A sodium sulfonate ionomer nucleating agent for polyethylene terephthalate, its preparation method and application

Abstract

This invention belongs to the field of organic synthesis technology, specifically relating to a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate (PET). The nucleating agent is either sodium vinyl sulfonate hydroxyethyl methacrylate ionomer or sodium vinyl sulfonate glycidyl methacrylate ionomer. This nucleating agent is obtained by reacting sodium vinyl sulfonate monomer, monomer X, and an initiator, wherein monomer X is either hydroxyethyl methacrylate monomer or glycidyl methacrylate monomer. This nucleating agent, when applied to the modification of PET, increases the melting and crystallization temperature of PET, accelerates the crystallization rate, and effectively reduces PET degradation, providing a new avenue for the application of PET as an engineering plastic and expanding the applicability of PET.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate, its preparation method, and its application. Background Technology

[0002] Polyethylene terephthalate (PET) is a thermoplastic polyester, available in non-engineering and engineering grades. PET possesses excellent physical and mechanical properties within a certain temperature range, such as high rigidity, high impact strength, and stability against many organic solvents and inorganic acids, making it widely applicable. However, the presence of benzene rings in the PET molecular backbone results in strong molecular chain rigidity. Furthermore, the highly polar ester groups linked to the benzene rings form a conjugated structure, further increasing the rigidity of the molecular chain and raising resistance to molecular motion. While PET possesses the flexible -CH2CH2- group, its short structure means the PET molecular chain remains predominantly rigid, leading to an increased crystallization temperature and decreased crystallization rate. This, in turn, makes PET difficult to process during injection molding, resulting in high mold temperatures and long production cycles, thus limiting its application in engineering plastics. Therefore, improving the crystallization rate has become one of the key technologies for the industrial modification of PET.

[0003] Adding nucleating agents during PET molding is an effective method to improve the crystallization properties of PET. Nucleating agents used in PET are generally classified into inorganic, organic, and polymeric types. Inorganic nucleating agents have poor dispersibility and ineffective nucleation. Organic nucleating agents are mostly hydroxy acid salts, whose nucleation mechanism is chemical nucleation, meaning they react with PET during processing to form nucleation sites for PET crystals, thus promoting PET crystallization, but causing PET chain breakage. Polymer nucleating agents are mostly ionomers; for example, Suryln resin developed by DuPont and AClyn ethylene acrylate ionomer developed by Honeywell are effective nucleating agents for PET. Currently, most effective nucleating agents for PET on the market are hydroxy acid salts, and other promising PET nucleating agents need to be developed. Summary of the Invention

[0004] The present invention aims to provide a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate, thereby providing a new PET nucleating agent and expanding the range of PET nucleating agents available on the market.

[0005] To achieve the above objectives, the present invention provides a nucleating agent for a sodium sulfonate ionomer of polyethylene terephthalate, wherein the nucleating agent is a sodium vinyl sulfonate hydroxyethyl methacrylate ionomer or a sodium vinyl sulfonate hydroxyethyl methacrylate ionomer, wherein the structure of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer is shown in formula (I), and the structure of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer is shown in formula (II).

[0006]

[0007] In equations (I) and (II), m and n are both natural numbers, and the value of m / n ranges from 0.1 to 9.

[0008] This invention also provides a method for preparing sodium sulfonate ionomer nucleating agent for polyethylene terephthalate, comprising the following steps:

[0009] S1. Mix sodium vinyl sulfonate monomer, X monomer and first solvent evenly to obtain a mixture. Dissolve the initiator in the second solvent and add it dropwise to the mixture. Heat to 70-80℃ and react for 3-6 hours. X monomer is hydroxyethyl methacrylate monomer or glycidyl methacrylate monomer.

[0010] S2. After the reaction is complete, the crude product is obtained by rotary evaporation. The crude product is dissolved and placed in a precipitant to precipitate. After purification and drying, the nucleating agent product is obtained.

[0011] Optionally, in step S1, the molar ratio between sodium vinyl sulfonate monomer and monomer X is 1:0.1 to 9, and the ratio of the sum of the moles of sodium vinyl sulfonate monomer and monomer X to the mole of the initiator is 100:1 to 0.1.

