CN116217904B - A kind of high toughness carbon dioxide-based polyester-polycarbonate and preparation method thereof - Google Patents

Abstract

The invention discloses a high-toughness carbon dioxide-based polyester-polycarbonate and a preparation method thereof. The invention uses commercial, simple and high-efficiency nonmetallic Lewis acid-base pair as a catalyst to catalyze and initiate propylene oxide, carbon dioxide, phthalic anhydride and norbornene dianhydride to carry out quaternary copolymerization reaction, so that the carbon dioxide-based polyester-polycarbonate containing double bonds is successfully prepared. The content of norbornene dianhydride in the polymer is 0.01-20%. The carbon dioxide-based polyester-polycarbonate containing double bonds is subjected to high-temperature melt extrusion in the presence of a thermal initiator and a crosslinking additive of trimethylolpropane tri (3-mercaptopropionic acid) ester, so that a crosslinked polymer containing pendent long side chains is obtained. The prepared crosslinked polymer has improved elongation at break and toughness compared with propylene oxide/phthalic anhydride/carbon dioxide terpolymer (PPC-P). The invention can be used for synthesizing modified polymethyl ethylene carbonate (PPC) biodegradable materials, and expands the application range of the PPC materials.

Description

A kind of high toughness carbon dioxide-based polyester-polycarbonate and preparation method thereof

Technical field

The invention relates to the technical field of polymer materials, in particular to a high-toughness carbon dioxide-based polyester-polycarbonate and a preparation method thereof.

Background technique

Terpolymer (PPC-P) prepared by copolymerization of propylene oxide, phthalic anhydride and carbon dioxide (CO ₂ ) is a new biodegradable plastic with high light transmittance and high barrier properties, and has huge application scenarios in the field of food packaging (CN 111378101A, J.CO ₂ Util.2021,49,101558). Compared with polymethylethylene carbonate (PPC) prepared by the traditional copolymerization of propylene oxide and carbon dioxide, PPC-P material exhibits improved glass transition temperature (T _g >45℃) and mechanical properties (>40MPa ), but has low elongation at break (<7%) and exhibits low toughness (~3MJ/m ³ ). Therefore, new methods need to be found to improve the toughness of PPC-P materials.

Summary of the invention

The object of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing high-tenacity carbon dioxide-based polyester-polycarbonate. The high toughness carbon dioxide-based polyester-polycarbonate is a cross-linked carbon dioxide-based polyester-polycarbonate containing hanging long side chains. The present invention uses a commercial, simple and efficient non-metallic Lewis acid-base pair as a catalyst to catalytically initiate the quaternary copolymerization of propylene oxide, carbon dioxide, phthalic anhydride and norbornene dianhydride, and successfully prepares a bis-containing bisulfite. Bonded carbon dioxide-based polyester-polycarbonate. The content of norbornene dianhydride in the polymer is 0.01-20%. The carbon dioxide-based polyester-polycarbonate containing double bonds is melt-extruded at high temperature in the presence of a thermal initiator and the cross-linking additive trimethylolpropane tris(3-mercaptopropionate) to obtain a polycarbonate containing long hanging side chains. Cross-linked polymers. The prepared cross-linked polymer has improved elongation at break and toughness compared with propylene oxide/phthalic anhydride/carbon dioxide terpolymer (PPC-P).

In order to achieve the above objects, the present invention adopts the following technical solutions:

A high-toughness carbon dioxide-based polyester-polycarbonate. Its base material is carbon dioxide-based polyester-polycarbonate containing double bonds. Its structure is as shown in formula (I). After functionalization, it is a cross-linked polymer with a structure As shown in formula (II), where a≥1,b≥1,c≥1,d≥0,a,b,c,d are all integers, (a+b)/(a+b+c+d )=0.2-0.5,d/(a+b+c+d)<0.1.

