Key Engineering Materials Vol. 869

Abstract: The article presents the results of a study of the effect of milled and chopped carbon fibers, with an average particle length of 0.2 and , respectively, on the mechanical properties of polyphenylene sulfide and its heat resistance. It was found that the introduction of carbon fibers leads to a significant decrease in the melt flow rate. It was shown that after a sharp decrease in impact strength at 10 % content of carbon fibers, its inverse improvement occurs with an increase in the filler content. Composites containing carbon fibers with length demonstrate higher impact strength. The introduction of a filler leads to a significant increase in the elastic modulus and strength of polyphenylene sulfide and its heat resistance.

Abstract: A comparative analysis of the effect on the porosity of composite filaments based on polyphenylene sulfone, polyetherimide and polyphenylene sulfide with discrete fibrous fillers, such factors as the filler concentration, melt viscosity and number of extrusion passes, was carried out. It is shown that with increasing filler content and decreasing melt viscosity, the porosity of composite filaments enhances. Upon repeated extrusion carbon-filled composites, a decrease in porosity is observed, however for glass-filled samples an increase in porosity is occurred. A comparative analysis showed that the filament samples based on polyetherimide have a higher porosity. The most resistant to pore formation are polyphenylene sulfone-based samples.

Abstract: The article presents the results of sizing of discrete carbon fibers with various substances and their effect on the properties of polyetherimide composites. As sizing agents, 1,3-diaminobenzene, 4,4'-dihydroxy-2,2-diphenylpropane, polyetherimide and oligoetherether sulfone were used. The study of physical and mechanical properties showed that all the substances used increase the properties of the carbon-filled composite based on polyetherimide. The highest mechanical properties are demonstrated by a composite containing carbon fibers treated with 1,3-diaminobenzene, which indicates improved compatibility of the filler and the polymer matrix and enhanced intermolecular interactions.

Abstract: The effect of the organoclay content in polyvinyl chloride plasticate on the features of the supramolecular structure and properties of the layered silicate nanocomposite was studied. X-ray diffraction studies showed that with an increase in the number of layered silicate nanofiller, the nanocomposite structure goes from intercalated to exfoliate. Using a combination of scanning and atomic force electron microscopy methods, it has been shown that when organomodified montmorillonite is introduced into polyvinyl chloride plastic compound, montmorillonite nanoparticles act as crystallization nuclei and along with the preservation of “old” supramolecular structures in the melt, “new” supramolecular formations appear. When studying the dependence of tensile strength of nanocomposite polyvinyl chloride on the content of nanofiller, it was found that the maximum strength of the nanocomposite is achieved at a 5-7 % organoclay concentration.

Abstract: We presented a scientific review of the literature on known biodegradable polymer composite materials and summarized the data on the effect of starch and thermoplastic starch on the biodegradability of industrially produced polymers. We considered the main starch plasticizers.

Abstract: Kinetics of urethane formation from isophorone diisocyanate and polycaprolactone diol and poly(butylene adipate) in acetone was studied by IR spectroscopy. It was found that poly(butylene adipate) is the most reactive oligoesterdiol, with the reaction being both non-catalyzed and catalyzed by dibutyltin dilaurate. It was shown that the cycloaliphatic group of isophorone diisocyanate is an order of magnitude more active than the aliphatic one in catalytic reactions of isophorone diisocyanate with investigated oligoesterdiols. Furthermore, waterborne polyurethanes based on the studied oligoesterdiols were synthesized and characterized by DLS, DSC, and TGA methods.

Abstract: The simple percolation model, in which critical indices are defined by the form of a reinforcing component of nanostructured composite structure, was proposed for the description of reinforcement degree for nanostructured composites polymer/2D-nanofiller. The indicated critical indices are close by absolute values to standard percolation indices. The form of reinforcing component controls the type of nanostructured composite. It has been shown that reinforcement degree of these nanomaterials is independent on modulus of elasticity of nanofiller, but is defined by its structure (aggregation level), created in polymer matrix. The percolation indices of a percolation model, which are due to the form of reinforcing component and nanocomposite type, are defined by its main characteristic – the fraction of phases division surface in overall sample volume and are the basic factor, controlling reinforcement degree of nanostructured composites.

Abstract: In laboratory conditions, the molding process was simulated by extrusion of a multifilament yarn with a diameter of the monofilament equal 250-350 μm from high performance plastics. The possibility of obtaining a microfilament bundle of polyetheretherketone, polyphenylene sulfide and polyetherimide using a specially made forming head is shown. The technological modes of extrusion have been worked out, which makes it possible to obtain thermoplastic fibers from the studied thermoplastics. It was revealed that the obtained microfilaments can be subjected to post-processing by cold drawing to reduce their diameter by 40-70 %.

Abstract: The dependence of the reduced viscosity of copolyarylene ether ketones on the chemical structure of diols and the conditions for copolycondensation is studied. It was shown that the structure of diols and the order of their introduction into the polycondensation reaction affect the reduced viscosity, impact strength, and temperature characteristics of copolyarylene ether ketones.

Abstract: The temperature-time modules of drying and heat treatment of polyetherketones and polyphenylene sulfides are revealed; which made it completely possible to get rid of sorption water and an upper limit noticeable worsens the thermal stability of polymers. The most vulnerable bonds in polysulfones to the effects of water at processing temperatures were found.