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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DRAFT OF THE BASIC SYSTEMATIZATION OF INORGANIC AND ORGANIC MACROMOLECULAR COMPOUNDS
The word polymers is usually related to plastics and rubber. This definition narrows down the meaning of the word to a very significant group of materials, but leaves out numerous other substances and materials that are also polymers. The consequence is the difficulty in observing the interconnection or comparability of polymers among each other or with other non-polymeric substances and materials. Therefore, a draft of the basic systematization of inorganic and organic macromolecular compounds has been elaborated.
Changes in global markets and the recent financial crisis have prompted companies to re-examine their value chain and carefully review the demarcation line between internal and sourced development and manufacturing resources to determine which are still strategic to the business. This has caused captive molders to re-visit value propositions and seek new ways to remain financially viable and strategically relevant to their parent companies. One approach is migration to a hybrid model supporting both captive and custom molding. This paper explores the merits of a hybrid model and issues associated with transitioning to a combined model in a corporate environment.
DIRECT ISOLATION OF POLYPHENYLENE ETHER-POLYSILOXANE BLOCK COPOLYMER
A polyphenylene ether-polysiloxane block copolymer is produced by oxidative coupling polymerization of 2,6 xylenol and a eugenol-terminated polydimethylsiloxane. The reaction takes place in a solvent, such as toluene, which needs to be removed in an polymer isolation step. The isolation can be done by precipitation of the polymer with an anti-solvent such as methanol, or by direct" isolation in a devolatilizing extruder as described in this paper. Process conditions to control the desired residual solvent content in the product are reported as well as the effect of the process on key product properties.
DIRECT ISOLATION OF POLYPHENYLENE ETHER-POLYSILOXANE BLOCK COPOLYMER
A polyphenylene ether-polysiloxane block copolymer is produced by oxidative coupling polymerization of 2,6 xylenol and a eugenol-terminated polydimethylsiloxane. The reaction takes place in a solvent, such as toluene, which needs to be removed in an polymer isolation step. The isolation can be done by precipitation of the polymer with an anti-solvent such as methanol, or by direct" isolation in a devolatilizing extruder as described in this paper. Process conditions to control the desired residual solvent content in the product are reported as well as the effect of the process on key product properties."
GAS PERMEABILITY OF ORIENTED POLY(ETHER-B-AMIDE) (PEBAX) COPOLYMERS
Poly(ether-b-amide) (PEBAX) thermoplastic elastomers are used in high flux applications such as gas separation membranes. PEBAX grades with high polyether soft block content are favorable for gas separation applications due to a high permeability. Permeability measurements on uniaxially oriented PEBAX films in the stretched and recovered state showed a significant decrease between the unoriented films and 400% strained films. WAXS and DSC were used to identify strain-induced crystallization of the polyether blocks, resulting in a 3.5x permeability decrease for oriented PEBAX films.
FACILE THERMOPLASTIC OLEFIN (TPO) DISPERSION USING EXTENSIONAL MIXING
The mixing performance of a small-scale extensional mixer (Spiral Fluted Extensional Mixer, or SFEM) was benchmarked against a mixing bowl. TPO blends were chosen for this evaluation, with a broad range of elastomer melt indices. Various statistical metrics were evaluated to quantify the degree of dispersion of the blends. The conclusion is that due to stronger extensional flow, the SFEM batch mixer indeed has potential to offer better TPO dispersion than mixers with rotors in which shear dominates. A single-screw extruder equipped with SFEM mixing elements achieved even finer dispersion, usually achievable only with twin screw extruders.
EXPERIMENTAL INVESTIGATIONS ON THE IMPACT BEHAVIOR OF HYBRID STEEL-FRP STRUCTURES IN 3-POINT-BENDING TESTS
This paper presents an experimental investigation of the mechanical behavior of hybrid metal hat sections, reinforced with fiber reinforced plastics in 3-point-bending tests. The combination of FRP laminates with metal structures leads to an advanced hybrid material system evaluated for future automobile primary structures. A systematic high velocity impact testing program under 3-point-bending was conducted. To evaluate the impact performance and damage resistance, the load-displacement curves referred to the single steel hat section were used. Variations of fiber types (carbon, glass, aramid) and combinations of such fibers are discussed. Furthermore, the influence of laminate thicknesses and fiber orientations is considered.
