Abstract:A phenylethynyl-terminated imide oligomer (PETI)was prepared from a triamine and 4-phenylethynylphthalic anhydride. The oligomer can be used to prepare high performance resin-based composite material via resin transfer moulding due to its low melt viscosity. The cured resin also exhibited excellent thermal stability with 5% weight loss at temperature above 531 C and higher glass transition temperature T g (410 C) than PETI series as a result of the introduction of star-branched units. The rheological propertie… Show more
“…A similar temperature dependency was reported by Yang et al. 31 for a PETI oligomer with similarities to MHT-R but prepared from a triamine and 4-phenylethynylphthalic anhydride. MHT-R appears to exhibit slightly lower absolute viscosity numbers.…”
Section: Resultssupporting
confidence: 83%
“…This is typical for thermally initiated phenylethynyl crosslinking and is similar to results obtained in previous studies on polymers with similar chemistries. 30,31 The total heat of reaction of MHT-R, ΔH is approximately 220 J/g, and hence lower than values for BMI (389 J/g) 32 and typical aeronautical grade amine cured epoxies (450 J/g). 33 Figure 1.Dynamic DSC-scans of MHT-R resin at a heating rate of 10℃/min.…”
Section: Resultsmentioning
confidence: 81%
“…The initiation of the exothermic curing reaction is at 320 C and the peak reaction rate is reached at 390 C. This is typical for thermally initiated phenylethynyl crosslinking and is similar to results obtained in previous studies on polymers with similar chemistries. 30,31 The total heat of reaction of MHT-R, ÁH is approximately 220 J/g, and hence lower than values for BMI (389 J/ g) 32 and typical aeronautical grade amine cured epoxies (450 J/g). 33 Rheometer tests, both in viscometry mode and oscillation mode, provide the foundation for evaluating the ability to process MHT-R.…”
In this study, an assessment of the composite processing-related properties of a newly developed 6-FDA-based phenylethynyl-terminated polyimide (available under the tradename NEXIMID Õ MHT-R) is presented. Processing schemes, used for preparing high quality carbon fibre-reinforced composites by the use of conventional resin transfer moulding are developed and presented. The influences of manufacturing parameters on glass transition temperature of the composites are presented. The results confirm that composites with exceptionally high T g , in the range between 350 and 460 C can be achieved. A manufacturing scheme that yields in composites with T g of 370 C is presented and proposed as a good candidate to serve as baseline for further studies.
“…A similar temperature dependency was reported by Yang et al. 31 for a PETI oligomer with similarities to MHT-R but prepared from a triamine and 4-phenylethynylphthalic anhydride. MHT-R appears to exhibit slightly lower absolute viscosity numbers.…”
Section: Resultssupporting
confidence: 83%
“…This is typical for thermally initiated phenylethynyl crosslinking and is similar to results obtained in previous studies on polymers with similar chemistries. 30,31 The total heat of reaction of MHT-R, ΔH is approximately 220 J/g, and hence lower than values for BMI (389 J/g) 32 and typical aeronautical grade amine cured epoxies (450 J/g). 33 Figure 1.Dynamic DSC-scans of MHT-R resin at a heating rate of 10℃/min.…”
Section: Resultsmentioning
confidence: 81%
“…The initiation of the exothermic curing reaction is at 320 C and the peak reaction rate is reached at 390 C. This is typical for thermally initiated phenylethynyl crosslinking and is similar to results obtained in previous studies on polymers with similar chemistries. 30,31 The total heat of reaction of MHT-R, ÁH is approximately 220 J/g, and hence lower than values for BMI (389 J/ g) 32 and typical aeronautical grade amine cured epoxies (450 J/g). 33 Rheometer tests, both in viscometry mode and oscillation mode, provide the foundation for evaluating the ability to process MHT-R.…”
In this study, an assessment of the composite processing-related properties of a newly developed 6-FDA-based phenylethynyl-terminated polyimide (available under the tradename NEXIMID Õ MHT-R) is presented. Processing schemes, used for preparing high quality carbon fibre-reinforced composites by the use of conventional resin transfer moulding are developed and presented. The influences of manufacturing parameters on glass transition temperature of the composites are presented. The results confirm that composites with exceptionally high T g , in the range between 350 and 460 C can be achieved. A manufacturing scheme that yields in composites with T g of 370 C is presented and proposed as a good candidate to serve as baseline for further studies.
“…For these years, phenylethynyl‐terminated imides (PETIs) have been widely employed as matrices and adhesive for high temperature applications due to its unique thermal curing process to afford thermoset resin with outstanding mechanical strength and toughness . Therefore, PETIs oligomers have received sustained attention . In recent years, it was found that phenylethynyl‐endcapped oligomers with calculated molecular weights as low as 750 g mol −1 could be melted at 280 °C to give low viscous and stable molten fluid, showing good features for resin transfer molding (RTM) processing.…”
A series of thermoset oligoimides have been prepared by the thermal polycondensation of 1,4-bis(2,3-dicarboxyl-phenoxy)benzene dianhydride with three different aromatic diamines in the presence of 4-phenylethynylphthalic anhydride as an end capping reagent. The aromatic diamines included 4,4 0 -oxydianiline, 2,2 0 -bis(trifluoromethyl)benzidine (TFDB) and 2-phenyl-4,4 0 -diaminodiphenyl ether (p-ODA). Effects of the chemical structures and molecular weights of the oligoimides on their aggregated structures, melt processability as well as the thermal and mechanical properties of the cured films were then systematically investigated. X-ray diffraction results indicated that ODA series oligoimides and TFDB series oligoimides showed crystallinity; however, the asymmetrical p-ODA enables the p-ODA series oligoimides to exhibit amorphous forms. So the p-ODA based oligoimides with molecular weight of 750 g mol −1 showed much lower melt viscosity at a low temperature and the melt viscosity could maintain below 1 Pa s −1 after isothermal aging for 2 h at any temperature in the range of 220-280 C by rheological measurements.
“…The heat flow of the sample as a function of temperature measured by differential scanning calorimetry (DSC) is extensively used as the raw data to study the cure kinetics. 5 –9 The activation energy and kinetic parameters of curing process are all deduced from isothermal or nonisothermal DSC cures. 10,11 Isoconversion methods are the most commonly used and most reliable methods for obtaining activation energies of curing reactions.…”
The curing kinetics of two different types of commercial epoxy resins were investigated by means of nonisothermal differential scanning calorimetry (DSC) in this work. The complex curve of measured heat flow of CYCOM 970 epoxy resin was simplified with the method of resolution of peak. Two typical autocatalytic curing reaction curves were gained and the kinetic parameters of the curing process were demonstrated by combination of those two reactions. The Kissinger method was adopted to obtain the values of the activation energy. The parameters of curing kinetic model were acquired according to the fitting of Kamal model. Isothermal DSC curve of CYCOM 970 epoxy resin obtained using the experimental data shows a good agreement with that theoretically calculated. Then, 603 epoxy resin was investigated by the simplified method and the kinetic parameters were received through the same procedure. The nonisothermal DSC curve tested according to the recommended cure cycle of 603 epoxy resin is also consistent with the calculated results. This improved simplified approach provides an effective method to analyze the curing kinetics of the epoxy resins with complex DSC curves as similar to this study.
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