SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Conference Proceedings
COMPUTATIONAL ANALYSIS AND DESIGN OF SINGLE SCREW EXTRUDERS HAVING SCREWS OF COMPLEX GEOMETRY WITH MIXING ELEMENTS
John Vlachopoulos | Nickolas Polychronopoulos | Shinichiro Tanifuji, November 2011
The methodology is based on some conventional models for flow in the hopper, solids bed and melting zone. In the melt pumping zone the Hele – Shaw approximation is applied, which describes spreading flow in two dimensions. The momentum and energy equations are solved layer – by – layer starting from the barrel wall. This methodology enables significant reduction of computer time required for simulation of extruders with complex screw geometry, over the fully 3D approach. Good agreement was obtained with some available experimental data and further evaluations of predictive capabilities are currently underway.
PROCESSING AND PROPERTIES OF BIOABSORBABLE PLLA-HA COMPOSITES
Shih-Po Sun | Lyndon Charles | Fei Peng | James R. Olson | Montgomery T. Shaw | Mei Wei, November 2011
Orthopedic procedures often require repair materials that can carry large loads without excessive deformation or failure. To this end, we designed composites using two biocompatible/bioabsorbable polymers, poly(L-lactic acid) (PLLA) and polycaprolactone (PCL). The latter was filled with nano-needles of hydroxyapatite (HA), while the PLLA was used in long-fiber form. Theory advises that the HA nano-needles must be of high aspect ratio and be aligned in the matrix to gain sufficient stiffness. We have explored several processing techniques for accomplishing this task, and have successfully made composites in the 8- to 10-GPa range. Variations of this structure will also be described.
STAGES MOULDING A NEW TECHNOLOGY FOR THE PRODUCTION OF PLASTIC PARTS
J. Escudero | J. Tirado | M.A. Rodriguez-Perez | J.A. de Saja | D. Rosa | J.A. Vazquez, November 2011
This paper presents a novel technology to produce plastic parts called “Stages Moulding”. The patented technology allows producing plastic parts with complex shapes, from a wide variety of polymers, with excellent surface quality, reduced thermal and mechanical stresses and possibility to produce parts with reduced weights. This novel process uses cheaper moulds and equipments than those used in injection moulding. The specific characteristics previously mentioned make this technology very promising for the production of plastic parts for different markets. The paper explains the main characteristics of this technology presenting some real examples of parts produced.
DEVELOPMENT OF STARCH BIOBASED AND BIODEGRADABLE PLASTICS FOR THEIR USE IN TRAYS FOR FOOD-PACKAGING
A. Lopez-Gil | M.A. Rodriguez-Perez | J.A. De Saja | F.S. Bellucci | M. Ardanuy, November 2011
This research work develops new methods to produce biodegradable starch-based trays for the purpose of replacing expanded polystyrene in the food packaging market. The starch based biopolymers present several drawbacks like poor mechanical properties and very high density. In order to overcome these drawbacks two research lines have been set up: blending thermoplastic starch with biobased reinforcements from agricultural wastes like barley straw and grape wastes, and testing the foamability of these materials with a Microwave-foaming method.
RELEVANCE OF THE FEMTOLASER NOTCH SHARPENING ON THE IMPACT FRACTURE OF POLYCARBONATE
David Arencón | Antonio B. Martínez | Pablo Moreno | Ana García, November 2011
The traditional sharpening through the razor blade method employed in the fracture characterization of polymers creates plastic deformation at the notch tip, which affects the fracture toughness values. Recently it has been applied a technique based on femtosecond pulsed laser ablation, which removes material with almost no heat dissipation, preventing melting and thermal deformation of the surrounding area and without plastic deformation at the crack tip. In this work, the fracture toughness of polycarbonate was studied using the Linear Elastic Fracture Mechanics testing procedure at impact velocity, evaluating the influence of crack sharpening by femtolaser or razor blade sliding.
EFFECT OF NANOCLAYS ON THE FOAMING BEHAVIOR OF RIGID POLYURETHANE MONITORED BY X-RAY RADIOSCOPY
S. Pardo-Alonso | S. Estravís | E. Solórzano | M.A. Rodríguez-Perez | J.A. de Saja, November 2011
X-ray radioscopy is a technique in which a series of radiographies are acquired during an evolving process. The present study aims to investigate the mechanisms occurring during the reactive foaming process of rigid polyurethane (PU) foams in its liquid state. The work addresses a comparative study of in-situ pore growth determination in PU foams with and without nanoadditives (nanoclays), based on the mentioned technique and thus providing a valid methodology to investigate the foaming process in all its stages. The results confirm that nanoparticles addition modify the final pore size most probably based on a higher nucleation rate at initial stages.
POLYURETHANE FOAM NANOCOMPOSITES: RELATIONSHIP BETWEEN MECHANICAL PROPERTIES AND FILLER-MATRIX CHEMICAL INTERACTION
S. Estravís Sastre | M. A. Rodríguez Pérez, November 2011
Nanofillers are added to rigid PU foams to improve their mechanical properties, however this expected behaviour is not always found. A poor dispersion of the fillers is usually accepted as a possible explanation, but chemical interaction between matrix and fillers could also result in a reduction of the final foam properties. In this study, polyurethane rigid foams (with and without nanoclays) have been produced and characterized. Different dispersion techniques have been used. The experimental results suggested that chemical interaction between fillers and matrix plays a critical role in the mechanical behaviour of these type of systems.