[0012] Optionally, in step S1, the first solvent is an aqueous ethanol solution, wherein the volume ratio of anhydrous ethanol to water in the aqueous ethanol solution is 1 to 10:3; the second solvent is deionized water.

[0013] Optionally, in step S1, the initiator is a sulfate-bisulfite.

[0014] Optionally, in step S2, the precipitant is anhydrous ethanol.

[0015] Optionally, in step S1, the initiator is dissolved in the second solvent and then added dropwise to the mixture at a rate of 4 to 8 seconds per drop.

[0016] The aforementioned sodium sulfonate ionomer nucleating agent for polyethylene terephthalate is used in the modification of polyethylene terephthalate. In application, the sodium sulfonate ionomer nucleating agent for polyethylene terephthalate is mixed evenly with polyethylene terephthalate, melt-blended at 250–270°C for 4–7 minutes, and then extruded and granulated to obtain the modified polyethylene terephthalate product. The mass ratio of the sodium sulfonate ionomer nucleating agent for polyethylene terephthalate to polyethylene terephthalate is 1:100–1000.

[0017] The working principle and beneficial effects of this invention are as follows: Firstly, the introduction of sodium sulfonate groups into the nucleating agent can generate ion clusters in the PET melt, providing nuclei and interfaces for crystallization, accelerating the ordered arrangement of molecular chains (heterogeneous nucleation mechanism). Furthermore, the flexible molecular chains of the nucleating agent can accelerate the movement of PET molecular chains, indirectly increasing the crystallization rate of PET. Secondly, the presence of metal salts allows the ionomer to maintain a stable structure above the melting point of PET, thereby providing more interfaces for PET crystallization. Therefore, the nucleating agent in this invention can increase the melting and crystallization temperature of PET and accelerate the crystallization rate. Moreover, compared to sodium styrene sulfonate polymers, the sodium vinyl sulfonate polymer in this invention has more flexible molecular chains and a stronger crystallization effect.

[0018] Furthermore, unlike hydroxyl acid salt nucleating agents, sulfonate-based nucleating agents do not cause PET degradation and a significant decrease in molecular weight, which in turn leads to a reduction in PET's mechanical properties. Additionally, hydroxyethyl methacrylate (HEMA) and glycidyl methacrylate (GMA) monomers have similar molecular structures to PET, and their transesterification reactions improve compatibility. Therefore, the introduction of HEMA or GMA monomers can improve the compatibility between the nucleating agent and PET, resulting in more uniform dispersion of the nucleating agent in PET and a significant modification effect.

[0019] Compared to sodium styrene sulfonate ionomers, the sodium vinyl sulfonate ionomers in this solution have more flexible chains and stronger crystallization effects. Furthermore, this solution can effectively reduce PET degradation and improve its mechanical properties, providing a new avenue for the application of PET as an engineering plastic and expanding its applicability. Attached Figure Description

[0020] Figure 1 The infrared spectrum of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer obtained in Example 3 of this invention;

[0021] Figure 2 The infrared spectrum of the sodium vinyl sulfonate glycidyl methacrylate ionomer obtained in Example 8 of this invention;

[0022] Figure 3The above is the 1H NMR spectrum of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer obtained in Example 3 of this invention;

[0023] Figure 4 The above is the 1H NMR spectrum of the sodium vinyl sulfonate glycidyl methacrylate ionomer obtained in Example 8 of this invention;

[0024] Figure 5 The above is the 1H NMR spectrum of the sodium styrene sulfonate hydroxyethyl methacrylate ionomer obtained in the comparative example of this invention.

