scholarly journals Tuning the dielectric behavior of poly(vinylidene fluoride-co-vinyl alcohol) using a facile urethane-based crosslinking method

2019 ◽  
Vol 10 (11) ◽  
pp. 1335-1343 ◽  
Author(s):  
Niels L. Meereboer ◽  
Ivan Terzić ◽  
Katja Loos
Keyword(s):  
Hysteresis Loop ◽  
Vinyl Alcohol ◽  
Vinylidene Fluoride ◽  
Crosslinking Density ◽  
Dielectric Behavior ◽  
Poly Vinylidene Fluoride ◽  
Double Hysteresis Loop

Crosslinking poly(VDF-co-VA) copolymers leads to a change from ferroelectric to double hysteresis loop behavior when the crosslinking density is increased.

scholarly journals Multiple-Step Melting/Irradiation: A Strategy to Fabricate Thermoplastic Polymers with Improved Mechanical Performance

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1812
Author(s):  
Jingxin Zhao ◽  
Jiayao Wang ◽  
Xiaojun Ding ◽  
Yu Gu ◽  
Yongjin Li ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Vinylidene Fluoride ◽  
Mechanical Performance ◽  
Crosslinking Density ◽  
Nucleation Density ◽  
Thermoplastic Polymers ◽  
3 Dimensional ◽  
Dimensional Network ◽  
Poly Vinylidene Fluoride ◽  
Multiple Step

To fabricate thermoplastic polymers exhibiting improved ductility without the loss of strength, a novel multiple-step melting/irradiation (MUSMI) strategy was developed by taking poly(vinylidene fluoride)/triallyl isocyanate (PVDF/TAIC) as an example, in which alternate melting and irradiation were adopted and repeated for several times. The initial irradiation with a low dose produced some local crosslinked points (not 3-dimensional network). When the specimen was reheated above the melting temperature, they redistributed in the PVDF matrix, which is an efficient way to avoid the high crosslinking density at certain positions and the disappearance of thermoplastic properties. During the subsequent cooling process, the crosslinked domains in the thermoplastic polymer matrix is expected to play double roles in turning crystal structures for enhancing the ductility without reducing strength. On one hand, they can act as heterogeneous nucleation agents, resulting in higher nucleation density and smaller spherulites; on the other hand, the existence of crosslinked structures restricts the lamellar thickening, accounting for the thinner crystal lamellae. Both smaller spherulites and thinner lamellae contribute to better ductility. At the same time, these local crosslinked points enhance the connectivity of crystal structures (including lamellae and spherulites), which is beneficial to the improvement of strength. Based on the influence of local crosslinked points on the ductility and strength, thermoplastic PVDF with much higher elongation at break and comparable yielding stress (relative to the reference specimen upon strong irradiation only once) was prepared via MUSMI successfully.

Dielectric Behavior of Lithium Tantalate (LiTaO3)/Poly(vinylidene fluoride) (PVDF) Nanocomposites Doped with MWCNTs

2017 ◽  
Vol 9 (3) ◽  
pp. 204-208
Author(s):  
Padmaja Guggilla ◽  
Courtney Walker ◽  
Matthew Edwards ◽  
Ashwith Chilvery ◽  
Brian Thomas
Keyword(s):  
Vinylidene Fluoride ◽  
Lithium Tantalate ◽  
Dielectric Behavior ◽  
Poly Vinylidene Fluoride
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