Synthesis and Cure Kinetic Studies of a New Trifunctional Imide Oligomer

2010 ◽  
Vol 152-153 ◽  
pp. 1775-1782
Author(s):  
Cheng Yang Wang ◽  
Xiao Gang Zhao ◽  
Xiao Hui Yu ◽  
Chang Wei Liu ◽  
Yun Liang Wang
Keyword(s):  
High Performance ◽  
Kinetic Studies ◽  
Curing Kinetics ◽  
Dynamic Mode ◽  
Processing Temperature ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Excellent Thermal Stability ◽  
High Performance Composite ◽  
High Performance Resin

A novel phenylethynyl-terminated imide oligomer was prepared from a trifunctional amine and 4-phenylethynylphthalic anhydride (PEPA). The oligomer can be used to prepare the high performance resin-based composite material via resin transfer molding (RTM) due to its low melt viscosity(<2Pa.s) between 250°C and 320°C.The cured resin exhibits excellent thermal stability than PETI series as a result of the introduction of star-branched units. The thermal analysis of the curing kinetics of resin was carried out by differential scanning calorimetry (DSC), with the rate of cure reaction and the degree of cure calculated in the dynamic mode and being tested under isothermal conditions. A reasonable agreement between the experimental data and the kinetic model has been obtained over the whole processing temperature range which was important for processing simulation and quality control of processing for high performance composite.

scholarly journals Curing Kinetics Analysis of Dgeba-Mda System

1994 ◽  
Vol 3 (3) ◽  
pp. 096369359400300
Author(s):  
G. Carotenuto ◽  
L. Nicolais
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Performance ◽  
Spectroscopic Analysis ◽  
Curing Kinetics ◽  
Kinetics Analysis ◽  
Epoxy System ◽  
Scanning Calorimetry ◽  
Step Process ◽  
Characterization Study ◽  
High Performance Composite

Thermoset polymers and thermoset based composites are normally polymerized and performed in a step process. This work studies the kinetics behavior of a commercial epoxy system used as matrices of medium and high performance composite materials. The characterization study was performed by differential scanning calorimetry (DSC) and spectroscopic analysis.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

Curing behaviors and properties of epoxy and self-catalyzed phthalonitrile with improved processability

2017 ◽  
Vol 30 (6) ◽  
pp. 710-719 ◽  
Author(s):  
Mingli Jiang ◽  
Yangxue Lei ◽  
Xiaobo Liu
Keyword(s):  
High Performance ◽  
Curing Kinetics ◽  
Adhesive Property ◽  
Thermal Stabilities ◽  
Practical Applications ◽  
Low Viscosity ◽  
System Composition ◽  
High Performance Resin ◽  
Initial Processing ◽  
Gel Transition

The curing behaviors for high-performance resin system phthalonitrile-containing benzoxazine and epoxy (BA-Ph/EP), particularly the effect of the binary system composition and processing conditions on their processabilities were investigated and discussed in this article. Results indicated that all BA-Ph/EP prepolymers exhibited low initial processing viscosity (<0.3 Pa s) and have kept stable low viscosity until gel transition. The suitable molding temperature (ranged from 150°C to 180°C) and molding time (ranged from 20 min to 80 min) could be selected for practical applications of BA-Ph/EP systems. The studies of curing behaviors and gelatinization for BA-Ph/EP systems give further understanding of the curing kinetics and guidance for the fabrication of high-performance copolymers/polymers. The introduction of EP could significantly improve the cross-linking density of BA-Ph/EP polymers, and the appropriate content of EP is the key fact for the improvement. In addition, the effects of postcuring conditions on thermal properties and the adhesive property of BA-Ph/EP polymers were monitored. The thermal stabilities and adhesive property of various polymers also showed an obvious influence with the introduction of EP. The systematic study of BA-Ph/EP system could enable a broadened industrial application, especially in the areas that require high-temperature resistance.

Rheological Behaviors Characterization and Modeling of a Novel Three-Branched Phenylethynyl-Terminated Imide Oligomer

2011 ◽  
Vol 199-200 ◽  
pp. 83-86
Author(s):  
Chang Wei Liu ◽  
Xiao Gang Zhao ◽  
Cheng Yang Wang ◽  
Xiao Hui Yu ◽  
He Jia ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Composite Material ◽  
High Performance ◽  
Resin Transfer Molding ◽  
Experimental Measurements ◽  
Melt Viscosity ◽  
Arrhenius Model ◽  
Excellent Thermal Stability ◽  
Transfer Molding ◽  
High Performance Resin

To prepare novel polyimides with enhanced thermal stability and low melt viscosity, a novel three-branched phenylethynyl-terminated imide oligomer was introduced. The oligomer can be used to prepare high performance resin-based composite material via resin transfer molding (RTM) due to its low melt viscosity (<2Pa.s) between 250°C and 320°C. The cured resin exhibits excellent thermal stability and higher glass transition temperature than PETI series as a result of the introduction of star-branched units. In this research, the rheological properties of the oligomer were measured and numerically fit with the dual Arrhenius model to predict the progression of the viscosity during cure. The calculated kinetic activation energies for gelation with two different Arrhenius equations, 120.8kJ/mol and 164kJ/mol, respectively,had some differences. The numerical results were compared with the experimental measurements, and it was found that the model predicts the experimental observations quite well.