[0025] Figure 6 Thermogravimetric analysis curves of PET and PET / VS-HEMA;

[0026] Figure 7 Thermogravimetric analysis curves of PET and PET / VS-GMA;

[0027] Figure 8 Crystallization curves of PET and PET / VS-HEMA during the cooling process at 20℃ / min;

[0028] Figure 9 Crystallization curves of PET and PET / VS-HEMA during the cooling process at 10℃ / min;

[0029] Figure 10 Crystallization curves of PET and PET / VS-GMA during the cooling process at 20℃ / min;

[0030] Figure 11 Crystallization curves of PET and PET / VS-GMA during the cooling process at 10℃ / min;

[0031] Figure 12 Field emission scanning electron microscope image of PET / VS-HEMA;

[0032] Figure 13 Field emission scanning electron microscope image of PET / VS-GMA;

[0033] Figure 14 This is a field emission scanning electron microscope image of PET / SSS-HEMA. Detailed Implementation

[0034] The following detailed description illustrates the specific implementation method:

[0035] Example 1

[0036] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is sodium vinyl sulfonate hydroxyethyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0037] (1) 0.27 g of sodium vinyl sulfonate (VS) monomer, 2.29 mL of hydroxyethyl methacrylate (HEMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70°C, it was added dropwise to the mixture at a rate of 5 drops / second. The reaction was allowed to proceed for 6 hours (the starting point of the reaction time was the moment when the initiator began to be added; other examples were the same as the comparative example).

[0038] (2) After the reaction is complete, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, sodium vinyl sulfonate hydroxyethyl methacrylate ionomer (nucleating agent) product is obtained.

[0039] Example 2

[0040] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is sodium vinyl sulfonate hydroxyethyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0041] (1) 0.55 g of sodium vinyl sulfonate (VS) monomer, 2.04 mL of hydroxyethyl methacrylate (HEMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 s / drop, and the reaction was allowed to proceed for 6 h.

[0042] (2) After the reaction is complete, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, sodium vinyl sulfonate hydroxyethyl methacrylate ionomer (nucleating agent) product is obtained.

[0043] Example 3

[0044] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is sodium vinyl sulfonate hydroxyethyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0045] (1) 0.82 g of sodium vinyl sulfonate (VS) monomer, 1.78 mL of hydroxyethyl methacrylate (HEMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 s / drop, and the reaction was allowed to proceed for 6 h.

[0046] (2) After the reaction is complete, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, sodium vinyl sulfonate hydroxyethyl methacrylate ionomer (nucleating agent) product is obtained.

[0047] Example 4

[0048] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is sodium vinyl sulfonate hydroxyethyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0049] (1) 1.09 g of sodium vinyl sulfonate (VS) monomer, 1.53 mL of hydroxyethyl methacrylate (HEMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 drops / second, and the reaction was allowed to proceed for 6 hours.

[0050] (2) After the reaction is complete, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, sodium vinyl sulfonate hydroxyethyl methacrylate ionomer (nucleating agent) product is obtained.

[0051] Example 5

[0052] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is a sodium vinyl sulfonate glycidyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0053] (1) 2.46 g of sodium vinyl sulfonate (VS) monomer, 0.28 mL of glycidyl methacrylate (GMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 drops / second, and the reaction was allowed to proceed for 6 hours.

[0054] (2) After the reaction is completed, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, the sodium vinyl sulfonate glycidyl methacrylate ionomer (nucleating agent) product is obtained.

[0055] Example 6

[0056] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is a sodium vinyl sulfonate glycidyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0057] (1) 2.19 g of sodium vinyl sulfonate (VS) monomer, 0.56 mL of glycidyl methacrylate (GMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 s / drop and the reaction was allowed to proceed for 6 h.

[0058] (2) After the reaction is completed, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, the sodium vinyl sulfonate glycidyl methacrylate ionomer (nucleating agent) product is obtained.

[0059] Example 7

[0060] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is a sodium vinyl sulfonate glycidyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0061] (1) 1.91 g of sodium vinyl sulfonate (VS) monomer, 0.83 mL of glycidyl methacrylate (GMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 drops / second, and the reaction was allowed to proceed for 6 hours.

[0062] (2) After the reaction is completed, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, the sodium vinyl sulfonate glycidyl methacrylate ionomer (nucleating agent) product is obtained.

[0063] Example 8

[0064] This embodiment provides a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate. The nucleating agent is a sodium vinyl sulfonate glycidyl methacrylate ionomer, and the preparation method of the nucleating agent includes the following steps:

[0065] (1) 1.64 g of sodium vinyl sulfonate (VS) monomer, 1.11 mL of glycidyl methacrylate (GMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 drops / second, and the reaction was allowed to proceed for 6 hours.