UNDERSTANDING THE CHALLENGES OF BONDING TPE MEDICAL TUBING TO TRADITIONAL CONNECTORS
The non or low polarity of TPEs is typically referenced as the main contributor to their poor bondability. This paper highlights additional technical factors in poor bondability with traditional solvents and commercial adhesives. Medical tubing OEMs focus on TPEs from 65A to 85A hardness depending on the specific application requirements. TPE hardness and modulus are shown to have significant influence on bonding strength. Often overlooked, ƒ??Poisson Effectƒ? is shown to be an important factor to cause low retention values with soft flexible TPEs. To overcome these challenges, we developed 3 patent pending bonding systems that significantly improve the bonding strength.
SOLID AND MICROCELLULAR RECYCLED POLY(ETHYLENE TEREPHTHALATE) (PET) BLENDS WITH CHAIN EXTENDERS (CE) AND NANOCLAY
Recycled poly(ethylene terephthalate) (RPET) chain extender (CE) and nanoclay were prepared via conventional and microcellular injection molding processes. The effects of CE loading levels and the simultaneous addition of nanoclay on the thermal and mechanical properties and cell morphology of the microcellular components were noted. The addition of 1.3 wt% CE enhanced the tensile properties and viscosity of RPET. The higher amount of CE (at 3 wt%) enhanced the viscosity, but margin of improvement in mechanical properties diminished. While the solid RPET and CE blends were fairly ductile, the samples with nanoclay and all microcellular specimens showed brittle fractural behavior.
IMPACT OF FIBER ORIENTATION ON PHYSICAL PROPERTIES OF GLASS-FILLED POLYBUTYLENE TEREPHTHALATE
A combination of experimental observations and simulation methods has been used to determine the effect of side- and end-gate locations, respectively, on tensile stress at break for glass-filled polybutylene terephthalate (PBT) polymer. A hypothesis based on the stress distribution in the molded bars of two respective geometries has been presented. Simulation techniques using C-mold software has been used to confirm the hypothesis. The two sets of data together show that stress non-uniformity in the bars can play a role in determining the location and path of failure.
VARIABILITY IN STANDARD TWO-PROBE AND FOUR-PROBE ELECTRICAL RESISTIVITY MEASUREMENTS OF CARBON NANOTUBE COMPOSITES
This study characterizes sources of variability in electrical resistivity measurements of polycarbonate (PC) and carbon nanotube (CNT) composites. A two-probe measurement configuration in compliance with ASTM D 257 and ESD STM 11.11/11.12 was modified by incrementally applying additional force to the probe. This modification was found to significantly reduce variability attributable to contact resistance. A four-point probe measurement configuration in compliance with ASTM F 43-93 and ASTM F 84-98 was used to characterize local variations in resistivity within injection molded disks.
DESIGN AND INJECTION MOLDING FACTORS THAT AFFECT OVERMOLDING BOND STRENGTH
The product development team should always be asking the question: How strong does the bond strength need to be for a product design. Some products get used once and do not require high performance bond strength, while others are handled often and require higher bond stength. This paper focuses on both the design and molding factors that affect the ultimate bond strength between a polar plastic substrate and an overmolding TPE compound. It reviews not only ultimate bond strength, but factors that influence bond strength consistency. This information is important to both the product designer and the injection molder.
POLYMER DEGRADATION DURING CONTOUR LASER TRANSMISSION WELDING
This paper presents an experimental technique for assessing material degradation during contour laser transmission welding. Polymer is characterized using thermal gravimetric analysis (TGA). The experimental TGA degradation data are fitted to a kinetic model using the Freeman-Carroll technique. This model allows the fraction of degraded material to be predicted as a function of temperature and time. A FEM model is then used to predict temperature as a function of time at the weld for different laser and material parameters. The two models are combined to estimate material degradation at the weld interface. These results are related to experimental observations.
SYNTHESIS AND THERMAL STABILITY STUDIES OF NOVEL THERMALLY STABLE EPOXY-POLYURETHANE COMPOSITES
A series of hydroxyl terminated bisphenol-A type novolac epoxy resins modified with benzoic acid (MEP) were prepared. The chemical structures of MEP were characterized using FTIR analyses. And epoxy-polyurethane composites were also obtained by curing reaction among MEP, cross linker polyisocyanate IL1351 and phthalic anhydride. The thermal stability of cured products was studied by thermogravimetric analysis (TGA). The thermal stability of the cured MEP with different ring-opening rate, cured bisphenol-A type novolac epoxy resins and cured alkyd polyol A450 were compared.
