Elastomers features

R.T. Tran, P. Thevenot, D. Gyawali, J.-C. Chiao, L.P. Tang, J. Yang, Synthesis and characterization of a biodegradable elastomer featuring a dual crosslinking mechanism. Soft Matter 6 (2010) 2449-2461. 

Uses Cover coat bonding agent tor EPDM, nonpolar elastomer Features General purpose bonds a wide variety of rubbers to metals and other substrates... 

Uses Blowing agent in printing inks, PU, PVC plastisols, fabrics, paper expanded microspheres as ultra-low density tillers tor use in engineered prods, in which other fillers would not be suitable, e.g., syn. marble and wood, coatings, sealants, explosives, auto, marine fillers, molding compds., composites, paint and crack fillers, cable fillings, elastomers Features Unexpanded microspheres Expancel 551 DE 20 [Expancel]... 

Uses Polyol for urethane applies, ind. tow- and high-dens, foams, coatings, adhesives, sealants, encapsulants, elastomers Features Not for use to make prepolymers or quasi-prepolymers Properties Pt-Co 300 clear liq. sp.gr. 1.09 vise. 270-3 cps acid no. 

Uses PU intermediate producing high< ualily flexible polyester slab foams for use in textile laminates, pkg., filter media, and in noncellular applies, such as coalings, adhesives, and elastomers Features Sal., crosslinked primary hydroxyl polyester rec. where good flexibility and solv. resist, are required Properties Pale liq. m.w. 2600 dens. 9.3 Ib/gal vise. 18,000 cps acid no. 1-2 hyd. no. 50 Lexorez 1101-60A [Inolex]... 

Uses PU intermediate for prod, of flexible PU foams, cast PU, noncellular applies., e.g., coalings, adhesives, and elastomers Features Rec. for foam applies, where high str., solv. resist., and elastic memory are required, cast PU with superior resist, to HC-based lubricants, fuels, and soivs., and noncellular applies, where good flexibility and solv. resist, are required... 

Uses PU intermediate for adhesives, coatings, and cast elastomers Features Mixed aliphatic/aromatic polyester polyol with all primary hydroxyl functionality the aromatic acid lends hardness and heat resist. Properties Gardner 4 solid m.w. 3200 dens. 10.2 Ib/gal vise. 8500 cps (60 C) acid no. 1.0 hyd. no. 35 Lexorez 3130-120 [Inolex]... 

Chem. Descrip. Calcium carbonate coated by org. media CAS 471-34-1 EINECS/ELINCS 207-439-9 Uses Eiller in plastics (rigid PVC, cables, calendered sheets, moldings, polyolefins, wh. masterbatches), paints (gloss enamels), elastomers Features Completely compat. with organic media easily dispersed Properties Wh. rhombohedral ctyst. fineness 57% < 2 p dens. 2.7 g/ cm bulk dens. 1.1 g/cm (packed) oil absorp. 15/100 g powd. brightness 97.5% ref. index 1.59 pH 9 hardness (Mohs) 3 Microblanc TMB [Microfill K. Zafranas]... 

Chem. Descrip. Sat., aliphatic, linear, hydroxyl-terminated polyester polyol Uses Polyester for flexible foams, sol n. coatings and adhesives, one-shot castables, castable prepolymers, and thermoplastic elastomers Features PUs exhibit solv. resistance, low temp, properties, low modulus elastomers, and resiliency Properties Liq. at R.T. 

Chem. Descrip. Ethylenebistetrabromophthalimide CAS 32588-76-4 EINECS/ELINCS 251-118-6 Uses Flame retardant for elec, parts, switches, connectors, computer housings, film, wire/cable, paints, hot melts, underhood automotive, and composites for PBT, FIIPS, ABS, PE, PP, epoxy, and elastomers Features Exc. UV and thermal stability, elec, props. 

Chem. Descrip. PTFE fluoroadditive CAS 9002-84-0 EINECS/ELINCS 204-126-9 Uses Improves perfomiance of printing inks and other coatings lubricant for themioplastics, thermosets, elastomers Features Nonagglomerated... 

