester can be precisely determined by chemical shift of resonance absorption peak, and the comparison of naphthalene ring, furan ring and-CH ₂ CH ₂ Chemical shift of the resonance absorption peak, indicating successful incorporation of 2, 5-furandimethanol into the copolyester unit.

FIG. 3 is a film pressed from the copolyester of example 1 (PECF-1): after the copolymerization modification, the oxygen transmittance of the copolyester material is reduced from 2050 cc/(-day) to 980 cc/(-day) before, the oxygen barrier property is obviously improved, the light transmittance of the film ultraviolet visible light at 600nm is improved from 70.5% to 91.1% before the modification, the light transmittance is obviously improved, and the application prospect in the field of transparent film materials is wide. The physical and mechanical properties, the thermal stability, the oxygen barrier property and the hydrophobic property are obviously improved, and the copolyester material modified by the 2, 5-furandimethanol has obvious advantages.

Example 2

This example differs from example 1 in that antimony acetate (8.94 mg,0.6 mmol) was used as the catalyst, and the other preparation processes were the same as in example 1 to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-2) in a yield of 72% and an intrinsic viscosity of 0.55dL/g.

Example 3

This example differs from example 1 in that manganese acetate (5.20 mg,0.60 mmol) was used as the catalyst, and the other preparation processes were the same as those of example 1 to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-3) with a yield of 76% and an intrinsic viscosity of 0.60dL/g.

Example 4

This example differs from example 1 in that the catalyst was adjusted to calcium acetate (4.74 mg,0.60 mmol), and the remaining preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-4) with a yield of 54% and an intrinsic viscosity of 0.47dL/g.

Example 5

This example differs from example 1 in that the catalyst was cobalt acetate (5.31 mg,0.60 mmol) and the rest of the preparation process was the same as example 1, to prepare polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-5) with a yield of 57% and an intrinsic viscosity of 0.48dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in table 1.

TABLE 1

	Example 1	Example 2	Example 3	Example 4	Example 5
						Yield (%)	86	72	76	54	57
Intrinsic viscosity (dL/g)	0.7	0.55	0.6	0.47	0.48
						Tensile Strength (MPa)	55.21	39.22	41.35	31.63	32.25
Elongation at break (%)	29.50	13.20	13.95	9.89	10.34
						Vicat softening point (DEG C)	120.2	108.2	109.58	106.42	106.98
Initial degradation temperature (. Degree. C.)	407.5	399.2	400.1	397.1	397.6
						Water contact angle (°)	75	69.75	70.12	68.25	69.21

From the table, the influence of different catalysts on the intrinsic viscosity of the copolyester material is obvious, the titanium catalyst has higher activity but is easy to hydrolyze, the antimony catalyst is limited due to the environmental protection problem, and the zinc acetate catalyst is selected, so that the yield and the molecular weight are obviously improved under the catalysis of zinc ions.

Example 6

This example differs from example 1 in that the mass of 2, 5-furandimethanol was adjusted to 0.32g (0.005 mol) and the remaining production process was the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-6) with a yield of 80% and an intrinsic viscosity of 0.61dL/g.

Example 7

This example differs from example 1 in that the mass of 2, 5-furandimethanol was adjusted to 1.28g (0.02 mol) and the remaining production process was the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-7) with a yield of 81% and an intrinsic viscosity of 0.67dL/g.

Fig. 4 shows the vicat softening point spectra of PECF copolyester materials (PECF-1, PECF-6, PECF-7) prepared in examples 1, 6, and 7, and it can be seen that the vicat softening point of the copolyester materials is significantly improved with increasing addition ratio of the modified monomer 2, 5-furandimethanol.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 2.

