CN114318577A - A method for improving the crystalline properties of polyester fibers by using GO-SiO2 composite nucleating additives - Google Patents

Abstract

The invention discloses a method for improving the crystalline properties of polyester fibers by using a GO-SiO ₂ composite nucleating additive. First, silicon dioxide (SiO ₂ ) is grown in situ on the surface of graphene oxide (GO), and then blocks are grafted. polymer (LMPET‑PEG) and the resulting hybrid particles were melt-spun blended with polyethylene terephthalate (PET) and characterized. The invention increases the compatibility of the additive and PET by grafting the block polymer, thereby adding it to the PET for spinning to increase the crystalline performance and thermal performance of the PET fiber. The modified PET fiber has good thermodynamic stability and good crystallinity, and has a very good application prospect.

Description

A method for improving the crystalline properties of polyester fibers by using GO-SiO2 composite nucleating additives

technical field

The invention relates to the fields of chemical modification and spinning, in particular to a method for improving the crystalline properties of polyester fibers by using a nucleation additive of graphene oxide and silica composite materials.

Background technique

Polyethylene terephthalate (PET), also known as polyester or really good, is the most important variety of thermoplastic polyester. It is obtained by transesterifying terephthalic acid and ethylene glycol, or synthesizing bishydroxyethyl terephthalate by esterification of terephthalic acid and ethylene glycol, and then conducting polycondensation reaction. PET has good mechanical properties, acid and alkali resistance, oil resistance, and low temperature and high temperature resistance. It is non-toxic, tasteless, hygienic and safe, and can be used for food packaging. It is widely used and has excellent performance.

In the crystallization process of polyester, silica acts as a crystal nucleus and is an impurity that promotes crystallization. The addition of silica increases the amount of heterogeneous nucleation, promotes the crystallization of molecules, accelerates the crystallization speed, and can effectively improve the crystallization properties of polyester. However, the dispersion of fillers in the polyester matrix is also a key factor affecting the properties of composites.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for improving the crystalline properties and thermal properties of PET fibers by utilizing a graphene oxide-containing nucleation additive.

The present invention is achieved through the following technical solutions:

Using GO-SiO ₂ composite nucleating additive to improve the crystalline properties of polyester fibers, GO-SiO ₂ +LMPET-PEG or GO-SiO ₂ +LMPET-PPG nanoparticles are granulated and blended with PET according to the proportion, and then the The granulation is melt-spun to prepare PET fibers containing modified silica;

Preparation of GO- _SiO2 hybrid composites: Take a small amount of GO nanosheets dissolved in deionized water for ultrasonic dispersion, then add twice as much anhydrous ethanol solution and ultrasonically treat, add ammonia water and TEOS solution, and adopt in-situ hydrolysis method, Using TEOS as a silicon source, it is converted into silicon dioxide on GO nanosheets after hydrolysis;

Preparation of GO-SiO ₂ + LMPET-PEG or GO-SiO ₂ + LMPET-PPG as nucleation additive for graphene oxide and silica composites: Weigh 20 mg of GO-SiO ₂ to 9.5 mL of ethanol + in the following proportions 0.5 mL of water, ultrasonically pulverized and dispersed, added 1 mL of IPTES to adjust the pH to 4-5 with formic acid, refluxed at 70 °C, and passed N ₂ for 6 h; after the reaction, washed with ethanol for 2-3 times to obtain GO-SiO2-IPTES. -SiO2-IPTES was dispersed in 10mL DMF, 50mg LMPET-PEG was dispersed in 5mL DMF, the two were mixed, 50μL dibutyltin dilaurate DBDU was added, heated to 70°C, and magnetically stirred for 10h to obtain GO- _SiO2 +LMPET- PEG nanoparticles; GO-SiO ₂ +LMPET-PPG nanoparticles can be obtained by replacing LMPET-PEG with LMPET-PPG.

In the method, the GO nanosheets are commercially available, the sheet diameter: 0.5-5 μm, the thickness: 0.8-1.2 nm; the molecular weight of LMPET is 5000-10000.

In the method, the PET used is commercially available fiber grade PET, and the intrinsic viscosity is 0.65-0.68 dL/g.

In the method, the proportion of synthesized GO-SiO ₂ +LMPET-PEG or GO-SiO ₂ +LMPET-PPG nanoparticles in the PET fiber is 0.2%-1%.

