Plateau modulus Temperature dependence

Elastic modulus temperature dependences obtained for all specimens thus studied (see Fig. 3.31) have the typical appearance of polymer composites based on linear binders. A sharp fall of elastic modulus for all composites studied above the glass-transition temperature and the absence of a viscoelasticity plateau indicate that the composite polymer binder is not a network polymer. 

Investigation of the linear viscoelastic properties of SDIBS with branch MWs exceeding the critical entanglement MW of PIB (about -7000 g/mol ) revealed that both the viscosity and the length of the entanglement plateau scaled with B rather than with the length of the branches, a distinctively different behavior than that of star-branched PIBs. However, the magnitude of the plateau modulus and the temperature dependence of the terminal zone shift factors were found to... 

Effects of Phase Segregation on Modulus. The magnitude of the modulus between as and h for 2,4-T-2P or 8 for 2,6-TDI block polyurethanes was found to highly depend upon hard-segment content. The presence of a plateau region in modulus-temperature plots has been attributed to phase segregation in block copolymers (27). The hard... 

According to a report presented by Fu et al. [180], the influence of POSS-triol on epoxy-amine reaction depends mostly on the magnitude of AT (Tg -Tc) used. Since Tg for epoxy cured with linear aliphatic diamine—2-methyl-1,5-pentadiamine (MPDA)—was higher than the Tg of the same epoxy cured with diamine-terminated polypropylene oxide (PPO), when cured at the same temperature, epoxy-cured MPDA showed a greater improvement in the value of Tg. Moreover, the addition of POSS-triol in tetraglycidyl diamino diphenyl methane (TGDDM) cured with MPDA also increased the rubbery plateau modulus (Fig. 6). 

The behavior of a thermoplastic material above its glass transition temperature depends on its level of crystallinity. As a noncrystalline (amorphous) polymer is slowly heated from a temperature below its Tg, it displays a large decrease in modulus as the glass transition temperature is reached. As one heats a semicrystalline plastic from a temperature below its Tg, it displays a relatively small modulus change at the glass transition temperature, followed by a plateau and then a decreasing modulus as the temperature increases and approaches the crystalline melting point. 

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