TABLE 2

	Example 1	Example 6	Example 7
				Yield (%)	86	80	81
Intrinsic viscosity (dL/g)	0.7	0.61	0.67
				Tensile Strength (MPa)	55.21	43.96	47.38
Elongation at break (%)	29.51	13.98	14.96
				Vicat softening point (DEG C)	120.2	114.6	127.2
Initial degradation temperature (. Degree. C.)	407.5	408.3	409.2
				Water contact angle (°)	75	70	85

As can be seen from Table 2, the addition amount of different modified monomers 2, 5-furandimethanol has an influence on the copolyester, because the introduction of furan rings does not damage the compatibility among PEN copolyester molecular chains, the introduction of furan ring units can improve the heat resistance of the material, excessive addition can lead to the reduction of the regularity and the crystallinity of the molecular chains, the heat resistance can be improved to a certain extent, but the introduction of excessive third monomers can lead to the reduction of the physical and mechanical properties of the material, and the addition of too little can lead to the insufficient obvious improvement of the copolyester material, so that the comprehensive performance is better when the addition amount of 2, 5-furandimethanol is 0.01mol, and the best technical effect can be obtained.

Example 8

This example differs from example 1 in that the catalyst amount was adjusted to 0.09mg,0.10mmol, and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-8) with a yield of 60% and an intrinsic viscosity of 0.49dL/g.

Example 9

This example differs from example 1 in that the catalyst was used in an amount of 27.30mg and 3.00mmol of the remaining preparation process was the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-9) in a yield of 80% and an intrinsic viscosity of 0.65dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 3.

TABLE 3 Table 3

	Example 1	Example 8	Example 9
				Yield (%)	86	60	80
Intrinsic viscosity (dL/g)	0.7	0.49	0.65
				Tensile strengthDegree (MPa)	55.21	36.01	45.05
Elongation at break (%)	29.51	10.50	14.50
				Vicat softening point (DEG C)	120.2	113.2	115.1
Initial degradation temperature (. Degree. C.)	407.5	400.1	403.7
				Water contact angle (°)	75	68	70

As can be seen from table 3, adjusting the amount of the catalyst has an effect on the performance of PECF materials, because the catalyst has a dual effect on the yield and the molecular weight under the catalysis of zinc ions, too much catalyst addition can cause the generation of aggravated side reactions, the yellowness is increased, the product quality is affected, too little addition can make the catalysis of zinc ions insignificant, and the intrinsic viscosity of the materials is smaller. The catalyst has a dual effect on the polycondensation reaction, both accelerating the forward progress of the reaction and catalyzing thermal degradation and side reactions, so that the catalyst is preferably used in an amount of 0.06mmol.

Example 10

This example differs from example 1 in that the transesterification reaction temperature was adjusted to 160℃and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-10) with a yield of 61% and an intrinsic viscosity of 0.46dL/g.

Example 11

This example differs from example 1 in that the transesterification reaction temperature was adjusted to 230℃and the remaining preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-11) with a yield of 80% and an intrinsic viscosity of 0.65dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 4.

TABLE 4 Table 4

From the above table it is clear that different transesterification temperatures have an effect on the properties of the material, the transesterification temperature being an important factor affecting the yield, since the esterification temperature has a significant effect on the transesterification rate and the transesterification time. Suitable temperatures may accelerate transesterification reaction times and affect yields. Too high a temperature will result in a reduced esterification rate, a reduced intrinsic viscosity, and too low a temperature will result in an increased reaction time and a reduced polyester color. The preferred transesterification temperature is therefore 200 ℃.

Example 12

This example differs from example 1 in that the transesterification reaction time was adjusted to 1h, and the other preparation processes were the same as those of example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-12) with a yield of 59% and an intrinsic viscosity of 0.45dL/g.

Example 13

This example differs from example 1 in that the transesterification reaction time was adjusted to 12 hours, and the other preparation processes were the same as those of example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-13) with a yield of 77% and an intrinsic viscosity of 0.61dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 5.

TABLE 5

	Example 1	Example 12	Example 13
				Yield (%)	86	59	77
Intrinsic viscosity (dL/g)	0.7	0.45	0.61
				Tensile Strength (MPa)	55.21	28.26	43.77
Elongation at break (%)	29.51	6.75	13.98
				Vicat softening point (DEG C)	120.2	108.9	118.6
Initial degradation temperature (. Degree. C.)	407.5	400.1	408.3
				Water contact angle (°)	75	68	80

From the above table, it is clear that adjusting the transesterification time has an effect on the performance of the copolyester, because the appropriate temperature can accelerate the transesterification speed, too long a reaction time can result in poor hue, reduced viscosity, too short a time can result in insufficient transesterification degree and low yield. Therefore, the best technical effect can be obtained when the transesterification reaction time in the present invention is 5 hours.

