Poly , oligomer with styrene

From the T S/h) vs T h/r) plot for the curing reaction of hydroxyl-terminated poly(tetrahy-drofuran) lelechelic oligomer with styrene illustrated in Figure 3.18 at a heating rate of... 

Copolymers with styrene and alkyl methacrylates were synthesized also. The coupling method was initially developed by Asami et al. (200. 210) who succeeded in preparing polymerizable oligomers from living poly(THF) by coupling with vinyl phenolate (CH2=CH-C H -0 ) or with vinylbenzyl alcoholate (CH2=CH-C H -CH20 ). The horaopolymerization and copolymerization of these Macroraers were studied (209). 

SEC with poly(styrene) calibration shows that the apparent molecular weight of the reaction products is in the range of 600-2500 Da, indicating that the oxidation yields oligomers with low degree of polymerization (DP=2-7). It should be noted that these reaction products are isolated after centrifugation and simple filtration, which implies that, after the biotransformation at the active center inside the complex, the derivatives formed are expelled in the aqueous phase. This may be due to their increased polarity or to their increased size or both. 

The slow crystallization of the PEO/LiX complex results in a decrease in ionic conductivity with storage time. To maintain the long-term stability of ionic conductivity, the mixture of PEO and a large poly(oxyethylene-vinyl styrene) oligomer and nitrile rubber is directly cross-linked by thermal polymerization, resulting in greatly improved stability of the ionic conductivity. 

The aim of the current work is to investigate the relationship between Tg, the length scale of the dynamic heterogeneity, the fragility, and the activation energy of pure poly(a-methyl styrene) and blends of poly(a-methyl styrene) with its oligomers. Our previous work [17] has shown that the mixture is an athermal blend. 

Figure 6.9 Separation of a poly(styrene) oligomer mixture of 2000 average molecular weight by open tubular column SFC using a linear density program (A) and an asymptotic density progreua in (B) with carbon dioxide as the mobile phase. (Reproduced with permission from ref. 115. Copyright Preston Publication, Inc.)...

Fig. 12. Separation of styrene oligomers by reversed-phase (left) and size-exclusion chromatography (right) (Reprinted with permission from [121]. Copyright 1996 American Chemical Society). Conditions (left) column, molded poly(styrene-co-divinylbenzene) monolith, 50 mm x 8 mm i.d., mobile phase, linear gradient from 60 to 30% water in tetrahydrofuran within 20 min, flow rate 1 ml/min, injection volume 20 pi UV detection, 254 nm (right) series of four 300 mm x 7.5 mm i.d. PL Gel columns (100 A, 500 A, 105 A, and Mixed C), mobile phase tetrahydrofuran, flow rate, 1 ml/min injection volume 100 pi, toluene added as a flow marker, UV detection, 254 nm temperature 25 °C,peak numbers correspond to the number of styrene units in the oligomers...

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