阅读说明：本技术 一种基于生物基改性聚碳酸亚丙酯、纤维的制备方法 (Preparation method of bio-based modified polypropylene carbonate and fiber ) 是由 郝超伟 来国桥 潘庆华 李泽 于 2020-08-26 设计创作，主要内容包括：本发明涉及生物可降解高分子材料技术领域,为解决目前聚碳酸亚丙酯热稳定性不佳的问题,本发明提出了一种基于生物基改性聚碳酸亚丙酯、纤维的制备方法,利用生物基改性剂呋喃二羧酸及其衍生物对PPC进行共聚改性,得到的产品可以明显改善聚碳酸亚丙酯的热性能及力学性能,同时又实现了完全生物降解,而且通过纺丝工艺纺成纤维,可用于手术缝合线、医药卫生及纺织服装领域,极大地拓展了PPC应用范围。(The invention relates to the technical field of biodegradable high polymer materials, and aims to solve the problem of poor thermal stability of the existing polypropylene carbonate, the invention provides a preparation method of a fiber based on bio-based modified polypropylene carbonate, the bio-based modifier furan dicarboxylic acid and derivatives thereof are utilized to carry out copolymerization modification on PPC, the obtained product can obviously improve the thermal property and mechanical property of the polypropylene carbonate, and simultaneously realizes complete biodegradation, and the fiber is spun by a spinning process, can be used in the fields of surgical sutures, medical sanitation and textile clothing, and greatly expands the application range of the PPC.)

1. The preparation method of the bio-based modified polypropylene carbonate is characterized by comprising the following steps:

(1) drying the propylene carbonate;

(2) esterification reaction: adding furan dicarboxylic acid and derivatives thereof into a propylene carbonate solution dissolved in a solvent, and adding a catalyst for condensation reaction to obtain a polyfurancarboxylic acid-propylene carbonate copolymer, namely the bio-based modified polypropylene carbonate.

2. The preparation method of the bio-based modified polypropylene carbonate according to claim 1, wherein the drying method in the step (1) comprises the following steps: the drying temperature is 20-40 ℃, and the drying time is 12-36 h.

3. The preparation method of the bio-based modified polypropylene carbonate according to claim 1 or 2, wherein the molecular weight of the polypropylene carbonate is 1000 to 10000, and the hydroxyl content is 20 to 80mg KOH/g.

4. The method for preparing the bio-based modified polypropylene carbonate according to claim 1, wherein the furan dicarboxylic acid and the derivatives thereof are selected from one or more of furan-2, 5-dicarboxylic acid, furan 3, 4-dicarboxylic acid, furan-2, 5-diacetic acid, furan 3, 4-diacetic acid, furan-2, 5-furylidene di (methylene) diacetic acid, furan-3, 4-furylidene di (methylene) diacetic acid, furan-2, 5-diformyl chloride, furan-3, 4-diformyl chloride, and the like; wherein the molar ratio of carboxylic acid groups to hydroxyl groups is controlled to be 0.8-1.6: 1.

5. the preparation method of the bio-based modified polypropylene carbonate according to claim 1, wherein the catalyst is one or more of isobutyl titanate, p-toluenesulfonic acid/stannous chloride composite catalyst, zinc acetate and n-butyl titanate, and the molar ratio of the catalyst to the hydroxyl of the polypropylene carbonate is 0.002-0.1: 1, wherein the solvent is an aprotic solvent.

6. The preparation method of the bio-based modified polypropylene carbonate according to claim 1, wherein the condensation reaction temperature is 50-150 ℃ and the reaction time is 1-5 h.

7. A method for preparing a fiber using the bio-based modified polypropylene carbonate obtained by the bio-based modified polypropylene carbonate-based preparation method according to any one of claims 1 to 6, wherein the method for preparing the bio-based modified polypropylene carbonate fiber comprises: drying the bio-based modified polypropylene carbonate, putting the dried bio-based modified polypropylene carbonate into a melt spinning machine, and preparing the fiber through the working procedures of screw melting, spinning manifold, spinning assembly, cooling, oiling, drafting, winding and the like.

