Molecular Weight dynamic mechanical analysis,

To extend the basic property profile of the bulk polymer and help better understand the high temperature mesomorphic state, high molecular weight PDPhS and its low molecular weight oligomers have been examined by X-ray diffraction analysis, DSC, dynamic mechanical analysis and high temperature optical microscopy. The results of this examination and interpretation of the results are presented. 

IPP-EPM blends were generally considered to be immiscible (92-95). Chen et al. (96) have reported miscibility and a LCST in blends of isotactic polypropylene and an ethylene-propylene terpolymer (EPDM). Seki et al. (97) reported that iPP was miscible with EPM with both 19 and 47 mol% of ethylene based on both transmission electron microscopy (TEM) and SANS. However, the molecular weight of the iPP was below 10, OOOgmoP. More recently both Nitta et al. (98) and Kamdar et al. (99) reported that the miscibility between iPP and EPM, whose molecular weight is higher than 100,000 g moP, is strongly dependent on ethylene content in EPM. The miscibility increases with decrease of ethylene content. IPP was miscible with EPM with ethylene content lower than around 17 mol% based on both dynamic mechanical analysis (DMA) and TEM. The EPM domain sizes decrease with decrease of ethylene content as shown in Fig. 2.3. 

Silicone pressure sensitive adhesives appear to be heterogeneous blends of MQ resin and a gum. A gum phase containing little if any dissolved resin is observed in the PDMS adhesive. A resin phase probably containing low molecular weight PDMS is detected by dynamic mechanical analysis. The PDMDPS adhesives are similar, except that the... 

Several of the preceding experiments point out the complexity of the PCL/SAN system where detailed results depend on several parameters including, in addition to the molecular weights of the constituent polymers, the composition of the SAN copolymer. Suggestions of fiuther complexities are hinted at in small changes in the differences between T s obtained by DSC and dynamic mechanical analysis with composition of the blends. 

Using a 1 1 molar mixture of both monomers and chemical oxidation with FeCls in air, Pomerantz et al. [49] prepared a high molecular-weight M = 1.38 X 10 ) copolymer, but they made no attempt to characterize it further. X-ray diffraction studies conducted by Chen and Ni [74] suggested an ordered layered structure similar to that of the 3-BT/3-DDT copolymer described above. Other workers [75] also prepared this copolymer and studied conformational defects using GPC, Dynamic Mechanical Analysis (DMA), UV-vis spectroscopy, and X-ray diffraction. 

Solid-state properties of the catenane copolymer were determined using DSC and dynamic mechanical analysis (DMA) and were compared with pure PC. DSC revealed a glass transition temperature of ca. 150°C for all the catenane copolymers 22 to 24, which is essentially the same as the pure PC sample of the same molecular weight. This insensitivity of the Jg to the presence of the catenane repeat unit is possibly on account of the considerable flexibility/mobiUty of these catenanes. DMA of the copolymer containing 20% (w/w) catenane showed three transitions at —100, —6, and - -80°C. The first and third transitions are observed in PC films while the —6°C was linked to the catenane ring/chain movements. 

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