1 Natural rubber can be divided into cigarette rubber, particle rubber, crepe rubber and latex according to different manufacturing processes and shapes. However, cigarette gum and particle gum are the main products in the market. Tobacco gum is made by curing, drying, smoking and other processes, and most of the natural rubber imported from China is tobacco gum; Granular rubber is made by curing, granulating, drying and other processes. Natural rubber made in China is basically granular rubber, also called standard rubber. Cigarette gum is generally classified according to its appearance, which is divided into six grades: super grade, first grade, second grade, third grade, fourth grade and fifth grade. Those that fail to reach Grade 5 are classified as external gluing. Granular rubber is generally classified according to internationally unified physical and chemical properties and indicators. These physical and chemical properties include impurity content, initial plasticity value, plasticity retention rate, nitrogen content, volatile matter, ash content and color index. Among them, the impurity content is the leading index, which is divided into five grades: 5L, 5, 10, 20 and 50. The contract delivery grades of natural rubber in Shanghai Futures Exchange are domestic first-class standard rubber SCR5 and imported tobacco flake rubber RSS3, among which domestic first-class standard rubber SCR5 is also commonly known as No.5 standard rubber, and all quality indexes of Natural Rubber GB 808 1 ~ 8090-87 issued and implemented by the State Bureau of Technical Supervision are implemented. Imported cigarette rubber RSS3 implements the International Standard for Grade Quality and Packaging of Natural Rubber (Green Paper) determined by the International Rubber Quality and Packaging Conference (version 1979).

Study on thermal degradation process and kinetics of 2 Acia000 1 grafted natural rubber

The thermal degradation kinetics of natural rubber grafted with methyl methacrylate and styrene polymer was studied by thermogravimetry -DTG method. It is found that the thermal degradation of natural rubber is a one-step reaction, and the thermal degradation process of grafted natural rubber is carried out step by step. With the increase of St content, the thermal degradation temperature and reaction activation energy of grafted natural rubber are higher and higher. The thermal degradation temperature and reaction activation energy of NR-g-St are higher than that of natural rubber, while that of NR-g-MMA is lower than that of natural rubber.

Structure and chlorination mechanism of ACia0002 chlorinated natural rubber

The chlorination mechanism and structure, degradation mechanism and stability of chlorinated natural rubber were introduced, and the development trend of related work was summarized.

ACia0003 Safety of Natural Latex Substitutes

Anti-fatigue effect of ACia0004 rare earth PMMA coated silicone-aluminoxane gel filled natural rubber

PMMA-coated silica-alumina gel was obtained by coating silica-alumina sol formed by water glass, aluminum nitrate and α -methacrylic acid with polymethylmethacrylate. At the same time, rare earth ions were doped in the reaction process, and the obtained rare earth doped PMMA microcapsule powder was filled into natural rubber. Through the analysis of mechanical properties, Young's modulus is generally improved in the market, and the anti-fatigue effect is remarkable. After ten thousand times of tensile fatigue, the retention rate of tensile strength is more than twice that of the reference sample. -

Mixed elasticity of ACia0005 poly 1, 2- propylene carbonate/natural rubber: Ⅰ. compound design

A new type of carbon dioxide * * * carbon 1, 2- propylene carbonate (PPC) and natural rubber (NR)*** mixed elastomer was designed by orthogonal method, and the optimized formula was screened out. When the amount of PPC is 30 phr and the amount of natural rubber is 70 phr, the tensile strength of * * elastomer is 18.9MPa and the elongation at break is 755%.

Study on the relationship between volatile fatty acid value and conductivity of ACia0006 natural latex

By changing the volatile fatty acid content, inorganic salt concentration and external temperature, the relationship between volatile fatty acid value and conductivity of natural latex was discussed.

ACia0007 regulates the adhesion and cohesion of mucilage through electrical excitation.

This paper introduces the process of preparing mucilage with chlorinated natural rubber XHK and * * * polymer CKMBN- 15 of 2- methyl -5- vinylpyridine and butadiene as the base material, and under the stimulation of external constant electric field (BNEN).

Effect of molding temperature of ACia0008 on bonding strength between natural rubber and metal

Taking semi-effective sulfur cured natural rubber vulcanizate as the research object, the influence of molding temperature on peel strength of bonded joints was studied and analyzed. It is found that when the molding temperature is high, the peel strength is also high.

