Regression analysis studies of polymer transitions II. TII from specific heat and other data for polyisobutylene

Boyer, Raymond F.; Enns, John B.

doi:10.1002/app.1986.070320323

Cited by 21 publications

(13 citation statements)

References 65 publications

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“…However, Rouse modes referred to the motion of Gaussian sub-molecular chains. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In addition, EVA, as a common thermoplastic elastomer, has been universally applied in enhancing toughness, adhesives and so on. They were called sub-Rouse modes, which had units that were longer than segments and shorter than Gaussian sub-molecular chains.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and molecular dynamics of ethylene-vinyl acetate copolymer/butyl rubber blends

Zhang

2015

RSC Adv.

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In this article, butyl rubber (IIR) was blended with ethylene-vinyl acetate copolymer (EVA) through a molten method. The crystal structure, morphology, crystallization and segmental dynamics were characterized.The crystal structure test indicated that IIR had no influence on the crystal form of EVA. Furthermore, the morphology showed that the blends changed from sea-island to a co-continuous structure. Moreover, the non-isothermal crystallization kinetics given by Mo's model showed that the rate of crystallization became fast as the content of EVA increased. In addition, the segmental dynamics characterization illustrated that EVA suppressed the molecular motions of IIR to a different degree. Longer units were more influenced than shorter units. It was also found that both crystallization and molecular dynamics had a close relationship with the morphology.

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Section: Introductionmentioning

confidence: 99%

Crystallization and molecular dynamics of ethylene-vinyl acetate copolymer/butyl rubber blends

Zhang

2015

RSC Adv.

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“…Figures 1 and 2 show the damping behaviors of CIIR and CIIR/PAc blend, among which only CIIR rubber or CIIR composition in CIIR/PAc blend is vulcanized by PR resin, whereas the PAc remains a linear molecular structure. From Figure 1, the DMA plots of vulcanized CIIR, it can be seen that two evident transitions appear on the about −40 and −20 °C, to which T g transition and T ll transition of CIIR can be attributed, respectively, according to Boyer 3, 4. Compared with the height of T g transition shoulder peak, the one of T ll transition is much higher and bigger, which demonstrates that greater contribution towards CIIR damping capability mainly originates from T ll transition of CIIR.…”

Section: Resultsmentioning

confidence: 94%

“…The reason why the transition behavior of CIIR composition is so sensitive to the content of BMA segments and crosslinking networks could be interpreted from the feature of CIIR T ll , though it is still with arguments. Boyer3–5 and others said that the T ll transition of CIIR derived from a retardation of CIIR macromolecular relaxation behaviors for disentanglement or other delayed movement by promissory structures. Anyhow, the liquid–liquid transition above T g generating at the time when the sample is annealed is easy to be suppressed.…”

Section: Resultsmentioning

confidence: 99%

“…Butyl rubber, a kind of copolymer of isobutylene and isoprene, can be divided into both nonhalogenation butyl rubber and halogenation butyl rubber, the latter like chlorobutyl rubber, CIIR, and bromobutyl rubber, BIIR, being the equal important commercial products. Capability of dissipating energy and strong dependence on temperature are the striking features of butyl rubber, and this is because the molecules of butyl rubber in which every interval carbon in main carbon chain bears two methyl groups as well as its unique aggregation state in which T ll transition a liquid–liquid transition, occurs above T g makes butyl rubber appear as an intense loss peak; its precise mechanics is still unclear 1–5. Butyl rubber has been used as conventional damping materials; however, since the loss peak occurs at relatively lower temperature region, butyl rubber nearly losses its valid damping function in the vicinity of ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

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Effect of miscibility and forced compatibility on damping properties of CIIR/PAc blend

Huang¹,

He²,

Wu³

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:In this study, a kind of novel damping materials was prepared based on the blend of chlorinated butyl rubber (CIIR) and polyacrylate (PAc) synthesized by different molar ratio of butyl methacrylate and ethyl acrylate. Research results from experiments and analyses by employing DMA, TEM, and FTIR show that whether at a cocured system or noncocured system, it can be achieved to shift a loss peak of CIIR towards a higher temperature region and to keep the damping value from markedlly decreasing, which broadens the effective damping function area of CIIR to the vicinity of ambient temperature. In the former system, the thermodynamical miscibility of CIIR and PAc, to some extent, is predominated by the molecular design of PAc, while in the latter system, covulcanized networks play a more significant role in improving compatibility and abating the peak split, though the suppression effect of thermal stress on the transition of CIIR T ll transition still can not be neglected. Furthermore, transition state derived from the cocuring CIIR and PAc cannot make the phase separation completely take place, and consequently results in the deformation of phase morphology of the cocured CIIR/PAc blend. It is the influence of thermodynamics miscibility and forced compatibility in different size that makes the suppression effect of foreign PAc on CIIR T ll transition be controllable.

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“…So it is anticipated that some simple and effective modifications to resolve the above shortcoming of the damping rubber. In contrast, due to the restrictions of glass transition for either IPNs or rubber blends [10], some recent studies have turned to other relaxation transitions which may be used to dissipate vibration or acoustic energy besides glass transition, such as liquid–liquid transition or cluster transition [11–13]. Therefore, the modification by exploring multiply roads of energy dissipations has become key technology in fabrications of damping rubbers.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of novel hindered phenol/phenol resin/nitrile butadiene rubber hybrids and their long‐period damping properties

2012

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To overcome the modification shortcoming of phenol resin (PR) in decreasing the loss factor peak (tan δmax) of nitrile butadiene rubber (PR/NBR) blends, the hindered phenol AO‐80/PR/NBR hybrids were successfully prepared. The tan δmax of the hybrids is found to increase with the increment of AO‐80 content while they almost remains the same widths of damping temperature range as PR/NBR blend. Their damping properties can be regulated well by controlling the content of AO‐80. Various experimental data of Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, and dynamic viscoelastic measurements (DMAs) show that the good damping properties of the hybrids result from the cooperative effect of two different relaxation transitions: the hydrogen bonds of nitrile group associated with hydroxyl group of AO‐80 besides their glass transition. The effect does not decrease the width of damping temperature range of the hybrids but really maintain a high value of tan δmax in a long duration; but it is found that the components of hybrids with the high content of AO‐80 become partly compatible after long‐period storage. So the content of AO‐80 is important to sustain the damping storage stability for NBR hybrids where the amount of AO‐80 below 50 phr is preferred. We believe that our studies provide some basic observations to serve the practical applications of NBR hybrids. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

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Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Cited by 21 publications

References 65 publications

Crystallization and molecular dynamics of ethylene-vinyl acetate copolymer/butyl rubber blends

Crystallization and molecular dynamics of ethylene-vinyl acetate copolymer/butyl rubber blends

Effect of miscibility and forced compatibility on damping properties of CIIR/PAc blend

Fabrication of novel hindered phenol/phenol resin/nitrile butadiene rubber hybrids and their long‐period damping properties

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