scholarly journals Glass Transition Temperature, Free Volume, and Curing Kinetics of Unsaturated Polyester

1993 ◽  
Vol 25 (9) ◽  
pp. 897-907 ◽  
Author(s):  
S C Ma ◽  
H L Lin ◽  
T L Yu
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Free Volume ◽  
Unsaturated Polyester ◽  
Curing Kinetics ◽  
Kinetics Of

scholarly journals Synthesis and Application of Arylaminophosphazene as a Flame Retardant and Catalyst for the Polymerization of Benzoxazines

2020 ◽  
Author(s):  
Natalia V. Bornosuz ◽  
Irina Yu. Gorbunova ◽  
Vyacheslav V. Kireev ◽  
Yulya V. Bilichenko ◽  
Larisa V. Chursova ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Flame Retardant ◽  
Curing Kinetics ◽  
Complex Nature ◽  
Flame Resistance ◽  
Step Model ◽  
Flammability Characteristics ◽  
And Shifts

A novel type of phosphazene containing additive that act both as catalyst and as flame retardant for benzoxazine binders is presented in this study. The synthesis of a derivative of hexachlorocyclotriphosphazene (HCP) and meta-toluidine was carried out in the medium of the latter, which made it possible to achieve complete substitution of chlorine atoms in the initial HCP. Thermal and flammability characteristics of modified compositions are revealed. The modifier catalyzes the process of curing and shifts the beginning of reaction from 222.0 C for pure benzoxazine to 205.9 C for composition with 10 phr of modifier. The additive decreases the glass transition temperature of compositions. Achievement of the highest category of flame resistance (V-0 in accordance with UL-94) is ensured both by increasing the content of phenyl residues in the composition and by the synergistic effect of phosphorus and nitrogen. Brief research of the curing kinetics disclosed the complex nature of the reaction. An accurate two-step model is obtained using extended Prout-Tompkins equation for both steps.

Reentanglement Kinetics of Freeze-Dried Polymers above the Glass Transition Temperature

2012 ◽  
Vol 45 (16) ◽  
pp. 6648-6651 ◽  
Author(s):  
Chao Teng ◽  
Yun Gao ◽  
Xiaoliang Wang ◽  
Wei Jiang ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Freeze Dried ◽  
Kinetics Of

scholarly journals Construction of a TTT-η Diagram of High-Refractive Polyurethane Based on Curing Kinetics

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3474
Author(s):  
Shidi Huang ◽  
Guiming Zhang ◽  
Weiping Du ◽  
Huifang Chen
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Gelation Time ◽  
Curing Kinetics ◽  
Processing Parameters ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Temperature Transformation

A time–temperature–transformation–viscosity (TTT-η) diagram can reflect changes in the physical states of a resin, which take on significance for the study of the curing process of polyurethane resin lenses. Coupling the differential scanning calorimetry (DSC) test, the curing kinetic parameters of 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI)/2,3-bis((2-mercaptoethyl)thio)-1-propanethiol (BES) polyurethane system were obtained. By phenomenological modeling, the relationships between degree, temperature, and time were obtained. An isothermal DSC test was carried out at 423 K. Based on the DiBenedetto equation, the relationships between glass transition temperature, degree of cure, and time were obtained, and the glass transition temperature was thus correlated with temperature and time. The gelation time at different temperatures was measured by rotary rheometry, and the relationship between gelation time and gelation temperature was established. The time–temperature–transformation (TTT) diagram of H6XDI/BES system was constructed accordingly. Subsequently, a six-parameter double Arrhenius equation was used as the basis for the rheological study. The viscosity was examined during the curing process. The TTT-η diagram was obtained, which laid the theoretical foundation for the optimization and setting of processing parameters.

