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9. Effect of Graphite Nanoplatelets on Fracture Behavior of HDPE/PA66 Microfibrillar Composites

Author

Kelnar, Ivan, Bal, Umitcan, Hodan, Jiri, Kapralkova, Ludmila, Krejcikova, Sabina, and Kotek, Jiri

Subjects
Graphite -- Research, Composite materials -- Mechanical properties -- Materials, Fracture (Materials) -- Research, Materials research, High density polyethylene -- Research, Polyethylene, Engineering and manufacturing industries, Science and technology
Abstract

Effect of in situ formation of PA66 fibrils and modification with graphite nanoplatelets (GNP) on fracture behavior of the high-density polyethylene (HDPE)-matrix microfibrillar composites (MFC) has been evaluated using tensile impact strength (TIS) and J-integral methods. According to J-integral, the main mechanism of failure is unstable crack growth; dissimilar layout of both methods causes different contribution of reinforcement with GNP and PA66 fibrils to fracture process evaluated. More marked orientation and parallel loading lead to increase in impact energy by both GNP and fibrils in TIS; on the other hand, much lower contribution of fibres and even negative effect of GNP preblended in HDPE was found for J-integral as a consequence of load acting in perpendicular direction. The fact that lower addition of GNP pre-blended in PA66 does not deteriorate impact behavior indicates that such modification of MFC is an efficient way to get materials with enhanced, well-balanced parameters, INTRODUCTION Short-fibre composites with a thermoplastic matrix are an important class of engineering materials with fair, well balanced properties [1]. In the case of mostly used inorganic fibres, the range [...]

Published
2019
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16. 2-Methyl-6-(4-aminophenyl)-4,5-dihydro-3(2H)-pyridazinone Synthon for Some New Annelated 1,2,3-Selena/Thiadiazoles and 2H-Diazaphospholes with Anticipated Biological Activity and Quantum Chemical Calculations

Author

El-Shamy, Ibrahim E., Hleli, Emna, El-Hashash, Maher A., Kelnar, Ivan, Abdellatif, Abdelmohsen Moustafa, El-Shamy, Ibrahim E., Hleli, Emna, El-Hashash, Maher A., Kelnar, Ivan, and Abdellatif, Abdelmohsen Moustafa

Abstract

A convenient and efficient synthetic protocol for the new selenadiazole. Thiadiazole and diazaphosphole derivatives incorporating a pyridazine moiety originating from 4-(4-aminophenyl)-4-oxobutanoic acid (1) were described. All newly synthesized compounds were evaluated for their antimicrobial activity using the disk diffusion method, and their cytotoxicity was evaluated against brine shrimp lethality bioassay. Using density functional theory (DFT), the frontier molecular orbital (FMO) and molecular electrostatic potential (MEPS) were studied to estimate the chemical reactivity and kinetic stability of each structure. Therefore, global descriptor parameters like electronegativity (chi), chemical hardness (eta), and global softness (sigma) were calculated. Consequently, the attained results were compared with the experimental data of the biological activity of the studied structures.

Published
2023

26. Effect of nanofiller on fibril formation in melt-drawn HDPE/PA6 microfibrillar composite

Author

Kelnar, Ivan, Fortelny, Ivan, Kapralkova, Ludmila, and Hromadkova, Jirina

Subjects
Polymeric composites -- Properties -- Analysis, Engineering and manufacturing industries, Science and technology
Abstract

Effect of layered silicates on structure of microfibrillar composites (MFCs) with reinforcing PA6 fibrils formed in situ by melt drawing was studied. Clay was added to HDPE/PA6 MFC using different mixing protocols including simultaneous addition, application of pre-made master-batches with both constituents and their combinations. In all cases, majority of nanofiller (NF) was contained inside PA6 fibrils. On the other hand, fibrils dimensions were significantly affected by the clay addition protocol; their marked increase in the case of simultaneous addition of all components and application of HDPE/C30 nanocomposite indicate important effect of NF migration to the PA6 phase in the course of mixing and melt drawing. The effect of properties of PA6 and HDPE phases and NF migration on the morphology evolution is discussed. It is shown that the fiber shape and volume after sample drawing are controlled by the interplay between the dispersed fibril extension and coalescence., INTRODUCTION Microfibrillar composites (MFCs) are formed by melt or cold drawing of polymer blends. In this process, original spherical inclusions of the dispersed polymer, such as semicrystalline polyamide or poly(ethyleneterephthalate), [...]

Published
2015
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