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

ANALYSIS OF MORPHOLOGY ON INJECTION MOLDED POLY (?æ-CAPROLACTONE) TISSUE ENGINEERING SCAFFOLDS

Zhixiang Cui, Yiyan Peng, Ke Li, Lih-Sheng Turng, Changyu Shen, May 2011

PCL/NaCl and PCL/PEO/NaCl were injection molded. The water soluble, sacrificial polymer, PEO, and NaCl particulates in the blend were leached by deionized water to produce porous and interconnected microstructure. The effect of leaching time on porous morphology and porosity was investigated. Results showed that PCL/NaCl blend composites had a relatively slow leaching rate due to a lack of connectivity between NaCl particulates. For PCL/PEO/NaCl blend composites, most of the PEO and NaCl particulates can be removed in a short time. This is because the leached PEO domains provide interconnected channels that allow water to reach and leach embedded NaCl particulates.

DEVELOPMENT OF COMPOSITE PIPES FOR RISER APPLICATION IN DEEP WATER

Ledjane Sobrinho, Veronica Calado, Fernando Bastian, May 2011

This work deals with the development of composite pipes for riser application in deep water. Initially, an epoxy resin system was toughened by rubber CTBN addition (10 wt%) as a way of improving the flexibility of future risers. Mechanical and thermal analyses were carried out for characterizing the polymeric systems. The influence of matrix toughening and the number of composite layers on the mechanical behavior of the tubes were studied using hydrostatic and split-disk tests. In both tests, the results indicate that the matrix plays an important role in composite fracture processes

THE USE OF PRESSURIZED WATER PELLETS AND SUPERCRITICAL NITROGEN IN INJECTION MOLDING

Eusebio Cabrera, Rachmat Mulyana, Jose Castro, L. James Lee, May 2011

In injection molding, cycle time, and warpage are critical factors for process economics and product quality. This work focuses on reducing cycle time, and warpage by utilizing water containing polymer pellets. Pellets were prepared by compounding a water carrier particle via extrusion, followed by a batch pressurizing process at a controlled pressure and temperature. Water containing polymer pellets were molded with and without supercritical nitrogen to further decrease the cycle time and minimize warpage. Preliminary results showed that the cycle time and part warpage could be reduced without a major effect on the mechanical properties.

FEM PARAMETRIC STUDY ON EFFECT OF CONSTITUTIVE BEHAVIOR ON SCRATCH VISIBILITY RESISTANCE OF POLYMERS

Mohammad Hossain, Hung-Jue Sue, May 2011

Three-dimensional finite element method (FEM) parametric study was performed to investigate the effect of asymmetric constitutive behavior on scratch visibility resistance of polymers. The scratch depth and shoulder height of the groove formed during the scratch, which is related to the scratch visibility resistance of polymers, is simulated by considering different asymmetric constitutive behaviors. The simulation results indicate that compressive behavior dominates the scratch visibility resistance of a polymer. Implication of the present findings for designing scratch resistant polymers is discussed.

MAINTAINING A STABLE ENGINEERED NANO-COMPOSITES PROCESS THROUGH MATERIAL CHARACTERIZATION

Andrew Salamon, Justin Lang, Kevin Menard, May 2011

There is excitement regarding the application of nanomaterials (NMs) in composites. The use of carbon nanotubes (CTNs), nanoparticles (NPs), or other NMs in composite epoxy materials increase strength and elasticity, and reduce the weight of the end product. Nano Composite Epoxy materials will introduce new and unique composite characteristics for industry and consumers. Characterizing NMs during their composite processing is quite different than characterizing previous bulk composite additives. There are additional concerns and characteristics to be aware of with NMs. This paper is an overview of nanomaterial characterization needed to ensure a stable nano-composite epoxy process from beginning to end.

MULTI-LAYER BLOWN FILMS FOR THERMOFORMED FOOD PACKAGING APPLICATIONS

Kam Ho, Daniel Ward, Kevin Kuklisin, Amanda Murphy, May 2011

Polyethylene and nylon are used in thermo-formable, multilayer films for food packaging. Through this study, we have developed film structures with up to 30% less nylon and equivalent or better oxygen and moisture barriers than a commercial pizza packaging film structure. These structures exhibited good thermoforming behavior at several draw ratios. We have applied three thermoform-ability indices for the assessment of a filmƒ??s thermoform-ability in this study. One of them was the dimensional thermoform-ability index reported by NOVA Chemicals Corp. The combination of all three indices provides rapid and accurate assessment of the thermoform-ability of film structures.

