CN110564120A

CN110564120A - Cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and preparation method thereof

Info

Publication number: CN110564120A
Application number: CN201910793279.6A
Authority: CN
Inventors: 陈建香; 龚申涛
Original assignee: Jiangsu University of Technology
Current assignee: Jiangsu University of Technology
Priority date: 2019-08-27
Filing date: 2019-08-27
Publication date: 2019-12-13

Abstract

The invention relates to a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and a preparation method thereof, wherein a cellulose derivative CAB or CAP can be compatible with a polyester chain part of PHBV, when the dosage of the cellulose derivative CAB or CAP accounts for 5-10 wt%, the cellulose derivative has obvious reinforcing and toughening effects on the PHBV, and the cellulose derivative can play a role of dilution so as to reduce the crystallization temperature of the PHBV, facilitate the processing and forming of the PHBV and save energy consumption to a certain extent; when the mass fraction of the cellulose derivative, particularly CAB, is 10 percent of that of the composite material, the impact property and the tensile property of the composite material are obviously improved.

Description

Cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and preparation method thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and a preparation method thereof.

Background

Poly (beta-hydroxybutyrate valerate), PHBV for short, is thermoplastic polyester fermented by microorganisms, and belongs to one of polyhydroxyalkanoate materials. The PHBV has the advantages of good biodegradability, biological tissue compatibility, anticoagulation property and the like. PHBV has excellent biocompatibility, can be used as a substitute for blood vessels and other tissues in transplantation operation, can promote the regeneration of natural tissues or the reconstruction of natural organs, and reduces the generation of immune response. The PHBV can also be used as a scaffold of human tissues, the rough scaffold surface can promote the growth of the human tissues along with the slow degradation of the PHBV, and gaps formed by the degradation of the PHBV scaffold can be permeated and exchanged by body fluid. However, the highly isotactic structure of PHBV leads the PHBV to have higher crystallinity, and the PHBV spherulite has larger size, thus being a hard and brittle material with poorer mechanical properties.

The mechanical properties of PHBV are mainly determined by its crystallization behavior and crystal structure, both of which are closely related to HV content. PHBV has high stereoregularity, a large crystallization tendency, a low glass transition temperature (lower than 0 ℃), and during storage, secondary crystallization of an amorphous phase easily occurs at ambient temperature, the crystallization process inhibits amorphous chains between crystals, resulting in higher crystallinity, and PHBV has high purity and a small nucleation density, easily forms large spherulites, causing circular fracture around the center of the spherulites and fracture in the radial direction, which causes the material to become brittle.

although PHBV has many excellent characteristics of biodegradability, biocompatibility, piezoelectricity, optical activity, etc., its application is greatly limited due to many defects that are difficult to overcome by itself, such as high price, hardness and brittleness, low thermal decomposition temperature, narrow processing window, slow crystallization rate, etc. Therefore, it is urgently required to modify it.

Disclosure of Invention

In order to solve the technical problems of high crystallization temperature and poor mechanical property of PHBV, a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and a preparation method thereof are provided.

The invention is realized by the following technical scheme:

A preparation method of a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material comprises the following steps: uniformly stirring poly (beta-hydroxybutyrate valerate) and cellulose derivative, placing the mixture into a torque rheometer, and carrying out melt blending to obtain a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material;

The cellulose derivative is Cellulose Acetate Butyrate (CAB) or Cellulose Acetate Propionate (CAP);

The mass fraction of the cellulose derivative in the composite material is 5-10%.

Preferably, the cellulose derivative is cellulose acetate butyrate.

Preferably, the cellulose derivative is present in the composite material in a mass fraction of 10%.

Further, the working temperature of the torque rheometer is 180 ℃, the rotating speed is 60r/min, and the melt blending time is 5 min.

The invention also aims to provide a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material prepared by the preparation method.

When the addition amount of the cellulose derivative is too large, on one hand, the viscosity of the system is obviously increased, the movement of a molecular chain is hindered, and the processing and the forming of poly (beta-hydroxybutyrate valerate) are not facilitated; on the other hand, the defects of the formed system are increased, so that the addition amount of the cellulose derivative accounts for 5-10 wt% of the composite material, and the prepared composite material has good mechanical property.

The working temperature of the torque rheometer is 180 ℃, the rotating speed is 60r/min, and the melt blending time is 5 min. Too short melt blending time is not favorable for uniform dispersion of the cellulose derivative in the poly (beta-hydroxybutyrate valerate), and too long time can degrade the matrix material, so that the control for 5min is more suitable.

The beneficial technical effects are as follows: the invention relates to a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material and a preparation method thereof, wherein cellulose derivatives (CAB and CAP) can be compatible with a polyester chain part of PHBV, and have obvious reinforcing and toughening effects on the PHBV when the dosage of the cellulose derivatives accounts for 5-10 wt%, and the cellulose derivatives can play a role of dilution so as to reduce the crystallization temperature of the PHBV, facilitate the processing and forming of the PHBV and save energy consumption to a certain extent. When the mass fraction of the cellulose derivative, particularly CAB, is 10 percent of that of the composite material, the impact property and the tensile property of the composite material are obviously improved.