[0066] (2) After the reaction is completed, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, the sodium vinyl sulfonate glycidyl methacrylate ionomer (nucleating agent) product is obtained.

[0067] Comparative Example

[0068] This comparative example provides an ionomer of sodium p-styrene sulfonate and hydroxyethyl methacrylate, and the preparation method of this ionomer is as follows:

[0069] (1) 1.73 g of sodium styrene sulfonate (SSS) monomer, 1.53 mL of hydroxyethyl methacrylate (HEMA) monomer, and an aqueous ethanol solution were mixed evenly to obtain a mixture; wherein the aqueous ethanol solution was prepared by mixing 18.75 mL of deionized water and 6.25 mL of anhydrous ethanol. 0.048 g of ammonium persulfate, 0.016 g of sodium bisulfite, and 15 mL of deionized water were mixed evenly and placed in a constant pressure dropping funnel. After the reaction system was heated to 70 °C, it was added dropwise to the mixture at a rate of 5 s / drop, and the reaction was allowed to proceed for 3 h.

[0070] (2) After the reaction is completed, the deionized water and solvent (ethanol) in the reaction system are evaporated to dryness to obtain crude product. The crude product is dissolved in deionized water and then placed in anhydrous ethanol to precipitate. After dialysis and vacuum drying, sodium styrene sulfonate hydroxyethyl methacrylate ionomer product is obtained.

[0071] The ionomer of sodium vinyl sulfonate hydroxyethyl methacrylate was characterized by Fourier transform infrared spectroscopy (FTIR), such as... Figure 1 As shown in the figure, 3470cm -1 The peak for the stretching vibration of OH is 2954 cm⁻¹. -1 The stretching vibration peak of CH is 2362 cm⁻¹. -1 The peak for CO2 is negligible, at 1647 cm⁻¹. -1 The peak represents the stretching vibration of the C=O group of the ester group, 1192–1040 cm⁻¹. -1 The peak represents the stretching vibration of the S=O group in sulfonic acid. (This is achieved through...) 1 H-NMR can further characterize the ionomer of sodium vinyl sulfonate hydroxyethyl methacrylate, thereby determining the structure of the ionomer.

[0072] The ionomer of sodium vinyl sulfonate glycidyl methacrylate was characterized by Fourier transform infrared spectroscopy (FTIR), such as... Figure 2 As shown in the figure, 2954cm -1 The stretching vibration peak of CH is 2362 cm⁻¹. -1 The peak for CO2 is negligible, at 1647 cm⁻¹. -1 The peak represents the stretching vibration of the C=O group of the ester group, 1192–1040 cm⁻¹. -1 The peak is the stretching vibration peak of the S=O group of the sulfonic acid group, 910 cm⁻¹. -1 This is the stretching vibration peak of the epoxy group. (Through...) 1 H-NMR can further characterize the ionomer of sodium vinyl sulfonate glycidyl methacrylate, thereby determining the structure of the ionomer.

[0073] Figure 3 The image shows the 1H NMR spectrum of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer obtained in Example 3. Figure 3It can be determined that the synthesized product in Example 3 is a random copolymer of sodium vinyl sulfonate hydroxyethyl methacrylate ionomer.

[0074] Figure 4 The image shows the 1H NMR spectrum of the sodium vinyl sulfonate glycidyl methacrylate ionomer obtained in Example 8. Figure 4 The random copolymer of the sodium vinyl sulfonate glycidyl methacrylate ionomer synthesized in Example 8 can be identified.

[0075] Figure 5 The 1H NMR spectrum of the sodium styrene sulfonate hydroxyethyl methacrylate ionomer obtained in the comparative example is shown below. Figure 5 It can be determined that the comparative synthesis is a random copolymer of sodium styrene sulfonate hydroxyethyl methacrylate ionomer.

[0076] The sodium vinyl sulfonate hydroxyethyl methacrylate ionomer or sodium vinyl sulfonate methacrylate glycidyl ester ionomer obtained in the examples was used as a nucleating agent and melt-blended with polyethylene terephthalate. The resulting product was then extruded and granulated to obtain modified polyethylene terephthalate. The nucleating agent and polyethylene terephthalate were melt-blended at 250–270°C for 4–7 minutes, and the mass ratio of the nucleating agent to polyethylene terephthalate was 1:100–1000.

