The influence of carbon-containing, magnetic and nano-dispersed additions on structure and electrophysical properties of polypropylene-based composite monofibers

There were PP- and iron-containing, fibrous, carbon- and nanodispersed-addition-based composite fibers prepared. There were addition content equals of 5.0%mass. There were blend of isotactic PP and addition homogenized in melt with one-screw lab extruder. There were zonal temperature on extruder equals of 230-250 o C. There were strangs receiving in bath of water and threated with knife granulation. Then, there were granules drying on air during 5h, and, then in thermal vacuum oven at 80±5 o C during 3h. Then, there are monofiber of 1 mm’s diameter formed on lab stand. Then, from one formed those others monofibers of different values of spinneret drawing (Фв, %). There were Фв for monofibers equals of 300 and 500%. Then, there were formed monofibers threated with thermoorientational drawing process at 150 oC. Then, there were monofibers of Фв value, which equals of 300%, drawn till draw degree λ=6, but, those others of Фв value, which equals of 500% - to λ=4. It is succeed, for composite monofibers, that orientational drawing process has had realized, until to the same value, as well as for one of virgin PP. But, when at formation and thermoorientational drawing processes, there were placing much number of breaks, as compared with monofiber of pure PP. When studying the structure with SEM technique, there was revealed microfibrillar structure of composite monofiber. When using optical microscopy, then there was determined irregularity for distribution of addition’s particles, leading to disproportional distribution of tension values at loading. It is revealed, for composite monofiber, at given value for content of addition, that electrical conductivity phenomenon is absent here. There are real ε’and imaginal ε’’ parts of complex dielectrical permittivity phenomenon, on frequency of 9 GHz, equals of 2.1 and 0.2, accordingly. It is established, that pure, non-drawn and composite monofiber itrinsically have satisfactory magnetic properties (σs=0.5 Gs∙cm3/g, Hc= 695 E). There are real μ’ and imaginal μ’’ parts of complex magnetical permittivity phenomenon equals of 1.1 and 0.02, accordingly.

Investigation of Polyetherimide Melt-Extruded Fibers Modified by Carbon Nanoparticles

The fibers based on thermoplastic partially crystalline polyetherimide R-BAPB modified by vapor grown carbon nanofibers (VGCF) were prepared by melt extrusion, exposed to orientational drawing, and crystallized. All of the samples were examined by scanning electron microscopy, X-ray scattering, and differential scanning calorimetry to study how the carbon nanofiller influences on the internal structure and crystallization behavior of the obtained R-BAPB fibers. The mechanical properties of the composite R-BAPB fibers were also determined. It was found that VGCF nanoparticles introduced into R-BAPB polyimide can act as a nucleating agent that leads, in turn, to significant changes in the composite fibers morphology as well as thermal and mechanical characteristics. VGCF are able to improve an orientation degree of the R-BAPB macromolecules along the fiber direction, accelerate crystallization rate of the polymer, and enhance the fiber stability during crystallization process.

Вплив орієнтаційного витягування на властивості сумішей поліефірів ПЕТg/ПЕТ

Rational conditions for orientational drawing of PETg/PET polyester blend during processing into tape products are established. Tensile strength and elongation at break for all test specimens were determined according to ISO 527-2: 2012. Tensile modulus - ISO 527-1: 2019, specimen density - PN-EN ISO 1183-1, change of linear dimensions of specimens - ISO 16012: 2015. It was found that the introduction of PET into PETg leads to an increase in tensile strength of the blend, which is probably due to the process of orientational crystallization of PET. When the orientations are higher than 5.5 times in the PETg /PET mixtures, cavitation foaming occurs, which leads to a decrease in the blend density, its turbidity and a decrease in tensile strength. Blends with a high content of PETg have a significant thermal shrinkage, which should be taken into account when processing and applying these polymers. Physical and mechanical properties of PETg/PET polyesters blend with different ratio in the process of orientational stretching are established. The tensile strength increases with the increase drawing ratio for blends with high PET content due to its orientation crystallization. The phenomenon of cavitation foaming in polyester blend with draw ratio more than 5.5 times is found, which is accompanied by a decrease in the density of the samples and their tensile strength. Presence of PETg in PET matrix decrease tensile strength and elongation and significantly increase thermal shrinkage. Low elongation at break found for PETg/PET blend specimen without orientation which increases dramatically with low draw ratios and then decrease with higher drawing ratio. The technological modes of realization of cavitation foaming for the PETg/PET mixture at orientation drawing ratio above 5.5 due to the different phase structure of the components of the mixtures have been established. The introduction of PETg into PET leads to a significant increase in thermal shrinkage and reduces the physical and mechanical performance of oriented products.