Scientific publications

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Customised Property Combinations 2007, Peter Niedersüß, Tonja Schedenig, Christelle Grein, Markus Gahleitner, Klaus Bernreitner. Customised Property Combinations Kunststoffe International Air-quenched blown film was solely a domain of polyethylene until a few years ago. With the polypropylene grades that have since then been introduced into this area of processing technology, the application and property spectrum of films produced by this method has considerably widened. New product developments in the area of random and heterophase copolymers are taking account of this trend and permitting economic solutions in the packaging sector
Italian Sewage and Drainage pipe systems Dynamic prospective with the new generation of PP-HM materials 2007, Carl-Gustaf Ek, Christian Goetzloff. Italian Sewage and Drainage pipe systems Dynamic prospective with the new generation of PP-HM materials Plastic Pipes & Fittings (SYSTERM S.p.A. Milano), (In Italian.)Polypropylene (PP) materials have been successfully used for the manufacturing of piping systems for a long time and have demonstrated their performance in pressure and non-pressure applications. Polypropylene block copolymers (PP-B) are predominantly used for the manufacturing of non-pressure sewage and drainage pipe systems. The latest generation of PP-B ma-terials- so-called PP-HM class (PP with higher modulus) - have been introduced in Italy few years ago and several Italian leading pipe manufacturers have de-signed innovative pipe systems with this new class of materials. The country is definitively now on track to shift from traditional materials (concrete, vitrified clay) to PP-HM based solutions for non-pressure sewage and drainage pipe systems.
Polypropylene Development - From Catalyst to Customer 2007, Wolfgang Neißl, Markus Gahleitner, Christelle Grein. Polypropylene Development - From Catalyst to Customer SPE International Polyolefins 2007 Conference, Houston/TX, USA, February 25-28, Over the last 20 years, the combination of an attractive technical property profile and an advantageous cost position has resulted in a massive volume increase for polyopropylene. The forecasts of market volume are positive for the next years as well, and there are a number of good reasons for that. New developments in the catalyst and process are together with an improved understanding of structure-property relations allow not only designing polymers close to the present customer needs, but also for future and previously not accessible application areas. While Ziegler/Natta type PP catalysts appear to be a mature area, new supporting technologies have opened a range of opportunities. At the same time, single-site PP catalysts are beginning to live up to their earlier promises in terms of yield and product design. New polymerisation plant designs are expanding the product range, and as a consequence of the ever increasing size of polymerisation plants, post-reactor modification is gaining importance for tailoring materials towards special niche market requirements. The wide field of high-impact copolymers has benefited from an improved understanding of relations between molecular structure, morphology and fracture mechanisms, as has the general modulus level of PP from a deeper insight into nucleation and crystallisation mechanisms. A number of new application fields will be presented, demonstrating the unabated innovation strength of PP
Highly Transparent Polypropylene Cast Films: Relationships Between Optical Properties, Additives, and Surface Structure 2007, Katharina Resch, Gernot Wallner, Christian Teichert, Markus Gahleitner. Highly Transparent Polypropylene Cast Films: Relationships Between Optical Properties, Additives, and Surface Structure Polymer Engineering and Science Polypropylene homopolymer and ethylene/propylenerandom-copolymer cast films formulated with various amounts of slip and antiblocking aids as well as acid scavengers and produced under different processing conditions were characterized with respect to surface structure and optical properties. The topographical analysis was done by atomic force microscopy (AFM). Optical properties were determined using a hazemeter and an UV/Vis/NIR spectrophotometer. AFM height images revealed a significant influence of processing conditions on the development of surface structures. Besides the occurrence of scratches displaying the replica of the metallic chill roll, particularly characteristic eight-shaped superlamellar crystalline features were affected by the cooling conditions. Relationships between surface enrichment of additives and vertical and lateral roughness parameters were established. In general, film types formulated without additives exhibit better optical properties. For film types formulated with polymer-processing aids, the diffuse-scattering power is reduced by low molecular weight, high amounts of acid scavenger aid, and antiblocking agents with low porosity. A separation of haze into its bulk and surface components indicated that total haze is dominated by surface haze. The comparison of haze and the vertical roughness parameters exhibited a tendency of a linear correlation.
Thermal history in processing and post-processing steps influencing the mechanical strength of polypropylene 2007, Markus Gahleitner, Maria Parisi, Sybille Frank, Stefano Piccarolo, Doris Machl. Thermal history in processing and post-processing steps influencing the mechanical strength of polypropylene Nordic Polymer Days 2007, Helsinki / Finland, May 29th-31st Long-term stability of plastic parts is not just determined by their chemical stability, i.e. their resistance to chain breakdown and decomposition, but also by the evolution of their mechanical properties over time. While chemical ageing of polymers has been studied widely, mostly in connection with stabilization efforts, the effects of physical ageing and ¡V in case of semicrystalline polymers ¡V stabilization of morphologypost-crystallisation have received much less attention. Earlier research in the frame of the EU-FP5-project DECRYPO have already shown strong effects of thermal history in the processing (cooling rate) and the post-processing phase (annealing) on modulus, impact strength and transparency of polypropylene. The effects can be understood by a combination of mechanisms ranging from change in concentration of rigid amorphous phase, secondary crystal formation through lamellar thickening up to interfacial strengthening effects in multiphase impact copolymers. These results will be summarized briefly, followed by a presentation of recent findings for post-crystallisation effects in Ñ- and Ò-phase PP. Fracture mechanisms are clearly changed in annealing above the crystalline mobility transition (TÑ,c), shifting the brittle-to-ductile transition to lower temperatures. The practical consequences of such changes on long-term stability under application conditions will finally be outlined.
