Rubber and plastic and use technology

Today rubber materials have become indispensable to people's lives, an important class of materials. However, with the continuous development of modern science and technology, the performance of the rubber material made increasingly extensive and demanding. To rubber and plastic and elastomer used in the growing attention, this article focuses mainly of rubber and plastic parts for blending with the formation of the elastomer to be introduced.http://www.prmindustry.com/ Abstract...Articles section Compatibility with the principle of rubber and
About the performance of rubber and materials used must be mentioned that the polymer blend. Rubber and plastic blend is conditional, not any of any of the rubber and plastics can be blended, rubber and plastic blends performance depends on the morphology of blends, and morphology by rubber and plastic components of the thermodynamic compatibility between, and the implementation of the method and process blend conditions, and other effects.
In discussing the morphology of blends of various types of literature, often a "compatibility", "miscibility" of a different formulation, generally "compatibility" means the mutual dissolution of thermodynamics, the "miscibility" characterization whether to obtain more uniform and stable morphology of the blends, regardless of whether the thermodynamics of blends of mutual dissolution. Therefore, even if the thermodynamic incompatibility of the blends, forced to rely on external conditions to achieve a good dispersion mixing, get the mechanical properties of rubber blends good, it can be called good miscibility.
Because rubber can follow the good miscibility of this principle, to achieve and use of rubber and plastic, will have a mutual complementarity between performance, thereby enhancing the elastic tensile strength, tear strength, abrasion resistance and modulus performance, but also can reduce the elongation at break and elasticity properties. For example, use in rubber and high styrene resin, modified phenolic resin, melamine resin, etc. can increase the strength; in diene rubber and PVC plastic can be used to improve resistance to ozone cracking; in the Butyl rubber and polyethylene can improve the insulation and so on.
Rubber blending methods
Implementation of the rubber powder blending methods blend, solution blending, latex blending and mechanical mixing. And comprehensive consideration to the conditions and costs, rubber plants use more mechanical mixing process.
Can be divided into a mechanical mixing method and the method Sec. A law is the first high-temperature thermoplastics in the mixer or melt plastics mixing machine, then cool, then add the rubber, turning, mixing well before showings. Sec Law, also known as masterbatch blend method, that is part of the first plastic and rubber in the mixer in the proportion of hybrid masterbatch, and then mixed with the rubber at lower temperatures. Sec method has the advantage of two-phase dispersed more evenly.
Mechanical mixing provides the driving force from the mechanical mixing and shearing. Mechanical mixing is the mechanical force of the system are under the process, are generally considered the process of the system of various components including the physical mixing and dispersion, but in fact, mechanical mixing process mechanical forces in addition to components of the mixture and distributed to provide energy, it will also trigger a chemical reaction between components of the force, the response of the rubber and plastic and have a major impact with the performance.
Rubber blending equipment including high mill, mixer, extruder and screw continuous mixer. Continuous mixer into mixing rotor screw extrusion modular and modular forms. Hot mill and mixer for the batch mixing equipment, screw extruder and continuous mixer for the continuous mixing equipment. Continuous mixer with a mixer and extruder screw the advantages of high efficiency, will become the main blending equipment.
Rubber blends and other considerations
Although the understanding and use of rubber and rubber blends miscibility principle of the method, but according to people over the years in practice in the field blends, rubber blends need to consider the following factors:
1 solubility parameter. Each polymer has its intermolecular forces reflect the solubility parameters δ, two kinds of polymer blends, the solubility parameter of choice as far as possible the difference Δδ is small, but greater than zero, because the smaller Δδ blend better , while a small difference to zero, then there is no two-phase, the meaning will be lost blend.
(2) polarity. Select the rubber and use, the traditional approach is a priority similar polarity, to avoid disparity in the two polar polymers, but with the compatibilization technologies, this consideration can be reduced.
3 viscosity. Viscosity average molecular weight of polymer characterization, the smaller the viscosity, the smaller the entropy of mixing, resulting in higher dispersion uniformity, micro-size smaller.
4 temperature. Temperature of the rubber blend is particularly important, because the plastic in the crystalline state at room temperature, and only when the temperature reaches a certain level in order to lift the crystal into the blend. As for the specific temperature value, depending on species may be. Such as the melting temperature of PVC is 150 ℃, only when the plastic melt blend well before entering the state, or very poor.
Compatibilization technology to fill the shortage
Most rubber and is incompatible with belonging to thermodynamics, although the viscosity, but they are still in the thermodynamically stable state, if the solubility parameters and structure of the very different mechanical mixing alone is difficult to make the system stable. Compatibilization technology just to fill this deficiency.
