S. Ozden

The synthesis of polyetheretherketones and investigations of their properties

Using hydroxyl-containing olygoketones with different condensation degrees and dichloranhydrides of isophthalic and terephthalic acids, polyetheretherketones (PEEK) were synthesized by means of acceptor-catalytic polycondensation, and their properties were investigated. It was shown that PEEK possesses a better solubility, a higher molecular weight and is characterized by high thermal and mechanical properties. The correlation between some properties of polyethers and the degree of condensation of olygoketones was also investigated.

High impact thermally stable block copolyethers

Block copolyethers characterised with high impact strengh values (I ≥ 140 kJ/m2) and stable physical and chemical properties for long duration under load (at 180–200°C) were obtained from 1,1-dichlor-2,2-di-(4-oxyphenyl)ethylene by acceptor catalytic polycondensation method. The dependence of the tensile and thermal properties of the block copolyethers on the molecular structure was investigated. It is shown that, after heat treatment the heat stability and the mechanical properties improved.

Aromatic block copolyesters stabilised with metallic salts of phosphinic acid

Stabilisers consisting of metallic salts of p-butoxyphenylcyclohexyl phosphinic acid were introduced into two industrial copolymers based on bisphenol-A and phenolphthalein respectively, and their effects on the mechanical and thermal properties were investigated. The mechanical properties were sensitive to the amount of stabiliser. Ductility and breaking strength increased with small additions, but as the amount of stabiliser increased, the process was reversed. On the other hand the modulus of elasticity showed a steady decrease. Similarly, the thermal stability also increased with small concentrations of additive, and decreased at higher concentrations. Heat treatment increased the brittleness and reduced the breaking strength.

The improvement of the fracture behaviour of polybutyleneterephthalate modified by highly dispersed metals

The failure mechanism of polybutyleneterephthalate (PBT) was improved by the addition of highly dispersed Fe/FeO to the polymer. The mechanical behaviour of the materials under impact was investigated. It was shown that the addition of Fe/FeO stabilised the failure mechanism of PBT and improved its mechanical properties. Increased interphases between crystalline and amorphous phases, decreased crystalline size, increased network entanglement density and decreased critical structural defect length were responsible for these improvements.

Synthesis and assessment of the properties of polyetherketones (PEK) based on olygoketonephenolphthaleines (OKPP)–polyester block copolymers

Different polyetherketones (PEK) based on olygoketonephenolphthaleines (OKPP) with different condensation degrees and dichloranhydrides of isophthalic and terephthalic acids were obtained by means of an aceptor-catalytic polycondensation. The correlation between the composition of the intitial olygoketones and the properties of the resultant polyetherketones was established. Some of the physico-chemical properties of PEK were also investigated. It was shown that as the initial length of OKPP increased the yield strength, heat stability, the glass transition temperature and melt temperature increased.

The Influence of Fe/FeO Mixture on the Molecular Fluctuation Networks of Polybutyleneterephthalate

The failure mechanism of high-density polybutyleneterephthalate (PBT) was improved by the addition of highly dispersed Fe/FeO particles to the polymer. The impact strength of PBT was measured and the results were used to model the physical structure and failure mechanism of PBT. Fractal analysis was used to investigate the molecular changes caused by the presence of the modifier. The addition of the modifier decreased the free volume, increased the density of the fluctuation network of molecular chains, increased the interphases between crystalline and amorphous phases, and improved the packing of the molecules. The best results were obtained for the addition of 0.05% Fe/FeO.