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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Strippability in cable extrusion
In cable industry, the ease with which a piece of jacket can be removed (stripped) from insulated multiwires is called strippability. A low stripe force is not only requested by customers and installers but it also makes the cable more flexible. The purpose of this paper is to present a method based on numerical approach to reduce the stripe force for a cable during extrusion. A correlation between the numerical parameter (pressure applied around the wires) and the stripe force measured on samples has been demonstrated afterwards it is used to design future extrusion pressure tooling.
Recycle of Internal and External streams of Polyetherimide Resin
One of the main advantages of polyetherimide (PEI) resin (Ultem* PEI) is its high thermal stability, making it an excellent candidate for using internal industrial recycle, external industrial recycle (sprues, runners, parts) and post-consumer recycle as raw material streams. A 30% glass fibre filled grade has been developed using up to 65% of non-virgin material. Mechanical properties were maintained even at high % usage of recycle. *(Trademark of Sabic Innovative Plastics IP B.V.)
Noryl GTX for thermal breaks
Aluminum has a high thermal conductivity which make them less suitable for window frames unless the inner and outer skin are separated by a thermal break. Currently glass reinforced Polyamide66 is used for this application. Noryl GTX* however has a thermal conductivity, measured on a extruded sample which is clearly below the thermal conductivity of Polyamide. Noryl GTX is also capable to withstand the high powder coating curing temperatures and meets the mechanical requirements for thermal breaks. By the upcoming, more stringent regulations on energy saving using Noryl GTX will help to meet these requirements.
HEAT MANAGEMENT IN THERMALLY CONDUCTIVE POLYMER COMPOSITES – PARTICLE SIZE EFFECTS
The particle-matrix interface in polymer composites may act as a barrier for heat transport, leading to a particle size and shape-dependent thermal conductivity. In this work, the effect of filler particle size and shape was studied for a model system of poly(butylene terephthalate) and silicon carbide. Within the particle size (0.5-100 μm) and volume (20-50 vol%) ranges studied, no influence on the thermal conductivity was observed. All experimental data could be well described by the Jiajun model.
HIGH FLOW GLASS FIBER FILLED AROMATIC POLYAMIDE RESINS
Novel idea of using hyperbranched polymers - dendritic aliphatic polyesters (DAP) as flow promoters in highly glass fiber reinforced aromatic polyamides (GF-PA) system is depicted in this paper. Different concentrations and types of DAPs are employed and these are found to be effective in modifying flow from 10% to 160% with as low as 0.5 to 3 weight % concentration for GF-PA without affecting the enabling mechanical and thermal properties.
MOLD OPTIMIZATION FOR METAL INSERT INJECTION MOLDING PROCESS
High quality, coupled with high efficiency of the process are two of the most important requirements for goods intended for automotive market. The case study here presented demonstrates how to satisfy quality requirements and increase production efficiency, while reducing production waste. An injection molding process with metal insert has been analyzed. New shape for mold feeding system has been obtained using Hagen-Poiseuille law as guideline and FE model to verify performance of proposed solutions.
THERMOFORMING PEI (POLYETHEREIMIDE) FOAM SHEET
Rigid PEI foam is based on amorphous thermoplastic PEI, with high thermal resistance, good FST performance and broad chemical resistance. Among the application benefits of PEI foam ‘machinability, good bonding to composite skin materials, low moisture uptake’, thermoformability is a unique characteristic. A specific technique has been developed to enable thermoforming of complex 3D-geometries. With the addition of an overmolded decorative layer, finished parts can be created with significantly reduced cycle time versus existing techniques.
“Digital Sampling” Bridging the gap between Virtual Reality and Color Development in Automotive Interiors
Digital Sampling as a solution to speed up Color Development Processes in Automotive Interiors is explored. The implementation of this tool reduces the amount of cycles needed for color approvals by 50% and is applicable to 80% of all interior parts. Virtual Reality Solutions are widely used in Automotive applications. This paper will show the benefits of linking Digital Sampling with Virtual Reality techniques and the resulting impact of realized time and cost savings on the bottom line.
