Plasticizer crosslinking

When plasticized polymers are in contact with the mother polymers, plasticizers are likely to migrate to mother polymers and the extent of their migration depends on a number of factors such as polymer-plasticizer system, polarity of polymer and plasticizer, crosslink density of polymer, molecular weight of plasticizer etc. 

There is a considerable literature on the effect of chemical composition on Tg. A number of factors have been shown to influence Tg, including backbone flexibility, steric effects, polarity, pendant groups, crystallinity, plasticizers, crosslink density, and co-polymerization (13,5). After a brief qualitative discussion of the first few factors, we will consider the last two in more detail. 

As can be imagined the radiation produced crosslinks and chain scissions act in opposite directions with respect to changing the physical properties of plastics. Crosslinks transform molten polyethylene from a liquid into an elastomer. The elastomeric properties thus produced make possible the so-called "memory effect" in which the irradiated PE, for example, when stretched at temperatures above its melting point and then cooled... 

Heat-cured denture base materials were introduced into dental use in 1937. These materials are prepared from a powder-liquid slurry. The liquid is methyl methacrylate to which are added a plasticizer, crosslinking agent and inhibitor. The powder is poly(methyl methacrylate) containing approximately one percent initiator, usually benzoyl peroxide. By subjecting this slurry to elevated temperature (about 75°C to 100°C) for one or more hours depending on the temperature employed, sufficient free radicals are produced from the initiator to yield a satisfactory denture. Other initiators have been proposed. 

Desmodur . [Bayer Miles] Polyurethane and isocyanates a esive for bonding textiles, leather, wood, metal, plastics crosslinking agent for adhesives. 

Uses Intermediate for paints mfg. of syn. fibers (esp. nylon 6), plastics, bristles, film, coatings syn. leather plasticizers crosslinking agent for polyurethanes synthesis of amino acid lysine isocyanate blocking agent polyamide 6 casting material... 

Uses Antimicrobial in cosmetics intermediate for epoxies, urethane resins, and antistatic lubricants for the textiles and plastics crosslinking agent for high-temp, resist, polyester or imide-amide wire enamels, acrylic, PU spec, coatings lubricant film-former Trade Names Dantocol DHE... 

Uses Monomer for adhesives, inks, photopolymers, coatings, sealants, elastomers, electronics, photopolymers, plastics crosslinking agent Trade Names SR 252... 

In elastomeric materials, the crosslink density is about 2 x 10 crosslinks/cm, or about one crosslink per 110 mers, while in the thermoset plastics, crosslink densities are 10-50 times higher. Whatever the type of polymer concerned, crosslinking serves to reduce or prevent creep and flow. As we shall see in Section 1.5.4, the modulus of elastomeric materials is directly proportional to the crosslink density. 

Uses Antimicrobial in cosmetics intermediate for epoxies, urethane resins, and antistatic lubricants for the textiles and plastics crosslinking agent for high-temp, resist, polyester or imide-amide wire enamels, acrylic, PU spec, coatings lubricant film-former DEDM hydantoin dilaurate Synonyms Diethylol dimethyl hydantoin dilaurate Di-(2-hydroxyethyl) dimethylhydantoin dilaurate Di-(2-hydroxyethyl)-5,5-dimethyl hydantoin dilaurate 2,4-lmidazolidinedione, 1,3-bis (2-decanoyloxyethyl)-5,5-dimethyl-Definition Diester of DEDM hydantoin Empirical C29H60N2O6 Properties M.w. 532.80... 

Equilibrium swelling is useful measurement to make when attempting to plasticize crosslinked elastomers. It is related to X t>y Eq. [6.4]. The concentration of plasticizer in the product (paint, varnish, solution) should always be less than its concentration at equilibrium swelling. Solubility parameters of polymers and plasticizers may also be consulted to determine compatibility. The difference between the solubility parameters of compatible polymer and plasticizer should be less than approximately 2 (MJ/m ) . ... 

The process for the batoh preparation of TPVs is very similar to the one described above. The process layout for a crosslinked rubber/plastic blend preparation is the same as that for non-crosslinked blends (Figure 3.6). The prcxress steps involved in a plastic-crosslinked rubber blend prcxluction by a batch process are ... 

In crosslinking semi-crystalline plastics, crosslinking takes place mainly in the amorphous, interiameiiar phase, while in the crystalline phase (the lamellae) recombination (heaiing) takes place up to higher doses. Crystallinity will undergo destruction oniy at higher doses. 

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