[0077] Application Example 1

[0078] The nucleating agent (sodium vinyl sulfonate hydroxyethyl methacrylate ionomer obtained in Example 3) was mixed with PET at a mass ratio of 1:100. Then, the mixture was melt-blended at 250-270°C and 60 rpm for 5 min, and extruded and granulated to obtain the modified polyethylene terephthalate, denoted as PET / VS-HEMA.

[0079] Application Example 2

[0080] The nucleating agent (sodium vinyl sulfonate glycidyl methacrylate ionomer obtained in Example 8) was mixed with PET at a mass ratio of 1:100. Then, the mixture was melt-blended at 250-270°C and 60 rpm for 5 min, and extruded and granulated to obtain the modified polyethylene terephthalate, denoted as PET / VS-GMA.

[0081] Application Example 3

[0082] The nucleating agent (sodium hydroxyethyl methacrylate ionomer obtained in the comparative example) was mixed with PET at a mass ratio of 1:100. Then, the mixture was melt-blended at 250-270°C and 60 rpm for 5 min, and extruded and granulated to obtain the modified polyethylene terephthalate, denoted as PET / SSS-HEMA.

[0083] In addition, pure polyethylene terephthalate was also processed under the same conditions as a reference sample, namely, pure polyethylene terephthalate was melt-blended at 250-270°C and 60 rpm for 5 min and then extruded and granulated.

[0084] The thermal decomposition temperature of the nucleating agent needs to be above the processing temperature of PET. Therefore, the thermal stability of PET blends with added nucleating agents can be characterized using thermogravimetric analysis (TGA). The results are as follows: Figure 6 and Figure 7 As shown. (Through) Figure 5 and Figure 6 It can be seen that the TGA curves of pure PET and PET / VS-HEMA and PET / VS-GMA are almost identical, indicating that the nucleating agent in this invention can remain solid without degradation below 400°C and can also play a role at the processing temperature of PET, thereby providing nucleation sites for pure PET.

[0085] PET, PET / VS-HEMA, and PET / VS-GMA were characterized using differential scanning calorimetry (DSC), and the results are as follows: Figure 8 , Figure 9 and Figure 10 , Figure 11 As shown. From Figures 8-11 As can be seen, compared to the PET sample, the modified PET exhibits significantly increased initial crystallization temperature and melt crystallization temperature. Furthermore, the half-peak width of the melt crystallization peak is narrower. These data all indicate that the vinyl sulfonate ionomer, acting as a nucleating agent, can effectively accelerate the crystallization rate of PET.

[0086] PET / VS-HEMA, PET / VS-GMA, and PET / SSS-HEMA were characterized by field emission scanning electron microscopy (FESEM), and the results are as follows: Figure 12 , Figure 13 and Figure 14 As shown. From Figure 12-14 It can be seen that the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer is more uniformly dispersed in the PET matrix, while the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer is dispersed more sparsely. Moreover, the dispersion effect of the sodium vinyl sulfonate hydroxyethyl methacrylate ionomer in the PET matrix is ​​better than that of the sodium styrene sulfonate hydroxyethyl methacrylate ionomer in the PET matrix.

[0087] The viscosities of pure PET, PET / VS-HEMA, PET / VS-GMA, and PET / SSS-HEMA were tested using an Ubbelohde viscometer, and the results are shown in Table 1.