ACia0009 Creep-resistant Natural Rubber Bearing

Creep phenomenon is common in other polymers of rubber workers. In order to prevent creep phenomenon to a certain extent and ensure the stability of product size, skeleton materials are often added to rubber products, and skeleton materials also play a reinforcing role. This paper mainly studies the creep resistance of rubber compound for natural rubber bearings from the formula. Through different formulation designs, the creep resistance of rubber compound is studied, the test process of tensile creep and compression creep of rubber is described, and the creep test data is analyzed and processed by extrapolation method, so as to predict the creep value after 15 years.

Research progress of ACia00 10 chlorinated natural rubber

The history, development, application and research status of chlorinated natural rubber are reviewed and expounded, and the basic structure and synthetic preparation technology of solution method and latex method are briefly introduced.

Study on pyrolysis chromatography-mass spectrometry of ACIA 0011-01chlorinated natural rubber

The structure of chlorinated natural rubber prepared by solution method and latex method was analyzed by high resolution pyrolysis gas chromatography-mass spectrometry (HRPyGC-MS).

Study on drying characteristics of chlorinated natural rubber particles by latex method by ACIA 00 12-0 1 thermogravimetry

Chlorinated natural rubber (CNR) has excellent acid and alkali resistance, wear resistance, seawater resistance, permeability resistance and flame retardancy, so it is widely used in coatings, adhesives, ink additives and making acid and alkali resistant products. The traditional CNR production process, namely "solvent method" of carbon tetrachloride, has been banned in developed countries because of serious environmental pollution, high equipment investment cost and harmful to the health of operators, and the new process will replace "solvent method" sooner or later.

The researchers studied the direct preparation of CNR from natural latex and obtained stable products. At the same time, the research of domestic and foreign researchers shows that the molecular structure and properties of CNR prepared by "latex method" and "solvent method" are quite different, so their drying characteristics are inevitably different. In the process of CNR production, drying is an essential process with the highest energy consumption and the greatest influence on the physical and chemical properties of products. We have made a preliminary study on the drying characteristics of natural rubber by latex method. The results show that "latex method" CNR is sensitive to heat, and heating conditions have great influence on its structure and properties.

Thermogravimetric method has the advantages of high sensitivity, rapidity, reliability and convenient use, and has become an important means to characterize the characteristics of polymers. There is no report about drying CNR by thermogravimetric analysis. In this paper, the drying characteristics of chlorinated natural rubber by latex method were studied by thermogravimetry. The infrared spectrum, solubility, viscosity and chlorine content of dry matter were determined.

Effect of ACIA 00 13-0 1 Coagulant on Properties of Natural Rubber

Natural rubber is an important industrial raw material. 199 The world's NR output exceeded 6 million tons, of which China's NR output exceeded 460,000 tons, ranking fifth in the world. Natural rubber is a kind of natural biosynthetic polymer with complex components. Except for 25% rubber hydrocarbon and 5% non-rubber component, the rest is mainly water. Natural latex must be cured and dried to make standard natural rubber. Therefore, the curing of natural latex is also one of the important links that affect the quality of NR. For a long time, natural rubber plantations or farms at home and abroad mainly use acetic acid as coagulant of natural latex. In recent years, some manufacturers, from an economic point of view, have adopted lower-priced formic acid instead of acetic acid as the coagulant of natural latex. Due to the strong acidity of formic acid, the curing speed of natural latex is fast and the curing process is difficult to control. Up to now, there are few reports about the influence of formic acid coagulants on NR properties. This paper reports the effects of formic acid and acetic acid as natural latex coagulants on the properties of natural rubber.

Study on Modification and Functionalization of ACia00 14 Natural Rubber

The epoxidized modification, powder modification, resin fiber modification, chlorination, hydrogenation (chlorination), cyclization and grafting modification of natural rubber and the mixed modification of * * with other substances were introduced. At the same time, thermoplastic natural rubber and liquid rubber were introduced, and the above modification was functionalized.

Quality control of ACia00 16 natural rubber factory

Natural rubber is one of the most commonly used rubber types and is used in many products. The current grading standard is far from reflecting its physical and mechanical properties, and the performance appraisal of purchased rubber is an important part to ensure the design performance of rubber compound in the follow-up work. This article has carried on the preliminary discussion to this.

Effect of ACia00 17 nano-ZnO on crosslinking reaction and thermal stability of natural rubber

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