scholarly journals MODIFICATION OF OLIGOESTER MALEINATE BY ALKYL ESTER OF N-MALEINIMIDOBENZOIC ACID

2019 ◽  
Vol 62 (12) ◽  
pp. 78-84
Author(s):  
Vladimir A. Danilov ◽  
Oleg A. Kolyamshin ◽  
Nadezhda E. Temnikova ◽  
Oleg V. Stoyanov ◽  
Marina V. Kolpakova
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Unsaturated Polyester ◽  
Ester Group ◽  
Thermomechanical Properties ◽  
Hydrocarbon Radical ◽  
Butyl Ether ◽  
Effect Of Substituents ◽  
Aromatic Group

When using products from unsaturated polyester resins (NPS), often increased requirements for thermal and chemical resistance are raised. Increasing the thermal stability of the PS is possible due to the modification of resins by polymerization compounds, which can copolymerize with both oligoether maleinate and styrene. One of such effective additives is N-phenylmaleinimides. The paper presents the results of modification of unsaturated polyester grade PN-1 UT with alkyl ethers n-maleinimidobenzoic acid. The properties of terpolymers are investigated. The effect of substituents of the aromatic group with N-phenylmaleinimides on the properties of terpolymers was investigated. It is also of interest to study the effect of substituents of the aromatic group in N-phenylmaleinimide on the properties of modified polymers. It is shown that terpolymers due to their maleinimides are superior in strength and thermomechanical properties of the copolymers of oligoestermaleinate and styrene. The increase in the size of the hydrocarbon radical substituents of the aromatic group of maleinimides contributes to the increase of the thermo-and physico-mechanical properties of terpolymers. It is also shown that the glass transition temperature of polymers depends on the content of maleinimides, as well as on the structure of the aromatic group. With an increase in the content of maleinimides (up to 5 wt. %) there is an increase in the glass transition temperature and the beginning of the destructive flow. The greatest increase in glass transition temperature (30 °C) is observed at a content of 3 wt. % butyl ether of n-maleimidobenzoic acid. The increase in the length of the hydrocarbon radical (С5Н11 and С8Н17) of the ester group of n-maleimidobenzoic acid leads to the appearance of a plasticizing effect. Synthesized terpolymers can be recommended as binders in the production of heat-resistant composite materials, in particular, fiberglass.

Cure Kinetics of Nanocomposites Prepared From Aqueous Dispersion of Nanoclay

2006 ◽  
Author(s):  
Levent Aktas ◽  
M. Cengiz Altan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Storage Modulus ◽  
Glass Fibers ◽  
Aqueous Dispersion ◽  
Cure Kinetics ◽  
Temperature Cycle ◽  
Waterborne Epoxy ◽  
Kinetics Of

The effect of nanoclay on the cure kinetics of glass/waterborne epoxy nanocomposites is investigated. First step in sample preparation involves dispersing Cloisite® Na+, a natural montmorillonite, in distilled water at 70°C with the aid of a sonicator. Then, desired amounts of dicyandiamide and 2-methyl imidazole, serving as cross-linkers, are mixed to the aqueous nanoclay solution. As the mixing continues, Epi-Rez 3522-W-60 waterborne epoxy resin is introduced to the solution and the compound is mixed for an additional 30 minutes. The nanoclay content of this batch is adjusted to be at 2wt%. An identical second batch, which does not comprise nanoclay, is also prepared to serve as the baseline data. Glass/waterborne epoxy prepregs containing 30% glass fibers are prepared from these batches and used to characterize the effects of nanoclay. The evolution of viscoelastic properties during curing are characterized by the APA2000 rheometer. Using the storage and loss moduli profiles during curing, gel time and maximum storage modulus are characterized. Effect of nanoclay on the glass transition temperature is determined by applying an additional temperature cycle following the cure cycle. In addition, mechanical performances of the samples are characterized by three point bending tests. Nanoclay is observed to yield 2-fold higher storage modulus during curing. Rate of curing is measured to be substantially slower for the samples comprising nanoclay. In addition, glass transition temperature improved by 5% to 99°C with the addition of nanoclay compared to 94.5°C for the samples without nanoclay. Flexural stiffness of the samples containing nanoclay is measured to be 20% higher than the samples without nanoclay while the strength remained virtually unaffected.

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