IMPROVING THE THERMAL INSULATION OF POLYSTYRENE FOAMS BY THE ADDITION OF CARBON BLACK.
Juan Lobos | Migue A. Rodriguez-Perez | Gemma Gasa | Miguel Muñoz, November 2011
This paper presents an investigation on the improvement of the thermal conductivity of polystyrene foams by using different types of carbon blacks as additives. Carbon blacks with different morphologies were used as IRblockers. To test the changes in the conductivity foams with densities between 20 and 100 kg/m3 were produced using the solid state foaming technique. The cellular structure and thermal conductivity were analyzed in detail. In addition the thermal conductivity was analytically modeled to study the influence of the different carbon black types on the heat flow by radiation. The best morphology to reduce the thermal conductivity has been detected.
STUDY ON RAPID MANUFACTURING TRAINING NEEDS IN THE EUROPEAN CONTEXT
Zaida Ortega | Mario D. Monzón, November 2011
Rapid Manufacturing (RM), as one of the most important emerging technologies, has a high potential as part of European industry, with a clear role in manufacturing process and economy. In this context, seven EU entities have proposed an e-learning program on these technologies, to increase its knowledge and use, with the aim of improving competitiveness in companies. Results on surveys prepared in this project with the aim of establishing the actual situation in Europe in this field and filled in by companies and training centres are presented in this communication, providing an overview of RM general knowledge and use.
THIN TPO FILM OVERMOLDING FOR VEHICLES INTERIORS DECORATION
Tu Le Ngo | Alain Choquet | Dominique Valligny, November 2011
Many vehicle manufacturers are aiming diversifying their car interiors with more daring colours and textures with limiting the amount of investment. For large interior parts, like instrument or door panels, special resins or painting technology was considered current state of the art. A new technology, thin TPO film overmoulding, could replace this current state of the art technology. The main paper objective of this paper is to describe the advantages and the issues in using thin thermoplastic olefin (TPO) foil overmolding as an alternative. This paper presents the new generation of TPO “ready for graining” soft foils and the innovative tooling & process needed to laminate the foil during the PP direct injection shot
EXPANDED INJECTED PP SYSTEM TO MAKE 25% LIGHTER ESTHETICAL INSTRUMENT PANEL
Christian Bey | Alain Choquet | Dominique Valligny, November 2011
By the year 2025, carbon emissions levels will require for the main vehicle in the world important weight reductions. Plastics components can now be expanded during injection keeping correct mechanical behavior to design vehicle interiors. The paper presents the instrument panel application and describes the importance of the Polypropylene (PP) material, the expansion technology and the related component, injection press and tooling designs. The paper aims to demonstrate how applications like visible instrument topper panels or side trimmings could be designed in purpose to respect esthetical and mechanical specifications
PRODUCTION OF POLYPROPYLENE (PP) FOAMS FROM A CONVENTIONAL PP GRADE. ANALYSIS OF CELLULAR STRUCTURE AND MECHANICAL PROPERTIES.
C. Saiz-Arroyo | M.A. Rodríguez-Pérez | J.A. de Saja, November 2011
Foaming of polypropylene is not trivial due to its weak melt strength and its semicristalline character. The solutions proposed up to now are based in crosslinking the polymeric matrix or in the use of special polypropylene grades. A collection of samples with relative densities in the range of 0.3-0.6 have been produced using a conventional PP grade. The improved compression moulding foaming process which uses a chemical blowing agent was used to produce the analyzed foams. The effect of chemical composition on both cellular and mechanical properties has been analyzed.
ADHESION BETWEEN POLYPROPYLENE AND STEEL BY OVER MOULDING
Miguel Sánchez-Soto | Silvia Illescas | Tobias Abt | Maria Virginia Candal | Jaime Francisco Gómez, November 2011
In this work, a hybrid polypropylene (PP)/steel car part (Traverse leg) was created by over moulding. PP was modified with 10%wt. of PP-g-Ma coupling agent. Different surface treatments were applied to the steel determining its influence on adhesion. Best peel strength was reached when the steel was sanded. Etching and shot peened plates showed similar but lower levels of adhesion. In all cases, the application of torch heating was necessary to create a thin layer of iron oxide strongly bonded to the steel and by reaction to the PP-g-Ma. To create adhesion a minimum steel temperature of 120ºC was necessary.
T.I.I.P.: A TRAINING AND RESEARCH GROUP IN INJECTION MOLDING
J. Castany | J. Fuentelsaz | F. Serraller | D. Mercado | I. Clavería | J. Aísa, November 2011
Created from University of Zaragoza, the group T.I.I.P. has developed its activities since 1989 around injection molding. This team has always worked as near as possible to the industry (its name includes “workshop”, not “laboratory") and, in its aims, it promotes the research work pushed from market demands. However, for an effective knowledge exchange, the members of the group T.I.I.P. have promoted hundreds of training courses teaching to all the injection´s actors, about how to arrange the whole process to improve final results. During these twenty years, fifteen doctoral theses and twenty friendly computer programs for training were made, closing the loop.
