Jerzy Słonecki

Biocompatibility studies of new multiblock poly(ester-ester)s composed of poly(butylene terephthalate) and dimerized fatty acid

This study was undertaken to evaluate the biocompatibility of new multiblock poly(ester-ester)s proposed as an alternative to Hunter silastic prosthesis used in a two-stage tendon reconstruction. Methanol-extracted polymeric material retained its weight, demonstrating the absence of leachable particles (e.g. low-molecular weight oligomers). Implantation tests indicated that the observed tissue changes were similar to those obtained with silicone, no evidence of contact necrosis being observed. The unchanged morphology of rat liver hepatocytes and the lack of parenchymal necrosis also indicated that exposure to the investigated polymers did not cause any cytotoxic reactions.

Physical and mechanical behavior of electron-beam irradiated and ethylene oxide sterilized multiblock polyester

The effect of two sterilization treatments (electron-beam radiation and ethylene oxide gas) on the structure and mechanical properties of a multiblock copolymer were investigated to establish the effects of the sterilizing procedures on potential biomedical material. The material was exposed for different radiation doses in order to find an optimum dose of electron-beam radiation. Characterization techniques employed include gel permeation chromatography, infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis and tensile testing. The optimal dose of radiation at which no change in structure and mechanical properties occurred was found as 25 kGy. Ethylene oxide gas treatment also did not affect the structure and properties of the polymer and it can be recommended as an alternative sterilization route for the studied polymer.

Influence of the chemical composition of poly[ester-block-ether]s on the phase structure

Abstract The influence of the chemical composition on the phase structure, and from this the structure-property relationships, of poly[ester-block-ether] (PEE) elastomers based on poly(butylene terephthalate) (PBT) hard segments and oligo(α,ω-dihydroxy poly(oxytetraniethylene)) (PTMO) and/or dimer fatty acid (DFA) soft segments was investigated using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile testing. Differences in thermal and mechanical properties with varying hard and soft segment composition are interpreted in terms of the phase miscibility of the various polymers studied.

Investigations of the hardness and thermal properties of copoly(ether-ester)s containing segments of different molecular weights

Abstract Copoly(ether-ester)s (CPPE) consisting of alternately arranged oligooxyethylene (PEO) soft segments of molecular weights 400 to 6000 and tetramethylene-terephthalate (4GT) hard segments was studied. The content of soft segments of copoly(ether-ester)s obtained varied over a wide range. Differential scanning calorimetry and hardness measurements in the temperature range from −70 to +150°C were carried out. At temperatures close to the melting point a significant change in hardness of CPEE occurs. This does not occur in those elastomers for which the enthalpy of melting ( H m ) of the soft segments approaches zero.

Dielectric Relaxation of Poly(ester‐block‐amide) Multiblock Copolymers

A series of poly(ester-block-amide)s, composed of crystallized sequences of poly(butylene terephthalate) (PBT) and an amorphous, aliphatic oligoamide (PA 36.6) obtained by the reaction of diamines and dimerized fatty acids, has been synthesized by polycondensation in the melt. The dielectric properties of these multiblock copolymers have been investigated as a function of temperature and PBT/PA ratio in the frequency range from 5 . 10 2 to 10 6 Hz. The melting and glass transition temperatures as well as the degree of crystallinity were characterized by means of DSC. The dielectric properties vary with temperature due to two relaxation processes: a) the β-relaxation process, associated with the local motion of polar groups attached to the soft and hard segments of the copolymer chain, and b) the α-relaxation process, associated with long-range molecular motions near the glass-transition temperature. This behaviour is near the grass-transition temperature. This behaviour is discussed by means of the Havriliak-Negami analysis.

