Scientific publications

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Title	Year
Effect of Material Structure and Additives on the Optical Properties of PP Cast Films 2006, Gernot Wallner, Katharina Resch, Christian Teichert, Markus Gahleitner, Wolfgang Binder. Effect of Material Structure and Additives on the Optical Properties of PP Cast Films Chemical Monthly, 137, 2006, 887-897 Polypropylene homopolymer and ethylene-propylene-random-copolymer cast films formulated with slip, anti-blocking, and acid scavenger aids were analyzed as to material structure and optical properties. The structural and topographical characterization was done by atomic force microscopy and by spectroscopic methods. Optical properties were determined using a hazemeter and an UV-VIS-NIR spectrophotometer. As to the effect of additives it was established that slip and antiblocking aids migrate to and accumulate on the surface, resulting in increased surface roughness and larger scattering identities close to the surface. Acid scavenger additives were shown to contribute to less significant slip aid domains and hence to lower haze. In general, films without additives showed much better optical properties. The separation of haze into its bulk and surface components revealed that the total haze is dominated by surface haze. printme	2006
Extending PP's foamability through tailored melt strength and crystallisation kinetics 2006, Jin Wang, Chul B. Park, Manfred Stadlbauer, Rick Folland, Wilhelmina Pirgov. Extending PP's foamability through tailored melt strength and crystallisation kinetics RAPRA Blowing Agents and Foaming Processes 2006, Munich, Germany, 16-17 May, 2006 The foamability of four polypropylene (PP) resins have been studied with varying both chain architecture (long-chain branching) and chain regularity (homo- and copolymers) of the foaming behaviors of these PP materials with high and low melt strength, as well as fast and slow crystallization kinetics, were investigated using butane as a blowing agent. Experimental results showed that the foamability of PP can be varied by tailoring the melt strength and crystallization kinetics through chain architecture. These fundamental learnings suggest that the combination of slow crystallization kinetics, as achieved with PP copolymers, and high melt strength, as achieved with long-chain branched PP gives the broadest processing window printme	2006
Stability Study On PP Nanocomposites 2006, Kshama Motha, Johannes Wolfschwenger. Stability Study On PP Nanocomposites Addcon, Köln October 17-18, 2006 Considering the continuing high interest and potential of polymer nanocomposites, insight into their process and long-term thermal stability is an important prerequisite to commercialisation of these materials. When considering organically modified layered silicates in particular, there are some drawbacks expected due to one or more of the following; the lower thermal stability of the surface treatment chemicals used at standard polymer processing conditions, metal impurities in the natural organoclays, the presence of free maleic anhydride in maleic anhydride grafted polymers used as compatibilisers for polyolefins, and the oligomeric nature of these compatibilisers. Solving the stability issues of nanocomposites forms an important sub-class within the many ongoing R&D activities in this area. The use of more thermally stable surfactants, alternative compatibilisers, and more pure layered silicates are some of the topics studied. We have conducted a study to investigate stability performance of PP nanocomposites with multiple extrusion, long-term thermal ageing, and Oxygen Induction Time (OIT) tests. The study showed that a nanocomposite formulation was comparable to neat PP in multiple extrusion testing and thus in process stability. However, long-term thermal ageing was considerably inferior to that of neat PP. Further studies will be undertaken to identify the significance of the possible factors as mentioned above, influencing nanocomposite stability. printme	2006
Polyolefin compounds and composites: Engineering materials of the 21st century 2006, Wolfgang Neißl. Polyolefin compounds and composites: Engineering materials of the 21st century 8th Austrian Polymer Meeting 2006, Linz/Austria, September 20-22, 2006 The rather conflicting requirements for polymer development in the 21st century are high property level, low energy consumption and environmental impact, low cost and wide applicability. Polyolefins as starting materials are increasingly attractive both due to their price-property relation and the many possible ways to modify their property profile. The low energy demand in production also makes them favourable from a sustainability perspective. As a consequence of the ever increasing size of polymerisation plants, post-reactor modification will gain in importance for tailoring materials towards special requirements. The processes start at compounding and blending but extend more and more into reactive modification. Examples of recent and actual developments will be covered in the presentation. On the non-reactive side, the modification of polypropylene with special polyethylene grades, engineering uses of long-glass-fibre reinforced polypropylene and the development of polyethylene/mineral compounds for new applications will be discussed. Even more possibilities are opened up when expanding into reactive modification. Here, the chances of morphology stabilisation in high-impact EP copolymer systems (see diagram below), the possibilities of PE crosslinking and the in-situ generation of silica nanoparticles will indicate the range of activities at Borealis. printme	2006
Rheological and compositional factors for morphology and mechanics of PP/PE blends 2006, Markus Gahleitner, Christelle Grein, Klaus Bernreitner, Irene Helland, Elisabeth Ingolic. Rheological and compositional factors for morphology and mechanics of PP/PE blends Annual European Rheology Conference (AERC) Hersonissos, Greece, 26.-28.April, 2006 Blends of different polyolefins, especially of polypropylene and polyethylene, open a wide range of possibilities for material design, combining the advantages of the two material classes. A general look at composition factors (comonomer content and distribution, eventual presence of long-chain branching) and the effect of phase rheology on the miscibility and phase morphology in these blends will be presented. Subsequently, several examples targeted at different application areas will be outlined, showing the chain of correlation from the component properties to the composition behaviour. Simple mixing rules and a basic understanding of blend rheology have been found to be sufficient for predicting the necessary combinations of components for various property expressions. The presence of long-chain branched components like LDPE and HMS-PP makes the situation significantly more complicated, but allows to reach otherwise impossible combinations. printme	2006