In the described method, the rotating speed used for centrifugation is 7000-10000 r/min, and the time is 6-10 minutes.

The method, the preparation of the GO/SiO ₂ hybrid composite material, adopts an in-situ hydrolysis method, uses TEOS as a silicon source, and converts it into silicon dioxide on GO nanosheets after hydrolysis; first, 0.06g of GO nanosheets are Dissolve in 60 mL of deionized water and sonicate; then add 120 mL of anhydrous ethanol solution and sonicate. After the ultrasonic treatment, 4 mL of ammonia water and 0.6 mL of LTEOS solution were added; then, the mixed solution was subjected to magnetic stirring for 20 hours to make it fully react; finally, the reaction solution was centrifuged and washed 2-3 times with a mixture of ethanol and water.

Described method, LMPET-PEG preparation method is as follows:

Take 18.3g LMPET and dissolve it in a 1:1 mass ratio of phenol and tetrachloroethane solution, react at 60°C, and heat up to 100°C until the reaction is completely dissolved (1 hour), and add a small amount of cross-linking agent ethylene glycol several times during the reaction process. (approximately 5 mL). Then, 0.03 g of polycondensation catalyst Sb ₂ O ₃ and 32 mL of PEG400 were added to the three-necked flask, the temperature was raised to 100° C., and the reaction was continued for 2-3 hours with stirring. After washing with a solution of phenol and carbon tetrachloride with a mass ratio of 1:1 to remove the residual LMPET from the reaction, it was washed twice with acetone and ethanol respectively, and the mixed solution was centrifuged to remove the residual impurities in the reaction. Vacuum dry.

Compared with the original pure PET fiber, the present invention has the following advantages:

1. The present invention increases the number of heterogeneous nucleation by growing silicon dioxide on the surface of graphene oxide as a nano-nucleating agent, promotes the crystallization of molecules, accelerates the crystallization rate, and effectively improves the crystallization performance of polyester. However, pure silica particles are prone to self-agglomeration and affect the effect of improving performance. Growing silica on the surface of graphene oxide can effectively solve this problem. This is because GO is an oxide of graphene, with carboxyl and carbonyl groups on the edge and hydroxyl and epoxide on the matrix. The presence of these functional groups makes GO extremely hydrophilic and has good compatibility with the polar polymer PET.

2. In the present invention, the synthesized GO-SiO ₂ hybrid composite material is added to PET, and the nucleating agent is successfully dispersed in the PET, and the crystallization and thermal properties of the PET fiber are improved under the condition of less addition amount. , in which the crystallization temperature was increased from 184 °C to 225 °C, and the thermal decomposition temperature was increased by 15 °C.

Description of drawings

Fig. 1 is the SEM image of the PET fiber prepared by the method of the present invention;

Fig. 2 is the XRD curve of the PET fiber prepared by the method of the present invention;

Fig. 3 is the DSC curve of the PET fiber prepared by the method of the present invention;

Detailed ways

The present invention will be described in detail below with reference to specific embodiments.

Example 1

The invention discloses a method for improving the crystalline properties of polyester fibers by utilizing the nucleation additive of graphene oxide and silica composite materials. The specific method steps are as follows:

Preparation of nucleation additives for graphene oxide and silica composites: Weigh 20 mg of GO-SiO ₂ into 9.5 mL of ethanol + 0.5 mL of water, ultrasonically pulverize and disperse, add 1 mL of IPTES and adjust the pH to 4-5 with formic acid, Reflux at 70°C, pass N ₂ for 6h. After the reaction, wash with ethanol for 2-3 times to obtain the sample GO-SiO ₂ -IPTES. The sample GO-SiO ₂ -IPTES was dispersed in 10 mL of DMF, 50 mg of LMPET-PEG was dispersed in another 5 mL of DMF, the two were mixed, and 50 μL of dibutyltin dilaurate DBDU was added, heated at 70 °C, and magnetically stirred for 10 h. That is, GO-SiO ₂ +LMPET-PEG nanoparticles are formed.

Preparation of PET fibers by using the nucleating additive of graphene oxide and silica composite materials: firstly, the obtained nucleating additive containing graphene oxide is granulated and blended with PET according to a certain proportion, and then the granules are melt-spun silk to prepare PET fibers containing modified silica.

