M. L. Kerber

Rheokinetics of the curing of epoxy oligomer ED-20 modified with epoxy phosphazenes

The effect of epoxy phosphazene on the curing parameters of an epoxy amine composition containing epoxy phosphazene was studied via rotational viscometry. The presence of epoxy phosphazene accelerates the process and changes the pattern of polymer-network formation. As a result, the dynamics of the increase in viscosity changes.

Influence of thermoplastic modifiers on the properties and the process of curing of epoxy polymers

The basic features of the rheokinetic behavior of an epoxy oligomer cured by 4,4‐diaminodiphenylsulfone have been determined. It has been established that the process of curing obeys the phenomenological equation of first order with self‐acceleration. Different modifiers based on linear thermally resistant polymers have been employed to improve the physicochemical properties of the compositions. Making such additions enabled us to increase the thermal resistance of materials and the resistance to impact loads.

Effect of montmorillonite on polypropylene crystallization

The effect of additions of pure and modified montmorrilonite on the polypropylene crystallization rate was studied within the framework of Avrami model. In the presence of these fillers in amounts of 2.5–5.0 wt %, both the crystallization rate and the degree of crystallinity increase, and at the content of these fillers increased to 10% and higher values these parameters decrease. Introduction of fillers enhances the mechanical properties of polypropylene, which allows the developed material to be recommended for the production of packaging film.

Mechanical Properties and Compatibility of High Density Polyethylene with Some Oligoesters

Abstract Miscibility of high density polyethylene and modifiers was evaluated using polymer-polymer interaction parameter and determined with the help of inverse gas chromatography. Mechanical, rheological properties and melting point changes were investigated. Measurements of mechanical properties showed that alloying of high density polyethylene with different oligoesters may produce higher strength and elongation than pure PE. The results obtained showed that compatibility of PE and additives may influence overall characteristics of the compositions. Mechanical properties of compatible alloys change monotonously when the concentration of modifiers increases. For unmiscible systems, the relationship between mechanical properties and oligoester concentration appears to display a curve with extremum. The performed study made it possible to choose optimum systems for use as an optical cable.

Investigating the Tensile Behaviour of Blends of Polypropylene and a Statistical Copolymer of Propylene and Ethylene

Polypropylene-based materials are currently widely used in different sectors of industry. Polypropylene has high physicomechanical properties, good resistance to corrosive media, and a higher heat resistance than polyethylene – another popular large-tonnage polymer. A wide range of modifiers are used to control the processing and service properties of polypropylene [1]. These modifiers include substances of different nature, among which are other high-molecular-weight compounds [2, 3]. In this case we are speaking of polymer blends. Blends of polyolefins, including polypropylene, with other polymers have already been studied by a number of researchers. Slonimskii et al. [4] investigated the properties of polypropylene (PP) and polyethylene (PE), and also each of them with polyisobutylene (PIB). Composites consisting of crystalline and amorphous polymers (isotactic polypropylene–polyisobutylene, isotactic polypropylene–amorphous polypropylene, polyethylene–polyisobutylene), of crystalline polymers (polypropylene–polyethylene), and of amorphous polymers (atactic polypropylene–polyisobutylene) were investigated. On the basis of X-ray diffraction data and the nature of the thermomechanical curves, the authors came to the conclusion that the given blends, even a blend of atactic and isotactic polypropylene, are incompatible. The incompatibility of crystalline polypropylene and polyethylene is particularly marked. Mikhailov et al. [5], investigating the polypropylene–polyethylene system, came to a different conclusion. According to their data, a blend containing 75 wt% polyethylene and 25 wt% polypropylene is compatible. With a different ratio of components, incompatible composites are formed. Here, the strength of films of the polymer blend increases as the content of crystalline polymer in the blend increases. Such a picture is observed with increase in the content of isotactic polypropylene (PP) in a blend with amorphous polypropylene and in a blend with polyisobutylene (PIB), and also for a polyethylene–polyisobutylene blend. In a polypropylene–polyethylene blend, the presence of polypropylene leads to an increase in the strength of the polyethylene.

Cure Kinetics Behavior and Properties of Epoxy-Amine Adhesives

Epoxy resins based adhesives are widely used nowdays. In the present work characteristics of curing processes of epoxy-amine systems were studied.