On the viscoelastic and plastic behaviour of methylmethacrylate- co - N -methylglutarimide copolymers

Tézé, L.; Halary, Jean Louis; Monnerie, L.; Canova, Luciano

doi:10.1016/s0032-3861(98)00337-1

Cited by 21 publications

(7 citation statements)

References 16 publications

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“…The slope changes slightly around the β transition temperature (20°C), in agreement with the fact that β motions are no good α motion precursors [38]. σ y /E decreases faster after the β transition, meaning that yielding is easier then.…”

Section: Dynamic Mechanical Analysissupporting

confidence: 71%

“…As shown in previous studies, strain softening tends to vanish at high temperatures (between T β and T α ) in the situations of β-α coupling[37,38]: the molecular motions involved at the yield point are quite similar to those responsible for the plastic flow. On the contrary, SSA presents a constant large value when α and β motions do not involve the same units and subunits: β-type motions and α-type motions are concerned in yielding and plastic flow, respectively.…”

supporting

confidence: 71%

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Characterization, structural transitions and properties of a tightly crosslinked polythiourethane network for optical applications

et al. 2005

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A new polythiourethane thermosetting system based on a diisocyanate and a trithiol was studied. After characterization of the reactive species, two critical temperatures, namely T g∞ (maximum glass transition temperature of the thermosetting system) and gel T g (T g of the material at the gel point), were determined. The conversion at gel point was also determined and compared to the theoretical prediction. Two different characteristics of the evolution of a reactive system, T g and conversion x as a function of time, were related. This is of particular interest for understanding the curing process, especially when non-isothermal cure schedules are used. Viscoelastic and plastic properties were investigated, with the aim of establishing connections between the chemical structure and properties through detailed analysis of the polymer chain motions (β and α relaxations). Measurements of the storage modulus at the rubbery plateau and of the critical strain intensity factor K Ic complete the study.

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Section: Dynamic Mechanical Analysissupporting

confidence: 71%

supporting

confidence: 71%

Characterization, structural transitions and properties of a tightly crosslinked polythiourethane network for optical applications

et al. 2005

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“…Figure 2 shows that a good agreement is found between T g and T ␣ values at sufficiently large MI content, as already reported for various amorphous systems. 6,7,22,23 On the other hand, this agreement fails at MT mol fractions larger than 0.7, because T ␣ [MTS] is unambiguously larger than T g [DSC] for I1 and I2. It is worth noticing that a broadening of the EЈ peak accompanies in these cases its reduction in amplitude, which is associated with the presence of crystalline domains in the samples.…”

Section: Glass Transition and Mechanical Relaxationsmentioning

confidence: 99%

“…Recently, a further stage was passed, thanks to the study of different series of methylmethacrylate-based random copolymers, 6,7 including either styrene units, 6 or N-substituted maleimide rings, 6,7 or N-methyl glutarimide rings 7 as the comonomer. The strain-softening amplitude, SSA (which is defined as the difference between the yield stress, y , and the plastic flow stress, pf , in compression testing) was shown to be strongly related to the possible coupling between the ␤ secondary transition and the glass transition motions.…”

