CN113150381A

CN113150381A - 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent and preparation method thereof

Info

Publication number: CN113150381A
Application number: CN202110599545.9A
Authority: CN
Inventors: 蔡艳华
Original assignee: Chongqing University of Arts and Sciences
Current assignee: Chongqing University of Arts and Sciences
Priority date: 2020-07-02
Filing date: 2021-05-31
Publication date: 2021-07-23
Anticipated expiration: 2041-05-31
Also published as: CN111732758A; CN113150381B

Abstract

The invention belongs to the technical field of organic polymer auxiliary compounds and preparation or chemical processing thereof, and discloses a1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent, which has the following structure:

the preparation method comprises the following steps of (1) mixing 1, 4-naphthalene dicarboxylic acid with thionyl chloride and N, N' -dimethylformamide catalyst, slowly heating, and stirring and refluxing; then evaporating to obtain the 1, 4-naphthaloyl chloride. Step (2), mixing 1, 4-naphthaloyl chloride with nicotinhydrazide, N' -dimethylformamide and triethylamine for reaction to form secondary mixed solution, and cleaning the secondary mixed solution; after the cleaning is finished, drying is carried out to obtain the 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent. The nucleating agent provided by the invention is applied to semi-crystalline plastics, can realize high crystallinity of the semi-crystalline plastics, improves the heat resistance of the semi-crystalline plastics, and enlarges the application range of the semi-crystalline plastics.

Description

1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent and preparation method thereof

Technical Field

The invention belongs to the field of organic polymer auxiliary compounds and preparation or chemical processing thereof, and particularly relates to a1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent and a preparation method thereof.

Background

The nucleating agent is a novel auxiliary agent suitable for synthesizing semi-crystalline plastics, and can be used for changing the crystallization behavior of resin, accelerating the crystallization rate, increasing the nucleation crystallization density and promoting the grain size refinement, so as to shorten the forming period and improve the physical and mechanical properties of the product, such as rigidity, thermal deformation temperature, impact resistance and the like.

The nucleating agent mainly comprises an inorganic nucleating agent and an organic nucleating agent, wherein the inorganic nucleating agent mainly comprises talc, montmorillonite, mica, halloysite, calcium carbonate, zinc citrate, silicon dioxide and the like; the organic nucleating agent mainly comprises aliphatic carboxylic acid metal compounds, sorbitol derivatives, aromatic carboxylic acid derivatives, organic phosphate, wood acid and derivatives thereof, sodium benzoate, bis (p-tert-butyl benzoic acid) aluminum carboxyl and the like. Organic nucleating agents can overcome the disadvantage of poor compatibility of inorganic nucleating agents with semi-crystalline plastic matrices, and therefore, organic nucleating agents are commonly used for molding semi-crystalline plastics.

Semicrystalline plastics have poor heat resistance, for example, polylactic acid has a heat distortion temperature of only about 60 ℃, and thus can be used only in a low-temperature environment, which greatly limits the application range of semicrystalline plastics.

Disclosure of Invention

The invention aims to provide a1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent and a preparation method thereof, so as to solve the problem of poor heat resistance of semi-crystalline plastics.

In order to achieve the above objects, the present invention provides the following technical solution, 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent, its structure is,

the invention also provides another technical scheme, and the preparation method of the 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent comprises the following steps:

step (1): acylation reaction

Mixing 13-18g of 1, 4-naphthalenedicarboxylic acid, 100-200ml of thionyl chloride and 1-6ml of N, N' -dimethylformamide catalyst, heating the mixture at the heating rate of 2-6 ℃/min until the heating temperature reaches 80 ℃, and stirring and refluxing the mixture for 30-45h in the heating process to form a mixed solution; evaporating the mixed solution to obtain 1, 4-naphthaloyl chloride; the reaction process is as follows:

step (2): amination reaction

Mixing and reacting 0.005-0.01mol of 1, 4-naphthaloyl chloride, 0.002-0.006mol of nicotinoyl hydrazine, 100-150ml of N, N' -dimethylformamide and 1-5ml of triethylamine to form a secondary mixed solution, and cleaning the secondary mixed solution by using deionized water; after cleaning, drying to obtain the 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent; the reaction process is as follows:

the beneficial effects of the technical scheme are as follows:

1. the nucleating agent provided by the technical scheme is prepared through acylation reaction and amination reaction and is used for processing semi-crystalline plastics. In the process of processing the semi-crystalline plastic, the semi-crystalline plastic can start to crystallize at the temperature of 150 ℃ and above, and the temperature is closer to the melting temperature of the raw materials, in other words, the semi-crystalline plastic can start to crystallize without being cooled to a low crystallization temperature, so that the crystallization time is greatly shortened, and the crystallinity is improved.

2. At present, partial semicrystalline plastics (such as polylactic acid) can not be crystallized basically at the cooling rate of 1 ℃/min, so that the whole crystallization process is very slow, and the industrial production is limited; when the nucleating agent provided by the technical scheme is used for processing the semi-crystalline plastic, the semi-crystalline plastic can also generate a crystallization peak value at a very fast cooling rate (such as 40-50 ℃/min), crystallization is realized in the cooling process, the crystallization time can be greatly shortened, and the actual industrial production is met (in the actual industrial production, in order to improve the efficiency, the cooling rate can be accelerated).

3. Experiments prove that when the nucleating agent provided by the technical scheme is used for processing semi-crystalline plastics, the crystallinity of the semi-crystalline plastics is very high and can reach about 64 percent, compared with the existing low crystallinity of the semi-crystalline plastics, the crystallinity is greatly improved, and the crystallinity can be directly reflected on the heat resistance of the semi-crystalline plastics; therefore, the heat resistance of the semi-crystalline plastic processed by the nucleating agent provided by the technical scheme is greatly improved, the heat-resistant temperature can reach about 150 ℃, and the application range of the semi-crystalline plastic is expanded.

4. Tests prove that the flow property of the semi-crystalline plastic prepared by the nucleating agent provided by the technical scheme reaches 10.9g/10min, and the nucleating agent has a very great promotion effect on industrial application of the semi-crystalline plastic.

Further, in the step (1), the mixture is cooled to room temperature before evaporation.

Has the advantages that: through cooling mixed liquid to room temperature, can play the effect of decompression, and then avoid mixed liquid to appear the condition of bumping when the evaporation, reduce the loss of product, and then improve output.

Further, in the step (1), the mixed solution is evaporated in a vacuum environment.

Has the advantages that: impurity doping in the external environment is avoided, and the high purity of the prepared 1, 4-naphthaloyl chloride is ensured; meanwhile, the evaporation effect is good in a vacuum environment.

Further, in the step (2), 1, 4-naphthaloyl chloride, nicotinoyl hydrazide, N' -dimethylformamide and triethylamine are mixed by using an ultrasonic technology.

Has the advantages that: the ultrasonic technology is utilized for mixing, and the mixing uniformity can be improved.

Further, in the step (2), before the secondary mixed liquid is cleaned, ice bath is firstly carried out and stirring is carried out for 2 hours, wherein the stirring speed is 1800-2600 r/min.

Has the advantages that: by reducing the temperature of the secondary mixed solution, the temperature of the 1, 4-naphthaloyl chloride in the mixed solution can be reduced, the activity of the 1, 4-naphthaloyl chloride is reduced, the condition that the 1, 4-naphthaloyl chloride is diffused at high temperature to cause insufficient reaction or byproducts is avoided, and the quality and the purity of the prepared nucleating agent are improved.

Further, in the step (2), after ice bath, the temperature of the secondary mixed liquid is raised to 70 ℃, and the temperature is kept for 6 hours.

Has the advantages that: however, at a low temperature, the activity of the acid chloride is lowered and the reaction is insufficient, and therefore, the temperature is raised again to increase the activity of the acid chloride that has not reacted and to allow the acid chloride to react sufficiently.

Further, in the step (2), when the secondary mixed solution is washed, the secondary mixed solution is poured into deionized water, and is filtered to obtain a filter cake.

Has the advantages that: impurities in the suspension can be removed, and the subsequent cleaning effect is improved.

