Dynamic mechanical and 13C n.m.r. analyses of the effects of antiplasticization on the β secondary relaxation of aryl-aliphatic epoxy resins

Heux, Laurent; Lauprêtre, F.; Halary, Jean Louis; Monnerie, L.

doi:10.1016/s0032-3861(97)00423-0

Cited by 57 publications

(65 citation statements)

References 21 publications

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“…On the other hand, it exhibits a much higher modulus at room temperature than its pure counterpart, in agreement with the molecular mechanism of antiplasticization detailed elsewhere. 13,14,25 As expected from the analyses given in the previous sections, A-1-DDM/AP actually presents a markedly higher value of SDR than A-1-DDM (Table III). A supplementary check on the behavior of this system can be made by noticing that it presents roughly the same characteristics of interest here (T g , ␣ r , modulus around room temperature) as the network A-1-80BAN.…”

Section: Residual Stresses In Epoxy Network Of More Complex Formulationsupporting

confidence: 71%

“…18,19 The antiplasticizer (AP) used in this study has for chemical formula as the result of the reaction of epoxyphenoxypropane and hydroxyacetanilide. AP was synthesized in our laboratory by following a procedure detailed elsewhere; 13,20 it was obtained in the form of a yellow amorphous material, and was used without further purification.…”

Section: Materials Chemicalsmentioning

confidence: 99%

“…4 -7 Thus, unambiguous results were obtained dealing with the glass transition temperature T g , 5,[7][8][9] , the free volume, 10 the secondary relaxation ␤, 5,11,12 and the antiplasticization phenomenon. 13,14 In the case of composites, additional pending questions refer to the interaction between matrix and fiber. It is known, for instance, that undesired thermally induced stresses develop at the end of the preparation of the glass-epoxy composite pieces while cooling the samples from cure temperatures above T g down to room temperature.…”

Section: Introductionmentioning

confidence: 99%

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Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Bauchiere

Halary

Monnerie

et al. 2000

J. Appl. Polym. Sci.

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ABSTRACT:The capability of epoxy-amine resins to develop residual stresses was studied as a function of temperature and network architecture. These residual stresses were induced while cooling epoxy-glass bilayers from temperatures higher than the network glass transition temperature, T g . This behavior was the result of the marked differences (␣ r Ϫ ␣ g ), in linear thermal expansion coefficient of the two components, as evidenced by the measurement of ␣ r for the epoxy networks under study. Various network architectures were selected, resulting from variation of (1) the chemical nature of both epoxide and curing agent, (2) the nature and relative amount of the chain-extensor agent, and (3) the stoichiometric ratio. Three ranges of cooling temperature were observed systematically: first, the range of temperatures above T g , where no stress has been detected, then an intermediate temperature range (from T g to T*), where stresses develop quite slowly, and finally, the low temperature range (T Ͻ T*), where a linear increase in stress accompanies the decrease of temperature. The two latter regimes were quantitatively characterized by the extent, T g Ϫ T*, of the first one and by the slope, SDR, of the second one. T g Ϫ T* values were shown to be governed by the T g of the network: the higher the T g , the larger the gap between T g and T*. This result was interpreted by accounting for the variation of relaxation rate at T g from one network to the other. It was also shown that a semiempirical relationship holds between SDR and T g : SDR decreases monotonically as T g increases. By inspecting the effects of network architecture in more details, it turned out that SDR is governed by the Young's moduli, E r (T Ϫ T g ), of the epoxy resins in the glassy state: the lower E r (T Ϫ T g ), the lower SDR in a series of homologous networks. As E r (T Ϫ T g ) values are known to be related to the characteristics of the secondary relaxation ␤, which depends, in turn, on crosslink density, SDR values were finally connected to the amplitude of the ␤ relaxation processes. This finding was corroborated by the measurements on an antiplasticized dense network. Finally, data relative to thermoplastic-filled networks showed that the addition of thermoplastic reduces the development of residual stresses, whatever the system, is homogeneous or biphasic.

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Section: Residual Stresses In Epoxy Network Of More Complex Formulationsupporting

confidence: 71%

Section: Materials Chemicalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Bauchiere

Halary

Monnerie

et al. 2000

J. Appl. Polym. Sci.

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show abstract

“…As discussed by Halary et al [62], the high-temperature part of the b-transition is related to a sort of local-scale cooperative motions. Consequently, the proportion of such cooperative motions is expected to decrease if the connectivity of the network is reduced, i.e.…”

Section: Dynamic Mechanical Analysis (Dma) Of An Epoxy Reference Seriesmentioning

confidence: 89%

Mechanical gradient interphase by interdiffusion and antiplasticisation effect—study of an epoxy/thermoplastic system

Munz

Sturm

Stark

2005

Polymer

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“…4 Of interest here, the labs of Halary and Monnerie [5][6][7][8][9] have generated extensive dynamic mechanical data on the rigid, semirigid, and flexible resins. Figure 1, reproduced from one of their publications, 8 typifies the response of the dynamic mechanical spectra to changes in topology achieved by decreasing crosslink density via diamine/monoamine substitutions.…”

Section: Influence Of Molecular Motionsmentioning

confidence: 99%

A discussion of the molecular mechanisms of moisture transport in epoxy resins

Soles

Yee

2000

J. Polym. Sci. B Polym. Phys.

276

185

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Dynamic mechanical and 13C n.m.r. analyses of the effects of antiplasticization on the β secondary relaxation of aryl-aliphatic epoxy resins

Cited by 57 publications

References 21 publications

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Mechanical gradient interphase by interdiffusion and antiplasticisation effect—study of an epoxy/thermoplastic system

A discussion of the molecular mechanisms of moisture transport in epoxy resins

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