HALOGEN-FREE FLAME RETARDANT POLYOLEFIN FOAMS FOR AUTOMOTIVE APPLICATIONS
S. Román Lorza | M. A. Rodríguez Pérez, November 2011
A new type of materials has been produced by means of creating a cellular structure in blends of LDPE/LLDPEg- MAH/ATH. The presence of the aluminium hydroxide (ATH) in a polymer blend, both as flame retardant and reinforcement, significantly increases the density of the end product. The aim of this work is to achieve a cellular structure by foaming these materials, when high loading levels up to 60wt% of ATH are included. As a result, a density reduction of 50% has been obtained together with excellent mechanical and flame retardant properties. A comparison of these properties between solid and foamed materials is included.
DEVELOPMENT OF MODIFIED POLYLACTIDE (PLA)
H. Kishimoto | A. Takenaka | H. Moriwaka | H. Enomoto, November 2011
Polylactide (PLA) and other bio-based plastics have been attracting much attention for environment problems. In this report, modified PLA resin have been developed and based on “Technology of Nano-Modification for Polymer”, such as control of softening and of crystallization in nano size. Two types of modified PLA of which one is clear and soft PLA for extrusion molding and another one is high moldability PLA for injection molding have been developed. These modified PLA have been applied as alternative plastics of PP and ABS to stationery, packaging, convenience goods, electrical appliance and so on. Performances and technologies will be presented.
EFFECT OF PHYSICAL AGING ON ENTHALPY RELAXATION AND EMBRITTLEMENT OF ELASTOMER THERMOPLASTIC BIODEGRADABLE POLY (L-LACTIDE/ ε-CAPROLACTONE)
Susana Petisco | Jone M. Ugartemendia | Jorge Fernández | Jose-Ramon Sarasua, November 2011
In the design of new polymeric materials the longterm stability and durability are matters of considerable importance. It is known that during physical aging volume contraction and densification of polymers occur and therefore physical properties such as mechanical or crystallization behavior of amorphous polymers may be affected. In this work the impact that physical aging has on two biodegradable poly(L-lactide/ε-caprolactone) (PLCL) copolymers differing on their randomness character was studied. Their thermal behavior has been evaluated by specific aging strategies using Differential Scanning Calorimetry (DSC).
IMPROVEMENT OF THE THERMAL DEGRADATION BEHAVIOUR OF PLLA/MWCNT COMPOSITES BY NANOTUBE PURIFICATION
Erlantz Lizundia | Jose-Ramon Sarasua, November 2011
The thermal degradation behaviour of poly (L-lactide) nanocomposites containing both as-received (MWCNT) and purified multi wall carbon nanotubes (p-MWCNT) was evaluated by means of thermogravimetric analysis (TGA). Composites with carbon nanotube contents of 0, 0.75, 1.25, 2.5, 4 and 5 wt. % were prepared. The thermal degradation process was analyzed in the light of Kissinger and Ozawa-Flynn-Wall (OFW) models revealing a lowering of the activation energy (E) due to iron and aluminium residues present in carbon nanotubes.
MECHANICAL PROPERTIES OF LACTIDE BASED SCAFFOLDS FILLED WITH INORGANIC BIOACTIVE PARTICLES
Aitor Larrañaga | Jose-Ramon Sarasua, November 2011
The mechanical properties of highly porous scaffolds have been investigated. Scaffolds of poly(Llactide)( PLLA) and poly(L-lactide/ε-caprolactone)(PLCL) filled with 5, 10 and 15 vol.% of Bioglass® (BG) and hydroxyapatite (HA) particles were prepared by a solvent casting/particulate leaching procedure. The thermal properties of the scaffolds were determined using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), while the morphology was characterized by scanning electron microscopy (SEM). All scaffolds presented a highly porous structure (≈90% porosity) and well-interconnected pores. Tensile test results revealed that the addition of bioactive particles increases the modulus and decreases the relative elongation at break.
DEVELOPMENT OF NANOSCALE INTERFACIAL MORPHOLOGY IN POLYMER-BASED NANO-CARBON HYBRID STRUCTURES FOR STRESS TRANSFER IMPROVEMENT
Marilyn L. Minus | Yiying Zhang | Kenan Song | Jiang Sha Meng | Emily C. Green, November 2011
Composites based on carbonaceous materials and polymers have been researched since the production of carbon fibers in the 1960s, leading to disruptive technological changes in the field of materials science. Today micro- and nano-scale carbon materials have opened new directions within this field to produce composites for high-performance applications. This work outlines in-situ analysis of the POLYMER-NANO interfacial zones in the composite as a function of nano-carbon structures. Stress transfer analysis of the composite interface couples nano-carbon structure with morphology and mechanical performance. This work addresses fundamental issues for materials design toward commercialization of polymer-based nano-composites meant for high-performance technologies.
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