The influence of bridge groups nature in diepoxy compounds on kinetics of curing process by diamines and on physical and mechanical properties of forming polymers

1981 ◽  
Vol 4 (8) ◽  
Author(s):  
E.A. Dzhavadyan ◽  
N.K. Redkina ◽  
T.I. Ponomareva ◽  
E.V. Prut ◽  
L.A. Dudina ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Curing Process ◽  
Kinetics Of

scholarly journals Curing Reaction Kinetics of the EHTPB-Based PBX Binder System and Its Mechanical Properties

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1266
Author(s):  
Xing Zhang ◽  
Yucun Liu ◽  
Tao Chai ◽  
Zhongliang Ma ◽  
Kanghui Jia
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Reaction Kinetics ◽  
Testing Machine ◽  
Curing Process ◽  
Binder System ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Curing Reaction ◽  
Kinetics Of

In this research, differential scanning calorimetry (DSC) was employed to compare the curing reaction kinetics of the epoxidized hydroxyl terminated polybutadiene-isophorone diisocyanate (EHTPB-IPDI) and hydroxyl terminated polybutadiene-isophorone diisocyanate (HTPB-IPDI) binder systems. Glass transition temperature (Tg) and mechanical properties of the EHTPB-IPDI and HTPB-IPDI binder systems were determined using the DSC method and a universal testing machine, respectively. For the EHTPB-IPDI binder system, the change of viscosity during the curing process in the presence of dibutyltin silicate (DBTDL) and tin 2-ethylhexanoate (TECH) catalysts was studied, and the activation energy was estimated. The results show that the activation energies (Ea) of the curing reaction of the EHTPB-IPDI and HTPB-IPDI binder systems are 53.8 and 59.1 kJ·mol−1, respectively. While their average initial curing temperatures of the two systems are 178.2 and 189.5 °C, respectively. The EHTPB-IPDI binder system exhibits a higher reactivity. Compared with the HTPB-IPDI binder system, the Tg of the EHTPB-IPDI binder system is increased by 5 °C. Its tensile strength and tear strength are increased by 12% and 17%, respectively, while its elongation at break is reduced by 10%. Epoxy groups and isocyanates react to form oxazolidinones, thereby improving the mechanical properties and thermal stability of polyurethane materials. These differences indicate that the EHTPB-IPDI binder system has better thermal stability and mechanical properties. During the EHTPB-IPDI binder system’s curing process, the DBTDL catalyst may ensure a higher viscosity growth rate, indicating a better catalytic effect, consistent with the prediction results obtained using the non-isothermal kinetic analysis method.

Influence of tension in T300/epoxy prepreg winding process on the performance of the bearing composites

2017 ◽  
Vol 36 (15) ◽  
pp. 1099-1115 ◽  
Author(s):  
Yu Qing Cui ◽  
Zhong Wei Yin ◽  
Hu Lin Li
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Physical And Mechanical Properties ◽  
Experimental Results ◽  
Curing Process ◽  
Heavy Load ◽  
Proper Method ◽  
Properties Of Composites

In recent years, composite bearings are increasingly employed in marine and heavy load situations due to the specific properties of composites. However, for the tape winding composite bearings, the tension in process has not been studied in depth. In this study, a device was manufactured to apply tension to the process and the prepreg tape was T300/epoxy. Specimens with different tension values were selected for the experiment and the autoclave technology was applied to the curing process. Then, the appearance image and roundness of the bearing composites were acquired. Meanwhile, physical and mechanical properties of the specimen as well as the residual stress were measured. The experimental results show that the influence of tension in winding process on bearing composites is significant and the optimum tension can be defined. Subsequently, the article analyzes the function of the tension and it is concluded that the wrinkles and waves on the surface of the T300/epoxy bearing composites can be eliminated using proper method and the optimum tension should be determined through testing and experiment.

Influence of Nanosized Silica Component on Physical and Mechanical Properties of a Composite Gypsum Binder

2014 ◽  
Vol 584-586 ◽  
pp. 1756-1760 ◽  
Author(s):  
Elena Valerievna Voitovich ◽  
Alla Vasilievna Cherevatova ◽  
Igor Vladimirovich Zhernovsky ◽  
Hans Bertram Fischer ◽  
Valeria Valerievna Strokova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
System Analysis ◽  
Setting Time ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Fine Crystalline Structure ◽  
Size And Morphology ◽  
Kinetics Of ◽  
Reduced Water ◽  
Nanosized Silica

The work presents the results of development of the composite gypsum binder (GB) with nanostructured binder on the basis of silica component (NBC). Introduction of NBC changes the kinetics of hardening, as well as improves physical and mechanical properties of gypsum system. Analysis of the microstructure of the GB has demonstrated in the presence of the NB the size and morphology of crystals are changed, promoting the formation of fine-crystalline structure and increase the contact area between new formations, compared to NBC – free gypsum system. Experimental studies have shown that the mechanical properties of the composite gypsum application of NBC increased, reduced water absorption, density increases, and increases the setting time.

scholarly journals Modification of Thiol-Ene Ionogels with Octakis(methacryloxypropyl) Silsesquioxane