8. The preparation method of the bio-based modified polypropylene carbonate fiber according to claim 7, wherein the drying is carried out at 40-80 ℃ for 12-24 h, the screw melting temperature is 160-270 ℃, the spinning box temperature is 190-220 ℃, a circular blowing cooling mode is adopted, the draft ratio is 1.6-3.0, and the spinning speed is 1000-5000 m/min.

9. The preparation method of the bio-based modified polypropylene carbonate fiber according to claim 1, wherein the circular blowing cooling mode is as follows: the cooling air temperature is 23 +/-2 ℃, the humidity is 60 +/-10 percent, and the air speed is 0.5 +/-0.1 m/s.

10. The application of the bio-based modified polypropylene carbonate fiber obtained by the preparation method of the bio-based modified polypropylene carbonate fiber according to claim 1 in the fields of surgical sutures, medicine and health and textile clothes.

Technical Field

The invention relates to the technical field of biodegradable high polymer materials, in particular to a preparation method of modified polypropylene carbonate and fiber based on a bio-base.

Background

Since the last century, a large number of synthetic polymer products are manufactured in large scale successively, which greatly enriches our production and life, but the vast majority of the synthetic polymer materials are non-degradable materials, which causes serious white pollution andthe greenhouse effect also greatly affects the physical and psychological health of human beings. Therefore, the development of biodegradable materials and the reduction of the greenhouse effect are urgent. The polypropylene carbonate (PPC) is a novel completely biodegradable environment-friendly material obtained by polymerizing carbon dioxide and propylene oxide under certain catalyst, pressure and temperature conditions, and has the characteristics of excellent normal-temperature flexibility, biocompatibility, transparency, barrier property and the like. Nowadays, the global industrialization is rapidly developed, PPC becomes a green and environment-friendly material with low cost and bidirectional function, namely, on one hand, a large amount of cheap greenhouse gas CO is consumed in the production process₂The reasonable substitution of petroleum resources is realized; on the other hand, the environmental pollution can be reduced through biodegradation after the use, so the method has obvious important application prospect. However, PPC has poor thermal stability and low strength, and is limited to a large extent when used as a single material (no single PPC material application is currently available). For this reason, many researchers have conducted extensive studies on improvement of thermal stability, and have modified the carbon dioxide resin material by physical or chemical methods to improve its properties, thereby expanding the range of applications of the carbon dioxide resin material. The mechanical and thermal properties are currently improved mainly by means of conventional blending or chemical modification. Such as CN107573476A, CN108164978A, CN107474502A, CN105924923A, Shandong chemical engineering, 2019, (48): 72-74, et al, describe modifications of physical blends whose modification is not very significant due to compatibility issues with the components of the mixture. Therefore, some studies for chemically modifying PPC are occasionally reported, but most of them have not been studied in depth and applied effectively.

Research has shown that the reason for the poor thermal stability of PPC is that it randomly breaks to form oligomers when heated, and the presence of the terminal hydroxyl groups of PPC makes it very susceptible to unzipping degradation and each time one cyclic propylene carbonate is pulled off from the end. Corresponding chemical modification works (CN110283326A, CN110283312A and CN110272538A) are carried out successively for improving the thermal property and the comprehensive property, and although the thermal property and the mechanical property can be obviously improved, the new problem is brought, namely, the introduced modified components can not be completely biodegraded, and certain limitation and obstruction are caused to the application of the degradable PPC.

Disclosure of Invention

In order to solve the problems of poor thermal stability and incapability of forming fibers of the existing polypropylene carbonate, the invention provides a preparation method of modified polypropylene carbonate and fibers based on a bio-base, the obtained product can obviously improve the thermal property and the mechanical property of the polypropylene carbonate, simultaneously realizes complete biodegradation, and the fibers are spun by a spinning process, can be used in the fields of surgical sutures, medicine and health and textile clothing, and greatly expands the application range of PPC.

