阅读说明：本技术 一种基于结合胶检测天然橡胶中炭黑的补强性能的方法 (Method for detecting reinforcing performance of carbon black in natural rubber based on bonding glue ) 是由 陈建 雷智强 唐成玉 刘莎 何宇 李�瑞 卿龙 刘平 李琳 龚勇 于 2020-08-17 设计创作，主要内容包括：本发明公开了一种基于结合胶检测天然橡胶中炭黑的补强性能的方法。采用超薄冷冻切片机制样后,使用原子力显微镜的轻敲模式,表征炭黑-橡胶复合材料时,利用形貌图和相图成像特点的差别,可以直接观察炭黑补强复合材料的结合胶的特点,得到结合胶的厚度,进而分析结合胶对橡胶性能的影响和炭黑在橡胶补强性能。该方法具有操作简单、不需过多的对样品进行处理、检测效率较高,检测图片清晰和检测准确度高等优点,具有更好的适用性,为研究填料的补强提供了新的方法和思路。(The invention discloses a method for detecting the reinforcing performance of carbon black in natural rubber based on bonding glue. After an ultrathin freezing microtome is adopted for sample preparation, when the carbon black-rubber composite material is represented by using a tapping mode of an atomic force microscope, the characteristics of the bonding glue of the carbon black reinforced composite material can be directly observed by using the difference of the imaging characteristics of a morphology graph and a phase diagram, the thickness of the bonding glue is obtained, and then the influence of the bonding glue on the rubber performance and the carbon black reinforcing performance in the rubber are analyzed. The method has the advantages of simple operation, no need of excessive sample treatment, high detection efficiency, clear detection picture, high detection accuracy and the like, has better applicability, and provides a new method and thought for researching the reinforcement of the filler.)

1. A method for detecting the reinforcing performance of carbon black in natural rubber based on bonding glue is characterized by comprising the following steps:

1) preparing a rubber product to be detected into a strip with a proper size by using a cutting knife, clamping the rubber product by using an AFM (atomic force microscope) special sample clamp, putting the rubber product into a slicer case, and fixing a tightening screw in the slicer;

the rubber product is prepared by mixing rubber, carbon black and one or more additives selected from reinforcing fillers, anti-aging agents, oil and a vulcanization system to form a rubber compound, and then carrying out a vulcanization reaction;

2) when the fixed rubber product reaches-100 to-60 ℃, slicing the rubber sample by using an AFM special slicing knife to cut a flat plane, cleaning the sample section by using absolute ethyl alcohol at normal temperature for 2-5 times, and placing the slice under a microscope to observe that no chips exist for later use;

3) scanning the section of the sample prepared in the step 3) in a tapping mode of an AFM probe under room temperature and atmospheric conditions to obtain a morphology graph and a phase graph;

4) the thickness of the bonding glue is measured by observing the topography and the phase diagram, and the strength of the reinforcing property of the carbon black in the rubber product can be obtained according to the thickness of the bonding glue.

2. The method for detecting the reinforcing property of carbon black in natural rubber based on bound rubber according to claim 1, wherein the vulcanization system comprises sulfur, a vulcanization accelerator and zinc oxide.

3. The method for detecting the reinforcing property of carbon black in natural rubber based on bound rubber according to claim 1, wherein the slicing speed is 1 to 3 mm/s.

4. The method for detecting the reinforcing performance of the carbon black in the natural rubber based on the bonding glue according to claim 1, wherein the slice thickness is 50-100 nm.

5. The method for detecting the reinforcing property of carbon black in natural rubber based on bound rubber according to claim 1, wherein the vulcanization time is 30-50 min.

Technical Field

The invention belongs to the technical field of rubber composite materials, and particularly relates to a method for detecting the reinforcing performance of carbon black in natural rubber based on bonding glue.