The preparation method of the above-mentioned high toughness carbon dioxide-based polyester-polycarbonate is characterized by comprising the following steps:

(1) Add the monomers norbornene dianhydride, phthalic anhydride, propylene oxide, Lewis base catalyst and organoborane into a high-pressure reaction kettle, fill it with carbon dioxide, and heat to perform a ring-opening copolymerization reaction. After the reaction is completed Purified carbon dioxide-based polyester-polycarbonate containing double bonds is obtained through precipitation, drying and granulation;

(2) The purified carbon dioxide-based polyester-polycarbonate containing double bonds is melt-extruded through a screw at high temperature in the presence of a thermal initiator and a cross-linking additive to obtain a cross-linked polymer containing long hanging side chains.

Preferably, the structure of formula (I) or formula (II) contains polyether, and the mass fraction of polyether in the polymer is less than 5%.

Preferably, in the above preparation method, the number average molecular weight of the carbon dioxide-based polyester-polycarbonate containing double bonds is 50-200kg/mol, and norbornene dianhydride is added to the carbon dioxide-based polyester-polycarbonate containing double bonds. The mass fraction of the ester is 0.01-20%, and the mass fraction of phthalic anhydride in the carbon dioxide-based polyester-polycarbonate containing double bonds is 15-45%.

Preferably, the molar ratio of the Lewis base catalyst and organoborane is 1:0.5-10, the feeding ratio of the Lewis base catalyst and phthalic anhydride is 1:50-5000, and the molar ratio of propylene oxide and phthalic anhydride is 1:50-5000. The feeding ratio is 1:2-16, and the feeding ratio of norbornedic anhydride and phthalic anhydride is 1:1-50. The carbon dioxide pressure of the ring-opening copolymerization reaction is 0.5-3MPa, the reaction temperature is 40-100°C, and the reaction time is 4-20h.

Preferably, the cross-linking additive is trimethylolpropane tris(3-mercaptopropionate).

Preferably, the molar ratio between the double bonds and thiol groups of the carbon dioxide-based polyester-polycarbonate containing double bonds and the thiol groups of the cross-linking additive is 1:1-2.

Preferably, the thermal initiator is one of dibenzoyl peroxide, azobisisobutyronitrile, dicumyl peroxide and di-tert-butyl peroxide; the thermal initiator accounts for double bonds. The mass fraction of carbon dioxide-based polyester-polycarbonate is 0.1-1%, the cross-linking temperature is 130-190°C, and the cross-linking time is 0.1-2h.

Preferably, the Lewis base catalyst is bis(triphenylphosphinyl)ammonium chloride or tetra-n-butylammonium chloride, and the organoborane is triethylboron, tributylboron or triphenylboron. .

Compared with the prior art, the present invention has the following beneficial effects:

(1) The norbornene dianhydride used in the present invention is cheap, 100% converted, and highly economical; it has no adverse effect on the propylene oxide/carbon dioxide/phthalic anhydride ternary copolymerization, and the double bonds are in the final polymerization and No cross-linking occurs during the treatment process, and existing processes can be used for polymerization and post-processing;

(2) The cross-linked carbon dioxide-based polyester-polycarbonate containing hanging long side chains prepared by the present invention can be generated in situ during processing, and the preparation process is simple.

(3) The cross-linked carbon dioxide-based polyester-polycarbonate containing hanging long side chains prepared by the present invention still maintains good light transmittance and degradation performance, and its mechanical strength is only slightly reduced compared to the PPC-P material. Improved elongation at break and toughness.

The present invention can be further explained and illustrated in conjunction with the following specific examples, but the specific examples do not limit the present invention in any way.

Description of drawings

The accompanying drawings are intended to further clearly illustrate and explain the technical solutions and embodiments of the present invention, and do not constitute a limitation of the present invention. In the accompanying drawings:

FIG. 1 is a hydrogen nuclear magnetic spectrum of the carbon dioxide-based polyester-polycarbonate containing double bonds obtained in Example 1 of the present invention.