The invention is realized by the following technical scheme: the preparation method of the bio-based modified polypropylene carbonate comprises the following steps:

(1) drying the propylene carbonate;

the drying method comprises the following steps: the drying temperature is 20-40 ℃, the drying time is 12-36 h, and the vitrification temperature of the PPC is very low, so the low temperature is needed during drying, the aggregates are prevented from being bonded into blocks, and the vacuum drying is preferred.

Preferably, the molecular weight of the polypropylene carbonate is 1000 to 10000, the hydroxyl content value is 20 to 80mg (KOH/g), and the hydroxyl value is determined by titration with a standard KOH solution, which means that the-OH content in each gram of sample is equivalent to the number of milligrams of KOH. PPC is a novel completely biodegradable environment-friendly material, and the molecular weight of the PPC is not too large, the PPC is degraded slowly when being too large, and the PPC is too small, has no strength and cannot be used.

(2) Esterification reaction: adding furan dicarboxylic acid and derivatives thereof into a propylene carbonate (PPC) solution dissolved in a solvent, adding a catalyst for condensation reaction to obtain a poly (furan carboxylic acid) -propylene carbonate copolymer (PFPC), namely the bio-modified polypropylene carbonate.

The furan dicarboxylic acid and the derivatives thereof are selected from one or more of furan-2, 5-dicarboxylic acid, furan 3, 4-dicarboxylic acid, furan-2, 5-diacetic acid, furan 3, 4-diacetic acid, furan-2, 5-furylidene di (methylene) diacetic acid, furan-3, 4-furylidene di (methylene) diacetic acid, furan-2, 5-diformyl chloride, furan-3, 4-diformyl chloride and the like; wherein the molar ratio of the carboxylic acid group to the hydroxyl group is controlled to be 0.8-1.6: 1, preferably 1.00-1.20, and more preferably 1.02-1.08, so as to ensure that the hydroxyl group is completely reacted.

Among them, furandicarboxylic acid (FDCA) is a bio-based chemical prepared by a chemical or biological method using biomass as a raw material, and has good biodegradability, a carbon number less than that of a benzene ring, an aromaticity weaker than that of a benzene ring, and an FDCA-based polymer even having better thermodynamic and mechanical properties than a phthalic acid/phthalic acid polymer.

The catalyst is isobutyl titanate [ Ti (iOPr)₄]P-toluenesulfonic acid (P-TS)/stannous chloride (SnCl)₂) Composite catalyst, zinc acetate [ Zn (Ac) ]₂N-butyl titanate [ Ti (OBu) ]₄The molar ratio of the catalyst to the hydroxyl groups of the polypropylene carbonate is 0.002-0.1: 1, preferably 0.005-0.05: 1.

The solvent is an aprotic solvent. Preferably, the solvent is one or more selected from tetrahydrofuran, toluene and dimethylformamide, and the amount of the solvent is the amount of the solute solvent.

Because the PPC polyhydric alcohol has poor thermal stability, is easy to thermally degrade and is not suitable for adopting melt polycondensation, the invention adopts solution or interface polycondensation, the condensation reaction temperature is 50-150 ℃, preferably 70-130 ℃, and the reaction time is 1-5 h.

The invention utilizes a chemical method and a bio-based modifier of furan dicarboxylic acid and derivatives thereof to carry out copolymerization modification on PPC, namely utilizes polypropylene carbonate (PPC) polyhydric alcohol to carry out condensation reaction with dibasic acid of furan dicarboxylic acid, thereby preparing the polyfurandicarboxylic acid-PPC copolymer, can obviously improve the thermal property and the mechanical property of PPC, simultaneously realizes complete biodegradation, and is obviously different from the traditional physical blending modification method. Compared with unmodified PPC, the thermal decomposition temperature of the polyfurandicarboxylic acid-PPC copolymer (PFPC) is increased by 20-80 ℃; the mechanical property is improved by 50-200%. The heat resistance and the mechanical property are obviously improved, the comprehensive performance of the PPC composite material is greatly improved, and the application field of the PPC is effectively widened.