Further, in the step (2), the filter cake is washed three times with deionized water.

Has the advantages that: and the multiple cleaning can remove more impurities, so that the purity of the prepared nucleating agent is improved.

Further, in the step (2), the filter cake is dried under vacuum at a temperature of 35 ℃.

Has the advantages that: the method has the advantages that evaporation is carried out under the vacuum condition, so that the influence of the external environment on the purity of the prepared nucleating agent can be reduced, and meanwhile, the drying effect is better under the vacuum condition.

Drawings

FIG. 1 is a reaction process of a nucleating agent provided by the present invention;

FIG. 2 is a nuclear magnetic resonance graph of a nucleating agent provided by the present invention;

FIG. 3 is a DSC curve of sample 1-sample 5 as it cools at a rate of 1 deg.C/min at a melting temperature of 170 deg.C;

FIG. 4 is a DSC curve of sample 1-sample 5 as they cool at a rate of 1 deg.C/min at a melting temperature of 180 deg.C;

FIG. 5 is a DSC curve of sample 1-sample 5 as it cools at a rate of 1 deg.C/min at a melting temperature of 190 deg.C;

FIG. 6 is a DSC curve of samples 1-5 as they cool at a rate of 1 deg.C/min at a melting temperature of 200 deg.C

FIG. 7 is a DSC curve of comparative example 1 to comparative example 4 when cooled at a rate of 1 deg.C/min at a melting temperature of 180 deg.C;

FIG. 8 is a DSC curve of comparative example 1 to comparative example 4 as cooled at a rate of 1 deg.C/min at a melting temperature of 190 deg.C;

FIG. 9 is a DSC curve of comparative example 1 to comparative example 4 when cooled at a rate of 1 deg.C/min at a melting temperature of 200 deg.C;

FIG. 10 is a DSC curve of comparative example 5 to comparative example 8 when cooled at a rate of 1 deg.C/min at a melting temperature of 180 deg.C;

FIG. 11 is a DSC curve of comparative example 5 to comparative example 8 as cooled at a rate of 1 deg.C/min at a melting temperature of 190 deg.C;

FIG. 12 is a DSC curve of comparative example 5 to comparative example 8 as cooled at a rate of 1 deg.C/min at a melting temperature of 200 deg.C;

FIG. 13 is a DSC curve of sample 2-sample 5 as it cools at a rate of 40 deg.C/min at a melting temperature of 190 deg.C;

FIG. 14 is a DSC curve of sample 2-sample 5 as it cools at a rate of 50 deg.C/min at a melting temperature of 190 deg.C;

FIG. 15 DSC curves of sample 2 to sample 5 isothermally at 140 ℃ for 180 min;

FIG. 16 DSC curves of sample 2 to sample 5 isothermally at 142 ℃ for 180 min;

FIG. 17 DSC curves of sample 2 to sample 5 isothermally at 144 ℃ for 180 min;

FIG. 18 DSC curves of sample 2-sample 5 isothermally at 146 ℃ for 180 min;

FIG. 19 DSC curves of sample 2 to sample 5 isothermally at 148 ℃ for 180 min;

FIG. 20 DSC curves of sample 2 to sample 5 isothermally at 150 ℃ for 180 min;

FIG. 21 is a graph of crystallinity versus time for samples 2-5 at 140 ℃;

FIG. 22 is a plot of PAID and PLLA geometries and leading edge rail energy;

FIG. 23 is a graph of isothermal crystallization curves for sample 2 through sample 5;

FIG. 24 is a graph of the thermogravimetric plots of sample 1-sample 5;

FIG. 25 is a graph of the flowability curves for sample 1-sample 5;

FIG. 26 is a graph of tensile strength for samples 1-5;

FIG. 27 is a plot of the elastic modulus of samples 1-5.