Figure 2 is an ultraviolet-visible light absorption spectrum chart of the cross-linked carbon dioxide-based polyester-polycarbonate containing pendant long side chains obtained in Example 3 of the present invention and the PPC-P material obtained in Comparative Example 1.

Detailed ways

Example 1:

In an anhydrous and oxygen-free environment, 16.0g phthalic anhydride, 50.2g propylene oxide, 164.4mg norbornene dianhydride, 60.0mg tetrabutylammonium chloride and 216μL tributylboron solution were added to the high-pressure solution in sequence. Fill the reaction kettle with 1.0MPa carbon dioxide and react at 80°C for 10 hours. After the reaction, release the carbon dioxide pressure, dissolve the product with methylene chloride, quench the reaction with dilute hydrochloric acid/methanol solution, and precipitate in ethanol to obtain the polymer. Polymerization After vacuum drying, molecular weight testing and nuclear magnetic analysis were performed. M _n =82.1kg/mol, PDI =1.28, and the content of norbornenedioic anhydride in the polymer is 1.0wt%. The purified carbon dioxide-based polyester-polycarbonate containing double bonds was mixed with azobisisobutyronitrile (0.7wt%) and trimethylolpropane tris(3-mercaptopropionate) ester ([-SH]/[ -C=C-]=1.5/1), through melt extrusion at 160°C with a screw, a cross-linked polymer containing hanging long side chains is obtained. The test results show that its T _g is 48°C, its tensile strength is 44.8MPa, its elongation at break is 18.2%, and its toughness is 5.8MJ/m ³ . The properties of the obtained product, carbon dioxide-based polyester-polycarbonate, are shown in Table 1.

Example 2:

In an anhydrous and oxygen-free environment, combine 14.0g phthalic anhydride, 50.2g propylene oxide, 4.0g norbornene dianhydride, 54.3mg bis(triphenylphosphorane) ammonium chloride and 324μL triphenyl The boron solution was added to the high-pressure reaction kettle in sequence, filled with 1.0MPa carbon dioxide, and reacted at 80°C for 15 hours. After the reaction, release the carbon dioxide pressure, dissolve the product with dichloromethane, quench the reaction with dilute hydrochloric acid/methanol solution, and precipitate in ethanol. The polymer was obtained, and the polymer was vacuum dried and subjected to molecular weight testing and nuclear magnetic analysis. M _n =132kg/mol, PDI =1.30, and the mass fraction of norbornenedioic anhydride in the polymer is 9.8wt%. The purified carbon dioxide-based polyester-polycarbonate containing double bonds was mixed with dicumyl peroxide (0.5wt%) and trimethylolpropane tris(3-mercaptopropionate) ester ([-SH]/[ -C=C-]=1.8/1), through melt extrusion at 180°C with a screw, a cross-linked polymer containing hanging long side chains is obtained. The test results show that its T _g is 44°C, its tensile strength is 43.6MPa, its elongation at break is 42.8%, and its toughness is 12.3MJ/m ³ . The properties of the obtained product, carbon dioxide-based polyester-polycarbonate, are shown in Table 1.

Example 3:

In an anhydrous and oxygen-free environment, combine 60.0g phthalic anhydride, 118.0g propylene oxide, 8.6g norbornene dianhydride, 232.5mg bis(triphenylphosphorane) ammonium chloride and 1.62mL triethyl The boron solution was added to the high-pressure reaction kettle in turn, filled with 1.0MPa carbon dioxide, and reacted at 80°C for 12 hours. After the reaction, release the carbon dioxide pressure, dissolve the product with dichloromethane, and quench the reaction with dilute hydrochloric acid/methanol solution. The polymer was obtained by precipitation, and the polymer was vacuum dried and subjected to molecular weight testing and nuclear magnetic analysis. M _n =80.2kg/mol, PDI =1.22, and the mass fraction of norbornenedioic anhydride in the polymer is 4.7wt%. The purified carbon dioxide-based polyester-polycarbonate containing double bonds was mixed with dibenzoyl peroxide (0.3wt%) and trimethylolpropane tris(3-mercaptopropionate) ester ([-SH]/[ -C=C-]=1.2/1), through melt extrusion at 150°C with a screw, a cross-linked polymer containing hanging long side chains is obtained. The test results show that its T _g is 46°C, its tensile strength is 44.2MPa, its elongation at break is 31.2%, and its toughness is 9.2MJ/m ³ . The properties of the obtained product carbon dioxide-based polyester-polycarbonate are shown in Table 1.