FAILURE ANALYSIS : MIGRATION OF PIGMENTS & SLIP ADDITIVE CASE STUDIES FROM THE INDIAN SUB-CONTINENT
The role of slip additives as a crucial contributing agent in product failures due to it’s migration to the surface of plastic films is explored in the context of 5 case studies highlighting different aspects of the complex interrelationships that exist between the base resins, the slip additive present in the base resins, slip agent added by the film processor in the form of masterbatches, the color pigments , processing condition / storage conditions and the products which are subsequently packed inside the flexible pouch or flexible laminates.
POLYETHYLENE: PROCESS SENSITIVITY IN ROTATIONAL MOLDING
Rotational molding is a unique process that puts unusual demands on the average polyethylene. This paper looks at the optimum process conditions for different polyethylenes and the sensitivity of impact properties to the oven time and temperature. Process conditions become critical for maintaining impact properties while running multiple types of molds on one spider or varying from standard process conditions with like molds.
Renewable Based High Performance TPU
The company Merquinsa SL | located in Barcelona | Spain | produces classical polyurethane as well as new (ECO) polyurethane based on several raw materials from renewable sources. This particular study was based on biogenic oil as primary renewable source for TPU. A new family of thermoplastic polyurethanes (TPU) is presented. This new TPU series has application for polyurethane adhesives | polyurethane for extrusion | and injection molding markets. A full range of vegetable plant-based sources derived from bifunctional polyols has been developed. The reaction of these polyols in the TPU formulation allows new TPU with a renewable content ranging from 30% to 90% by weight. Compared to the standard petrochemical-based grades | the new ‘green-TPU’ shows better hydrolytic resistance | and maintain equivalent mechanical properties like first-class thermoplastic polyurethanes. Merquinsa will present the latest results for its ECO-TPU range | based on different renewable raw materials.
RADIATION CROSSLINKING: HIGH PERFORMANCES MATERIALS FOR PLASTIC MOULDED PARTS
Radiation crosslinking has been in use since the seventies for halogen-free and heat-resistant cables and wires | for hot-water pipes or for heat shrinkable tubes, and tyres. During the last decade | the technology has been developed rapidly on plastic moulded parts | not only by the means of Electron Beam (largely used for extruded products) | but also under Gamma rays. It improves considerably the performances of a great number of plastics among those thermoplastics, elastomers and TPE. It reinforces their dimensional stability in chemically aggressive and high temperature conditions. Such modified polymers offer new material potentialities and solutions for various sectors: packaging | automotive | E&E.
A MULTICRITERIA SIMULATION OPTIMIZATION METHOD APPLIED TO INJECTION MOLDING
Injection Molding (IM) is one of the most important processes for mass-producing plastic products. To help im-prove and facilitate the molding of plastic parts | advanced computer simulation tools have been developed. This paper presents a simulation optimization methodology for IM processes which consider multiple performance measures. It is able to find a set of efficient solutions without having to evaluate a large number of simulations. Its main compo-nents are metamodeling | design of experiments | and Data Envelopment Analysis. The method is illustrated and de-tailed here using a real injection molding case.
ADVANCES IN PLASTICS JOINING TECHNOLOGIES FOR THE ASSEMBLY OF MEDICAL DEVICES
With demand for the use of plastics in Medical Devices expected to continue growing | there is also a growing demand for improved control and analysis of related assembly processes. Additionally there is a growing demand to use plastics in MEMS and Micro-fluidics for analytical and drug delivery devices. Therefore manufacturers are increasingly looking for joining technologies that are particulate free and will not occlude miniature channels. These trends have led to the introduction of several new methods to control | monitor and analyze the assembly process as well as led to the use of new plastics joining technologies such as Laser and Infra Red Welding.
STRUCTURE AND PROPERTY CHANGES INDUCED BY WEATHERING TO VARIOUS PLASTIC PACKAGING FILMS
The effect of accelerated weathering on the structure and properties of single | metallized and multilayer films used in food packaging was studied | by exposing specimens of the above films to repeated ageing cycles, under the combined action of UV radiation | humidity and heat. Films made of polypropylene (PP) undergo severe chain scission upon irradiation and lose mechanical strength. The metallic coating cannot prevent PP from degradation. PE and PET films show modest decrease of mechanical properties. Multilayer films (PE/EVOH/PE | PE//PET) present a decrease of mechanical properties reflecting degradation of their weak component.