Background

Through the automobile industry developed for over 130 years, the automobile industry is now used as an important force for promoting a new technological revolution and an industrial revolution, is used as an important support for building a strong country, is used as an important support for national economy, and is closely related to the travel of people and the promotion of ecological civilization. The automobile tyre is an important component of the automobile and plays roles of bearing the whole weight of the automobile, ensuring good adhesion between the wheel and the road surface and the like. The importance of carbon black as a reinforcing filler for a tread is self-evident because the quality of the tread rubber directly affects the safety and ride comfort of an automobile, which is the portion of a tire tread in direct contact with the ground. In the beginning of the last century, i.e. 1910, the firm tricot company (b.f. goodrich) first found that the addition of a large amount of carbon black in rubber improves the wear resistance of tires, thus greatly extending the useful life of the tires, while also protecting the carbon black from static electricity by rational treatment, as mentioned in patent CN 103358828A. Thereafter, the demand for carbon black has increased substantially, and the transition of carbon black from the colorant identity to the new identity of the reinforcing filler has also been accomplished. The carbon black becomes a raw material of rubber with the industrial dosage second to that of raw rubber, the carbon black industry develops rapidly, and the rubber reinforced by the carbon black also has better practicability and obtains greater commercial value, so that the carbon black industry and the rubber industry are closely linked together. About 90% of the carbon black product is used in the rubber industry, with about 67.5% being used in tires and 22% being used in other rubber articles.

However, since the carbon black has a reinforcing effect on rubber and determines the properties of the carbon black itself, it is only clear that new carbon black can be developed. The reinforcing effect of carbon black on rubber has a profound influence on the development of the rubber industry, so that the reinforcing mechanism and the corresponding reinforcing model of the carbon black on the rubber are always the research focus and hot spot of industrial researchers. Through the efforts of scientists and the progress of related scientific research equipment, although a great deal of research results are provided for the mechanism of carbon black reinforced rubber and some mature reinforcing mechanisms are extracted, no accepted unique and authoritative mechanism can perfectly explain the reinforcing effect of the carbon black on the rubber. Therefore, the reinforcing effect of the carbon black on the rubber, the action mechanism of the carbon black rubber composite material and the like are still worth deeply researching.

At present, a filler network theory, a molecular chain sliding theory, a van der waals network theory and a bonding glue theory are several reinforcing theories with higher recognition degree, wherein the bonding glue theory considers that the bonding position of the carbon black rubber can generate the bonding glue, and when external acting force is applied to the bonding glue, the bonding glue can prevent stress concentration and delay the breakage of a molecular chain. The most fundamental reinforcing effect of carbon black on rubber is the nature of the carbon black-rubber bond, and the characteristics of the bond generated at the bonding position also influence the reinforcing capability of the carbon black. The bonding gum is also called carbon black gel, and refers to rubber chemically bonded with the surface of carbon black in the process of blending the rubber and the carbon black. It is a value to measure the effect of the filler in combination with the rubber. The bonding glue is used for representing the interaction between the rubber and the filler, and the higher the content of the bonding glue is, the stronger the acting force between the rubber and the filler is, and the better various physical properties of the rubber product such as strength, elasticity, tearing, abrasion performance and the like are. Therefore, many experts have involved the concept of a binder in the study of filler reinforcement for rubber, and have attempted to solve the mechanism of filler-reinforced rubber by studying some properties of the binder. At present, the rubber compound is soaked in a benign solvent, the content of the bound rubber is calculated by measuring the mass reduction of a tested rubber sample, and the operation is complicated. However, since no suitable measurement method is currently available for the performance of the binder, the research on this aspect cannot be widely conducted, and no report has been made so far on the characterization of the reinforcing performance of carbon black by determining the thickness of the binder.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for detecting the reinforcing performance of carbon black in natural rubber based on bonding glue, provides a new method for representing the reinforcing performance of the carbon black, and provides more choices for the research of rubber products.

