Characterization of the deformation behavior of dynamic vulcanizates by FTIR spectroscopy

Abstract

To clarify the deformation mechanisms and to improve the mechanical properties of dynamic vulcanizates, we studied their deformation behavior by Fourier‐transform infrared (FTIR) spectroscopy. It was found that the orientation in the dispersed phase (EPDM phase) is higher than in the matrix (PP phase) upon loading. The orientation of the rubber phase increases continuously. In the thermoplastic phase, a change of the deformation mechanism takes place. With respect to the total strain of the material, the orientation in the thermoplastic phase of the dynamic vulcanizates is lower, and in the elastic phase, it is higher than the corresponding orientation of the pure components. During stress relaxation, there is an increase of the orientation in the crystalline PP phase. Simultaneously, a decrease of the orientation in the EPDM phase is observed. Upon unloading, the orientation recovery in the EPDM phase is always complete, while the orientation recovery in the PP phase is reversible only at low strains. The critical point, where the elastic deformation gets lost, corresponds to the minimum in the orientation function curve. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 148–158, 2001

Rheological, mechanical and morphological properties of thermoplastic vulcanizates based on high impact polystyrene and styrene‐butadiene rubber

“…The tensile set at break increases markedly with the increasing HIPS loading when the HIPS content is below 50 wt %, where the dynamic vulcanized HIPS/SBR blends behave as TPVs. Generally, the dynamic vulcanizates exhibit large reversibility and small residual strains 27. The elastomeric crosslinked SBR particles dispersed in the HIPS matrix enable the HIPS/SBR blends to elastically recover from a highly deformed state.…”

“…Generally, the dynamic vulcanizates exhibit large reversibility and small residual strains. 27 The elastomeric crosslinked SBR particles dispersed in the HIPS matrix enable the HIPS/SBR blends to elastically recover from a highly deformed state. As a result, higher SBR loading lead to lower tensile set at break, as shown in Figure 6.…”

Molecular deformation mechanisms of isotactic polypropylene in α‐ and β‐crystal forms by FTIR spectroscopy

“…Infrared spectroscopy is chemically specific and quite susceptible to chain conformation. A combination of Fourier transformed infrared (FTIR) spectroscopy and mechanical testing (i.e., rheo‐optic methods) have been used effectively to characterize the orientation behavior of α‐PP, which has been documented in numerous publications13–16 For β‐PP, however, investigations of deformation behavior has focused mainly on the β–α transformation 4, 5, 8, 17–19. Thus, the objective of this work was to compare the structural changes of α‐ and β‐PP during uniaxial deformation at room temperature.…”

Deformation and molecular orientation in films of metallocene polypropylene, ethylene–butylene rubber, and their 80/20 (w/w) blend revealed by the simultaneous kinetic measurement of microscopic infrared dichroism, macroscopic stress, and mesoscale strain

“…Such results reflect stiffness differences in both components that lead to local strain differences in the heterogeneous material. 34 It is well known that the microscopic deformation in polymer blends containing rubbery spheres is highly inhomogeneous, and the molecular orientation in the matrix should vary strongly with position in the vicinity of the rubbery domains. The matrix in the polar zones between adjacent rubbery domains in the draw direction acts as an interconnecting ligament.…”