Comparative example 1:

In an anhydrous and oxygen-free environment, add 16.0g phthalic anhydride, 50.2g propylene oxide, 120.0mg bis(triphenylphosphinyl)ammonium chloride, and 216μL triethylboron solution to the high-pressure reaction kettle in sequence , fill with 1.0MPa carbon dioxide, react at 80°C for 8 hours, release the carbon dioxide pressure after the reaction, dissolve the product with dichloromethane, quench the reaction with dilute hydrochloric acid/methanol solution, and precipitate in ethanol to obtain the polymer. The polymer was vacuum dried and subjected to molecular weight testing and nuclear magnetic analysis. M _n =83.9kg/mol, PDI =1.26, the mass fraction of norbornenedioic anhydride in the polymer is 0wt%, and it is a PPC-P material. The test results show that its T _g is 50°C, its tensile strength is 45.3MPa, its elongation at break is 6.9%, and its toughness is 2.9MJ/m ³ . The properties of the resulting products are shown in Table 1.

Comparative example 2:

In an anhydrous and oxygen-free environment, combine 60.0g phthalic anhydride, 118.0g propylene oxide, 7.97g norbornene dianhydride, 232.5mg bis(triphenylphosphorane) ammonium chloride and 1.62mL triethyl The boron solution was added to the high-pressure reaction kettle in turn, filled with 1.0MPa carbon dioxide, and reacted at 80°C for 12 hours. After the reaction, release the carbon dioxide pressure, dissolve the product with dichloromethane, and quench the reaction with dilute hydrochloric acid/methanol solution. The polymer was obtained by precipitation, and the polymer was vacuum dried and subjected to molecular weight testing and nuclear magnetic analysis. M _n =78.9kg/mol, PDI =1.24, and the mass fraction of tetrahydric anhydride in the polymer is 4.6wt%. The purified carbon dioxide-based polyester-polycarbonate containing double bonds was mixed with dibenzoyl peroxide (0.3wt%) and trimethylolpropane tris(3-mercaptopropionate) ester ([-SH]/[ -C=C-]=1.2/1), through melt extrusion at 150°C with a screw, a cross-linked polymer containing hanging long side chains is obtained. The test results show that its T _g is 43°C, its tensile strength is 33.6MPa, its elongation at break is 16.2%, and its toughness is 4.4MJ/m ³ . The properties of the resulting products are shown in Table 1.

As can be seen from Table 1, the toughness of Examples 1-3 is significantly improved compared to Comparative Example 1. In addition, the toughness of Example 3 is also much greater than that of Comparative Example 2. In addition, the cross-linked carbon dioxide-based polyester-polycarbonate containing hanging long side chains obtained in Example 3 still maintains good light transmittance properties, and the 1mm thick sheet still has more than 85% light transmittance in the range of 600-800nm. light rate. Therefore, the cross-linked carbon dioxide-based polyester-polycarbonate containing hanging long side chains prepared by the present invention has increased elongation at break and improved toughness compared to PPC-P materials, and remains basically unchanged Mechanical strength and good light transmission properties. Therefore, the present invention can be applied to the modification of PPC materials.

Table 1 Properties of cross-linked carbon dioxide-based polyester-polycarbonates containing pendant long side chains

^aMolecular weight of carbon dioxide-based polyester-polycarbonate containing double bonds. ^b Use tetrahydrophthalic anhydride instead of norbornedioic anhydride. ^cThe content of tetrahydrophthalic anhydride in the polymer.

