Latex swelling properties

Because of its excellent high- and low-temperature properties, many products used in the arctic and tropical areas of the world are made from natural rubber. However, it is not suitable for applications where there is contact with naphtha, e.g, gasoline hoses, because the solvent swells the material. Almost all clastic bands arc made from natural rubber. Because of its excellent tack properties, the material is used in solvent and latex form as the base for adhesives. 

Other Classification Criteria. Other levels of classification should be superimposed on the above. These include latex, suspension, and bulk type syntheses, all of which result in different properties of the final materials. Uses of plastic-forming and elastomer-forming monomers and crystalline and amorphous structures must be distinguished. The tacticity of the polymers is sometimes important. Of course, the ratio of both polymer masses dictates the overall morphology. Physical operations such as swelling, annealing, and orienting must be considered in any complete treatment. 

In the industrial production of structured AN-Bu-St (ABS) latex particles, the grafting copolymerization of AN and St on crossUnked polybutadiene (PB) seed latex is carried out in emulsion polymerization. Therefore, information on the effect of PB crosslinking density on the swelling of PB latex particles by a St-AN monomer mixture is very important for the production of ABS copolymers with desired properties. Mathew et al. [177] studied the effect of several thermodynamic parameters, such as the crosslinking density, particle size and monomer mixture composition on the swelling behavior of PB latex particles by pure St and AN, and St-AN mixtures of various compositions. They reported... 

Other modified mbbers are tire mbber, peptized mbber, powdered mbber, skim mbber, and superior performing mbber (SP) (made by blending normal latex and prevulcanized latex before coagulation and drying by conventirmal methods). SP mbbers confer superior extrasion properties such as better surface smoothness and lower die swell when blended with natural and synthetic mbbers. 

Effect of the Substrate Latex Characteristics. Many authors (4, II, 12, 13) have noted the great influence of the latex substrate on the structure and properties of ABS. Among the characteristics of the backbone latex, three have been reported as being very important. These are the degree of cross-linking of the polymer substrate (gel content, swelling index), the average... 

The method of preparing superparamagnetic particles developed by Charmot [109] uses hydrophobic non-porous polystyrene seed particles of narrow size distribution. A seeded polymerization is carried out to increase the particle size (1.35 pm) and a terpolymer is formed around the seed particles by a dispersion polymerization of styrene, DVB and 4-vinylpyridine in toluene. The toluene containing cobalt precursor swells the latex particles, which results in a homogeneous distribution of the metal precursor. A thermolysis reaction is conducted in the presence of 4-vinylpyridine, and the release of carbon monoxide indicates the decomposition of the metal salt into cobalt. The main problem of this method is the particle surface deformation during the evolution of carbon monoxide. The amount of crosslinker, however, cannot be reduced below a certain level without significantly modifying the properties of the particles. 

Amongst the above mentioned compatibilization methods, the obtaining of IPNs and SIPNs often proved to be a promising and very efficient route. An IPN is a polymer alloy comprised of two or more chemically crosslinked polymers. The difference between polymer blends and IPNs is that the latter ones swell instead of dissolving in solvents and do not creep or flow. Types of IPNs include sequential, simultaneous, latex and gradient IPNs and may also be thermoplastic (i.e. when physical crosslinks are imphed). Thermoplastic IPNs behave as thermosets at ambient temperature, but usually flow when heated at certain temperatures, possess IPN properties and often exhibit dual phase behavior [1]. 

The group of Gu Z. in the 2009, reported the behavior of styrene butadiene/ rubber/organo-bentonite nanocomposite prepared from latex dispersion, content was lower than 12 mass%. The results showed were that presence of organo-bentonite in the nanocoposite affects direct in the thermo stability, mechanical properties and swelling behavior, which was attribute to the good barrier properties of the dispersed nanoparticles. The dispersion is an important factor that can affect various properties such as thermal stability [81]. 

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