DYNAMIC MECHANICAL ANALYSIS OF FDM RAPID PROTOTYPING PROCESSED POLYCARBONATE MATERIAL
This paper aims to investigate the dynamic mechanical properties of Polycarbonate material processed by Fused Deposition Modeling (FDM) rapid prototyping process. Frequency sweep is performed in Dynamic Mechanical Analysis (DMA) 2980 equipment to get modulus, damping and viscosity values. The effects of FDM parameters (built style, raster width, and raster angle) over these properties are presented. Frequency sweep experiment is done with the range of 10 Hz to 100 Hz in three different isothermal temperatures. It is found that solid normal built style gives more modulus and viscosity values than the other built styles.
EXFOLIATION AIDS FOR PREPARATION OF POLYMER-LAYERED SILICATE NANOCOMPOSITES
The use of supercritical CO2 and two cosolvents were examined to aid exfoliation of an organoclay within a thermoplastic polyolefin. The study examined the manner in which the gas environment was used in the presence of the clay, compatibilizer and matrix. This was done with an extensional flow mixer. The results of the work showed that supercritical CO2 was most effectively utilized when in the presence of the organoclay and compatibilizer as it melted. Both water and ethanol were effective cosolvents, producing smaller tactoids with a narrower size distribution. Ethanol was found to be the most effective as a cosolvent.
HOT MELT MIXING OF INDOMETHACIN AND SOLUPLUS FOR ORAL DELIVERY
An amorphous solid suspension for oral drug delivery was prepared via Hot Melt mixing 30wt% of Indomethacin (INM) with Soluplus. The melt mixed sample was characterized through optical microscopy, DSC, FR-IR and XRD. Dissolution test showed that INM release was pH-dependent; in the case of the amorphous solid suspension within 1h 90% of INM was released at pH7.4, while only 0.02% at pH1.2, probably a consequence of hydrogen bonds formed between INM and the polymer. The fastest release was obtained from the foamed amorphous solid suspension, followed by un-foamed amorphous solid suspension, then pure INM and finally the physical mixture.
EFFECT OF THE ADDITION OF CARBON NANOTUBES WITH POLYSTYRENE GRAFTING ON THE GLASS TRANSITION BEHAVIOR OF POLYSTYRENE
The effect of single-walled carbon nanotubes on the glass transition of polystyrene with and without polystyrene grafting has been quantified. Three different molecular weights, 2,800, 15,000 and 50,000 g/mol, of polystyrene were grafted to the nanotubes with the weight fractions of grafted chains approximately the same. Composites with 50 K grafted nanotubes were statistically identical in terms of the glass transition temperature and change in heat capacity. Composites with lower molecular weight grafted nanotubes did show significant differences vs. the composites with ungrafted nanotubes, especially in terms of the change in heat capacity.
EFFECT OF MOLECULAR WEIGHT DISTRIBUTION ON THE WELD-LINE INTERFACE IN INJECTION MOLDED POLYPROPYLENE
On the basis of a coarse-grained molecular dynamics with bead-spring polymer chain model, we investigated an interdiffusion of macromolecules of the separated flow fronts and stress-strain behavior under simple extensional deformation of the interfacial region. In polydisperse system, it is predicted that depletion of long chains takes place at the interface where short chains preferentially locate. Significant improvement of interfacial strength is predicted when molecular weight distribution is narrow enough to have a considerable overlap between long chains belonging to each phase separated by the interface. The calculation result reproduced the experiment on the interfacial strength of polyolefin material.
A GREEN PROCESS FOR THE SYNTHESIS OF MESOPOROUS SILICA MATERIALS
In this paper, mesoporous silica and functionalized silicas were prepared by a green template, polyamidoamine (PAMAM) dendrimers. Three silane coupling agents, 3-triethoxysilylpropyl- amine (APTES), -methylacryloyl oxypropyl trimethoxysilane (MAPTMS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (AEAPTMS) were used for modification on pore surface. The characters of synthesized silicas were investigated in detail. The results showed that controllable pore diameters, narrow pore size distributions, high surface area and pore volume were achieved. The PAMAM template can be feasibly removed by using water extraction.
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