Claims (6)

1. The high-toughness carbon dioxide-based polyester-polycarbonate is characterized in that the substrate material is carbon dioxide-based polyester-polycarbonate containing double bonds, and the structure is shown as a formula (I); the functionalized crosslinked polymer has a structure shown as a formula (II), wherein a is more than or equal to 1, b is more than or equal to 1, c is more than or equal to 1, d is more than or equal to 0, a, b, c and d are integers, (a+b)/(a+b+c+d) =0.2-0.5, and d/(a+b+c+d) <0.1;

the structure of the formula (I) or the formula (II) contains polyether, and the mass fraction of the polyether in the polymer is less than 5%;

the preparation method of the high-toughness carbon dioxide-based polyester-polycarbonate comprises the following steps:

(1) Adding monomer norbornene dianhydride, phthalic anhydride, epoxypropane, a Lewis base catalyst and organoborane into a high-pressure reaction kettle, filling carbon dioxide, heating to carry out ring-opening copolymerization reaction, and obtaining purified carbon dioxide-based polyester-polycarbonate containing double bonds through precipitation, drying and granulation after the reaction is finished;

(2) The carbon dioxide-based polyester-polycarbonate containing double bonds obtained by purification is subjected to high-temperature melt extrusion by a screw in the presence of a thermal initiator and a crosslinking additive, so as to obtain a crosslinked polymer containing pendent long side chains;

the molar ratio of the double bonds of the double bond-containing carbon dioxide-based polyester-polycarbonate to the mercapto groups of the crosslinking additive is 1:1-2;

the crosslinking additive is trimethylolpropane tri (3-mercaptopropionic acid) ester.

2. The method for preparing high toughness carbon dioxide based polyester-polycarbonate according to claim 1, comprising the steps of:

(1) Adding monomer norbornene dianhydride, phthalic anhydride, epoxypropane, a Lewis base catalyst and organoborane into a high-pressure reaction kettle, filling carbon dioxide, heating to carry out ring-opening copolymerization reaction, and obtaining purified carbon dioxide-based polyester-polycarbonate containing double bonds through precipitation, drying and granulation after the reaction is finished;

(2) And (3) carrying out high-temperature melt extrusion on the carbon dioxide-based polyester-polycarbonate containing double bonds obtained by purification by a screw in the presence of a thermal initiator and a crosslinking additive to obtain the crosslinked polymer containing the pendent long side chains.

3. The method according to claim 2, wherein the number average molecular weight of the carbon dioxide-based polyester-polycarbonate having a double bond is 50 to 200kg/mol, the mass fraction of norbornene dianhydride in the carbon dioxide-based polyester-polycarbonate having a double bond is 0.01 to 20%, and the mass fraction of phthalic anhydride in the carbon dioxide-based polyester-polycarbonate having a double bond is 15 to 45%.

4. The process according to claim 2, characterized in that the molar ratio of lewis base catalyst to organoborane is 1:0.5-10, the feed ratio of the Lewis base catalyst to the phthalic anhydride is 1:50-5000, the feeding ratio of propylene oxide to phthalic anhydride is 1:2-16, the feed ratio of norbornene dianhydride to phthalic anhydride is 1:1-50; the carbon dioxide pressure of the ring-opening copolymerization reaction is 0.5-3MPa, the reaction temperature is 40-100 ℃, and the reaction time is 4-20h.

5. The preparation method according to claim 2, characterized in that the thermal initiator is one of dibenzoyl peroxide, azobisisobutyronitrile, dicumyl peroxide and di-tert-butyl peroxide; the thermal initiator accounts for 0.1-1% of the carbon dioxide-based polyester-polycarbonate containing double bonds, the crosslinking temperature is 130-190 ℃, and the crosslinking time is 0.1-2h.

6. The preparation method according to claim 2, wherein the Lewis base catalyst is bis (triphenylphosphine) ammonium chloride or tetra-n-butyl ammonium chloride, and the organoborane is triethylboron, tributylboron or triphenylBoron base _。