Kinetic studies on the cure reaction of hydroxyl-terminated polybutadiene based polyurethane with variable catalysts by differential scanning calorimetry

e-Polymers ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Ma Hui ◽  
Liu Yu-Cun ◽  
Chai Tao ◽  
Hu Tuo-Ping ◽  
Guo Jia-Hu ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Reaction Rate ◽  
Catalytic Effect ◽  
Kinetic Studies ◽  
Rate Equations ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Pot Life ◽  
Cure Reactions

AbstractThis paper employs differential scanning calorimetry (DSC) to investigate the reactions of hydroxyl-terminated polybutadiene (HTPB) binder and isophorone isophorone diisocyanate (IPDI) with two different cure catalysts, namely, dibutyl tin dilaurate (DBTDL) and stannous octanoate (TECH). This study evaluates the effects of two cure catalysts (i.e. DBTDL and TECH) on rate constants of the polyurethane cure reactions. Throughput the study, the kinetic parameters and the curing reaction rate equations are obtained. The present work concludes that both catalysts had a catalytic effect on the HTPB-IPDI system, but that the catalytic effect of DBTDL was higher than that of TECH. The binder system with the TECH catalyst displayed a longer pot-life and lower toxicity compared with the DBTDL. Additionally, this study investigates the binder system’s viscosity build-up at 35°C and the viscosity build-up results were in agreement with the DSC analysis results.

Thermally Stable Polyimide/Silica Hybrid: Synthesis, Characterization and Optical Nonlinearity

2010 ◽  
Vol 123-125 ◽  
pp. 1275-1278
Author(s):  
Guang Yu Wu ◽  
Cheng Yao ◽  
Feng Xian Qiu
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Nonlinear Optical ◽  
Sol Gel ◽  
Optical Nonlinearity ◽  
29Si Nmr ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Electro Optic

An intercalation nonlinear-optical (NLO) polyimide was synthesized based on the 3,3’, 4,4’- Bisphenyltetracarboxylic (BPDA) and [(6-nitrobenzothiazole-2-yl)diazenyl]phenyl-1,3- diamine (NBADA). Then, hybrid polymer was synthesized by the sol-gel technique. FT-IR spectroscopy and 29Si NMR were used to characterize the structure of the hybrid. The results revealed that Q3, Q4 and T3 are the major microstructure elements in forming a network structure. The surface morphology, particle size, crystallinity and the thermal stability of the hybrid were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). DSC and TGA results showed that the glass transition temperature (Tg) and the decomposition temperature (Td) at 5% mass loss were 243, 359°C and 355, 456°C, respectively. These results showed that the hybrid material had excellent thermal stability than the pure polyimide. The electro-optic coefficients of nonlinear optical polyimide and hybrid were measured at the wavelength of 832 nm. The electro-optic coefficients were 22 and 19pm/V (poling voltage of 3.8KV, 210°C) and the values remained well (retained＞93% for more than 100h). The results suggest that the materials have potential applications for high performance optical device.

A new resin with improved processability and thermal stability

2016 ◽  
Vol 29 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Liping Sheng ◽  
Jingcheng Zeng ◽  
Suli Xing ◽  
Changping Yin ◽  
Jinshui Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Synergistic Effect ◽  
Curing Temperature ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Curing Time ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Excellent Thermal Stability

To maintain outstanding thermal stability, amino- and hydroxyl-containing phthalonitrile monomers, 4-(4-aminophenoxy)-phthalonitrile (APN) and 4-(4-hydroxyphenoxy)-phthalonitrile (HPN) were selected and synthesized. Their structures were confirmed by proton nuclear magnetic resonance spectroscopy. Their curing polymers were characterized by Fourier transform infrared spectroscopy. The self-catalytic curing behaviors of the monomers were investigated by differential scanning calorimetry (DSC) at different heating rates. From the results, APN exhibits a higher curing temperature, while HPN exhibits a longer curing time. Then, mixtures of these monomers were investigated by DSC. The result shows that the 50/50 mixture exhibits different autocatalytic behaviors: the curing temperature is lower than that of APN and the curing time of the mixture is shorter than that of HPN. Furthermore, thermogravimetric analysis shows that the polymer from the mixture exhibits higher temperature of 5% weight loss ( T5%) and char yield value at 800°C than those of the polymers from each monomer. All these results indicate that the new mixture resin exhibits improved processability with excellent thermal stability, attributed to the synergistic effect between similar monomers; the synergistic effect optimizes the cure reaction kinetics and promotes cross-linking reactions, thereby producing an excellent resin; this approach is a new method for improving the processability without sacrificing thermal stability.

Core Programs of High-Performance Composite Materials

1998 ◽  
Author(s):  
A. Crasto ◽  
D. Anderson ◽  
R. Esterline ◽  
K. Han ◽  
C. Hill
Keyword(s):  
Composite Materials ◽  
High Performance ◽  
High Performance Composite

pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase

2019 ◽  
Vol 26 (10) ◽  
pp. 743-750 ◽  
Author(s):  
Remya Radha ◽  
Sathyanarayana N. Gummadi
Keyword(s):  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Kinetic Studies ◽  
Structural Features ◽  
Structure Stability ◽  
Kcal Mole ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Ph Dependent ◽  
Ph Range

Background:pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry.Objective:The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase.Methods:Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase.Results:The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1.Conclusion:The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0–7.0.

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