Among them, the preparation method of GO- _SiO2 hybrid composite material is as follows:

First, 0.06 g of GO nanosheets were dissolved in 60 mL of deionized water for ultrasonic dispersion. Then 120 mL of anhydrous ethanol solution was added and sonicated. After sonication, 4 mL of ammonia water and 4 mL of TEOS solution were added. Then, the mixed solution was subjected to magnetic stirring for 20 hours to sufficiently react. Finally, the reaction solution was centrifuged and washed 2-3 times with a mixture of ethanol and water.

Wherein, the preparation method of LMPET-PEG is as follows:

Take 18.3g LMPET and dissolve it in a 1:1 mass ratio of phenol and tetrachloroethane solution, react at 60°C, and heat up to 100°C until the reaction is completely dissolved (1 hour), and add a small amount of cross-linking agent ethylene glycol several times during the reaction process. (approximately 5 mL). Then, 0.03 g of a polycondensation catalyst Sb2O3 and 32 mL of PEG400 were added to the three-necked flask, the temperature was raised to 100° C., and the reaction was continued for 2-3 hours with stirring. After washing with a solution of phenol and carbon tetrachloride with a mass ratio of 1:1 to remove the residual LMPET from the reaction, it was washed twice with acetone and ethanol respectively, and the mixed solution was centrifuged to remove the residual impurities in the reaction. Vacuum dry.

Through the analysis of the scanning image of the PET fiber, as shown in Figure 1, a is the pure PET fiber, and b is the PET fiber with a content of 1 wt% of the graphene oxide and silica composite material. It can be seen from the figure that the fibers are micron and the surface of the fibers is smooth, indicating that the nucleation additive containing graphene oxide is relatively uniformly dispersed in PET.

Through the analysis of XRD and DSC, as shown in Figure 2 and Figure 3, respectively, the addition of graphene oxide-containing nucleation additives increases the crystallinity of PET fibers, and the crystallization temperature increases by about 41 °C. The addition of nucleating additives of silica composites has a significant effect on improving its performance.

Example 2

Preparation of nucleation additive for graphene oxide and silica composites: Weigh 20 mg of GO- _SiO2 hybrid composite into 9.5 mL of ethanol + 0.5 mL of water, ultrasonically pulverize and disperse, add 1 mL of IPTES and adjust the pH to 4-5, reflux at 70℃, pass N ₂ for 6h. After the reaction, wash with ethanol 2-3 times. The sample GO-SiO ₂ -IPTES obtained in the previous step was dispersed in DMF (10 mL), 50 mg of LMPET-PPG (polypropylene glycol) was dispersed in DMF (5 mL), the two were mixed, and 50 μL of LDBDU (dibutyl tin dilaurate) was added and heated for 70 ℃, magnetic stirring for 10h. That is, GO-SiO ₂ +LMPET-PPG nanoparticles are formed.

Preparation of PET fibers by using the nucleating additive of graphene oxide and silica composite materials: firstly, the obtained nucleating additive containing graphene oxide is granulated and blended with PET according to a certain proportion, and then the granules are melt-spun silk to prepare PET fibers containing modified silica.

Among them, the preparation method of GO- _SiO2 hybrid composite material is as follows:

First, 0.06 g of GO nanosheets were dissolved in 60 mL of deionized water for ultrasonic dispersion. Then 120 mL of anhydrous ethanol solution was added and sonicated. After sonication, 4 mL of ammonia water and 0.6 mL of LTEOS solution were added. Then, the mixed solution was subjected to magnetic stirring for 20 hours to sufficiently react. Finally, the reaction solution was centrifuged and washed 2-3 times with a mixture of ethanol and water.

Among them, the preparation method of LMPET-PPG is as follows:

Take 18.3g LMPET and dissolve it in a 1:1 mass ratio of phenol and tetrachloroethane solution, react at 60°C, and heat up to 100°C until the reaction is completely dissolved (1 hour), and add a small amount of cross-linking agent ethylene glycol several times during the reaction process. (approximately 5 mL). Then, 0.03 g of polycondensation catalyst Sb2O3 and 32 mL of PPG were added to the three-necked flask, the temperature was raised to 100° C., and the stirring reaction was continued for 2-3 hours. After washing with a 1:1 mass ratio of phenol and carbon tetrachloride solution to remove the residual LMPET from the reaction, it was washed twice with acetone and ethanol respectively, and the mixed solution was centrifuged to remove the residual impurities from the reaction. Vacuum dry.

