Dielectric, mechanical and rheological studies of phase separation and cure of a thermoplastic modified epoxy resin: incorporation of reactively terminated polysulfones

Mackinnon, Alexander J.; Jenkins, Stephen D.; McGrail, P.T.; Pethrick, Richard A.

doi:10.1016/0032-3861(93)90399-u

Cited by 74 publications

(38 citation statements)

References 21 publications

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“…However, the further use of epoxies is limited because of their inherent brittleness, poor crack resistance. In recent years, the feasibility of toughening highly crosslinked networks with high modulus and high T g thermoplastics has been investigated [7][8][9][10][11][12]. Addition of thermoplastics into thermosets leads to different phenomena.…”

Section: Introductionmentioning

confidence: 99%

Effect of polyethersulfone and N,N’-bismaleimido-4,4’-diphenyl methane on the mechanical and thermal properties of epoxy systems

Rajasekaran¹,

Alagar²,

Chozhan³

2008

Express Polym. Lett.

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Abstract. In order to improve thermo mechanical properties of cured epoxy resin, hydroxyl terminated polyethersulfone (PES) and N,N′-bismaleimido-4,4′-diphenyl methane (BMI) were incorporated to diglycidyl ether of bisphenol A (DGEBA) type epoxy resin and cured with diaminiodiphenylmethane (DDM). The resulting hybrid matrices, in the form of castings, were characterized for their mechanical properties like tensile, flexural and impact strength. Differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis of the matrices were also performed to determine the glass transition temperature and thermal stability of the matrix systems. The results obtained from mechanical and thermal studies indicated that the incorporation of polyethersulfone into epoxy resin improved the toughness and thermal stability of the systems. This is attributed to the formation of interpenetration polymer networks (IPNs) composed of the epoxy network and the linear PES. The incorporation of BMI into polyethersulfone modified epoxy systems increased thermal stability, glass transition temperature, tensile and flexural properties and decreased the impact strength. Scanning electron microscopy studies of polyethersulfone modified epoxy and BMI incorporated polyethersulfone modified epoxy systems exhibit homogeneous morphology confirming efficient chemical interaction and formation of intercrosslinked network structure.Keywords : polymer composites, thermal properties, mechanical properties, morphology, moisture absorption eXPRESS Polymer Letters Vol.2, No.5 (2008) [339][340][341][342][343][344][345][346][347][348] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2008.40 homogeneous hybrid thermoplastic modified epoxy with low fractions of thermoplastics [18]. It is reported that the incorporation of high performance thermoplastics into a thermoset resin system leads to significant improvements in mechanical properties [9,[19][20][21][22] [28][29][30][31][32]. Bismaleimides posses high crosslinking ability, high glass-transition temperature, high thermal ability, high char yield, excellent fire resistance, superior specific strength and specific modulus, and low water absorption. In continuation of our earlier studies, an attempt has been made in the present investigation to improve both toughness and thermo-mechanical properties of epoxy resin by incorporating hydroxyl terminated polyethersulfone (PES) and N,N′-bismaleimido-4,4′-diphenyl methane(BMI). Materials and methodsEpoxy resin [diglycidyl ether of bisphenol A (DGEBA)] LY556 (epoxy equivalent 189 and viscosity 10 000 cP) and 4,4′-diaminodiphenylmethane (DDM) were obtained from Ciba-Geigy (India). N,N′-bismaleimido-4,4′-diphenyl methane was synthesized in our laboratory as per the reported procedure ( Figure 1) [33]. Hydroxyl terminated polyethersulfone was supplied by Jilin University, China was used as received. The chemical structures of materials used are presented in Figure 2.340 Rajasekaran et al. -eXPRESS Polymer Let...

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Section: Introductionmentioning

confidence: 99%

Effect of polyethersulfone and N,N’-bismaleimido-4,4’-diphenyl methane on the mechanical and thermal properties of epoxy systems

Rajasekaran¹,

Alagar²,

Chozhan³

2008

Express Polym. Lett.

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“…In initially miscible epoxy systems blended fects, n is a real number between 0 and 1, s is the direct current (dc) conductivity, 1 o is the perwith tougheners like elastomers 3 or thermoplastics, 10,20 a phase separation will occur under curmittivity of free space (8.85 1 10 014 F/cm), 1 r is the relaxed dielectric permittivity, 1 u is the unreing and yield biphasic materials. In these heterogeneous systems, the differences of conductivity laxed dielectric permittivity, t is the relaxation time of the dipoles, and v is the angular freand permittivity between two media produce an accumulation of charges' carriers at the interface quency.…”

Section: Methodsmentioning

confidence: 99%

“…26,27 If the conduction is ionic the ion mobility through the crystalline regions will observed only at the end of the polymerization, with a phase inverted morphology. 10,20 Two of the aims be decreased. This type of conduction was frequently invoked to account for the low but finite of this article are to show how microdielectrometry can be used to detect phase separation in high glass conductivity of many of the more insulating poly8ea4 on21 / 8ea4$$on21 07-22-97 00:00:57 polaas W: Poly Applied mers.…”

Section: Introductionmentioning

confidence: 99%

Buildup of thermoset and crystallization of thermoplastics studied by electrical techniques

Friedrich

Vinh‐tung

Boiteux

et al. 1997

J. Appl. Polym. Sci.

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Up to now, few techniques were available that allowed nondestructive in situ characterization of polymerization during the curing of a thermoset resin. Dynamic dielectric measurements made over a wide range of frequencies provide a sensitive and convenient control to follow up the epoxy-amine cure or to follow the formation of the thermoplastic materials. The direct current measurements and the time of flight measurements were developed to confirm interpretation of the electrical techniques in terms of correlations of the evolution of the conductivity and the network formation and also to evaluate the real value of the ion mobility and its evolution in a course of reaction.

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“…To interpret the data gathered from these processes it is necessary to have available suitable reference systems. A range of model systems have been reported and include rubber modified-carboxy terminated acrylonitrile butadiene (CTBN)-epoxy resin [35,36], and thermoplastic modified resins used in aircraft manufacture [37][38][39]. A number of studies have attempted to establish correlations between the dielectric data and other physical measurements of the cure processes of resin [40][41][42][43][44][45], glass [46], and carbon fibre [47][48][49][50].…”

Section: Application Of Dielectric Monitoringmentioning

confidence: 99%

Dielectric non-destructive testing approach to cure monitoring of adhesives and composites

Garden

Hayward

Pethrick

2007

Proceedings of the Institution of Mechanical Engineers, Part G:

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In the fabrication of many composite and adhesively bonded structures it is desirable to determine the extent to which complete cure is achieved. This review briefly discusses the fundamental issues which are involved in the monitoring of the cure process in thermoset resins. The application of the dielectric method is described as a non-destructive probe for the monitor of the cure process in thermoset resin systems. The principles of the technique are illustrated with reference to a simple epoxy-amine structural adhesive. Possible correlations between the changes in the dielectric properties with other physical property changes of a resin, e.g. viscosity, during cure are discussed.

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Dielectric, mechanical and rheological studies of phase separation and cure of a thermoplastic modified epoxy resin: incorporation of reactively terminated polysulfones

Cited by 74 publications

References 21 publications

Effect of polyethersulfone and N,N’-bismaleimido-4,4’-diphenyl methane on the mechanical and thermal properties of epoxy systems

Effect of polyethersulfone and N,N’-bismaleimido-4,4’-diphenyl methane on the mechanical and thermal properties of epoxy systems

Buildup of thermoset and crystallization of thermoplastics studied by electrical techniques

Dielectric non-destructive testing approach to cure monitoring of adhesives and composites

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