2-ethylhexyl moiety

Plasticizers. Plasticizers are materials that soften and flexibilize inherently rigid, and even britde polymers. Organic esters are widely used as plasticizers in polymers (97,98). These esters include the benzoats, phthalates, terephthalates, and trimeUitates, and aUphatic dibasic acid esters. Eor example, triethylene glycol bis(2-ethylbutyrate) [95-08-9] is a plasticizer for poly(vinyl butyral) [63148-65-2] which is used in laminated safety glass (see Vinyl POLYMERS, poly(vinyl acetals)). Di(2-ethyUiexyl)phthalate [117-81-7] (DOP) is a preeminent plasticizer. Variation of acid and/or alcohol component(s) modifies the efficacy of the resultant ester as a plasticizer. In phthalate plasticizers, molecular sizes of the alcohol moiety can be varied from methyl to tridecyl to control permanence, compatibiUty, and efficiency branched (eg, 2-ethylhexyl, isodecyl) for rapid absorption and fusion linear (C6—Cll) for low temperature flexibiUty and low volatility and aromatic (benzyl) for solvating. Terephthalates are recognized for their migration resistance, and trimeUitates for their low volatility in plasticizer appHcations. 

Polymeric plasticisers have been used as partial or total replacements for di(2-ethylhexyl)adipate (DEHA) in PVC cling film to reduce levels of plasticiser migration when used for food contact. Castle et al. [792] used SEC in combination with H 1-NMR and MS for the isolation and identification of seven individual oligomers in the most commonly employed polymeric plasticiser, poly(butylene adipate) (Reoplex R346). Both mass (RI) and specific ester moiety (UV) were being monitored (Figure 4.21). The oligomers were identified... 

Jen et al. have investigated a copolymer PAE comprising electron-accepting 9,9-bis(2-ethylhexyl)-2,7-diethynyl fluorene and hole-transporting thiophene moieties in an alternating fashion (Table 3, entry 12) [119]. The design was based on the assumption that the combination of fiuorenyl and thiophene moieties would lead to a balanced transport of electrons and holes. The sterically hindered substituents were introduced with the hope that they would prevent intermolecular interactions and, thus, keep the PL quantum efficiency high. 

Further on, a wide variety of esters were detected containing specific molecular moieties characterizing man made chemicals. E.g. the 2-ethylhexyl group represents a molecular substructure frequently used in the technosphere dominantly as the corresponding alcohol or acid, but the natural occurrence of this molecular moiety is very scarce. Thus, the detected 2-hydroxypropylester of 2-ethylhexanoic acid represents a specific anthropogenic contaminant. The fro-propyl and butyl esters identified also reflect mainly the emission of technical contaminants chiefly derived from migration processes of polymer additives. 

Nakache et al. attempted the polymerization of isodecyl acrylate (ISODAC) in anionic sodium di-2-ethylhexyl phosphate (SEHP) vesicles [9]. QLS and freeze fracture TEM were used to characterize the morphologies and no polymer phase separation was reported. Entrapment of hydrophobic moieties was possible in the polymerized vesicles, but hydrophiHc moieties could not be entrapped. Polymerized vesicles were apparently more temperature stable than unpolymerized structures and the addition of electrolytes induced polymer precipitation. 

Andersson and coworkers have prepared solar cells based on blends of poly(2,7-(9-(2 -ethylhexyl)-9-hexyl-fluorene)-fl/t-5,5-(4, 7 -di-2-thienyl-2, l, 3 -benzothiadiazole) (223) and PCBM [416]. The polymer shows a Amax (545 nm) with a broad optical absorption in the visible spectrum and an efficiency of 2.2% has been measured under simulated solar light. The same group has also reported the synthesis of low bandgap polymers 200 (1 = 1.25 eV) and 224 (1 = 1.46 eV) which have been blended with a soluble pyrazolino[70]fiillerene and PCBM, respectively, to form bulk heterojunction solar cells of PCE of 0.7% [417] and 0.9% [418]. Incorporation of an electron-delident silole moiety in a polyfluorene chain affords an alternating conjugated copolymer (225) with an optical bandgap of 2.08 eV. A solar cell based on a mixture 1 4 of 225 and PCBM exhibits 2.01% of PCE [419]. 

For a comparative study, fluorene was selected as another rigid it-center, which was derived as two homologs with a different substitution at C9-position one is with di-2-ethylhexyl- and the other with spiro-fluorenyl moieties. While the former (JI2) bears electron-rich flexible dialkyl substituents the latter (713) features an added rigidity to the fluorene 7t-center, which preserves the rigidity and planarity for the chromophores. Regardless of the difference in the 71-centers (either 712 or 713), as long as the D or A is the same, electrochemical properties of the D/D or A/A pair chromophores (201 and 301, or 203 and 303) are almost identical (30). In other words, there is no measurable difference in the redox property modulations by 712 and 713. 

Methyl methacrylate-2-ethylhexyl acrylate-MA terpolymers, in the compositional range 40-50 42-52 8, have been prepared in naptha at 130-140 C to obtain coating resins/ Postreaction of the materials with trimethylol-propane, which introduced both hydroxyl and carboxyl sites on the terpolymer backbone, provided reactive moieties for amino-resin crosslinkers. Unsaturated monohydroxy dialkyl maleates and fumarates, such as 2-hydroxyethyl isobutyl fumarate, have also been copolymerized with various acrylate-methacrylate combinations to obtain low-viscosity, heat-hardening, filmforming copolymers.These copolymers may also be crosslinked with amino resins to provide valuable protective coating. 

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