Cure and thermal properties of brominated epoxy systems

Nae, Hemi

doi:10.1002/app.1987.070330410

Cited by 13 publications

(8 citation statements)

References 2 publications

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“…The cured epoxy resins studied are generally thermally stable up to 300°C, followed by decomposition in one step (300-420°C). The same thermal behavior was reported for DGEBA epoxy resin/epoxidized oil mixtures (16) and other epoxy resins such as N,N,N′,N′-tetraglycidyl-1,1-bis[(4amino-3-methyl)phenyl]cyclohexane (18) and brominated epoxy resins (19). However, our results are lower than those obtained for fish (20) and tung oil (21) thermosetting polymers (400-560°C), which present three different decomposition stages in air.…”

Section: Resultssupporting

confidence: 83%

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Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil

Gerbase

Petzhold

Costa

2002

J Americ Oil Chem Soc

159

113

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Mechanical and thermal properties of materials prepared by curing epoxidized soybean oil with various cyclic acid anhydrides in the presence of tertiary amines were investigated by dynamic mechanical thermal analysis and thermogravimetry. All samples presented thermoset material characteristics that were dependent upon the type of anhydride, the anhydride/epoxy molar ratio, and epoxy group content. The thermosets obtained from anhydrides with rigid structures as such phthalic, maleic, and hexahydrophthalic showed higher glass transition temperatures (Tg) and cross-linking densities. As expected, the Tg decreased as the anhydride/epoxy ratio decreased. The influence of the degree of epoxidation of soybean oil on the mechanical properties and Tg was also investigated. It was found that the higher the epoxy group amount, the higher the Tg and hardness. Cured resins exhibited thermal stability up to 300°C, except for those prepared with dodecenylsuccinic anhydride, which began to decompose at lower temperature. They presented excellent chemical resistance when immersed in 1% wt/vol NaOH and 3% wt/vol H 2 SO 4 solutions but poor chemical resistance in the presence of organic solvents.Vegetable oils represent an interesting renewable source for the production of useful chemicals and new materials (1). Soybean oil is readily available in bulk and is mainly composed of TG molecules derived from unsaturated acids, such as oleic acid (22%), linoleic acid (55%), and linolenic acid (7%). Although unsaturated acids possess double bonds, which are the reactive sites for coatings and paints, they need to be functionalized by the introduction of epoxy, hydroxyl, or carboxyl groups in order to be used for preparation of polymeric materials.Soybean oil can be epoxidized by different methods (2-4) yielding conversions and selectivities higher than 90%. Industrially, it is used mainly as a polyvinyl chloride additive to improve stability and flexibility. New applications have been made possible by the use of photochemically initiated cationic curing (5) and by the preparation of thermosetting materials such as epoxy resins.Epoxy resins are widely used as adhesives and as matrices in composite materials because of their good physical and chemical properties. Toughness and other properties of epoxy resins can be significantly improved by the modification of classical epoxy resins, such as those based on diglycidylether of bisphenol A (DGEBA). Epoxidized vegetable oils prepared from the most unsaturated oils, e.g., soybean oil or linseed oil, can be used for such purpose.In this work we report dynamic mechanical properties of different materials prepared by curing fully and partially epoxidized soybean oil (ESO) with various cyclic acid anhydrides in the presence of tertiary amines. Thermal and chemical resistance were also investigated. MATERIALS AND METHODSPhthalic anhydride (PA), hexahydrophthalic anhydride (CH), maleic anhydride (MAL), and N,N′-dimethylaniline (ARO) were purchased from Aldrich Chemical Co. (Milwaukee, WI) and purif...

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Section: Resultssupporting

confidence: 83%

“…The networks obtained with partially ESO have lower Tg and cross-linking densities (entries [16][17][18][19]. The data presented in Table 1 show that the higher the epoxidation level of the soybean oil, the higher the Tg of the network.…”

Section: Resultsmentioning

confidence: 99%

Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil

Gerbase

Petzhold

Costa

2002

J Americ Oil Chem Soc

159

113

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“…However, the smaller width observed in their study is consistent with the faster curing rate for their epoxy system containing a 1:1 mixture of standard and brominated DGEBA. According to the references [36,38], at a curing temperature of 175 8C the time required for 90% conversion is 57 min for an epoxy mixture with 40% of the brominated DGEBA and 226 min for the neat standard DGEBA. Thus, in the case of the latter system a much longer time is available for interdiffusion processes and wider IPs can be expected.…”

Section: Concentration Mapping Across the Interphasementioning

confidence: 99%

“…In addition, the polarity of the brominated DGEBA may cause differences in the interfacial interactions [36]. Also a faster curing reaction was reported for systems with brominated DGEBA [36,38].…”

Section: Introductionmentioning

confidence: 95%

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

Munz

Sturm

Stark

2005

Polymer

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“…This may result in reducing the free volume available for molecular motion and increase the rigidity of the molecule resulting in enhanced thermal and mechanical properties of the 3D‐cured network. Furthermore, it has been reported by Naé et al that BE resins could function as chain extenders to reduce brittleness of thermosetting systems.…”

Section: Introductionmentioning

confidence: 99%

Toughening of epoxy systems by brominated epoxy

Sheinbaum

Weizman

et al. 2018

Polymer Engineering & Sci

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Blends of brominated epoxy (BE) and conventional epoxy resins were studied following curing with aliphatic triethylenetetramine (TETA), etheric (polyether diamine-PEA4), and aromatic (3,3 0 -diamino diphenyl sulfone [DDS]) hardeners. The addition of BE resulted in an increase in T g in all tested blends. Blends with 50 wt% BE cured with TETA demonstrated an increase in flexural modulus and flexural strength, while preserving the elongation. Blends with 40 wt% BE cured with PEA4 and 50 wt% BE cured with DDS resulted in a significant enhanced tensile elongation. The shear strength of all cured systems decreased moderately with the addition of BE exhibiting a mixed mode failure. Analysis of the fracture morphology using electron microscopy supported the increase of toughness levels as a result of incorporating BE to conventional epoxy. A unique nodular and rough fracture morphology was obtained, which is related to a toughening mechanism caused by the addition of BE. It was concluded that blends of BE and conventional epoxy could be used as structural adhesives having high T g , enhanced mechanical properties and increased toughness. POLYM. ENG. SCI., 00:000-000, 2018.FIG. 6. SEM micrograph of fractured surface of DGEBA/BE blends: (a) DGEBA cured by PEA4, (b ) the magnified image of the small square in a, (c) 40 wt% BE blend PEA4 -cured system, (d) the magnified image of the small square in (c), (e) 60 wt% BE blend PEA4-cured system, (f) the magnified image of the small square in (e).

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Cure and thermal properties of brominated epoxy systems

Cited by 13 publications

References 2 publications

Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil

Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil

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

Toughening of epoxy systems by brominated epoxy

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