Example 14

This example differs from example 1 in that the temperature of the polycondensation reaction was adjusted to 260℃and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-14) with a yield of 64% and an intrinsic viscosity of 0.51dL/g.

Example 15

This example differs from example 1 in that the polycondensation reaction temperature was adjusted to 330℃and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-15) with a yield of 76% and an intrinsic viscosity of 0.62dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 6.

TABLE 6

	Example 1	Example 14	Example 15
				Yield (%)	86	64	76
Intrinsic viscosity (dL/g)	0.7	0.51	0.62
				Tensile Strength (MPa)	55.21	37.50	44.21
Elongation at break (%)	29.51	10.50	14.02
				Vicat softening point (DEG C)	120.2	110.1	119.3
Initial degradation temperature (. Degree. C.)	407.5	399.3	404.1
				Water contact angle (°)	75	69	71

As can be seen from the above table, adjusting the temperature of the polycondensation reaction affects the performance of the material, the polycondensation process is a complex chemical reaction process, which not only leads to chain segment growth, but also leads to degradation reaction with reduced chain segment, the too high temperature of the polycondensation reaction leads to reduced intrinsic viscosity, the too low material performance leads to lower polycondensation reaction rate, small molecules are difficult to remove, thermal degradation and other side reactions are aggravated, and in the embodiment, the intrinsic viscosity is increased and then reduced along with the increase of the reaction temperature, so that the best technical effect is obtained at 290 ℃.

Example 16

This example differs from example 1 in that the polycondensation reaction time was adjusted to 1h, and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-18) with a yield of 51% and an intrinsic viscosity of 0.42dL/g.

Example 17

This example differs from example 1 in that the polycondensation reaction time was adjusted to 12 hours, and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF-19) with a yield of 79% and an intrinsic viscosity of 0.65dL/g.

The materials prepared in the above examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 7.

TABLE 7

	Example 1	Example 16	Example 17
				Yield (%)	86	51	79
Intrinsic viscosity (dL/g)	0.7	0.42	0.65
				Tensile Strength (MPa)	55.21	26.85	45.05
Elongation at break (%)	29.51	6.52	14.50
				Vicat softening point (DEG C)	120.2	110	115.1
Initial degradation temperature (. Degree. C.)	407.5	400	403.7
				Water contact angle (°)	75	68	70

From the above table, the different polycondensation times have an influence on the performance of the copolyester, because the polycondensation reaction is a process of gradually polymerizing small molecules into macromolecules, the reaction time is shorter, the growth of molecular chain segments is not facilitated, the reaction time is too long, the content of side reactions is high, and the intrinsic viscosity is reduced. In conclusion, the best technical effect is obtained when the polycondensation reaction time is 5 hours.

Comparative example 1

This comparative example was different from example 1 in that no 2, 5-furandimethanol was added, and the other preparation processes were the same as in example 1, to obtain polyethylene naphthalate (PEN-1) with a yield of 81% and an intrinsic viscosity of 0.53dL/g.

Comparative example 2

This comparative example was different from example 1 in that no nitrogen atmosphere was maintained, and the remaining preparation process was the same as example 1, to obtain polyethylene naphthalate (PEN-2), and the polyester synthesized without the nitrogen atmosphere was dark yellow in color, poor in color, 78% in yield, and 0.57dL/g in intrinsic viscosity.

Comparative example 3

This comparative example differs from example 1 in that no 2, 5-furandimethanol was added, stannous octoate (12.15 mg, 0.06 mmol) was used as a catalyst, and the rest of the preparation process was the same as example 1, to obtain polyethylene naphthalate (PEN-3), and the obtained PEN copolyester material was dark yellow in color, lower in molecular weight, 56% in yield, and 0.36dL/g in intrinsic viscosity.