[0088] Table 1 Viscosity Test Results

[0089] Serial Number sample Intrinsic viscosity (dL / g) Viscosity-average molecular weight (g / mol) 1 PET 1.103 <![CDATA[3.4×10 4 ]]> 2 PET / VS-HEMA 1.009 <![CDATA[3.2×10 4 ]]> 3 PET / VS-GMA 1.072 <![CDATA[3.3×10 4 ]]> 4 PET / SSS-HEMA 1.065 <![CDATA[3.3×10 4 ]]>

[0090] The above test results show that both nucleating agents in this invention (sodium vinyl sulfonate hydroxyethyl methacrylate ionomer and sodium vinyl sulfonate hydroxyl methacrylate ionomer) can increase the crystallization temperature of PET, accelerate the crystallization rate of PET, and effectively reduce the degradation of PET (compared to the degradation caused by hydroxyl acid salt nucleating agents). This provides a new approach for the application of PET as an engineering plastic and expands the applicability of PET. Furthermore, the degree of transesterification reaction between epoxy groups and PET is less than that between hydroxyl groups and PET, resulting in the poorer dispersibility of sodium vinyl sulfonate hydroxyethyl methacrylate ionomer in PET compared to sodium vinyl sulfonate hydroxyethyl methacrylate ionomer and sodium p-styrene sulfonate hydroxyethyl methacrylate ionomer. Therefore, the modification effect of sodium vinyl sulfonate hydroxyl methacrylate ionomer on the crystallization properties of PET is also slightly worse, but the reaction degree is smaller, resulting in less PET degradation. Consequently, the intrinsic viscosity and viscosity-average molecular weight of PET / VS-GMA are also higher.

[0091] The above are merely embodiments of the present invention. The invention is not limited to the fields covered by these embodiments. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can improve and implement this solution based on the guidance provided in this application and their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness or practicality of the invention. The scope of protection claimed in this application should be determined by the content of its claims. The specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A sodium sulfonate ionomer nucleating agent for polyethylene terephthalate, characterized by: The nucleating agent is sodium vinyl sulfonate methacrylate hydroxyethyl ester ionomer or sodium vinyl sulfonate methacrylate glycidyl ester ionomer, the structure of the sodium vinyl sulfonate methacrylate hydroxyethyl ester ionomer is shown in formula (I), and the structure of the sodium vinyl sulfonate methacrylate glycidyl ester ionomer is shown in formula (II); In formula (I) and formula (II), m and n are both natural numbers, and the value range of m / n is 0.1-9.

2. A process for preparing a sodium sulfonate ionomer nucleating agent for polyethylene terephthalate as claimed in claim 1, characterized by: The method comprises the following steps: S1, uniformly mixing sodium vinyl sulfonate monomer, X monomer and a first solvent to obtain a mixed solution, dissolving an initiator in a second solvent, and then adding the initiator into the mixed solution drop by drop, heating to 70-80 DEG C, and reacting for 3-6 hours; wherein the X monomer is a hydroxyethyl methacrylate monomer or a glycidyl methacrylate monomer; S2, after the reaction is completed, the crude product is obtained by spin-drying, the crude product is dissolved and then precipitated in a precipitant, and the nucleating agent product is obtained after purification and drying.

3. The method of claim 2, wherein: In step S1, the molar ratio between the sodium vinyl sulfonate monomer and the X monomer is 1:0.1-9, and the molar ratio between the sum of the moles of the sodium vinyl sulfonate monomer and the X monomer and the initiator is 100:1-0.

1.

4. The method of claim 2, wherein: In step S1, the first solvent is an ethanol aqueous solution, and in the ethanol aqueous solution, the volume ratio of anhydrous ethanol to water is 1-10:3; the second solvent is deionized water.

5. The method of claim 2, wherein: In step S1, the initiator is a sulfate-sulfite.

6. The method of claim 2, wherein: In step S2, the precipitant is anhydrous ethanol.

7. The method of claim 2, wherein: In step S1, after the initiator is dissolved in the second solvent, the initiator is added into the mixed solution drop by drop at a drop rate of 4-8 s / drop.

8. The application of the sodium sulfonate ionomer nucleating agent for polyethylene terephthalate in the modification of polyethylene terephthalate.

9. Use according to claim 8, characterized in that: The sodium sulfonate ionomer nucleating agent for polyethylene terephthalate is uniformly mixed with polyethylene terephthalate, melt-blended at 250-270 DEG C for 4-7 minutes, extruded and granulated to obtain the modified polyethylene terephthalate product.

10. Use according to claim 9, characterized in that: The mass ratio of the sodium sulfonate ionomer nucleating agent for polyethylene terephthalate to polyethylene terephthalate is 1:100-1000.

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