Glass transition temperature-temperature-property (TgTP) diagram for EPY epoxy system

Abstract

Evolution of storage and loss moduli during conversion progress of the filled epoxy system EPY ® (Epidian 6 with triethylenetetramine), applied for the production of machine foundation chocks, was studied using dynamic mechanical thermal analysis (DMTA). The results obtained and the results previously reached by differential scanning calorimetry (DSC) and rotational viscometry made possible to determine the diagram glass transition temperature-temperature-property (TgTP) for the investigated system, where Tg is the direct measure of conversion and P denotes property under investigation -loss modulus. This way of using T g in this diagram makes possible the linearization of the relationships among the temperatures corresponding to the maxima and minima of the physical properties and the extent of cure. The lines within T g TP diagram show the courses of structural transformations during cure i.e. glass transition (T g ), β-transition (T β ) and gelation ( gel T g ). The diagram lines separate several regions which are dependent on the extent of cure and the material shows different physical properties within each of them. TgTP diagram calculated for the EPY ® material can facilitate understanding of the relationships among transitions and material properties.

Comparative Analysis of Polyurethane Drive Belts with Different Cross-Section Using Thermomechanical Tests for Modeling the Hot Plate Welding Process

“…It should be noted that the change in the measured mechanical parameters and the glass transition temperature T g SS occurs to the same extent for all the methods of analysis presented (analysis of the shear storage modulus G ′, the shear loss modulus G ″, and the loss angle δ ), which indicates the correct selection of the test methodology [ 48 , 54 , 57 , 58 , 59 , 60 ].…”

“…Two types of samples were used for testing [ 48 , 49 , 50 , 51 , 52 ]: Type A samples, taken from the belt of the circular cross-section and diameter d = 18 mm, machined into the form of rectangular beams of the following dimensions: 53.50 ± 0.31 × 10.21 ± 0.20 × 3.74 ± 0.33 mm, Type B samples, taken from the flat belt, guillotined into the form of rectangular beams of the following dimensions: 49.67 ± 0.13 × 9.84 ± 0.15 × 3.93 ± 0.08 mm. …”

“…The measurement system recorded the response of the belts to forced oscillations in the form of the shear storage modulus G ′, the shear loss modulus G ″, the loss angle δ , and the value of the current temperature T where the sample is located. These DMTA tests were performed with the following assumptions [ 48 , 52 , 53 ]: Temperature range from −100 to +180 °C recorded in continuous mode, Rate of temperature change = +5 °C/min during heating and = −5 °C/min during cooling, Oscillation amplitude A = 0.02%, Oscillation frequency f = 1 Hz. …”

“…Soft segment glass transition temperature values T g SS are determined on the basis of the characteristic points of the cyclical loading response [ 48 , 54 , 57 , 58 , 59 , 60 ]: Intersections of tangent relations of the shear storage modulus G ′ and temperature, The maximum value of the shear loss modulus G ″, The maximum value of the loss coefficient tan δ . …”

Development of Novel Thin-Ply Technology for Carbon Fibre Composite Materials

“…A further possible mechanism for the increased strength is that the increased temperature allowed the resin matrix to cure further, making the material stronger. Thermosetting materials, such as epoxy resins, experience molecular cross-linking during the curing process [115]. If the resin matrix within the laminates was not fully cured during the manufacturing process, it is possible that the additional heat from the tensile test enabled more crosslinks to form.…”