Poly(vinylidene fluoride)–acrylic rubber partially miscible blends: Phase behavior and its effects on the mechanical properties

Abstract

A phase diagram of poly(vinylidene fluoride) (PVDF) and acrylic rubber (ACM) was plotted, and the effects of the extent of miscibility on the mechanical properties of the polymer blends were examined. A compressible, regular solution model was used to forecast the phase diagram of this blend. The model prediction, the lower critical solution temperature (LCST) over the upper critical solution temperature (UCST), was done qualitatively according to the experimentally determined phase diagram by differential scanning calorimetry (DSC), optical microscopy, and rheological analysis. These experimental methods showed that this system was miscible in ACM-rich blends (>50% ACM) and partially miscible in PVDF-rich blends. A wide-angle X-ray diffraction study revealed that PVDF/ACM blends such as neat PVDF had a characteristic a-crystalline peak. The partially miscible blends displayed up to 350% elongation at break; this was a significant increment of this parameter compared to that of neat PVDF(20%). However, the miscible blends showed elongation of up to 1000% [again, a remarkable increase compared to chemically crosslinked ACM (220%)] and displayed excellent mechanical properties and tensile strength and a large elongation at break. For the miscible and partially miscible blends, two different mechanisms were responsible for this improvement in the mechanical properties. It was suggested that in the partially miscible blends, the rubbery depletion layer between the spherulite and the conventional rubber cavitations mechanism were responsible for the increase in the elongation at break, whereas for the miscible blends, the PVDF spherulite acted as a crosslinking junction. The stretched part of the tensile samples in the partially miscible blends showed characteristic b-crystalline peaks in the Fourier transform infrared spectra, whereas that in the miscible blends showed a-crystalline peaks.

Crystalline polymorph transition in poly(vinylidene fluoride) (PVDF)/acrylic rubber(ACM)/clay partially miscible hybrid

“…In our previous studies [20][21][22][23], we found that the neat PVDF, and the miscible composites of PVDF/ACM blends form a polymorph and PVDF/Clay nanocomposite induce both b and c polymorphs. To study the crystalline structure of PVDF in partially miscible hybrid of PVDF/ACM/Clay, we conducted further XRD analysis.…”

“…Recently, PVDF/ACM blends have been studied [11,[17][18][19][20][21][22]. In our earlier papers [20][21][22], we have investigated various aspects of miscibility and crystallization behaviors for PVDF and ACM systems.…”

“…In our earlier papers [20][21][22], we have investigated various aspects of miscibility and crystallization behaviors for PVDF and ACM systems. We demonstrated that PVDF and ACM are miscible in blends with less than 50 % PVDF and partially miscible in the blends with more than 50 wt% PVDF.…”

Different thermal analysis technique application in determination of fold surface-free energy

“…This method is widely used in the literature [11][12][13][14][15][16][17][18][19][20][21][22][23]. However, results obtained from the kinetic approach are controversial.…”

“…In our previous paper, miscibility of this blend has been investigated [20,21] by plotting the phase diagram of this blend, Fig. 1.…”