Oriented polypropylene film technologies

Today consumers expect product to have good protection. Flexible packaging materials play a great role in many industries. BOPP film is one of the most popular materials that is in demand in almost any field where flexible packaging is required. Most oriented plastic films have a biaxial orientation, the characteristics of which perfectly correspond to the requirements of modern flexible packaging. General improved barrier properties are achieved due to the orientation of the chains of molecules. Tension in the longitudinal direction is usually performed using the machine direction orientation (MDO) through the rollers with increasing speed. For all transversely oriented films, the stretching process occurs using a transverse directional orientation (TDO), where the film is fixed at both ends and, after passing through the oven at different temperatures and it is stretched in the transverse direction

3D printing of polymer matrix composites for space: A review andpromises

Today scientists try to present technologies that can help in solving social issues. Three-dimensional printing methods are currently manufactured products for all industries. This paper provides an overview of the creation of high-temperature polymer composite materials by three-dimensional printing technology for space applications. Additive technologies make it possible to find a balance between the required physical and mechanical properties and at the same time to ease construction, which can significantly reduce the cost of manufacturing products in comparison with traditional materials and methods of processing. To increase the physicomechanical properties and operating temperature of high-temperature plastics, composite materials are created with the addition of dispersed and fibrous fillers. The most common fillers are carbon and fiberglas

Research of Adhesion Bonds Between Gas-Thermal Coating and Pre-Modified Base

Nature of adhesive bonds between gas-thermal nickel alloy coating and carbon steel base was examined using laser profilometry, optical metallography, transmission and scanning electron microscopy. The steel surface was plastically pre-deformed by an ultrasonic tool. Proved that ultrasound pre-treatment modifies the steel surface. Increase of dislocation density and formation of sub micro-structure are base elements of surface modification. While using high-speed gas-flame, plasma and detonation modes of coatings, surface activation occurs and durable adhesion is formed. Ultrasonic pre-treatment of base material is effective when sprayed particles and base material interact through physical-chemical bond formation. Before applying high-speed gas flame and plasma sprayed coatings, authors recommend ultrasonic pretreatment, which creates periodic wavy topography with a stroke of 250 microns on the steel surface. Before applying detonation sprayed coatings, authors recommend ultrasound pretreatment that create modified surface with a uniform micro-topography

Research of surface activating influence on formation of adhesion between gas-thermal coating and steel substrate

Estimation of influence of physical and thermal activating on adhesion between steel substrates and thermal coatings has been performed. The substrates with surfaces obtained by and ultrasonic surface plastic deformation were used. To evaluate physical activating, preheating of the substrates to 600°С was performed. To evaluate the effect of thermal activating, the substrate surfaces after interfacial detachment were examined. Bonded areas on the substrate surfaces were measured by means of optical profilometry. The experiments have shown that surface physical activating is the main factor in formation of the adhesive bond between the coating and the substrate processed with the proposed methods

Ultrasonic plastic deformation of steels

In the work we demonstrate the possibility of forming thin surface and near-surface layers with submicrocrystalline structure under ultrasonic plastic deformation of machined steels. Formation of fine gradient textures up to nanocrystalline allows significant changing physical and mechanical properties of machined steels. Ensures improvement of microstructure, produces internal compressive strains which improves the cyclic strength of machine parts

Ultrasonic Surface Treatment of Titanium Alloys. The Submicrocrystalline State

The paper presents the results of the research on improvement of physical-and mechanical properties of titanium alloys VT1-0 and VT6 by modification of surfaces using ultrasonic treatment, and a comprehensive study of the microstructure and mechanical properties of modified surface layers. It has been established that exposure to ultrasonic treatment leads to formation in the surface layer of a structure with an average size of elements 50 x100 nm, depending on the brand of titanium alloy

Application of atomic force microscopy methods for testing the surface parameters of coatings of medical implants

Atomic force microscopy methods are used to study calcium phosphate coatings that are formed on surfaces of various materials, which are used in medicine, by radio-frequency magnetron sputtering of a hydroxyapatite target. The roughness parameters and values of the surface potentials of metal, polymer, and hybrid substrates are determined in a semicontact regime. Calcium phosphate coatings increase the roughness of surfaces of polymer and metal materials, thus presenting a stimulating factor for the attachment and proliferation of osteogenic cells. Using the Kelvin method, it is shown that calcium phosphate coatings change the surface potential of substrates

Investigations and Non-destructive Testing in New Building Design

Mechanical rebar couplers are preferable in the advanced building construction and structural design of antiseismic elements. The paper presents destructive inspection techniques used to investigate stress fields (tensile and compressive) and deformation curves for mechanical rebar splicing. The properties of mechanical rebar splicing are investigated by the non-destructive testing digital radiography. The behavior of real connections (column-to-column, beam-to-column) is studied under static and dynamic loads. Investigation results allow the elaboration of recommendations on their application in the universal prefabricated antiseismic structural system developed at Tomsk State University of Architecture and Building, Tomsk, Russia