Crystallization behaviors of poly(vinylidene fluoride) and poly(methyl methacrylate)-block-poly(2-vinyl pyridine) block copolymer blends

Abstract

In this study, blends of poly(vinylidene fluoride) and different contents of poly(methyl methacrylate)-block-poly(2-vinyl pyridine) block copolymer (BCP) (PMMA-b-P2VP) are prepared by solution mixing. The phase separation and crystallization behaviors of PVDF and PMMA-b-P2VP blends were characterized by X-ray scattering from small angle to wide angle at different annealing temperatures. The non-isothermal crystallization kinetics of the blends is investigated by differential scanning calorimetry (DSC). During the non-isothermal cooling process, PVDF in blends has higher onset crystallization temperature than that of pure PVDF, which may be attributed to a weak phase separation seen from X-ray scattering patterns, in favor of the nucleation of PVDF. A unique crystallization behavior in DSC test is that as the PVDF content in the blends is dispersed as 30 mass%, degree of crystallinity turns out to be the highest among the blends, even higher than PVDF itself, although the crystallization rate is decreasing with the BCP content. By a novel treatment of dividing the X t * t plot to three stages, it can be found that the relative degree of crystallinity at the end of nucleation process can be responsible for the unusual crystallization behavior. Incorporation of BCP definitely increases the hydrophilic property of PVDF materials by water contact angle test. Understanding of PVDF crystallization in the system with BCP guides the further development of high-performance PVDF membrane materials.

Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

“…The crystallinity ( X c ) was calculated from:Xc=ΔHm/ϕΔHm∗×100% where ΔH m is the melting enthalpy measured from the differential scanning calorimetry curves, ΔH m * is the melting enthalpy for 100% polymer crystallinity, and φ is the weight fraction of PVDF in the films. From literature, ΔH m * is reported to be 104.5 J/g for the 100 % crystalline material [44].…”

Beta Phase Crystallization and Ferro- and Piezoelectric Performances of Melt-Processed Poly(vinylidene difluoride) Blends with Poly(methyl methacrylate) Copolymers Containing Ionizable Moieties

“…41,42 Other block-like copolymers were studied to modify the electroactive PVDF properties such as zwitterionic blocks or poly(2-vinylpyridine), but no piezoelectric or ferroelectric measurements were shown. 43,44 It could also be noticed that peculiar relaxor or antiferroelectric-like properties were also depicted for PVDF-based materials blends with several copolymers (P(VDF-TrFE-CTFE)-g-PMMA, P(VDF-TrFE-CTFE)-g-PEMA, P(VDF-TrFE-CTFE)-g-PS; CTFE = chlorotrifluorethylene; PEMA = poly(ethyl methacrylate); PS = polystyrene) with interesting perspectives for energy storage or as supercapacitors. 45−47 In this context, the use of functional PMMA-based copolymers clearly represents an interesting approach to develop new PVDF/PMMA materials with enhanced physical properties, and a specific examination is mandatory.…”

Balancing processing ease with combustion performancein aluminum/PVDF energetic filaments

“…To assess the impact of Al loading on PVDF crystalline domains, crystallinity was calculated using Eq. ( 1), where ΔH m is the measured melting enthalpy of the blend (see Table 2), ΔH* m represents the melt enthalpy of 100% α-crystalline PVDF (i.e., 104.5 J/g [18,19]), and ϕ represents PVDF weight fraction [20].…”