The bio-based modified polypropylene carbonate is dried and then placed in a melt spinning machine, and the fiber is prepared through the working procedures of screw melting, spinning manifold, spinning assembly, cooling, oiling, drafting, winding and the like.

The drying is carried out for 12-24 h at the temperature of 40-80 ℃, and preferably vacuum drying is carried out.

The melting temperature of the screw is 160-270 ℃, preferably 170-230 ℃, and more preferably 180-220 ℃; the temperature of a spinning box body is 190-220 ℃, in order to avoid uneven cooling of filaments, a circular blowing cooling mode is adopted, the drafting is between a first hot roller and a second hot roller, the drafting ratio is 1.6-3.0, preferably 1.8-2.6, and more preferably 2.0-2.4; the spinning speed is 1000-5000 m/min, preferably 1500-3800 m/min, and more preferably 2000-3000 m/min.

Preferably, the circular blowing cooling mode is as follows: the cooling air temperature is 23 +/-2 ℃, the humidity is 60 +/-10 percent, and the air speed is 0.5 +/-0.1 m/s.

The monofilament titer of the prepared fiber is 0.60dtex to 4.0 dtex; the breaking strength of the fiber is 1.4-4.0 cN/dtex, the yarn unevenness is 1.5-2.0, and the elongation at break is 20-80%.

The polyfurandicarboxylic acid-PPC copolymer is spun into fibers through a spinning process, can be used in the fields of surgical sutures, medicine and health and textile clothing, and greatly expands the application range of PPC.

Compared with the prior art, the invention has the beneficial effects that:

(1) the thermal property and the mechanical property of the modified polypropylene carbonate based on the bio-base are obviously improved, and the performance is durable;

(2) PFPC-based fibers are prepared by regulating and controlling a spinning process, so that the application field of the PPC material is greatly expanded and extended.

Detailed Description

The present invention is further illustrated by the following examples, in which the starting materials are either commercially available or prepared by conventional methods.

Wherein, PPC polyol: new biomaterials, henan tianguan; furan dicarboxylic acid: it is commercially available.

Example 1

200g of PPC dihydric alcohol (the number average molecular weight is 2000) is dried in a vacuum oven at 40 ℃ for 12h, cooled and then placed in tetrahydrofuran to be stirred and dissolved, then 15.92g of furan-2, 5-dicarboxylic acid (the molar ratio of carboxylic acid groups to hydroxyl groups is 1.02: 1) is added, after mechanical stirring and uniform mixing is accelerated, 0.68g of isobutyl titanate (the molar ratio of catalyst to hydroxyl groups of PPC polyhydric alcohol is 0.01: 1) is added, the mixture is heated to 100 ℃ and then is mechanically stirred and blended for reaction, and after the reaction is carried out for 3h, the polyfurandicarboxylic acid-PPC copolymer, namely the bio-based modified polypropylene carbonate, is obtained.

Tests show that compared with unmodified PPC, the thermal decomposition temperature of the polyfurandicarboxylic acid-PPC copolymer composite material is increased by 15 ℃; the mechanical properties are improved by 30%, as shown in table 1.

Preparation example 1

The bio-based modified polypropylene carbonate prepared in example 1 is dried at 80 ℃ for 12h and then placed in a melt spinning machine, and is made into fibers through the working procedures of screw melting, spinning manifold, spinning assembly, cooling, oiling, drafting, winding and the like. Wherein the melting temperature of the screw is 188 ℃; the temperature of a spinning box body is 190 ℃, the temperature of cooling air of circular blowing is 23 ℃, the humidity is 60%, the wind speed is 0.6m/s, the drawing ratio between a first hot roller and a second hot roller is 2.0, and the spinning speed is 2800 m/min.

The monofilament titer of the prepared fiber is 3.0dtex, and the breaking strength of the fiber is 2.3 cN/dtex; the yarn evenness was 1.8 and the elongation at break was 35%.