Optimisation of rodrun LC3000/PP compatibilised blends: Influence of the compatibiliser and LCP contents on the rheological, morphological and mechanical properties 2006, Susana Filipe, Joao Manuel Maia, Catarina Rosa Leal, A.R. Menon, A. P. Duarte, Maria Teresa Cidade. Optimisation of rodrun LC3000/PP compatibilised blends: Influence of the compatibiliser and LCP contents on the rheological, morphological and mechanical properties Journal of Polymer Engineering, 25 (5), 2006, 511-545 The present study focuses on the optimisation of LCP/TP compatibilised systems. This study was essentially devoted to the influence of different LCP and compatibiliser contents on the final morphological, rheological and mechanical properties of the blends. Rheologically, we used both standard small amplitude oscillatory shear and large amplitude oscillatory shear (LAOS) experiments in order to improve the understanding of the mechanisms behind the mechanical reinforcement that might be helpful in the optimisation of liquid crystalline polymer and thermoplastic blends. The results revealed that LAOS, in particular, is highly sensitive to different morphologies and may be correlated with the effectiveness of compatibilisers, which is not surprising since the flow behaviour of LCPs is highly complex and non-linear, with lower non-linear characters obtained for those blends that showed a higher fibrillar formation and better mechanical properties printme	2006
Uniaxial extensional flow behavior of immiscible and compatibilized polypropylene/liquid crystalline polymer blends 2006, Susana Filipe, Maria Teresa Cidade, Joao Manuel Maia. Uniaxial extensional flow behavior of immiscible and compatibilized polypropylene/liquid crystalline polymer blends Rheol. Acta,, 45 (3), 2006, 281-289 In this work liquid crystalline polymer (LCP) and thermoplastic (TP) blends with and without compatibilizer were studied with respect to their elongational flow behavior, under uniaxial extensional flow. This knowledge is important because in processes involving dominantly extensional deformations, like the case of the formation of the LCP fibrillation, transient extensional flow properties become more important than transient or steadyshear properties. In systems characterized by disperse phase morphologies (10 and 20 wt%) the LCP acts as a plasticizer, decreasing the viscosity of the system and increasing its durability with respect to that of the matrix. On the other hand, for a system in which a co-continuous morphology is present (40 wt% LCP) fibrils and droplets deformation occurs simultaneously, leading to a much higher strain hardening and durability. Moreover, the addition of compatibilizers to the blends gives rise to an increase of the strain hardening and to a decrease of the durability, which is in accordance with the mechanical properties, namely a higher Young's modulus and lower elongation at break, in comparison with noncompatibilized systems. printme	2006
Durability testing for 100 year lifetime for buried non-pressure plastic pipes 2006, Gunnar Bergström, Stefan Nilsson, Kristian Thörnblom, Carl-Gustaf Ek, Harald Herbst, Anders Stenström. Durability testing for 100 year lifetime for buried non-pressure plastic pipes Plastics Pipes XIII, Washington DC, October 2-5,, 2006, Session 3B, 11 pages For plastics pipes used for underground drainage and sewerage there is at present no internationally accepted method for the evaluation of durability. This makes it difficult to make an objective assessment for both new materials and new pipe designs entering the market. This paper presents a possible future structure of such a durability evaluation for non-pressure pipes. Based on an experimental study of pipes made from a filled and an unfilled PP material and one made from an HDPE material different damage mechanisms and changes in pipe characteristics were observed when the pipes were exposed to long-term deflection and long term (one-year) ageing at +95 °C. A CAED methodology is also described which was used to investigate the distribution and time dependence of pipe stresses. printme	2006
Evolution of the Morphological and Rheological Properties along the Extruder Length for Compatibilized Blends of a Commercial Liquid-Crystalline Polymer and Polypropylene 2006, Susana Filipe, Maria Teresa Cidade, Manfred Wilhelm, Joao Manuel Maia. Evolution of the Morphological and Rheological Properties along the Extruder Length for Compatibilized Blends of a Commercial Liquid-Crystalline Polymer and Polypropylene Journal of Applied Polymer Science, 99 (1), 2006, 347-359 In a previous article, we reported on the evolution of the morphological and rheological properties along the length extruder for blends of a liquid-crystalline polymer (LCP), Rodrun LC3000, and polypropylene (PP). In this work, we extended this study to compatibilized PP/ Rodrun LC3000 blends, containing 10 wt % LCP and different compatibilizers, to determine the influence of the addition of a compatibilizer during the processing and, consequently, on the final properties of such systems. The results revealed that the addition of compatibilizers led to a decrease in the mean diameters of the LCP structures, in comparison with those presented by the noncompatibilized blend containing the same LCP content. This phenomenon occurred more quickly for those blends in which compatibilization was carried out in an efficient way. Linear oscillatory shear was mainly sensitive to the type of morphology present in the blends, whereas nonlinear oscillatory shear was more sensitive to the evolution in the droplet/fibril size and along the extruder length. printme	2006
Visualisation of relationships between interwoven variables within polyolefin technology 2006, Arild Follestad. Visualisation of relationships between interwoven variables within polyolefin technology Austrian Polymer Meeting, Johannes Kepler University, Linz, Austria, Septemeber 19 - 22, 2006., 2006 Poster: - Relationships of many variables at the same time must often be considered within polyolefin technology. Such relationships are often hard to get feeling for, communicate and discuss. However, there are simple and efficient tools for accelerated understanding. printme	2006