Polyisobutylene, dynamic mechanical

Landel, R. F. The dynamic mechanical properties of a model filled system Polyisobutylene-Glass Beads. Trans. Soc. Rheology 2, 53—75 (1958). 

FIG. 13.24 Frequency-temperature correlation map for dynamic mechanical, dielectric and NMR measurements on Polyisobutylene. The a and P relaxation regions are shown. Measurements ( ) NMR (O) Dielectric ( ) Mechanical. The full lines are the WLF equation (curved) and the Eyring Equation (straight). From Schlichter (1966). Courtesy John Wiley Sons, Inc. 

FIGURE 6.9 Loss tangent of polyisobutylene measured by dynamic mechanical spectroscopy and calculated from the recoverable creep compliance. These are not master curves the abscissa is the actual frequency (Plazek et al., 1995). 

Details are given of the preparation of blends of bitumen with BR, butyl rubber, polyisobutylene, chlorinated PF, polychloroprene latex, and a PU elastomer. Characterisation was undertaken using fluorescence optical microscopy, DSC, and dynamic mechanical thermal analysis. 18 refs. 

Figure 7.2 Approximate distribution functions of relaxation (Mj) and retardation (Lt) times for polyisobutylene. (Reproduced from Marvin, R.S. (1954) The dynamic mechanical properties of polyisobutylene, in Proceedings of the Second International Congress of Rheology (ed. V.C.W. Harrison), Butterworths, London, pp. 156-164. Copyright (1954) Elsevier Ltd.)...

Marossy K, Deak G, Keki S and Zsuga M (1999) Thermally stimulated discharge current and dynamic mechanical investigation of polyisobutylene-polybutylene terephthalate thermoplastic multiblock copolymers, Macromolecvles 32 814-818. 

Hg. 17. Schematic relaxation map based on the concept of Lobanov and Frenkel and actual data on polyisobutylene. Tp and Tg tend to intersect at 1000/7, /= 10, and follow Tp at higher frequencies. 7 corresponds to the quasisiatic temperature of 7/( from - 7 data. Dynamic mechanical loss data on PIB follow the dashed line at left labeled 7. The quasistatic value of 7 is also from Cp-T data. 7 j(static)/7 (static) = 1,2. 

Ferry and co-workers observed that polyisobutylene exhibits double loss peaks in dynamic mechanical studies as a function of temperature and as a function of reduced frequency - "fast" Tg and "slow" T>Tg loss peaks. Similar mechanical loss peaks were reported for cis-trans- iny polybutadiene, both as a function of temperature " and frequency by Sidorovitch and co-workers. 

Molecular dynamics (MD) is an invaluable tool to study structural and dynamical details of polymer processes at the atomic or molecular level and to link these observations to experimentally accessible macroscopic properties of polymeric materials. For example, in their pioneering studies of MD simulations of polymers, Rigby and Roe in 1987 introduced detailed atomistic modeling of polymers and developed a fundamental understanding of the relationship between macroscopic mechanical properties and molecular dynamic events [183-186]. Over the past 15 years, molecular dynamics have been applied to a number of different polymers to study behavior and mechanical properties [187-193], polymer crystallization [194-196], diffusion of a small-molecule penetrant in an amorphous polymer [197-199], viscoelastic properties [200], blend [201,202] and polymer surface analysis[203-210]. In this article, we discuss MD studies on polyethylene (PE) with up to 120,000 atoms, polyethylproplyene (PEP), atactic polypropylene (aPP) and polyisobutylene (PIB) with up to 12,000 backbone atoms. The purpose of our work has been to interpret the structure and properties of a fine polymer particle stage distinguished from the bulk solid phase by the size and surface to volume ratio. 

FIG. 94 Mechanical loss spectra and dynamic torsion G modulus vs temperature for polyisobutylene (by Schmieder and Wolf) [109]. (From Ref. 2.)... 

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