Detailed Description

The following is further detailed by way of specific embodiments:

the parameters of examples 1-6 of a1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent are shown in Table 1:

TABLE 1

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6
							1, 4-naphthalenedicarboxylic acid (g)	15	13	14	16	17	18
Thionyl chloride (ml)	150	100	120	160	175	200
							Dimethylformamide catalyst (ml)	3	1	2	4	5	6
Nicotinazide (mol)	0.004	0.002	0.003	0.0035	0.0045	0.006
							N, N-dimethylformamide (ml)	120	100	110	130	140	150
Triethylamine (ml)	3	1	2	3.5	4.5	5

1, 4-naphthalene dicarboxylic acid dihyrozide nucleating agent, which has the structure as follows:

performing molecular structure characterization on the 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent by using a Fourier transform infrared spectrometer and a nuclear magnetic resonance tester, wherein the nuclear magnetic resonance result is shown in figure 2; the infrared test data are: (FT-IR) v: 3439.6, 3234.2, 3007.0, 1683.1, 1659.4, 1630.2, 1596.0, 1580.9, 1524.8, 1477.4, 1422.8, 1380.7, 1348.3, 1308.7, 1264.1, 1198.9, 1169.5, 1149.2, 1087.2, 1030.1, 901.8, 825.9, 767.7, 711.1, 630.8cm^-1. The nuclear magnetic resonance spectrum is: (¹H NMR)δ：ppm；10.91(s，1H，NH)，10.71(s，1H，NH)，9.15(s，1H，Py)，8.32～8.82(m，3H，Py)，7.61～7.78(m，3H，Naphth)。

Now, taking example 1 as an example, a method for preparing a1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent will be described, wherein the reaction process is shown in FIG. 1.

A preparation method of 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent comprises the following steps:

step (1): acylation reaction

15g of 1, 4-naphthalenedicarboxylic acid was mixed with 150ml of thionyl chloride and 3ml of N, N' -dimethylformamide as a catalyst to form a mixture. The mixture was then heated at a rate of 5 ℃/min and the temperature was stopped when the heating temperature rose to 80 ℃. The mixture is stirred and refluxed during heating so that the mixture is fully reacted, and a mixed solution is formed after stirring and refluxing for 36 hours.

Cooling the mixed solution to room temperature, and evaporating the mixed solution in a vacuum environment to obtain 1, 4-naphthaloyl chloride; the reaction process is as follows:

step (2): amination reaction

Extracting 0.008mol of 1, 4-naphthaloyl chloride prepared in the step (1), then adding 0.004mol of nicotinoyl hydrazine, 120ml of N, N' -dimethylformamide and 3ml of triethylamine, and carrying out mixing reaction by using an ultrasonic technology to form secondary mixed liquid;

the secondary mixed liquid is subjected to ice bath for 2h, the secondary mixed liquid is continuously stirred in the ice bath process, the stirring speed is 1800-2600r/min, and 2300r/min is used in the embodiment. After ice-bath, the secondary mixture was warmed to 70 ℃ and kept warm for 6 h.

And pouring the secondary mixed solution into deionized water, cleaning, and performing suction filtration to obtain a filter cake. Washing the filter cake for three times by using deionized water, placing the washed filter cake under a vacuum condition, and drying the washed filter cake at the temperature of 35 ℃ to obtain the 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent; the reaction process is as follows:

example 2-example 6 differed from example 1 only in the parameters as shown in table 1.

Experiment:

selecting a diphenylpropionic acid sebacoyl hydrazine nucleating agent as a comparative example 1, wherein the structure of the diphenylpropionic acid sebacoyl hydrazine nucleating agent is as follows:

the infrared spectrum test data of the diphenyl propionic acid sebacoyl hydrazine nucleating agent are as follows: IR (KBr) v: 3448.0, 3315.8, 3216.3, 3029.2, 2924.0, 2850.4, 1633.4, 1600.7, 1530.3, 1483.5, 1450.9, 1414.5, 1377.3, 1219.4, 1188.7, 1159.4, 1071.1, 1029.9, 933.0, 750.3, 720.9, 698.2 cm-1. The nuclear magnetic resonance spectrum is: 1H NMR (DMSO, 400MHz) delta: ppm; 9.72(s, 1H, NH), 9.67(s1H, NH), 7.09-7.33 (m, 5H, Ar), 2.81-2.84 (t, 4H, CH2), 2.40-2.44 (t, 2H, CH2), 1.18-1.25 (m, 6H, CH 2).