Electrically conductive PC/ABS polymer nanocomposites for automotive industry
Multiwall carbon nanotubes are widely studied as nanostuctured electrically conductive filler for polymers with high efficiency at low percentages. In this contribution the physical and thermal properties of PC/ABS based nanocomposites obtained by melt compounding and containing different amounts of nanotubes and nanoclay were investigated. A complex selective segregation of fillers inside specific polymer phases has been observed | thus explaining the low percolation threshold obtained for electric conductivity. The goal was to obtain lightweight electrically conductive polymers in order to reduce the chemical treatments necessary for the chrome-plating of the automotive components | with enormous economical and ecological advantages.
Lab scale development and industrial scale-up of PET based nanocomposites technology for packaging applications
Polyethylene-terephthalate (PET) has become the dominant material for packaging due to its optical clarity when blow moulded and relative low permeability to oxygen and carbon dioxide. In order to further improve PET’s barrier properties | if impermeable nanoparticles are incorporated into the polymer | the gas molecules are forced to wiggle around them in a random walk | hence diffusing by a tortuous path. Moreover | the molecular mobility in the polymer matrix is diminished | thus leading to a decrease in diffusivity of such small molecules. In this research two different strategies have been followed: the first | based on blending PET with an aromatic polyamide (PA) and the second based one on the use of different kinds of inorganic nanoparticles. Several nanocomposites based on pristine PET or PET/PA blends and different nanoclays (natural and organically modified layered silicates | POSS® | i.e. polyhedral oligomeric silsesquioxanes) have been prepared by melt blending optimizing formulations and process parameters. Moreover industrial trials proved that the nanocomposite materials developed could be successfully stretch-blow moulded to give bottles with decreased gas permeability than PET.In particular PET/POSS based bottles are characterised by an optical clarity comparable to the one of pristine PET based containers.
MULTIFUNCTIONAL ACTIVE NANOCOMPOSITES FOR FOOD PACKAGING APPLICATIONS
Results on the active performance of oxygen scavenging, free radical scavenging and antimicrobial clay-based nanocomposites are presented. The antioxidant nanoclay was modified to exhibit high dispersion and efficiency when incorporated into EVOH and in a multilayer system of LLDPE-EVOH-LLDPE. Oxygen scavengers based on iron were also incorporated into LDPE | HDPE and PET, which exhibited some color but little impact in optical properties. Finally | incorporation of silver based clays into PLA matrixes allowed to obtain antimicrobial composites | showing high antimicrobial activity. The presented active systems are alternatives to preserve and extend the shelf-life of packaged products.
ELECTROSPUN NANOFIBROUS MATS BASED ON POLY (LACTIC ACID) AND POLY (ε-CAPROLACTONE) CONTAINING TETRACYCLINE HYDROCHLORIDE AS AN ACTIVE WOUND DRESSING
Electrospun nanofibrous mats made from poly (lactic acid) and poly (ε-caprolactone) containing tetracycline hydrochloride antibiotic as an active wound dressings were prepared and their properties investigated. Samples of poly (lactic acid) and poly (ε-caprolactone) solutions in chloroform/dimethylformamide (9/1) with 9, 12 and 15 (w/v)% containing 500 μg/ml drug were prepared. These nanofibrous samples were then investigated by pre-designed tests such as scanning electron microscopy | water-uptake capacity | UV-vis spectroscopy and antibacterial drug evaluations. The results showed that 15 (w/v)% poly (ε-caprolactone) samples with 500 μg/ml concentration tetracycline hydrochloride had a higher release rate efficiency compared with the other nanofibrous samples.
POLYSILOXANE/LAYERED SILICATE HYBRIDS: MODELLING OF MECHANICAL PERFORMANCE IN RELATION WITH NANOCOMPOSITE STRUCTURE
Nanocomposite blends | based on condensation type polysiloxane rubber | reinforced with organically modified montmorillonite (OMMT) nanoparticles | were prepared via the sonication process. Two grades of commercial montmorillonite | namely Cloisite 30B and Cloisite 20A | with different types of organic modification were studied. A significant improvement of mechanical properties of the pure polysiloxane was observed by the incorporation of the examined types of clay reinforcements. Comparison between the experimental and theoretical values of elastic modulus was performed by the use of micromechanical simulation models | such as the Halpin-Tsai model | that interrelates Young’s modulus with clay structure in the nanocomposite.
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