Multiblock terephthalate copolymer as impact modifier for poly(propylene)/poly(butylene terephthalate) blends

The melt polycondensation method was investigated for the synthesis of a multiblock copolymer. The copolymer consisted of hard segments of poly(butylene terephthalate) (PBT) and soft segments of dimerised fatty acid. This multiblock copolymer was characterised by 1H and 13C NMR and FTIR spectroscopies and differential scanning calorimetry. The 1H NMR method was used for estimating quantitatively the amount of the hard/soft segments. The polymer morphology was characterised using light microscopy and transmission electron microscopy. The investigated polymer was used in a small amount as an additive to poly(propylene)/PBT blends in order to evaluate its influence on the morphology and impact properties of these blends. Die Synthese eines Multiblock-Copolymeren durch Polykondensation in der Schmelze wurde untersucht. Das Copolymere, bestehend aus harten Poly(butylenterephthalat)-Segmenten und weichen Segmenten aus dimerisierter Fettsauren, wurde mit 1H- und 13C-NMR-Spektroskopie, FTIR-Spektroskopie und DSC untersucht. Aus dem 1H-NMR-Spektrum wurde die Konzentration der harten und weichen Segmente bestimmt. Die Polymermorphologie wurde mittels Lichtmikroskopie und Transmissionselektronenmikroskopie charakterisiert. Die untersuchten Copolymeren wurden in kleinen Mengen als Additive in Polypropylen/PBT-Blends eingemischt, um deren Einflus auf die Morphologie und Impact-Eigenschaften der Blends zu untersuchen.

Selected dielectric and relaxation properties of PBT-DFA multiblock elastomers

The results of experimental investigations of poly(butylene terephthalate)-dimerized fatty acid (PBT-DFA) elastomers using dilatometric measurements, dielectric spectroscopy as well as ultrasonics are presented. Relaxation properties of the polymers are characterized in relation to the degree of crystallization of the hard segments. The variation of the polymer properties with temperature has been ascribed to two relaxation processes: glass transition (α-relaxation) and second order (β-transition) of the soft phase of elastomers.

Dimer Fatty Acid-Modified Poly[Ester-b-Ether]S: Synthesis and Properties

Abstract Thermoplastic elastomers of the poly[ester-b-ether] copolymer type (PEE) comprising a hard block of poly(butylene terephthalate) (PBT) and oligoether soft segments, differing in the molecular weight of the oligoether [α, ω-dihydroxy poly(oxytetramethylene) (PTMO); M n= 650, 1000, and 2900 g/mol] were synthesized and analyzed. Synthesized PEEs were modified by a dimer fatty acid (DFA, M n = 570 g/mol) as a component of the soft segments. Each copolymer (consisting of one hard-segment component and two components of the soft segments) was obtained in a two-stage process involving transesterification and polycondensation in the melt. Elastomer series were prepared with a constant PBT mass ratio of 50; the content of PTMO and DFA segments was changed. Differential scanning colorimetry results showed a single glass transition temperature for the mixed PTMO-DFA soft phase, which indicates that ether and aliphatic units are able to create a homogenous amorphous phase.

Dynamics of soft segments phase in copoly(etherester) elastomers: a spin probe study

Two oligodiols, poly(ethylene oxide)glycol and poly(propylene oxide)glycol, and synthesized copoly (etherester) elastomers having these oligodiols as soft segments were investigated by the spin probe method. It was found that the rotational mobility of the probes is connected with the local mode α+β and β-relaxations in these materials. Comparison of the results obtained with analogous data for poly(oxytetramethylene) and related elastomers have shown that the relaxation runs for all oligodiols are almost the same and no difference was found for elastomers.

Ultrasonic characterization of thermoplastic multiblock elastomers

Abstract The propagation of ultrasound waves in thermoplastic multiblock elastomers was investigated by measurements of the ultrasound velocity and attenuation. Three polymer series with amorphous-crystalline structure were studied. The soft-segment material was composed of three different oligomers for the three series: poly(1,4-oxypropylene)diol for series A, oligo(oxyethylene)diol for series B, and dimerized fatty acid for series C. The hard-segment material was composed of poly(butylene terephthalate) (PBT). The ultrasound velocity and attenuation of these elastomers with variable hard-segment concentration were investigated as a function of the temperature. The observed relaxation processes were ascribed to the glass transition of the soft phase. The possibility of a general description of these systems is discussed.