It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims (7)

1. Using GO-SiO₂The method for improving the crystallization performance of the polyester fiber by compounding the core forming additive is characterized in that GO-SiO₂+ LMPET-PEG or GO-SiO₂The + LMPET-PPG nano particles are granulated and blended with PET according to the proportion, and then the produced particles are melt spun to prepare the PET fiber containing the modified silicon dioxide;

GO-SiO₂preparation of hybrid composite material: according to the following proportion: dissolving 0.06g of GO nano-sheets in 60mL of deionized water, performing ultrasonic dispersion, then adding 120mL of absolute ethyl alcohol, performing ultrasonic treatment, adding 4mL of ammonia water and 4mL of TEOS solution, adopting an in-situ hydrolysis method, taking TEOS as a silicon source, and converting the TEOS into silicon dioxide on the GO nano-sheets after hydrolysis;

graphene oxide and bisNucleating additive GO-SiO of silicon oxide composite material₂+ LMPET-PEG or GO-SiO₂Preparation of + LMPET-PPG: weighing 20mg of GO-SiO in the following proportion₂Adding into 9.5mL ethanol +0.5mL water, ultrasonic pulverizing, dispersing, adding 1mL IPTES, adjusting pH to 4-5 with formic acid, refluxing at 70 deg.C, introducing N₂6 h; washing with ethanol for 2-3 times after the reaction is finished to obtain GO-SiO2-IPTES, dispersing GO-SiO2-IPTES into 10mL of DMF, dispersing 50mg of LMPET-PEG into 5mL of DMF, mixing the two, adding 50 mu L of dibutyltin dilaurate DBDU, heating to 70 ℃, and magnetically stirring for 10 hours to obtain GO-SiO₂+ LMPET-PEG nanoparticles; the LMPET-PEG is replaced by LMPET-PPG to obtain GO-SiO₂+ LMPET-PPG nanoparticles.

2. The method of claim 1, wherein: the GO nano-sheet is commercially available, the sheet diameter is 0.5-5 mu m, and the thickness is 0.8-1.2 nm; the molecular weight of LMPET is 5000-.

3. The method of claim 1, wherein: the PET used was a commercially available fiber grade PET having an intrinsic viscosity of 0.65 to 0.68 dL/g.

4. The method of claim 1, wherein: synthetic GO-SiO₂+ LMPET-PEG or GO-SiO₂The proportion of the + LMPET-PPG nano particles in the PET fiber is 0.2-1%.

5. The method of claim 1, wherein: the rotation speed for centrifugation is 7000-10000r/min, and the time is 6-10 minutes.

6. The method of claim 1, wherein: the GO/SiO₂Preparing a hybrid composite material, namely, adopting an in-situ hydrolysis method, taking TEOS as a silicon source, and converting the TEOS into silicon dioxide on GO nano-sheets after hydrolysis; firstly, dissolving 0.06g of GO nano-sheets in 60mL of deionized water for ultrasonic dispersion; 120mL of absolute ethanol solution was then added and sonicated. After the ultrasonic treatment is finished, adding 4mL of ammonia water and 0.6mL of TEOS solution; then, mixingMagnetically stirring the mixed solution for 20 hours to fully react; finally, the reaction solution was centrifuged and washed 2-3 times with a mixture of ethanol and water.

7. The method of claim 1, wherein: the preparation method of LMPET-PEG is as follows:

dissolving 18.3g of LMPET in a mixed solution of phenol and tetrachloroethane with the mass ratio of 1: 1, reacting at 60 ℃, heating to 100 ℃ after complete dissolution, and adding a small amount of cross-linking agent ethylene glycol for several times in the reaction process; then, 0.03g of polycondensation catalyst Sb was added to the three-necked flask₂O₃And 32ml PEG400, heating to 100 ℃, and continuously stirring for reaction for 2-3 hours; washing with phenol and carbon tetrachloride solution in the mass ratio of 1 to remove the residual LMPET, washing with acetone and ethanol twice, centrifuging to remove the residual impurities, and vacuum drying the obtained LMPET-PEG.

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