The adipic acid dibenzoylhydrazine nucleating agent is selected as a comparative example 2, and the structure of the adipic acid dibenzoylhydrazine nucleating agent is as follows:

the infrared spectrum test data of the adipic acid dibenzoylhydrazine nucleating agent are as follows: infraredspectrum (IR) v: 3362.3, 3236.2, 3032.8, 2940.3, 2863.8, 1693.6, 1647.9, 1603.9, 1575.9, 1523.2, 1491.2, 1467.1, 1420.5, 1385.8, 1343.6, 1308.8, 1270.5, 1222.2, 1187.1, 1168.2, 1128.8, 1027.8, 968.8, 929.1, 900.6, 804.0, 692.2cm "1; the nuclear magnetic resonance spectrum is: 1H nuclear magnetic resonance (1H NMR, 400MHz) delta: ppm; 0.33(s, 1H, NH), 9.89(s, 1H, NH), 7.48-7.88 (m, 5H, Ar), 2.22(s, 2H, CH2), 1.62(s, 2H, CH 2).

Preparation of experimental samples:

the levorotatory polylactic acid (PLLA) and the nucleating agent (NAHA) provided in example 1 were dried under vacuum at 35 ℃ for 48 hours, the residual moisture was removed, and the levorotatory polylactic acid (PLLA) and the nucleating agent (NAHA) were melt-blended in a rotary mixer to form a mixture. The rotary mixer used in the embodiment comprises a mixing barrel, a rotary rod coaxially fixed in the mixing barrel, a motor coaxially fixed with the rotary rod barrel, a feed inlet and a discharge outlet, wherein the rotary rod is wound with a spiral blade; the periphery of the mixing barrel is provided with a heating coil which is communicated with a power supply, and a switch is arranged between a passage formed by the heating coil and the power supply.

During blending, the mixing temperature is set to 190 ℃, the rotating rod rotating speed is set to be 32rpm/min or 64rpm/min, the rotating rod rotating speed is preferably 64rpm/min in the use process, and the mixing time is 7 min. The mixture was hot pressed at 180 ℃ under 20MPa and then cold pressed at room temperature for 5min to give a sample with a thickness of 0.4 mm. When preparing the sample, the proportion of the nucleating agent in the material is 0 wt%, 0.5 wt%, 1 wt%, 2 wt% and 3 wt%, and the sample is named as sample 1: PLLA (i.e. PLLA0 wt% NAHA), sample 2: plla0.5 wt% NAHA, sample 3: PLLA1 wt% NAHA, sample 4: PLLA2 wt% NAHA, sample 5: PLLA3 wt% NAHA.

Blending sebacoyl dihydrazide (HAD) diphenylpropionate and poly (l-lactide) (PLLA) provided in comparative example 1 in the same manner as above to prepare comparative samples, wherein the proportions of the nucleating agents in the materials are 0.5 wt%, 1 wt%, 2 wt% and 3 wt%, respectively, and the prepared comparative samples are labeled as follows: comparative example sample 1: plla0.5wt% HAD, comparative example sample 2: PLLA1 wt% HAD, comparative example sample 3: PLLA2 wt% HAD, comparative example sample 4: PLLA3 wt% HAD.

Comparative samples were prepared by blending dibenzoylhydrazide adipate (BAAD) and poly-L-lactic acid (PLLA) as provided in comparative example 2, with nucleating agent concentrations of 0.5 wt%, 1 wt%, 2 wt% and 3 wt%, and the prepared comparative samples were labeled: comparative example sample 5: plla0.5wt% BAAD, comparative example sample 6: PLLA1 wt% BAAD, comparative example sample 7: PLLA2 wt% BAAD, comparative example sample 8: PLLA3 wt% BAAD.

The above samples 1 to 5 and comparative samples 1 to 8 were subjected to the following experiments:

1 non-isothermal crystallization behavior of polylactic acid (PLLA)

DSC curve analysis at a Cooling Rate of 1.11 ℃/min

The DSC curves of the melting crystals of the above samples 1 to 5 were analyzed by Differential Scanning Calorimetry (DSC), and after melting of the samples 1 to 5 at 170 ℃, 180 ℃, 190 ℃ and 200 ℃, the samples were cooled at a cooling rate of 1 ℃/min, the DSC curves are shown in fig. 3, 4, 5 and 6, respectively, and the specific parameters of the samples 2 to 5 are shown in table 2.