Drawings

FIG. 1 is a DSC curve at a temperature decrease rate of 10K/min for examples 1 to 4 and comparative examples 1 to 3.

FIG. 2 is a diagram of the spherulite morphologies of examples 1 and 3 and comparative example 1, wherein the scale bars in the diagram are 10 μm.

Detailed Description

The invention is further described below with reference to the figures and specific examples, without limiting the scope of the invention.

Example 1

2.5g CAB and 47.5g PHBV are melted and blended for 5min in a rotational rheometer with 180 ℃ and 60r/min of rotation speed, thus obtaining the cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material.

Examples 2 to 8

Examples 2-8 are the same as example 1 except for the composition and ratio of the components, as shown in table 1.

Comparative example 1

This comparative example was prepared in the same manner as in example 1, except that the cellulose derivative was not added, as shown in Table 1.

comparative example 2

This comparative example is prepared in the same manner as example 1, except for the components in the proportions shown in Table 1.

Comparative example 3

The comparative example is the same as the preparation method of example 1, except for the composition and the mixture ratio of the components, which are shown in Table 1.

TABLE 1 compositions and ratios of examples 1-8 and comparative examples 1-3

Differential Scanning Calorimetry (DSC) analysis tests are carried out on examples 1 to 4 and comparative examples 1 to 3, a DSC curve at a cooling rate of 10K/min is shown in figure 1, and it can be seen from the curve that the crystallization temperature of the composite material is reduced along with the increase of the content of CAB or CAP, the CAB and CAP have good effects on the reduction of the crystallization temperature of PHBV, and the lower crystallization temperature is more beneficial to processing and forming operations.

The morphology of the spherulites in the examples 1, 3 and 1 was observed by a polarization microscope, as shown in fig. 2, the morphology of the pure PHBV spherulites in the comparative example 1, the morphology of the PHBV composite material after CAB addition in the example 1, and the morphology of the PHBV composite material after CAP addition in the example 3. As can be seen from FIG. 2, the addition of CAB and CAP can improve the crystal morphology and nucleation density of PHBV, so that the spherulite morphology of PHBV is clearer.

The unnotched impact strength test was performed according to the current GB/T1843 standard and the tensile strength test was performed according to the current GB/T1040 standard for examples 1 to 4 and comparative examples 1 to 3, and the test results are shown in Table 2.

TABLE 2 Performance data for materials prepared in examples 1-4 and comparative examples 1-3

	Unnotched impact Strength (KJ/m)²)	tensile Strength (MPa)
			Example 1	8.5	41.27
Example 2	10.2	40.08
			Example 3	8.2	38.76
Example 4	8.8	35.83
			Comparative example 1	7.9	27.75
Comparative example 2	8.1	35.11
			Comparative example 3	8.2	31.25

As can be seen from the data in Table 2, the toughening effect of CAP on PHBV is not as good as CAB, when 2 wt% of CAB is added in comparative example 2, the toughening effect on PHBV can be achieved to a certain extent, it can be seen that the impact resistance of the material can be improved by adding CAB, and the higher the CAB content in the system is, the better the impact resistance is, when the CAB addition in example 2 is 10 wt%, the toughening effect of CAB on PHBV is significant, the unnotched impact strength is increased by about 29.1% as compared with PHBV, and the tensile strength is increased by about 44.4% as compared with PHBV.

After CAB and CAP are added, the tensile property of the material is obviously improved. When the weight fraction of CAB and CAP in the system is 5%, the tensile strength of the PHBV composite material is the maximum. When the weight percentage of CAB and CAP is 10%, the composite material has the effects of strengthening and toughening PHBV.

In conclusion, the reinforcing and toughening effect of CAB is better than that of CAP when the addition amount of CAB is 10 wt%.

Claims

1. A preparation method of a cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material is characterized in that the poly (beta-hydroxybutyrate valerate) and a cellulose derivative are uniformly stirred and placed in a torque rheometer for melt blending to obtain the cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material;

The cellulose derivative is cellulose acetate butyrate or cellulose acetate propionate;

2. The method for preparing the cellulose derivative-modified poly (β -hydroxybutyrate valerate) composite according to claim 1, wherein the cellulose derivative is cellulose acetate butyrate.

3. The method for preparing a cellulose derivative-modified poly (β -hydroxybutyrate valerate) composite according to claim 1 or 2, wherein the cellulose derivative is present in the composite in an amount of 10% by mass.

4. the preparation method of the cellulose derivative modified poly (beta-hydroxybutyrate valerate) composite material according to claim 1 or 2, wherein the working temperature of the torque rheometer is 180 ℃, the rotating speed is 60r/min, and the time for melt blending is 5 min.

5. A cellulose derivative-modified poly (β -hydroxybutyrate valerate) composite prepared by the preparation method according to claim 1 or 2.