Poly a methylstyrene PaMS

Similar craze breakdown morphologies have been observed for dust-free films of polymethylmethacrylate (PMMA), poly(a-methylstyrene) (PaMS) and poly(styrene-acrylonitrile) (PSAN) Large pear-shaped voids nucleate at the craze-bulk polymer interface, never in the craze mid-rib, and thus this mode of craze breakdown seems to be a dominant one for all glassy polymers. 

Similar behavior has been found for dust-free films of poly(methylmethacrylate) (PMMA) and poly(a-methylstyrene) (PaMS) as shown in Figs. 35b and 35c and we expect similar results for any glassy polymer that deforms predominantly by crazing at low temperatures (i.e., one in which scission-dominated crazing occurs in preference to shear deformation). 

A qrdization procedure similar to that described above for PS was used with a-methylstyrene. It involves the synthesis of a linear a,o>-difunctional poly(a-methylstyrene) (PaMS) by lithium naphthalide-initiated polymerization of aMS, followed by end-to-end coupling with l,4-bis(bromomethyl)benzene (DBX) under high dilution. The cydization step is carried out by simultaneous addition of THF solutions of the PaMS dianions and DBX at -100 °C. A sample of the matching linear... 

In a second method, the non-radiative energy transfer method (NRET), the energy is transferred from a donor to a receptor chromophore, when the distance between them is of the order of 2-5 nm. Phase separation is concluded from a decrease of the chromophore energy transfer. The method has been used to study PVC miscibility with PMMA or with SAN PS or poly-a-methylstyrene (PaMS) with PS-aMS copolymer PS or PaMS or PBS [poly(tert-butyl styrene)] or PS + PBS with PS-BS copolymer etc. (Morawetz 1980, 1981, 1983 Albert et al. 1986). 

Recently, Hadjichristidis, Hirao, and coworkers synthesized complex macromolecular chimeras (a Greek term), which include novel multicomponent linear and miktoarm star polymers containing polypeptide blocks based on a high-vacuum technique (Karatzas et al., 2008). Indeed, 3-arm AB2,3-arm ABC, 4-arm A2B2, and 4-arm AB2C were synthesized, where A, B, and C were polypeptides, PS, and PI or poly(a-methylstyrene) (PaMS), respectively (Figure 13.3). 

In this section, we present the effect of block composition (block length ratio) on the linear dynamic viscoelasticity of disordered PS- /ocfc-poly(a-methylstyrene) (PaMS) copolymers and also SI diblock copolymers in the disordered state. Table 8.3 gives a summary of the molecular characteristics for seven PS- tocA -PaMS copolymers, and Figure 8.38 gives thermograms of differential scanning calorimetry (DSC) for the seven... 

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