Example 2

200g of PPC dihydric alcohol (the number average molecular weight is 4000) is dried in a vacuum oven at 20 ℃ for 36h, the mixture is placed in toluene after being cooled and stirred to be dissolved, 8.1g of furan-3, 4-dicarboxylic acid (the molar ratio of carboxylic acid groups to hydroxyl groups is 1.04: 1) is added, after the mixture is stirred mechanically and mixed uniformly, 0.57g of stannous chloride (the molar ratio of catalyst to the hydroxyl groups of PPC polyhydric alcohol is 0.03: 1) is added, and the mixture is heated to 90 ℃ to be stirred mechanically and mixed for reaction. Reacting for 2 hours to obtain the polyfurandicarboxylic acid-PPC copolymer, namely the modified polypropylene carbonate based on the bio-based.

Tests show that compared with unmodified PPC, the thermal decomposition temperature of the polyfurandicarboxylic acid-PPC copolymer composite material is increased by 20 ℃; the mechanical properties are improved by 38%, as illustrated in table 1.

Preparation example 2

The bio-based modified polypropylene carbonate prepared in example 2 is dried at 70 ℃ for 16h and then placed in a melt spinning machine, and is made into fibers through the working procedures of screw melting, spinning manifold, spinning assembly, cooling, oiling, drafting, winding and the like. Wherein the melting temperature of the screw is 191 ℃; the temperature of a spinning box body is 195 ℃, the temperature of cooling air of circular blowing is 22 ℃, the humidity is 70%, the wind speed is 0.5m/s, the drawing ratio between the first hot roller and the second hot roller is 2.2, and the spinning speed is 2600 m/min.

The monofilament titer of the prepared fiber is 2.5dtex, and the breaking strength of the fiber is 2.75 cN/dtex; the yarn evenness was 1.9, and the elongation at break was 40%.

Example 3

200g of PPC triol (the number average molecular weight is 6000) is dried in a vacuum oven at 30 ℃ for 24h, the mixture is placed in dimethylformamide to be stirred and dissolved after being cooled, 9.94g of furan-2, 5-diacetic acid (the molar ratio of carboxylic acid group to hydroxyl group is 1.08: 1) is added, mechanical stirring is carried out, the mixture is accelerated and mixed uniformly, and then 1.07g of P-toluenesulfonic acid (P-TS)/zinc acetate (Zn (AC) with equal molar ratio are added₂Heating the composite catalyst (the molar ratio of the catalyst to the hydroxyl of the PPC polyhydric alcohol is 0.06: 1), and mechanically stirring and blending the catalyst to 125 ℃ for reaction for 3 hours to obtain the bio-based modified polypropylene carbonate.

The thermal decomposition temperature of the bio-based modified polypropylene carbonate is increased by 50 ℃ compared with that of the unmodified PPC; the mechanical properties are improved by 80%, as illustrated in table 1.

Preparation example 3

The bio-based modified polypropylene carbonate prepared in example 3 is dried at 80 ℃ for 16h and then placed in a melt spinning machine, and is made into fibers through the working procedures of screw melting, spinning manifold, spinning assembly, cooling, oiling, drafting, winding and the like. Wherein the melting temperature of the screw is 200 ℃; the temperature of a spinning box body is 202 ℃, the temperature of cooling air of circular blowing is 24 ℃, the humidity is 70%, the wind speed is 0.45m/s, the drawing ratio between a first hot roller and a second hot roller is 2.4, and the spinning speed is 2900 m/min.

The single filament number of the prepared fiber is 2.1dtex, and the breaking strength of the fiber is 3.0 cN/dtex; the yarn evenness was 1.9, and the elongation at break was 33%.

Test example

Table 1: PPC sample and its copolymer sample test data

The above-described preferred embodiments are merely illustrative and explanatory of the present invention and are not restrictive of the invention as claimed. Although the present invention has been described in detail by the inventor, it is obvious that various modifications and/or additions can be made to the described embodiments or replacements can be made by those skilled in the art according to the disclosure of the summary of the invention and the embodiments, and the technical effects of the present invention can be achieved, therefore, the detailed description is omitted. The terms appearing in the present invention are used for illustration and understanding of the technical aspects of the present invention, and do not constitute limitations of the present invention.