TABLE 2

DSC curves of the melt crystallization of the above comparative example sample 1 to comparative example sample 8 were analyzed by Differential Scanning Calorimetry (DSC), and DSC curves of the comparative example sample 1 to comparative example sample 8 were respectively shown in fig. 7, fig. 8, fig. 9, fig. 10, fig. 11, and fig. 12, after melting at 180 ℃, 190 ℃, and 200 ℃, and cooling at a cooling rate of 1 ℃/min.

As can be seen from fig. 3 to 12 and table 2, the crystallization process includes two stages of nucleation and crystal growth, and no melt crystallization peak occurs because sample 1 is not doped with NAHA, but PLLA itself has very poor nucleation capability. Comparative example sample 1 to comparative example sample 8, melt crystallization peaks occurred when cooled at melt temperatures of 180 ℃, 190 ℃ and 200 ℃ at a cooling rate of 1 ℃/min, with melt crystallization peaks for samples 1 to 4 occurring between 123 ℃ and 133 ℃, and for comparative sample 5 to comparative sample 8 occurring between 136 ℃ and 144 ℃.

Whereas, when samples 2 to 5 were cooled at a cooling rate of 1 ℃/min at melting temperatures of 170 ℃, 180 ℃, 190 ℃ and 200 ℃, the melting crystallization peak (up to 160 ℃) appeared at temperatures higher than 145 ℃ due to the lower crystallization rate, indicating that PLLA begins to crystallize at this time, and the initial crystallization temperature was much higher than that of sample 1 and comparative samples 1 to 8. It is shown that samples 2-5 begin to crystallize when crystallization approaches the melting temperature of PLLA, i.e., PLLA begins to crystallize without cooling to a low crystallization temperature, resulting in a shorter time for complete crystallization of PLLA and an increased rate of crystallization. Meanwhile, as the concentration of NAHA in PLLA increases, the melting crystallization peak moves towards a high temperature direction, which shows that the initial temperature of crystallization increases, further accelerates the crystallization of PLLA, shortens the crystallization time and improves the crystallization rate.

Usually, the melting point of pure PLLA is 160 to 170 ℃, the theoretical crystallization temperature range is above the glass transition temperature and below 0.85 times of the melting point, so the theoretical upper limit of the PLLA crystallization temperature is 144.5 ℃. Whereas, sample 2-sample 5 had a melting temperature of 170 ℃ and an onset crystallization temperature of more than 160 ℃, meaning that the theoretical upper limit of crystallization was broken after the addition of NAHA to the PLLA.

In conclusion, by doping 1, 4-naphthoic dihyrozide Nucleating Agent (NANH) in the polymerization process of the levorotatory polylactic acid (PLLA), crystallization can occur at high temperature, and the time for starting crystallization behavior breaks through the theoretical upper crystallization temperature limit of PLLA, which is a breakthrough in the field. And calculating a formula according to the crystallinity: the melting temperature-reducing crystallization enthalpy/(93 × 1-X)), wherein the melting temperature-reducing crystallization enthalpy, i.e., Δ Hc, 93 is the crystallization enthalpy corresponding to 100% crystallization, and X is the percentage content of NANH, and is calculated to be that the melting temperature is reduced at a rate of 1 ℃/min at 200 ℃, so that the crystallinity of the sample 5 can reach 63.96% (usually, the crystallinity of pure PLLA and PLLA doped with the existing nucleating agent is very low), and the crystallinity is greatly improved.

Furthermore, as the crystallinity of PLLA increases, the internal structural rule of PLLA at high temperature is indicated, and the structural difficulty of breaking the rule by high temperature is large, so that the heat resistance of PLLA can be improved; and the increased crystallinity also makes the PLLA prepared more heat resistant, thereby expanding the temperature range in which the PLLA is used. Detection proves that the heat-resistant temperature of the PLLA can reach more than 150 ℃ by doping the NAHA in the PLLA, and the service temperature of the PLLA in industry is completely met.