In order to achieve the purpose, the invention adopts the following technical scheme: a method for detecting the reinforcing performance of carbon black in natural rubber based on bonding glue comprises the following steps:

1) preparing a rubber product to be detected into a strip with a proper size by using a cutting knife, clamping the rubber product by using an AFM (atomic force microscope) special sample clamp, putting the rubber product into a slicer case, and fixing a tightening screw in the slicer;

the rubber product is prepared by mixing rubber, carbon black and one or more additives selected from reinforcing fillers, anti-aging agents, oil and a vulcanization system to form a rubber compound, and then carrying out a vulcanization reaction;

2) when the fixed rubber product reaches-100 to-60 ℃, slicing the rubber sample by using an AFM special slicing knife to cut a flat plane, cleaning the sample section by using absolute ethyl alcohol at normal temperature for 2-5 times, and placing the slice under a microscope to observe that no chips exist for later use;

3) scanning the section of the sample prepared in the step 3) in a tapping mode of an AFM probe under room temperature and atmospheric conditions to obtain a morphology graph and a phase graph;

4) the thickness of the bonding glue is measured by observing the topography and the phase diagram, and the strength of the reinforcing property of the carbon black in the rubber product can be obtained according to the thickness of the bonding glue.

Preferably, the vulcanization system includes sulfur, a vulcanization accelerator, and zinc oxide.

Preferably, the slicing speed is 1-3 mm/s.

Preferably, the slice thickness is 50-100 nm.

Preferably, the vulcanization time is 30-50 min.

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

1. according to the invention, after a sample is prepared by adopting an ultrathin freezing microtome, when the carbon black-rubber composite material is represented by using a tapping mode of an atomic force microscope, the characteristics of the bonding glue of the carbon black reinforced composite material can be directly observed by using the difference of the imaging characteristics of a morphology graph and a phase diagram, so that the thickness of the bonding glue is obtained, and the influence of the bonding glue on the rubber performance and the carbon black reinforcing performance in the rubber are further analyzed. Firstly, a sample is cut and prepared under a low-temperature condition, so that the interference on the internal appearance during the preparation of the sample at the conventional temperature is avoided; and secondly, the slice is scanned in a tapping mode of an Atomic Force Microscope (AFM), so that the influence of friction, adhesion, electrostatic force and the like on the sample due to the fact that the needle point is dragged by the sample in a traditional contact mode is avoided, the defect that the sample is scratched by the needle point in the scanning process is effectively overcome, a morphology graph and a phase graph are accurately obtained, and the accuracy of the result is guaranteed. The invention can also be applied to the detection of the filler in other polymers, provides a new method and thought for researching the reinforcement of the filler, and has good application prospect.

2. The method directly detects the carbon black reinforcing performance through the appearance image and the phase image of the sample slice, has the advantages of simple operation, no need of excessive sample processing, higher detection efficiency, clear detection image, high detection accuracy and the like, has better applicability, and can be widely popularized and applied to the technical field of rubber compounds.

3. The method disclosed by the invention can provide a method for future rubber research, and the properties of the bonding adhesive can be further researched by observing the difference between the phase close to the carbon black and the phase close to the rubber.

Drawings

FIG. 1 is a graphical representation of different sizes of carbon black N115 compounds of example 1; a is the size 500 nm x 1000 nm, B is the size 1000 nm x 1000 nm, C is the size 5000 nm x 5000 nm.

FIG. 2 is a phase diagram of different sizes of the carbon black N115 compound of example 1; a is the size 500 nm x 1000 nm, B is the size 1000 nm x 1000 nm, C is the size 5000 nm x 5000 nm.

FIG. 3 is an atomic force microscope image of the size of 200 nm X200 nm of the carbon black N115 compound of example 1; a is a topographic map and b is a phase map.

FIG. 4 is a cross-sectional profile of carbon black particles taken at the position of a scribe line in the AFM image of example 1.

FIG. 5 is an atomic force microscope image of the carbon black N330 compound of example 2 having a size of 200 nm X200 nm; a is a topographic map and b is a phase map.

FIG. 6 is a cross-sectional profile of carbon black particles taken at the position of the scribe line in the AFM image of example 2.

FIG. 7 is an atomic force microscope image of the size of 200 nm X200 nm of the carbon black N550 compound of example 3; a is a topographic map and b is a phase map.

FIG. 8 is a cross-sectional profile of carbon black particles taken at the position of the scribe line in the AFM image of example 3.

Detailed Description

The present invention will be described in further detail with reference to the following specific embodiments and the accompanying drawings. The experimental procedures are not specifically described in the following examples, and are carried out in a conventional manner using reagents which are generally commercially available.