Use of 4- and 5-substituted bis(indenyl)zirconium dichlorides in homo- and copolymerization of ethylene and a-olefins 2007, Simo Toikkanen, Tanja Piel, Tapio Saarinen, Barbro Löfgren, Esa Kokko, Päivi Pitkänen. Use of 4- and 5-substituted bis(indenyl)zirconium dichlorides in homo- and copolymerization of ethylene and a-olefins Nordic Polymer Days, Helsinki, Finland, 29-31.5. In recent years, studies on metallocene catalyst systems have shown that a small change in the metallocene structure can lead to very different catalytic behaviour in a-olefin polymerization. The metallocene catalyst systems have potential for very high productivity per mass of catalyst and capability to control molecular weight and its distribution and forcopolymers, the comonomer content and cistribution statistics.
Single Site Catalyst Development in BorstarÂ® Technology 2007, Anneli Pakkanen, Päivi Pitkänen. Single Site Catalyst Development in BorstarÂ® Technology Nordic Polymer Days, Helsinki, Finland 29-31.5. In recent years Borealis has been active in developing both unimodal and bimodal materials using metallocene catalysts. The single site nature of metallocenes yield resins with narrow distributions of molecular weight and comonomer, and are therefore an excellent starting point for tailoring of bimodal polymer structures. This paper discusses the opportunities of single site catalyst in Borstar PE technology, the requirements the process demands of the catalyst, and the properties achieved. The catalyst activity and performance can be affected greatly by the selection of right type of single site complex and substituents, but also through correct process parameters. The Borstar PE process together with single site catalyst technology enables an expansion of polymer property window to meet our customerÂs needs. The bimodal mPE combines improved processability with balanced product properties: good optical and mechanical properties, excellent sealing properties, and low organoleptics. Applications like film, extrusion coating, moulding, pipe and cable benefit on the improved property balance.
Effect of Metallocene Structures on their Performance in Ethene Polymerisation 2007, Tanja Piel, Tapio Saarinen, Barbro Löfgren, Esa Kokko, Janne Maaranen, Päivi Pitkänen. Effect of Metallocene Structures on their Performance in Ethene Polymerisation Macromolecular Chemistry and Physics Six (Cp)(4-phenyl-indenyl)MCl2 (A) and four (Cp)(1-phenyl-indenyl)MCl2 (C) (M¼Zr/Hf) based complexes were tested in ethene homo- and copolymerisation under different conditions to explain how the differences in the complex structure affect the polymerisation process and the formed polymer. Polymerisation experiments reveal that hafnocene catalysts need a higher amount of MAO to reach the maximum activity than zirconocenes. Hafnocenes also incorporate better 1-hexene. Catalysts with the Cp? or 1,2,4-Me3Cp ligand show higher activity, and work well with [HNMe2Ph][B(C6F5)4]/TIBA as cocatalyst, but produce polymers with lower Mn than the corresponding catalyst with a plain Cp ligand. The Cp? ligand seems to prevent 1-hexene incorporation. A methyl group in the 2-position of (Cp)(4-PhInd)ZrCl2 decreases the activity and Mn but favours 1-hexene insertion. Polymerisation activity is higher with catalysts with a 1-PhInd-ligand than with a 4-PhInd-ligand.
Aineettomien oikeuksien hallinta rempallaan 2007, Kalle Kallio, Hilkka Knuuttila. Aineettomien oikeuksien hallinta rempallaan Kemia-Kemi In Finnish
Multiphase PP Blends for Automotive Interior: Composition Effects on Surface Structure and Scratch Resistance 2006, Doris Machl, Christelle Grein, Klaus Bernreitner. Multiphase PP Blends for Automotive Interior: Composition Effects on Surface Structure and Scratch Resistance SPE ANTEC 2006, Charlotte, NC, USA, 07.-11.05. This paper outlines surface properties like scratch and gloss performance in PP/EPR blends consisting of a PP matrix and a dispersed EPR phase with crystalline PE core particles. A brief overview of the influence of intrinsic polymer parameters and processing conditions is given. The shape and size of the dispersed EPR in polypropylene resin have a strong impact on both gloss and scratch performance. One of the major factors will be the molecular weight of the EPR particles. The bigger they are, the lower the gloss and the higher the scratch resistance. In addition to polymer design, processing conditions play a major role. It was found that injection speed is one of the main controlling factors during injection molding.