Dynamic mechanical analysis and creep behaviour of β-PVDF films

Mano, João F.; Sencadas, Vítor; Costa, Ana M. S.; Lanceros-Méndez, S.

doi:10.1016/j.msea.2002.12.002

Cited by 84 publications

(52 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two main relaxations are detected in all experiments, in agreement with previous DMA results [12]. In the low temperature region, a process is found with a maximum in tan δ at ca.…”

Section: Dynamic Mechanical Analysissupporting

confidence: 91%

Characterization of poled and non-poled β-PVDF films using thermal analysis techniques

2004

Self Cite

View full text Add to dashboard Cite

Abstract␤-poly(vinylidene fluoride)-␤-PVDF-exhibits ferroelectric properties due to the special arrangement of the chain units in the crystalline phase. The ferroelectric phase can be optimised by poling the original stretched film, that tends to align the randomly organised crystallites against the applied field. In this work, polarised and non-polarised ␤-PVDF from the same batch are characterised by mechanical tests and a series of thermal analysis techniques, including DMA, TMA and DSC. The films exhibit mechanical anisotropy, and in the longitudinal direction the poled film presents larger mechanical properties, due to the higher structural organisation. Poled and non-poled show similar crystallinity levels but the melting temperature probed by DSC is higher for the non-poled film; for both films the melting peak exhibits a complex shape, indicating a heterogeneous crystalline organization. Two relaxation processes were found (␤ and ␣ c ) by dynamic mechanical analysis (DMA). The ␤ process, attributed to segmental motions in the amorphous phase, appears at the same temperature in both directions, but its intensity was found to be higher for the films tested in the longitudinal direction. For a given direction, the poled films exhibit lower peaks, due to the more organised amorphous structure. At higher temperature, the ␣ c -relaxation was related to the contraction of the films in the longitudinal direction during heating, recorded by thermal mechanical analysis (TMA). The onset of molecular mobility within the crystalline phase allows for cooperative diffusion processes in the amorphous phase, generating the randomisation of the initially oriented structure.

show abstract

“…Two main relaxations are detected in all experiments, in agreement with previous DMA results [12]. In the low temperature region, a process is found with a maximum in tan δ at ca.…”

Section: Dynamic Mechanical Analysissupporting

confidence: 91%

Characterization of poled and non-poled β-PVDF films using thermal analysis techniques

2004

Self Cite

View full text Add to dashboard Cite

show abstract

“…This suggests the PVDF phase transformation from α-phase to β-phase, which is supported by respective studies (Lanceros-Mendez et al, 2001;Mano et al, 2004). The appearance of peaks in region 1400-1000 cm −1 suggest favourable compatibilty between PVDF surface and collagen film, which may due to the interaction of free radicals that created during plasma modification to C-C backbonds with amine group on the chemical structure of collagen.…”

Section: Discussionsupporting

confidence: 60%

“…This suggests the PVDF phase transformation from α-phase to β-phase, which is supported by respective studies (Lanceros-Mendez et al, 2001) and (Mano et al, 2004). Figure 6 shows the FTIR spectrum of stretched PVDF (dotted lines), while plasma treated-stretched PVDF is shown by the smooth line.…”

Section: Unstretched and Stretched Pvdfsupporting

confidence: 69%

Dielectric Properties of Collagen on Plasma Modified Polyvinylidene Fluoride

Dhia¹

2012

American Journal of Applied Sciences

View full text Add to dashboard Cite

Problem statement:The attachment of biopolymers such as collagen on inert polymeric template created great challenge due to hydrophobic nature of polymeric material. The modification of PVDF for improved adhesion and introduction of specific functionalities have been widely recognized in various industrial applications. Typical methods for modifying polymer surface such as chemical etching and UV irradiation are not favorable as it requires high temperature and the use of chemical solvents. However plasma modification is suitable as it utilizes low heat and a clean environment, thus preventing contamination on the deposited collagen. Approach: Free standing orientated Poly (Vinylidene Fluoride) (PVDF) films were fabricated by solution casting method and dried in a convention oven. The dried PVDF films were orientated in a tensile machine at temperature 70°C enclosed in a custom made environmental chamber. The pulling rates of 5 mm min −1 were utilized with a draw ratio of 2 (R = L final /L initial ). The PVDF film was plasma treated for 60 sec to enhance the hydrophilic property of PVDF and utilized as template for collagen deposition. The deposited collagen on surface of PVDF was left in desiccators at temperature of 24°C for complete drying. Results: The untreated and plasma-treated PVDF template were observed for water contact angle measurement, the functional group and dielectric properties of collagen were observed and measured by FTIR and SOLARTRON respectively. Conclusion:The orientated PVDF films were produced at pulling speed of 5 mm min −1 and temperature of 70°C. The hydrophobic PVDF surface was transformed to a hydrophilic surface by plasma treatment for collagen deposition. The FTIR result shows the overlapping peaks of C-H and C-F in range 1500-1000 cm −1 which indicates the C-C bonding of collagen and PVDF. The significant increase in dielectric constant is a result from the favorable bonding between collagen and PVDF template.

show abstract

“…This phenomenon have been reported in a variety of flexible semi-crystalline polymers, including polyethylene, poly(methylene oxide), poly(ethylene oxide), and isotactic polypropylene. 49,50 For the neat PVDF, the relaxation peak locates at about 120 C, and it gradually shifts to low temperature with the increasing content of MWNTs. The trend is consistent with that of the content ratio of a-form to b-form in PVDF crystals.…”

Section: Fracture Morphology Of the Compositesmentioning

confidence: 99%

Effect of multiwalled carbon nanotubes on crystallization behavior of poly(vinylidene fluoride) in different solvents

He¹,

Sun²,

Zheng³

et al. 2010

J of Applied Polymer Sci

View full text Add to dashboard Cite

In this study, the poly(vinylidene fluoride) (PVDF)-multiwalled carbon nanotubes (MWNTs) composites have been prepared by solution casting in two different solvents: dimethyl sulfoxide (DMSO) and dimethylacetamide (DMAc). Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) results showed that the crystal phases of PVDF are quite different in the two solvents. When DMSO is used as the solvent, the PVDF crystalline phases could be greatly alternated from a-form to b-form by the incorporation of MWNTs. While the crystalline structure of PVDF hardly change in the case of DMAc. The DSC and polarized optical microphotographs implied that MWNTs not only act as nucleating agents for PVDF but also confine the crystallization of PVDF. Besides, it was found that the storage modulus (E 0 ) of the composites were significantly enhanced with an appropriate content of MWNTs. And when using DMSO as the solvent, one relaxation process emerges in the loss tan d (loss factor) curves of the neat PVDF and PVDF/ MWNTs composites, while it was not observed in the DMAc system. The obtained results revealed that varing solvents have different effects on the crystallization behavior of PVDF with the addition of MWNTs.

show abstract

Dynamic mechanical analysis and creep behaviour of β-PVDF films

Cited by 84 publications

References 26 publications

Characterization of poled and non-poled β-PVDF films using thermal analysis techniques

Characterization of poled and non-poled β-PVDF films using thermal analysis techniques

Dielectric Properties of Collagen on Plasma Modified Polyvinylidene Fluoride

Effect of multiwalled carbon nanotubes on crystallization behavior of poly(vinylidene fluoride) in different solvents

Contact Info

Product

Resources

About