Section: Introductionmentioning

confidence: 99%

On the viscoelastic and plastic behavior of semiaromatic polyamides

Choe

Brûlé

Bisconti³

et al. 1999

J. Polym. Sci. B Polym. Phys.

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Different semiaromatic polyamides (SAPA) have been synthesized by step‐growth polymerization of an aliphatic diamine, M (the 2‐methyl 1,5‐pentanediamine), and isophthalic acid, I, or terephthalic acid, T, or mixtures of these two diacids. The influence of the relative amount of randomly distributed MT units on the viscoelastic properties of the materials was investigated. It was shown that the glass transition Tg, as deduced from DSC thermograms, and the relevant mechanical relaxation Tα raise when the content of MT units increases. In contrast, the broad low‐temperature secondary relaxation, called γ, does not markedly depend on the MT content. Samples systematically studied in the absence of any moisture did not exhibit the intermediate‐temperature secondary relaxation, called β, which is characteristic of the wet polyamides. The study of the plastic behavior was focused on the samples MI and I5, which are strictly amorphous, and contain 0% and 50 mol % of MT units, respectively. Mechanical experiments were carried out in both the compression and traction modes, at temperatures ranging from −80°C to Tg. Analysis of the compression data was based on the inspection of the temperature dependence of elastic modulus, E(T), yield stress, ςy, plastic flow stress, ςpf, and strain softening ςy − ςpf. Whereas the plots of ςy as a function of temperature, T, reveal some differences between MI and I5 behavior, a unique master curve was obtained by plotting ςy/E(T) vs. T − Tg, which means that the plastic behavior of these materials is controlled by their chain packing in the glassy state. The strain softening profile of MI and I5 is similar to that already reported in the case of brittle vinyl polymers. This observation is consistent with the traction data, which give evidence for the occurrence of the tensile yielding of MI and I5 at temperatures rather close to Tg. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1131–1139, 1999

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“…Recent studies carried out in our laboratory have provided comprehensive evidence for the relations existing between the yielding behavior and the character of the molecular motions involved in the main mechanical relaxation α and in the sub-Tg secondary relaxations (β, γ). Different families of amorphous polymers have been investigated, including poly(methyl methacrylate) and methyl methacrylate-based copolymers (Tordjeman et al, 1997;Tézé et al, 1999), semi-aromatic polyamides (Choe et al, 1999;Brulé et al, 2001), epoxyresins (Rana, 2002) and blends of polystyrene and poly(phenylene oxide) (Creton et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Molecular Analysis of the Mechanical Behavior of Plasticized Amorphous Polymer

Boughalmi¹,

Jarray²,

Larbi³

et al. 2006

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Analyse moléculaire du comportement mécanique de polymères plastifiés -Les effets de la plastification sur le comportement mécanique ont été étudiés sur deux familles de matériaux à base de poly(méthacrylate de méthyle) (PMMA) et de poly(chlorure de vinyle) (PVC). Le PMMA a été mélangé avec du poly(fluorure de vinylidène) (PVDF) dans des proportions massiques en PVDF variant de 0 à 40 %, compositions pour lesquelles ces échantillons sont totalement amorphes. Le di-octylphtalate (DOP) a été mécaniquement dispersé dans le PVC dans des proportions massiques en DOP variant de 0 à 20 %. Le comportement en relaxation des échantillons a été étudié par analyse thermique différentielle avec une rampe de température de 10 °C·min -1 et par analyse dynamique mécanique à une fréquence de 1 Hz sur une plage de température allant de -100 °C jusqu'à 150 °C. Les courbes contrainte -déformation ont été réalisées en compression à une vitesse de déformation de 2.10 -3 s -1 . L'analyse des données a révélé le rôle déterminant des mouvements de relaxation β dans le comportement plastique. En considérant la partie non élastique du travail fourni, une corrélation a été trouvée entre cette quantité et les mouvements de relaxation α et β. Abstract -Molecular Analysis of the Mechanical Behavior of Plasticized Amorphous PolymersPlasticization effects on the mechanical behavior were investigated on two families of materials based on poly(methyl methacrylate) (PMMA) and poly(vinyl chloride) (PVC), respectively. For this purpose, PMMA was blended with poly(vinylidene fluoride) (PVDF) by co-precipitation from solution, all over the

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On the viscoelastic and plastic behaviour of methylmethacrylate- co - N -methylglutarimide copolymers

Cited by 21 publications

References 16 publications

Characterization, structural transitions and properties of a tightly crosslinked polythiourethane network for optical applications

Characterization, structural transitions and properties of a tightly crosslinked polythiourethane network for optical applications

On the viscoelastic and plastic behavior of semiaromatic polyamides

Molecular Analysis of the Mechanical Behavior of Plasticized Amorphous Polymer

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