DSC Curve analysis of samples 2-5 at Cooling rates of 1.240 deg.C/min, 50 deg.C/min

FIGS. 13 and 14 are DSC graphs showing that samples 2 to 5 are melted at 190 ℃ and then cooled at cooling rates of 40 ℃/min and 50 ℃/min, respectively. In practical application, rapid cooling is usually required in consideration of time cost, so that a DSC curve at a multi-stage cooling rate is analyzed. It can be found through experiments that even at the high cooling rate of 40 ℃/min and 50 ℃/min, the crystallization peaks of the samples 2 to 5 can still appear, and particularly the crystallization peaks of the

samples

4 and 5 are particularly obvious. Therefore, the nucleating agent provided by the invention has very good promoting and accelerating effects on the nucleation and crystallization of PLLA.

1.3 DSC curve analysis of samples 2-5 isothermal at 140 deg.C, 142 deg.C, 144 deg.C, 146 deg.C, 148 deg.C, 150 deg.C for 180min

The DSC curves of the melt crystallization of the above comparative example sample 2 to comparative example sample 5 were analyzed by Differential Scanning Calorimetry (DSC), and the DSC graphs of the samples 2 to 5 were isothermal for 180min at a high temperature of 140 ℃ to 150 ℃, as shown in fig. 15 to 20, respectively.

Theoretically, in the high-temperature region of 140-150 ℃, the motion capability of polylactic acid molecular chains is very strong, and homogeneous nucleation of the polylactic acid molecular chains is almost impossible to occur, but a melting peak exists in the melting process, so that the crystallization is confirmed to occur in the isothermal process, and the nucleation is the premise of the crystallization, which shows that the NAHA is doped to promote the crystallization and nucleation of the polylactic acid, and confirms the function of NANH in the polylactic acid matrix. In addition, with the increase of the crystallization temperature, the melting peak of the crystal moves towards the high temperature direction, and the crystal grows more fully at higher temperature, so that the grown crystal is more perfect, the crystal moves towards the high temperature direction, the method can be suitable for the actual production of enterprises, and the existing process is improved.

1.4 analysis of the crystallinity curves at 140 ℃ for samples 2 to 5 as a function of crystallization time

The changes of crystallinity with crystallization time at a high temperature of 140 ℃ for samples 2 to 5 are shown in FIG. 21. As can be seen from fig. 21, samples 2 to 5 rapidly crystallize at a high temperature of 140 ℃, especially the crystallization speed rapidly increases in the first 2min, and after 2min, the crystallization speed tends to be stable. Wherein

samples

4 and 5 can complete crystallization in about 2.3min, and sample 3 can complete crystallization in about 3.2 min. This indicates that samples 2 to 5 can complete crystallization rapidly, and thus can be applied to industrial production, resulting in an improvement in production efficiency and productivity.

Leading edge rail energy of 2PAID and PLLA

Preliminary theoretical analysis using the DMol3 system of MS software resulted in the geometry and leading edge trajectory energy plots for PAID and PLLA as shown in fig. 22. PAID has a HOMO (highest occupied molecular orbital) and LUMO (lowest energy level orbital) of-0.2011 eV and-0.099 eV, respectively, PLLA has a HOMO (highest occupied molecular orbital) and LUMO (lowest energy level orbital) of-11.082 eV and PLLA of 0.251eV, respectively. According to the leading edge orbital theory, the energy difference between the LUMO of PAID and the HOMO of PLLA is 10.983eV, which is less than the energy difference between the LUMO-HOMO of PLLA itself, 11.333 eV; according to the leading edge orbital theory, the energy difference between the LUMO of PAID and the HOMO of PLLA is 10.983eV, which is less than the energy difference between the LUMO-HOMO of PLLA itself, 11.333 eV; through further analysis of the molecular structures of PLLA and PAID, it is thought that their interaction may occur at C ═ O of PLLA and N — H of PAID; therefore, the interaction between the PIAD and PLLA can enhance the nucleation effect of PLLA.