Comparative example 4

The comparative example is different from example 1 in that no catalyst is added, the rest of the preparation process is the same as that of example 1, polyethylene naphthalate (PEN-4) is prepared, the yield of the obtained PEN copolyester is 12%, the intrinsic viscosity is only 0.13dL/g, and the practical application value is not realized.

The materials obtained in the above comparative examples were subjected to performance test, and the results of comparison with example 1 are shown in Table 8.

TABLE 8

	Example 1	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
						Yield (%)	86	81	78	56	12
Intrinsic viscosity (dL/g)	0.7	0.53	0.57	0.36	0.13
						Tensile Strength (MPa)	55.21	36.89	39.23	16.47	/
Elongation at break (%)	29.51	10.38	10.95	5.23	/
						Vicat softening point (DEG C)	120.2	110.3	114	118	/
Initial degradation temperature (. Degree. C.)	407.5	400.1	403	401.6	390
						Water contact angle (°)	75	68	71	69	/

As can be seen from the table, compared with the unmodified material, the modified polyethylene naphthalate-2, 5-furandimethanol copolyester has the advantages that the intrinsic viscosity is improved to a certain extent, the physical and mechanical properties, the thermal stability, the hydrophobic property and the like are obviously improved, and the 2, 5-furandimethanol modified copolyester material has obvious advantages.

According to the invention, the polyethylene naphthalate-2, 5-furandimethanol copolyester (PECF) synthesized by using 2, 5-furandimethanol, 2, 6-dimethyl naphthalate and ethylene glycol under the catalysis of acetate has the characteristic viscosity stabilized at 0.50-0.70 dL/g, the Vicat softening point of the modified material is obviously improved to 127.2 ℃, the heat resistance is obviously improved, the dimensional stability of the material when heated is good, the material can be applied to higher temperature environments, meanwhile, the PECF copolyester material has better thermal stability, the initial degradation temperature is 407.5 ℃, the thermal stability is better, and the processing window is wide. The water contact angle is improved from 64 degrees to 91 degrees, the tensile strength is improved to 55.21MPa, the oxygen transmission rate is reduced from 2050 cc/(-day) to 980 cc/(-day), the oxygen barrier property is obviously improved, the material has excellent thermal stability, hydrophobicity and physical and mechanical properties, can be applied to the fields of films, packaging materials and the like, and has very broad market application prospect.

It should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered in the scope of the claims of the present invention.

Claims

1. A 2, 5-furandimethanol modified polyethylene naphthalate, characterized by:

the structural formula of the 2, 5-furandimethanol modified polyethylene naphthalate is shown as (I):

wherein m and n are arbitrary positive integers.

2. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 1, wherein: comprising the steps of (a) a step of,

2, 5-furandimethanol, glycol, 2, 6-dimethyl naphthalate and a catalyst are put into a reaction kettle, and are heated to 160-230 ℃ for one time under the nitrogen atmosphere to carry out transesterification reaction;

and heating to 260-330 ℃ for the second time, and carrying out polycondensation reaction under a vacuum condition to obtain the polyethylene naphthalate-2, 5-furandimethanol copolyester.

3. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the molar ratio of the 2, 5-furandimethanol to the glycol is 0.05-0.3:1.

4. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the molar ratio of the ethylene glycol to the dosage of the 2, 6-naphthalic acid dimethyl ester is 2-4:1.

5. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the catalyst comprises one or more of manganese acetate, antimony acetate, zinc acetate, calcium acetate, cobalt acetate or stannous octoate.

6. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 5, wherein: the molar ratio of the catalyst to the 2, 6-naphthalic acid dimethyl ester is 1 multiplied by 10 ^-5 ～3×10 ^-4 :1。

7. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the reaction time of the transesterification reaction is 1-12 h.

8. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the vacuum condition, wherein the vacuum degree is 5-100 Pa.

9. The process for producing 2, 5-furandimethanol-modified polyethylene naphthalate according to claim 2, wherein: the polycondensation reaction is carried out for 1-12 h.

10. Use of the 2, 5-furandimethanol modified polyethylene naphthalate according to claim 1 in the preparation of food packaging materials, circuit board substrates and cosmetic packaging materials.