Synthesis and characterization of a biodegradable elastomer featuring a dual crosslinking mechanism. Soft Matter, 6 (11), 2449 -2461. 

Dewald, A.H. Poe, B.L. Landers, J.P. Electrophoretic microfluidic devices for mutation detection in clinical diagnostics. Exp. Opin. Mol. Diag. 2008,2 (8), 963-977. Leslie, D.J. Easley C.J. Seker, E. Karlinsey, J. Utz, M. Begley, M.R. Landers, J.P. Frequency-specific flow control in microfluidic circuits with passive elastomer features. Nature Phys. 2009, 5 (3), 231-235. 

Uses Finishing agent, softener, lubricant for improving texture and hand of textiles, leather, and paper, and for elastomers Features Highly stable to chemicals and oxidation... 

Thermal Oxidative Stability. ABS undergoes autoxidation and the kinetic features of the oxygen consumption reaction are consistent with an autocatalytic free-radical chain mechanism. Comparisons of the rate of oxidation of ABS with that of polybutadiene and styrene—acrylonitrile copolymer indicate that the polybutadiene component is significantly more sensitive to oxidation than the thermoplastic component (31—33). Oxidation of polybutadiene under these conditions results in embrittlement of the mbber because of cross-linking such embrittlement of the elastomer in ABS results in the loss of impact resistance. Studies have also indicated that oxidation causes detachment of the grafted styrene—acrylonitrile copolymer from the elastomer which contributes to impact deterioration (34). 

Diarylamiaes fuactioa as mbber antioxidants by breaking the peroxidative chain reactions leading to mbber deterioration. Nearly all commercial synthetic mbbers (see Elastomers, synthetic), including neoprene, butyl, styrene—butadiene, and the acrylonitrile—butadiene mbbers, can be protected with about 1—2% of an alkylated diphenylamine. DPA itself is not used as a mbber antioxidant. An objectionable feature of these antioxidants is that they cause discoloration and staining which limits their use to applications where this is not important. 

The addition polymerization of diisocyanates with macroglycols to produce urethane polymers was pioneered in 1937 (1). The rapid formation of high molecular weight urethane polymers from Hquid monomers, which occurs even at ambient temperature, is a unique feature of the polyaddition process, yielding products that range from cross-linked networks to linear fibers and elastomers. The enormous versatility of the polyaddition process allowed the manufacture of a myriad of products for a wide variety of appHcations. 

Aging Properties. The main features of ethylene—acryhc elastomers are heat (177°C) and oil resistance. At elevated temperatures, ethylene—acryhc elastomers age by an oxidative cross-linking mechanism, resulting in eventual embrittlement, rather than reversion. A general heat... 

In the hard polymer/elastomer combinations, the elastomer is often chosen to be a polar mbber or it is cross-linked in some cases it is both. Either of these features improves the resistance to oils and solvents (44). 

Elastomers are a special sort of cross-linked polymer. First, they are really linear polymers with just a few cross-links - one every hundred or more monomer units - so that a molecule with a DP of 500 might have fewer than five cross-link points along its length. And second, the polymer has a glass temperature which is well below room temperature, so that (at room temperature) the secondary bonds have melted. Why these two features give an elastomer is explained later (Chapter 23). 

Blends or alloys of polyacetals with polyurethane elastomers were first introduced by Hoechst in 1982, who were then followed by other manufacturers. The key features of these materials are their improved toughness with little change in other important properties. There are two aspects with respect to the impact toughness ... 

A very special type of ABA block copolymer where A is a thermoplastic (e.g., styrene) and B an elastomer (e.g., butadiene) can have properties at ambient temperatures, such as a crosslinked rubber. Domain formations (which serves as a physical crosslinking and reinforcement sites) impart valuable features to block copolymers. They are thermoplastic, can be eaisly molded, and are soluble in common solvents. A domain structure can be shown as in Fig. 2. 

---