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 385
Author(s):  
Aneta Lewandowska ◽  
Piotr Gajewski ◽  
Katarzyna Szcześniak ◽  
Mariola Sadej ◽  
Piotr Patelski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Network Formation ◽  
Physical And Mechanical Properties ◽  
Imidazolium Ionic Liquid ◽  
Puncture Strength ◽  
Oligomeric Silsesquioxane ◽  
Conductive Properties ◽  
Kinetics Of

The effect of polyhedral oligomeric silsesquioxane (POSS) on the synthesis and properties of hybrid organic–inorganic ionogels was investigated using octakis(methacryloxypropyl) silsesquioxane (methacryl-POSS). Ionogels were prepared in situ by thiol-ene photopolymerization of triallyl isocyanurate with pentaerythritol tetrakis(3-mercaptopropionate) in a mixture of imidazolium ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImNTf2) and propylene carbonate (PC). Investigations included the kinetics of hybrid materials formation and selected physical and mechanical properties. The disadvantage of ionogels without the methacryl-POSS modifier is leakage and insufficient mechanical properties. Modifying the thiol-ene matrix by the addition of methacryl-POSS made it possible to obtain non-leaking ionogels with improved mechanical and conductive properties. The steric hindrance of POSS cages and high-density network formation played important roles in ionogel synthesis: decrease of polymerization rate (with almost no effect on conversion), as well as dimensions of the formed polymer spheres during dispersion polymerization (highly cross-linked polymer has poorer solubility in polymerizing medium at a similar conversion, and nucleation begins at lower conversion), an increase of glass transition temperature and puncture strength. Hybrid ionogels with high ionic conductivity in the range of 4.0–5.1 mS∙cm−1 with the maximum parameter for 1.5 wt.% addition of the methacryl-POSS were obtained, which can be associated with ion-pair dissociations in ionic liquid clusters caused by methacryl-POSS.

MODELING OF THE CURING PROCESS OF A POLYMER RESIN AND CHANGES IN MICROHARDNESS IN ITS VOLUME

2021 ◽  
pp. 92-99
Author(s):  
V.I. Postnov ◽  
◽  
S.M. Kachura ◽  
E.A. Veshkin ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Degree Of Conversion ◽  
Curing Temperature ◽  
Curing Process ◽  
The Finite Element Method ◽  
Polymer Resin ◽  
Family Of Curves ◽  
The Family ◽  
Thermophysical Modeling

Curing parameters have the greatest impact on the physical and mechanical properties of FRP, therefore their optimum value is of particular importance for obtaining quality products. During curing temperature of the inner layers of the FRP can increase unevenly, which can lead to the formation of a gradient in the degree of conversion and heterogeneity of physical and mechanical properties. The article is devoted to the development of a mathematical model of the curing process of the EDT-69N resin, taking into account the kinetic parameters of curing and implementation thermophysical modeling using the finite element method. The correspondence of the family of curves for the degree of conversion along the sample cross-section and the family of microhardness curves is also shown.

scholarly journals Effect of complex flame retardant on physico-chemical properties of orthophthalic unsaturated resin

2020 ◽  
pp. 26-29
Author(s):  
Y. M. Yevtushenko ◽  
Y. A. Grigoriev ◽  
I. O. Kuchkina ◽  
E. V. Afoshina ◽  
G. A. Krushevsky
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Flame Retardant ◽  
Unsaturated Polyester ◽  
Chemical Properties ◽  
Physical And Mechanical Properties ◽  
Polyester Resins ◽  
Physico Chemical ◽  
Kinetics Of

A brief review of the results of studies on reducing the combustibility of composite materials based on unsaturated polyester resins is presented. A flame retardant orthophthalic unsaturated resin based on a complex flame retardant was developed and studied. It is shown that the category for resistance to burning of the resin is achieved with 15–20% filling of the complex flame retardant based on ammonium polyphosphate, melamine and pentaerythritol. The kinetics of curing and physical and mechanical properties of the composite material are evaluated.

scholarly journals SHOTCRETE IN MINE CONSTRUCTION

Vestnik MGSU ◽  
2017 ◽  
pp. 780-787 ◽  
Author(s):  
Vyacheslav Aleksandrovich Alekseev ◽  
Aleksey Igorevich Kharchenko ◽  
Vadim Gennad’evich Solovyev ◽  
Roman Nikolaevich Nikonorov
Keyword(s):  
Mechanical Properties ◽  
Performance Improvement ◽  
Experimental Analysis ◽  
Calculation Method ◽  
Physical And Mechanical Properties ◽  
Well Bore ◽  
Chemical Additives ◽  
Subsurface Structures ◽  
Fast Development ◽  
Kinetics Of

This article deals with concerns of construction of subsurface structures with the use of shotcrete as a support, the samples of mine construction with application of shotcrete have been shown, in particular projected mine with vertical well bore. The calculation method for construction of well bore with the use of shotcrete support has been stated, the major analytical relationships have been set out, a graph showing the growth of strength in a support has been generated for several sites according to the results of actual geotechnical survey. The research of properties of concrete with fast development of strength has been implemented for mine engineering and construction of transportation infrastructure. The results of experimental analysis of shotcrete with organo-mineral and chemical additives have been listed. Performance improvement of physical and mechanical properties of shotcrete has been proven when the complex active nano agent added into composition of the binder. Improved kinetics of development of strength related to accelerated admixture helps in proportioning concrete compositions for practically any firm and medium-firm grounds during construction of support of subsurface structures.

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