Effects of POSS addition on Non-isothermal crystallization and morphology of PVDF

Martins, Johnny N.; Bianchi, Otávio; Wanke, Cesar Henrique; Castel, Charles Dal; Oliveira, Ricardo Vinícius Bof de

doi:10.1007/s10965-015-0871-7

Cited by 18 publications

(22 citation statements)

References 44 publications

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“…Under conditions that the parameter assumes the zero value the polymer system assumes the behavior of second ideal two‐phase model or has ideal lamellar structures . The values found for the structural parameters of pure EVA were similar to the ones found in the literature .…”

Section: Resultssupporting

confidence: 81%

“…The EVA and hydrolyzed EVA samples showed a high correlation peak ( q near 0.5 nm −1 ) that is characteristic of semicrystalline polymer with lamellar structure, as shown in the SAXS curves in Figure (a). The desmeared data are plotted on a relative scale, that is, on the abscissa is the scattering vector, defined by

q = \frac{4 π}{λ sin (θ)}

.…”

Section: Resultsmentioning

confidence: 90%

“…The semicrystalline polymer can be explained through the use of pseudo two‐phase system considering the polymer structure is composed of periodical stacks of alternate lamellar crystals and amorphous layers . In this approach, the lamellar structures are characterized by the long period ( L p ), amorphous lamellar thickness ( L a ), and crystalline lamellar thickness ( L c ), which are achieved using the one‐dimensional (1D) correlation function, γ( r ) .…”

Section: Methodsmentioning

confidence: 99%

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Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Paradinha

Dias

Wanke

et al. 2016

J of Applied Polymer Sci

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Ethylene-vinyl acetate copolymer (EVA) was modified by hydrolysis using dielectric heating. The modified EVA was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis (TG), 1 H Nuclear magnetic resonance (NMR), gel permeation chromatography, and small-angle X-ray scattering. The results showed that the EVA was hydrolyzed with degree between 36.1 and 42.6% according to 1 H NMR and TG results. The relative reaction rate for the sample prepared in the oil bath was 9%/h, while in the dielectric was 150%/h for 15 min. This significant improvement was due to the specific effect of microwave-assisted reactions through dipole rotation and ionic polarization contributions. The hydrolysis reaction promoted a reduction of the pendent group size of EVA backbone. This change directly contributed to increasing melt temperature, crystallization temperature, melt and crystallization enthalpies. Also, decreased the long period, increased the volume crystallinity, and caused reductions amorphous/ crystalline interface and two-phase model deviations.

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Section: Resultssupporting

confidence: 81%

q = \frac{4 π}{λ sin (θ)}

.…”

Section: Resultsmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Paradinha

Dias

Wanke

et al. 2016

J of Applied Polymer Sci

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“…Figure shows the non‐isothermal crystallization curves at various rates for neat PVDF and PVDF/GNP composites. It can be seen that crystallization temperature range became broader with increasing cooling rate, and crystallization peak temperature was shifted towards the lower temperature side owing to the time‐dependent crystallization progress . The values of crystallization onset temperature ( T o ), peak temperature ( T p ), and crystallization enthalpy (Δ H c ) for the samples are listed in Table .…”

Section: Resultsmentioning

confidence: 99%

Filler network structure and crystallization behavior of polyvinylidene fluoride/graphene nanoplatelet composites using SEM, DSC, rheological, and in situ measurement approach

Shi

Yang

Miao

et al. 2019

Polymer Crystallization

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In this work, solution blending was used to prepare series of polyvinylidene fluoride (PVDF)/graphene nanoplatelet (GNP) nanocomposites to investigate the effect of GNP content on the formation of filler network structure. Thermorheological complexity was observed with increasing GNP content, which was substantiated by morphological observation. Three classical thermal conduction models were adopted and compared with the measured thermal conductivity as a function of GNP loading, among which the Agari model presented the most reasonable prediction. A four‐parameter model was proposed to reflect the cooling behaviors of the PVDF/GNP composites with the aid of an in‐situ temperature measurement, suggesting the formation of GNP network structure in the composites. The incorporation of GNP showed an obvious nucleating effect on the crystallization of PVDF without altering its crystal form. Owing to the competition between spatial effect and heterogeneous nucleation, both crystallization rate and enthalpy achieved the maximum values when 6% GNP was added.

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“…The crystallization degree ( X c ) was calculated as following equation: X c = Δ H m /

Δ H_{m}^{0}

, where Δ H m is fusion enthalpy and

Δ H_{m}^{0}

corresponds to fusion enthalpy of neat PVDF 100% crystallized ( X c = 1),

H_{m}^{0}

= 104.6 J/g . The crystallization half‐time ( t 1/2 ) was determined as follows: t 1/2 = ( T 0 − T 1/2 ) / ϕ, where T 0 is the onset crystallization temperature, T 1/2 is the temperature where the relative degree of crystallinity is 0.5, and ϕ is cooling rate . According to Table , peak melting temperature ( T m ) of wear debris is slightly higher than that of unworn PVDF.…”

Section: Resultsmentioning

confidence: 99%

Friction‐induced electroactive β polymorph of poly(vinylidene fluoride)

Xin

2018

J of Applied Polymer Sci

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Poly(vinylidene fluoride) (PVDF) has been widely used in electric devices due to electroactive b polymorph. In this article, we probe the formation of b phase under friction by spectroscopy and thermal analysis. During continuous friction, entire sliding of PVDF is identified with two regimes, i.e., running-in and steady-state. At initial running-in period, friction surfaces are dominated by plastic strain, which leads to striking formation of b phase from a polymorph (a!b). Subsequently, melting-flow domains almost cover friction surfaces at steady-state. Thus, formation of b crystal is correspondingly induced by shear crystallization. Nevertheless, b-crystal content at steady-state is lower than that at running-in. With sliding proceeding, moreover, b-crystal content exhibits a gradually decreasing tendency, attributed to rising surface temperature. Besides, the friction-induced b phase is further confirmed by evaluation of wear debris. Overall, friction plays a crucial role as to the formation of b phase. V C 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46395.

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Effects of POSS addition on Non-isothermal crystallization and morphology of PVDF

Cited by 18 publications

References 44 publications

Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Filler network structure and crystallization behavior of polyvinylidene fluoride/graphene nanoplatelet composites using SEM, DSC, rheological, and in situ measurement approach

Friction‐induced electroactive β polymorph of poly(vinylidene fluoride)

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