Compatibilization techniques are:
1 add a compatibilizer. Is added to improve the system compatibility with rubber and compatibilizer agent, whose role is to reduce the surface tension of the two-phase, so that the two polymer chains at the interface is started and get together. Is a polar rubber such as nitrile rubber, polypropylene, a non-polar plastics, mechanical mixing alone is difficult to make them uniform blend. If adding the compatibilizer to make blends can be achieved.
(2) local aggregation. Monomer or polymer as a primary component, add it to the other component, obtained by blending copolymer. For example, in NR by adding methyl methacrylate monomer, obtained by blending a high-strength copolymer - MG rubber.
3 Total cross-linking. Have accepted to join the two-phase cross-linking, fastness to blend with the interface of cross-linked by further improving the performance of a total mixed. A typical example is the DCP added NR / EVA blends, the total cross-linked by anti-compression to improve performance.
Application Stories
In recent years, the above theory successfully applied to the actual production of many examples, such as:
1 rubber and high styrene polymers and use of applications: rubber and high styrene polymer and after use, can give many valuable properties of vulcanized rubber, such as increased rubber hardness, stiffness, tensile strength, tear strength and resistance to grinding and so on. These and the most widely used components used to manufacture various rubber soles. This is due to join the high styrene resin, rubber soles, not only to improve their physical performance, but also gives many of its unique "leather-like" performance. In addition, the soles wear resistance also improved significantly.
(2) rubber and polyethylene, and with the application: the most widely used polyethylene and butyl rubber and is used for manufacturing tire inner tubes, carcass and sidewall. Especially the inner tube rubber, butyl rubber can be used in place of the polyethylene part of carbon black, vulcanized rubber to improve the flexibility, while maintaining the rest of the performance indicators.
3 rubber and PVC, and use the application: nitrile rubber and PVC blends are widely used in the manufacture of vulcanized rubber resistant to atmospheric effects. With the use of plastic and PVC content increases, resistance to ozone also increased. But also in the PVC content of 20% to 30%, the crack that is not happening. These materials are commonly used in various technical fields, such as the manufacture of cables and transmission oil, petroleum products, gaseous hydrocarbons as well as a variety of ozone tubes, but also produce petroleum products and chemicals in contact under the conditions of the seals and gaskets used.
Derivative theory and technology
Has been widely used in rubber and used in actual production, and also in the process has been largely improved, and the rubber and used by the generated branch out some of the theories and technology research in recent years has become a new hot spot.
1 dynamic vulcanization. The late seventies early eighties, the preparation of thermoplastic elastomers beyond the traditional pathway, another way to use rubber and polyolefin plastic to prepare by melt blending thermoplastic elastomer (TPE).
This method not only simple, low-cost, the proceeds of a new product known as polymer alloy. This thermoplastic elastomer with thermoplastic resin as the main component in the melt state by adding elastomer. Two-phase at high temperature / shearing after mixing, the rubber component as the dispersed phase continuous phase dispersed in the plastic and place curing. The resulting TPE both easy processing of thermoplastic resin, but also has the mechanical properties of rubber. The rubber can complete on their own existing equipment such dynamically vulcanized thermoplastic elastomer processing. In recent years, dynamic vulcanized blends have been achieved in foreign industrial production and commercialization of supply. Quite a few universities and research institutes are also actively engaged in research and development.
2 interpenetrating network (IPN). This is directed through two mutually cross-linked polymer network. Be the first one monomer and crosslinking agent, generating network 1, then the second monomer and crosslinker in which swelling and polymerization to generate the network 2, then the two networks to each other through the formation of interpenetrating polymer networks blends. Their micro size of the compatibility of the two networks are based on the degree to which. Interpenetrating network formed in the two-phase interface. Crosslink density is larger, the micro-size smaller. Two network capacity to be fully interoperable, get the ideal blend results in performance reflects the extraordinary double synergy, that is from the reinforcing effect of the rubber phase, while the plastic phase toughening.
With the manufacture of rubber and plastic and rubber products, rubber, industrial production is an important current development directions. Rubber blends, not only change a single material such shortcomings, but also significantly improve the physical and chemical properties of rubber products, and mechanical properties. With the development of science, one must increasingly developed new composite materials, through the different materials from each other, the composite material has excellent overall performance and reasonable use, in order to meet the needs of objective reality. I believe the 21st century will be the era of composite materials, rubber and with a greater development will certainly

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     Peter  Huang