Mechanisms of Toughening Thermoset Resins

Huang, Yongqi; Hunston, D. L.; Kinloch, A. J.; Riew, C. K.

doi:10.1021/ba-1993-0233.ch001

Cited by 57 publications

(36 citation statements)

References 22 publications

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“…The dispersed poly(methyl methacrylate) particles in silicone epoxy provides the stress concentration zones for matrix yielding and poly (alkyl methacrylate) cavitation. The cavitation around each of the particles supports earlier proposed mechanisms for enhanced toughness observed in elastomer modified thermosets 21 . Thus, the SEM provides physical evidence of improved energy absorption during the fracture process.…”

Section: Scanning Electron Microscope Of Silicone Epoxy/pmma Semi Ipnssupporting

confidence: 86%

Synthesis and Characterization of Silicone epoxy resin /poly (methyl methacrylate) Interpenetrating Polymer Networks

Hussinaiah¹

2014

IOSRJEN

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-Semi interpenetrating networks (IPNs) of the Silicone epoxy resin and poly (methyl methacrylate) (PMMA) were prepared by the sequential mode of synthesis. These were characterized with respect to their mechanical properties, namely, tensile strength, elongation at break. Thermal properties were studied by differential scanning calorimetry, thermogravimetry and dynamic mechanical thermal analysis. The morphological features were studied through scanning electron microscopy(SEM). The effects of variation of the blend ratios between silicone epoxy and poly(methyl methacrylate) on the above-mentioned properties were examined. There was a gradual increase of tensile strength with consequent increases in elongation at break for both types of IPNs with increases in PMMA content up to 30% and further the above properties were decreased with increasing PMMA. The weight retentions in the thermal decomposition of both the semi-IPNs and full IPNs were higher than the silicone epoxy system. This enhancement was would be related to the presence of the unzipped methyl methacrylate monomer, which acted as radical scavengers in the silicone epoxy degradation. An inward shift and lowering (with respect to pure epoxy) of the Tg of the IPNs was observed. The fractography as studied by SEM shows change in fracture mechanics from shear yielding to crazing with increasing PMMA content.

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Section: Scanning Electron Microscope Of Silicone Epoxy/pmma Semi Ipnssupporting

confidence: 86%

Synthesis and Characterization of Silicone epoxy resin /poly (methyl methacrylate) Interpenetrating Polymer Networks

Hussinaiah¹

2014

IOSRJEN

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“…Epoxy resins are frequently modified by dissolving in a small proportion (10% -20%) of a liquid rubber con taining reactive end groups such as carboxyl-terminated acrylonitrile copolymer (CTBN) [5] and amine-terminated butadiene acrylonitrile copolymer (ATBN) [6]. Although CTBN and ATBN oligomers are very efficient in improving the fracture properties of epoxy resins but make the resultant material thermally unstable.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Thermal Properties of Chemically Modified Epoxy Resin

Ikram¹,

Munir²

2012

OJSTA

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Diglycidyl ether of bisphenol-A (DGEBA), having number average molecular weight (M n ) 375, was modified by incorporating the hydroxyl terminated polybutadiene (HTPB) based prepolymer using isophorone diisocyanate as a coupling agent. To increase the compatibility between the epoxy resin and HTPB part, polar groups were introduced in the later to achieve physical and chemical interactions between the two phases. The finally modified DGEBA system was cured with amine based hardener. FTIR and 1 H-NMR were used to monitor the whole modification procedure. The rubber particles size and distribution was monitored as a function of HTPB contents in the resin system using scanning electron microscopy (SEM). The mechanical, thermal and thermo-mechanical properties have shown that the tensile strength, toughness, ductility and impact strength of the modified cured system have been successfully increased at some optimum HTPB contents without affecting the inherent thermal and thermo-mechanical stability associated with DGEBA resin system. Some of the mechanical properties like flexural modulus, tensile modulus and compressive strength decreased with increasing rubber contents.

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“…However, the use of these resins is limited because of their low fracture toughness (~100 J/m 2 ), higher viscosity (400 cP), and higher cost relative to Unfortunately, decreasing the styrene content in vinyl-ester resins does not offer an acceptable solution to this problem. As the styrene content is reduced, the resin viscosity increases, making it difficult to use inexpensive molding techniques (1,9). In addition, Dow Derakane 441-400 uses 27% less styrene than Derakane 411-350 (6) but has less than half the fracture toughness (5,8).…”

Section: Introductionmentioning

confidence: 99%

“…Low molecular weight vinyl-ester monomers have poor fracture properties because of their high cross-link densities (9,19). High molecular weight vinyl-ester monomers yield resins with high fracture properties via matrix toughening.…”

Section: Introductionmentioning

confidence: 99%

Predicting the Viscosity of Low VOC Vinyl Ester and Fatty Acid-Based Resins

LaScala¹,

Jeyarajasingam²,

Winston³

et al. 2005

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)December 2005 ARL-TR-3681 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTStyrene and methacrylated fatty acid (MFA) monomers were used as reactive diluents in the vinyl ester resins. The viscosities of these resins were measured as a function of reactive diluent content and type, temperature, and vinyl ester molecular weight to determine the operating window for composite manufacture. The viscosity decreased exponentially with reactive diluent content. Styrene and MFA monomers affected the viscosity in the same manner, but not to the same extent. The viscosities of resins using both diluents were accurately predicted using a logarithmic rule of mixtures from the two-component viscosity functions. The viscosity increased exponentially and predictably as a function of the vinyl ester number average molecular weight. Increasing the temperature decreased the viscosity in an Arrhenius manner. The activation energy for viscous flow decreased linearly as the diluent content increased, but was unaffected by vinyl ester molecular weight, fatty acid chain length, and unsaturation level. Overall, the resin viscosity was modeled as simple functions of the resin temperature, vinyl ester molecular weight, styrene content, MFA content, MFA chain length, and MFA unsaturation level, which are all known quantities for a formulated resin. Therefore, the operating window for various liquid molding operations was predicted for standard DGEBA-based vinyl ester resins and low VOC/HAP resins. SUBJECT TERMSlow VOC vinyl esters, styrene, viscosity

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Mechanisms of Toughening Thermoset Resins

Abstract: MATERIALS SCIENTISTS ARE CONCERNED WITH QUANTITATIVE MECHANISMSof toughening and hope to predict the life expectancy of toughened thermosets. This endeavor should enable chemists to develop new polymers or tailor existing polymers to meet new requirements.

Cited by 57 publications

References 22 publications

Synthesis and Characterization of Silicone epoxy resin /poly (methyl methacrylate) Interpenetrating Polymer Networks

Synthesis and Characterization of Silicone epoxy resin /poly (methyl methacrylate) Interpenetrating Polymer Networks

Mechanical and Thermal Properties of Chemically Modified Epoxy Resin

Predicting the Viscosity of Low VOC Vinyl Ester and Fatty Acid-Based Resins

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