3 isothermal crystallization behavior of polylactic acid (PLLA)

Differential Scanning Calorimetry (DSC) analyzed the isothermal crystallization curve of sample 5 and the results are shown in figure 23. As can be seen from FIG. 23, the semicrystallization time of sample 5 at the crystallization temperature of 135 ℃ was 0.3min, and it was possible to complete the crystallization in a short time, thereby shortening the crystallization time.

4 thermogravimetric analysis

The thermo-gravimetric stability analysis of samples 1-5 was performed using a Q500 apparatus from TA, with the samples placed in the apparatus and heated from room temperature to 650 degrees at 5 degrees per minute under flowing air, with the experimental results shown in fig. 24. As can be seen from fig. 24, the doping of the NAHA in the PLLA resulted in a small drop in the initial thermal decomposition temperature of the PLLA, but the drop was very small, and the initial thermal decomposition temperature of sample 5 was also only 7.6 ℃ (the effect of the drop in the initial thermal decomposition temperature of 7.6 ℃ was very small at temperatures above 330 ℃), and was little for the specific use. In general, the polymer is doped with the aid, the initial decomposition temperature of the original polymer is greatly reduced due to the compatibility of the aid or the low decomposition temperature of the aid, and the NAHA has very little influence on the initial thermal decomposition temperature of the PLLA, has little influence on the thermal decomposition resistance of the PLLA, does not generate great influence on the use of the PLLA, and ensures that the PLLA still has a wider use range.

5 flow test analysis

The results of the fluidity test analysis of samples 1 to 5 at 180 ℃ under a standard load of 21.6kg are shown in FIG. 25. As can be seen from fig. 25, the flowability of PLLA can be greatly improved by doping NAHA in PLLA, especially in sample 5, the flowability reaches 10.9g/10min, which is very advantageous for subsequent product processing, and the product can be rapidly flowed and molded, so that a very large processing time cost can be saved.

6 tensile Strength test analysis

Tensile strength tests were performed on samples 1-5, with specific parameters as shown in fig. 26. As can be seen from fig. 26, the tensile strength of samples 2 to 5 is significantly higher than that of sample 1, wherein the tensile strength of sample 4 reached 52.5MPa, which is 1.25 times that of sample 1.

7 experimental analysis of modulus of elasticity

The modulus of elasticity tests were performed on samples 1-5, with specific parameters as shown in FIG. 27. As can be seen from FIG. 27, the modulus of elasticity of samples 2 to 5 is significantly higher than that of sample 1, wherein the modulus of elasticity of sample 2 reaches 2040MPa, which is 1.3 times that of sample 1.

It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention, and these changes and modifications should not be construed as affecting the performance of the invention and its practical application.

Claims

1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent, characterized in that: the structure of the utility model is that,

2. the method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 1, comprising the steps of:

step (1): acylation reaction

step (2): amination reaction

3. the method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 2, wherein: in the step (1), the mixture is cooled to room temperature before evaporation.

4. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 3, wherein: in the step (1), the mixed solution is evaporated in a vacuum environment.

5. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 4, wherein: in the step (2), 1, 4-naphthaloyl chloride, nicotinoyl hydrazine, N' -dimethylformamide and triethylamine are mixed by using an ultrasonic technology.

6. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 5, wherein: in the step (2), before cleaning the secondary mixed liquid, ice bath is firstly carried out and stirring is carried out for 2 hours, wherein the stirring speed is 1800-2600 r/min.

7. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 6, wherein: in the step (2), after ice bath, the temperature of the secondary mixed liquid is raised to 70 ℃, and the temperature is kept for 6 hours.

8. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 7, wherein: and (3) in the step (2), when the secondary mixed solution is cleaned, pouring the secondary mixed solution into deionized water, and performing suction filtration to obtain a filter cake.

9. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 8, wherein: and (3) in the step (2), washing the filter cake three times by using deionized water.

10. The method of preparing 1, 4-naphthalenedicarboxylic acid dihyrozide nucleating agent as defined in claim 9, wherein: in the step (2), the filter cake is dried at the temperature of 35 ℃ under the vacuum condition.