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

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1091 ◽  
Author(s):  
Eftihia Barnes ◽  
Jennifer A. Jefcoat ◽  
Erik M. Alberts ◽  
Mason A. McKechnie ◽  
Hannah R. Peel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Weight Ratio ◽  
Tensile Modulus ◽  
Physical And Mechanical Properties ◽  
Free Standing ◽  
Composite Surface ◽  
Poly Vinylidene Fluoride

Cellulose nanofibrils (CNFs) are high aspect ratio, natural nanomaterials with high mechanical strength-to-weight ratio and promising reinforcing dopants in polymer nanocomposites. In this study, we used CNFs and oxidized CNFs (TOCNFs), prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process, as reinforcing agents in poly(vinylidene fluoride) (PVDF). Using high-shear mixing and doctor blade casting, we prepared free-standing composite films loaded with up to 5 wt % cellulose nanofibrils. For our processing conditions, all CNF/PVDF and TOCNF/PVDF films remain in the same crystalline phase as neat PVDF. In the as-prepared composites, the addition of CNFs on average increases crystallinity, whereas TOCNFs reduces it. Further, addition of CNFs and TOCNFs influences properties such as surface wettability, as well as thermal and mechanical behaviors of the composites. When compared to neat PVDF, the thermal stability of the composites is reduced. With regards to bulk mechanical properties, addition of CNFs or TOCNFs, generally reduces the tensile properties of the composites. However, a small increase (~18%) in the tensile modulus was observed for the 1 wt % TOCNF/PVDF composite. Surface mechanical properties, obtained from nanoindentation, show that the composites have enhanced performance. For the 5 wt % CNF/PVDF composite, the reduced modulus and hardness increased by ~52% and ~22%, whereas for the 3 wt % TOCNF/PVDF sample, the increase was ~23% and ~25% respectively.

scholarly journals Synthesis and characterization of biological nanomaterial/poly(vinylidene fluoride) composites

2021 ◽  
Author(s):  
Eftihia Barnes ◽  
Jennifer Jefcoat ◽  
Erik Alberts ◽  
Hannah Peel ◽  
L. Mimum ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Chemical Properties ◽  
Hydrated Cellulose ◽  
Functionalized Surfaces ◽  
Poly Vinylidene Fluoride ◽  
Superior Mechanical Properties ◽  
Physical And Chemical

The properties of composite materials are strongly influenced by both the physical and chemical properties of their individual constituents, as well as the interactions between them. For nanocomposites, the incorporation of nano-sized dopants inside a host material matrix can lead to significant improvements in mechanical strength, toughness, thermal or electrical conductivity, etc. In this work, the effect of cellulose nanofibrils on the structure and mechanical properties of cellulose nanofibril poly(vinylidene fluoride) (PVDF) composite films was investigated. Cellulose is one of the most abundant organic polymers with superior mechanical properties and readily functionalized surfaces. Under the current processing conditions, cellulose nanofibrils, as-received and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidized, alter the crystallinity and mechanical properties of the composite films while not inducing a crystalline phase transformation on the 𝛾 phase PVDF composites. Composite films obtained from hydrated cellulose nanofibrils remain in a majority 𝛾 phase, but also exhibit a small, yet detectable fraction of 𝛼 and ß PVDF phases.

The structural spectra of high dilutions and their unconventional application

2021 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Saurav Arora
Keyword(s):  
Raman Spectroscopy ◽  
Electrical Properties ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
Water Structure ◽  
Laser Raman Spectroscopy ◽  
Oh Groups ◽  
Laser Raman ◽  
Poly Vinylidene Fluoride ◽  
High Dilutions

