Studies on the properties of epoxy resins modified with chain-extended ureas

He, Shan; Shi, Kun; Bai, J.; Zhang, Zengkun; Li, Liang; Du, Zongjie; Zhang, Baolong

doi:10.1016/s0032-3861(01)00450-5

Cited by 63 publications

(32 citation statements)

References 26 publications

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“…On the one hand, as mentioned above, adding BAOBE can decrease the cross-link density of the cured network, and the cross-link density has a great effect on the toughening. 35 On the other hand, the liquid crystalline phase would separate from the matrix in the form of microfibers with a very high aspect ratio after curing, and the high rigidity as well as the molecular packing of liquid crystalline domains would act as crack stoppers, which prevent the propagations of cracks and increase the absorbed energy. 36,37 .…”

Section: The Dma Analysis Of the Modified Bmi Resinsmentioning

confidence: 99%

Novel Bismaleimide Resins Modified by Allyl Compound Containing Liquid Crystalline Structure

Wang

Chen

et al. 2016

Adv Polym Technol

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ABSTRACT:A novel allyl compound containing liquid crystalline structure, i.e., 4,4'-bis(4-allyloxy benzoic acid) phenyl ester (BAOBE), was synthesized. The chemical structure of BAOBE was characterized by Fourier transform infrared (FTIR) spectroscopy and 1 H NMR spectra, and the liquid crystalline properties were confirmed by polarized optical microscopy (POM). Besides, a series of modified bismaleimide (BMI) resins were prepared based on N,N -4,4 -bismaleimidodiphenylmethylene (BDM), BAOBE, and O,O'-diallyl bisphenol A (DABPA). The results of thermogravimetric analysis (TGA) indicate that the modified resins have excellent thermal stability with the highest temperatures for 5% weight loss above 438°C. The results of dynamic mechanical analysis (DMA) suggest that the glass transition temperature (T g ) of the modified resins are above 280°C. Besides, the introduction of BAOBE leads to a significant improvement in the flexural and impact properties of the modified BMI resins. Compared with the resin with only DABPA as a modifier, the highest flexural and impact strength can reach 156.2 MPa and 15.6 kJ/m 2 , increased by 19.2% and 90.2%, respectively. C

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Section: The Dma Analysis Of the Modified Bmi Resinsmentioning

confidence: 99%

Novel Bismaleimide Resins Modified by Allyl Compound Containing Liquid Crystalline Structure

Wang

Chen

et al. 2016

Adv Polym Technol

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“…Epoxy resins are easy to cure with various curing agents, 1,2 and the epoxy resins possessed excellent heat and solvent resistance, good mechanical and electrical properties, good adhesion of many substrates. [3][4][5][6] Recently, various modified and novel synthesized epoxy resins were reported, such as the liquid crystalline epoxy resin, 7 the UV-curable epoxy resin, 8 the cycloaliphatic epoxy resin, 9 the benzoxazine type epoxy material, 10 naphthyl/dicyclopentadiene, 11 etc.…”

Section: Introductionmentioning

confidence: 99%

Intermolecular force and thermal properties of the sulfonyl epoxy blends cured with DGEBA epoxy

Chiu¹,

Tsai²,

Chou³

et al. 2010

J of Applied Polymer Sci

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The sulfonyl epoxy monomer (SEP) was synthesized and further to blend with the diglycidyl ether of bisphenol A (DGEBA). The glass transition temperature (T g ) of the SEP/DGEBA blended materials increased from 103.7 to 163.8 C. The cross-linking density and polymer chain self-association intra-molecular action affected more than that the polymer-polymer intermolecular action (hydrogen bonding) in the SEP blended with the DGEBA materials. The excess stabilization energy in the overall stabilization was only 0.00145% (14.5 ppm), which indicated that the polymer-polymer intermolecular action was weak. The thermal degradation of the SEP segments could form various sulfate derivatives at lower temperature and analyzed by the TGA/GC/Mass. The sulfate derivatives could generate the thermal stable chars, which provided the ''shielding effect'' and antioxidation property. Additionally, these chars could also improve the protective effect and inhibit the thermal-oxidation decomposition under the air atmosphere.

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“…PU-epoxy systems have been reported previously and are commonly used in the coating industries and structural applications to mitigate the brittle nature of neat epoxy systems. [9][10][11][12] To achieve the intended elastomeric characteristics, PUs are often derived from flexible toluene diisocyanate and poly(propylene glycol). However, the quantity of PU that is added inadvertently results in the formation of PU-epoxy blends.…”

Section: Introductionmentioning

confidence: 99%

Polyurethane‐modified epoxy resin: Solventless preparation and properties

Ong

Jusoh

Bakar

et al. 2008

J of Applied Polymer Sci

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A polyurethane-modified epoxy resin system with potential as an underfill material in electronic packaging and its preparation procedure were studied. The procedure enabled the practical incorporation of an aliphatic polyurethane precursor, synthesized from poly(ethylene glycol) and hexamethylene diisocyanate without a solvent, as a precrosslinking agent into a conventional epoxy resin. With a stoichiometric quantity of the polyurethane precursor added to the epoxy (ca. 5 phr), the polyurethane-modified epoxy resin, mixed with methylene dianiline, exhibited a 36% reduction in the contact angle with the epoxy-amine surface, a 31% reduction in the cure onset temperature versus the control epoxy system, and a viscosity within the processable range. The resultant amine-cured thermosets, meanwhile, exhibited enhanced thermal stability, flexural strength, storage modulus, and adhesion strength at the expense of a 5% increase in the coefficient of thermal expansion. Exceeding the stoichiometric quantity of the polyurethane precursor, however, reduced the thermal stability and modulus but further increased the coefficient of thermal expansion.

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Studies on the properties of epoxy resins modified with chain-extended ureas

Cited by 63 publications

References 26 publications

Novel Bismaleimide Resins Modified by Allyl Compound Containing Liquid Crystalline Structure

Novel Bismaleimide Resins Modified by Allyl Compound Containing Liquid Crystalline Structure

Intermolecular force and thermal properties of the sulfonyl epoxy blends cured with DGEBA epoxy

Polyurethane‐modified epoxy resin: Solventless preparation and properties

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