Marek Kozlowski

On the compatibility of the IPP/PA6/EPDM blends with and without functionalized IPP I. Thermo-oxidative behaviour

Abstract Binary isotactic polypropylene (IPP)/polyamide 6 (PA6) and ternary IPP/PA6/ethylene–propylene diene terpolymer (EPDM) blends in various ratios were obtained in a Haake Rheocord mixer. Processing behaviour was changed in the presence of IPP functionalized with bismaleimide (BMI), maleic anhydride (MA) and acrylic acid (AA) as reactive compatibilizing agents. The thermal and thermo-oxidative behaviour of blends was studied by differential scanning calorimetry and thermogravimetry. The functionalized IPPs modify the crystallinity degree and the decomposition behaviour of both IPP and PA6 as a result of chemical reactions of functional groups with those of the PA6. The changes depend on the IPP/PA6 or IPP/PA6/EPDM ratio, the chemical nature and amount of the functionalized IPP. On the basis of the processing and thermal data one can conclude that the compatibilizing agent effect increases in the following order: IPP-AA

Influence of Accelerated Weathering on the Properties of Polypropylene/Polylactic Acid/Eucalyptus Wood Composites

In the view of producing environmentally friendly materials without compromising properties, new composites containing polypropylene as a matrix and eucalyptus wood, with or without 15% of polylactic acid, were melt processed. In order to improve compatibility between components, a chemical modification of wood with toluene-2,4-diisocyanate (TDI) was realized and evidenced by changes in FT-IR and XPS spectra. The morphological, mechanical, and thermal characterizations of the obtained composites were evaluated before and after accelerating weathering. The results showed that the material comprising 15% TDI-modified wood, PP, and 15% PLA exhibited the best properties.

Processing conditions, morphology and properties of a polycarbonate + a thermotropic polymer liquid crystal blend

Abstract We have investigated phase structure—properties relationships of polycarbonate (PC) + a polymer liquid crystal (PLC) blends processed in a twin-screw extruder at several conditions. The PLC is PET/0.82 PHB—a copolyester of poly(ethylene terephtalate) and p-hydroxybenzoic acid. For comparison the blend was additionally extruded in a wide range of shear rates in a capillary rheometer at two different spinning rates and compression-molded. The blend processed in the rheometer exhibits lower values of modulus and tensile strength than the blend extruded due to destruction of the initial orientation and dispersion level gained during extrusion. The orientation of PLC-rich islands increases up to the shear rate of 50–100 s−1, whereas deformation at higher shear rates exhibits a droplet-breakup phenomenon, confirmed by SEM micrographs. The rheological measurements (oscillation mode) evidence a high shear thinning of the PLC. By contrast, the influence of the deformation rate on the viscosity for PC and the blend is negligible, suggesting also a low interaction level in the interfacial area. This conclusion was confirmed by dynamic mechanical measurements. As expected, our experiments prove that structure and properties of the blend are affected by processing (shear and elongation) conditions. Increasing shear rate leads to elongation of dispersed domains but exceeding critical values can lead to droplet breakup and destruction of created structure. The unique morphology created during extrusion can be destroyed during additional processing (in rheometer). Formation of fibrils is also dependent on additional treatment—spinning speed. Optimized spinning speed can lead to 50% increase in stiffness of the blend.

Liquid Crystal Polymer Blends

Abstract Two-component blends of polymer liquid crystals with polysulfone or polypropylene have been investigated. Tensile properties, melt rheology and morphology of two-component systems have been presented. The orientation conditions under melt processing have been related to the phase structure and mechanical strength of the blends. Enhancement of interfacial adhesion has been attempted by means of compatibilization with the maleated modifiers.

Polymer composites as sensing materials for liquid organic solvents – preliminary results

Abstract Carbon black-filled polymer composites were investigated as sensing materials for organic liquids. Polypropylene and polystyrene which were selected as matrices and various amounts of carbon black were considered as the main factors influencing sensitivity of the composites in view of the percolation theory. Disposable filaments were produced of these materials. Change in their electrical resistivity was measured upon immersion in benzene, toluene, xylene, ethylbenzene and their mixtures. It has been found that studied materials were sensitive to the composition of liquid mixtures of organic solvent. Relationships between the filament response and volumetric fraction of the components were presented. The studied materials have shown promising sensing properties, which suggest their applicability for identification and quantification of multicomponent organic liquids.

Halloysite with Iron Oxide Inclusions as a Soft Ferromagnetic Filler for Polymer Composites

Natural mineral fillers for polymer composites have frequently been investigated as cheap and easily obtainable alternatives to carbon nanotubes or synthetic short fibres. In this paper we have investigated a natural product from a deposit located in Poland and containing halloysite clay and ferromagnetic particles as main components. In order to assess the homogeneity and possible application fields of polyethylene-based composites prepared from these materials, the composites were evaluated by studying their melt rheology, mechanical properties, wetting, magnetic properties and surface morphology.

Design and Manufacture of Polymeric Scaffolds

Scaffolds are porous materials designed for organ replecement, which are manufactured with a shape and mechanical properties matched to that of original tissue. Such structures are sieved with cells, genes and proteins, that grow in the scaffold pores and after maturation may be implanted into the body. Scaffolds described in this paper are biodegradable and were fabricated from polylactide by three groups of technology: batch foaming and extrusion foaming, electrospinnig, moreover the microstucture was designed first with CAD technique, then fabricated by means of a rapid prototyping. Microstructure of scaffold was evaluated by the scanning electron microscopy.

Influence of Filler Geometry on Melt Strength of Poly(lactid acid) Composites with Different Electrically Conductive Fillers

Polymer materials manufactured of natural resources have been characterized. Polylactid acid (PLA) was used as a matrix for composites filled with carbonaceous fillers of different geometry (carbon black and carbon nanofibres). Polymer strands made of electrically conductive PLA composites have a promising potential as materials for fabrication of sensors sensitive to strain, temperature or organic solvents. For better understanding of the correlation between processing parameters of PLA composites and their sensing ability the melt characteristics have been evaluated using a capillary rheometer and Rheotens melt strength tester. Strain sensing was monitored under three point bending by means of electrical conductivity measurements.

Molecular Modeling at Plastic Recycling

The possibility to model the new materials from recycled, post industrial polymer rejects by molecular modeling methods was investigated by comparison of the results obtained from the simulation process and the experiments.

Starch-based multiphase polymer materials

Abstract Biocomposites prepared by melt blending were investigated. The blends were composed of synthetic and natural macromolecules, including poly(vinyl alcohol), aliphatic-aromatic polyester and thermoplastic starch. Mechanical properties of the composites, their microstructure, melt rheology and thermal characteristics are presented. Influence of water on the properties as well as the degradation rate of the materials has been estimated as a function of their composition. Such materials may find applications for packaging as well as in medicine and biology as polymeric scaffolds, drug delivery systems etc.