Until few years, the so-called implausible science, homeopathy, was on the verge of being rejected on conventional physicochemical grounds. The mere selection of ultrahigh dilutions (UHD) (homeopathic potencies) for experimentation by mainstream scientists seemed impossible, but the curiosity to explore the science behind homeopathy kept igniting intellectual alma mater who subjected homeopathy to laboratories and test tubes, to know beyond its clinical application. Still, there exist a huge gap and a challenge to convince a conventional scientist to go beyond his domains and look for something which is apparently invisible (beyond Avogadro). But gradually we are overcoming this dogma and exploring the finer aspects and applications of UHDs. Much research has been undertaken, at least, to protect the identity of UHDs, and we are now verge of proving the plausibility of homeopathy from every aspect. This issue of International Journal of High Dilution Research features two interesting articles on nature of UHDs and their unconventional application. The first article by NC Sukul et al aimed to decipher the nature of the water structure of UHDs of two commonly used homeopathic drugs Natrum muriaticum and Sulphur by Laser Raman Spectroscopy. This work is in the series undertaken by the group, who earlier experimented using Nuclear Magnetic Resonance; Electronic, Vibrational and Raman spectroscopy to shown differences in UHDs of various drugs. The present experiment could differentiate the intensities (potencies) of Nat-m and Sulph when compared to their controls, on the basis of hydrogen bond strength and free OH groups. The second article by Nandy et al proposes a new dimension to the application of UHD. In an interesting manner, the author used UHDs of Ferrum metallicum and Zincum oxidatum to improve the electrical properties of the electroactive Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP). The PVDF-HFP composite films were synthesized in their usual way, but an incorporation of Ferrum and Zinc-o could make the film as homeo-PVDF-composite. This enhancement of the electrical properties and are possibly due to the presence of nanoparticle, as hypothesized by the group. The nature and application of UHDs are promising but challenging areas, which can only be validated through extensive research and validation. The realm of UHDs is expanding, and the day is not far when plausibility of homeopathy would be proved from every aspect, but at the same time we should also keep the momentum of research at pace in clinical research too!

scholarly journals Effect of Filler Nature on Chemical Resistance and Microhardness of Epoxy Composite Films

2015 ◽  
Vol 16 (3) ◽  
pp. 528-533
Author(s):  
G. Martinyuk ◽  
O. Aksimentyeva ◽  
N. Skoreiko ◽  
V. Zakordonskyi
Keyword(s):  
Mechanical Properties ◽  
Chemical Resistance ◽  
Filler Content ◽  
Epoxy Composite ◽  
Composite Films ◽  
Physical And Mechanical Properties ◽  
Epoxy Composites ◽  
Mineral Filler ◽  
Operating Characteristics ◽  
Mineral Fillers

We investigated the processes of water absorption, chemical stability and microhardness of films of epoxy composites that contained as the polymer matrix the epoxy resin UP-655 and mineral fillers: graphite, mica, aluminum oxide at their content (0 - 30 % mass). It found that introduction of mineral fillers significantly affects on all complex of operating characteristics of the films. Increase of filler content, especially mica, to 20 %, resulting in slower process and reducing the quantity of absorbed moisture by films. In the study of physical and mechanical properties of filled epoxy composites was established that the introduction of mineral filler significantly affects their microhardness, and the nature of the exposure is determined by the type and filler content.

The Irradiation Crosslinking of Poly(vinylidene fluoride-​chlorotrifluoroethylene)

2014 ◽  
Vol 716-717 ◽  
pp. 7-10
Author(s):  
Jian Chen
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Ultraviolet Irradiation ◽  
Vinylidene Fluoride ◽  
Loss Modulus ◽  
Great Influence ◽  
Poly Vinylidene Fluoride ◽  
Content Support

Vinylidenefluoride (VDF) and chlorotrifluoroethylene (CTFE) copolymers were crosslinked by ultraviolet irradiation, chlorotrifluoroethylene content has a great influence on the crosslinked copolymers, high CTFE content support more joint pots, the properties of the copolymer shows higher storage modulus, the loss modulus gets smaller. The copolymer mechanical properties gets much higher.

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