MONOLAYER AND MULTILAYER POLYOLEFIN FILMS INCORPORATING POLYMERIC MICROSPHERES

Sarah Schirmer, Christopher Thellen, Jo Ann Ratto, Matthew Burke, Gregory Pigeon, Jeanne Lucciarini, May 2011

Monolayer and multilayer high density polyethylene (HDPE) and polypropylene (PP) blown and cast films were processed with 1.6%, 2.4% and 3.3% microspheres by weight. The films were analyzed for density, tensile properties and tear strength. The multilayer blown films for both polyolefins showed the most decrease in density with the highest loading of microspheres. The monolayer and multilayer HDPE films showed a significant increase in Young's modulus with low loadings of microspheres for both cast and blown films while the PP values decreased for all microsphere films.

STUDY ON THE DEGRADATION RATE OF POLYANHYDRIDE (POLY(SEBACIC ACID), DIACETOXY TERMINATED, PSADT) FOR POTENTIAL DRUG DELIVERY AND TISSUE ENGINEERING SCAFFOLD APPLICATIONS

Zhixiang Cui, Yiyan Peng, Lih-Sheng Turng, Changyu Shen, Wanju Li, May 2011

The degradation rate of polyanhydride (poly(sebacic acid), diacetoxy terminated) is investigated. PSADT tablets are formed using a compression molding device under three different processing temperatures, then immersed into phosphate buffer saline (PBS) for degradation experiments. The mechanisms of degradation and the degradation rate are characterized by the change in molecular weight, reduction in specimen mass, and decrease of specimen thickness. The surface morphology at different degradation times is observed by scanning electron microscope (SEM). The results show that PSADT exhibits the behavior of surface erosion due to the fact that near zero-order degradation kinetics was observed in its degradation process.

SUPERIOR RESISTANCE TO THERMO-OXIDATIVE AND CHEMICAL DEGRADATION IN POLYAMIDES

Gary Kozielski, Coreen Lee, Jennifer Thompson, Steven Mok, May 2011

DuPont's SHIELD Technology allows polyamide resins to be used at higher temperatures than previously achieved. This technology combines several innovations: a new polymer backbone, polymer modifications and additives to enhance performance. The resistance to thermo-oxidative damage and chemical degradation is superior to standard polyamide resins. Examples of improved performance include: Improved air oven aging - retaining >50% of initial mechanical properties after 1000 hours atC Improved fluid aging resistance - maintaining >75% of its impact strength after 5000 hrs at 150C in hot oil. ƒ?› Improved CaCl2 resistance, resisting cracks three times the number of cycles of standard glass-reinforced nylons

AN EASY METHOD TO MONITOR LACTIDE POLYMERIZATION WITH A BORON FLUORESCENT PROBE

Alexander Zestos, Cassandra Fraser, Guoquing Zhang, Songpan Xu, Ruffin Evans, Jiwei Lu, May 2011

The solvent-free controlled ring-opening polymerization (ROP) of lactide is commercially important. A fluorescent dye, difluoroboron 4-methoxydibenzoylmethane (BF2dbmOMe) is employed to probe lactide bulk ROP by measuring the emission from solidified aliquots at room temperature. During polymerization, the fluorescence of BF2dbmOMe in solid-state aliquots exhibited a systematic shift from yellow to blue, accompanied by a reduction in decay lifetime. The fluorescence color change is sensitive to monomer conversion, not polymer molecular weight. The long-wavelength emission with perceivably longer lifetimes arises from BF2dbmOMe dye aggregates, while the dissolved individual dye molecules are responsible for the blue fluorescence with a shorter lifetime.

STABILIZATION OF POLY(BUTYLENE TEREPHTHALATE) FOR DURABLE APPLICATIONS

Tom Thompson, Stephen Andrews, Markus Grob, May 2011

PBT is an engineering plastic used in molding applications where protection against demanding temperature or light exposure environments is necessary to retain useful properties. Heat & light stabilization of PBT was assessed under thermal aging or light exposures. PBT specimens were subjected to oven aging for 600 hours. The loss rate of physical properties, melt stability, and changes in discoloration were observed. Hindered phenolic antioxidants and phosphite stabilizers were evaluated, providing improved physical properties and reduced discoloration. PBT was subjected to WOM & outdoor light weathering. Protection was possible with a UV-absorber or combined with a hindered amine light stabilizer.

MULTIFUNCTIONAL NANOPAPER FOR WEAR RESISTANT AND CONDUCTIVE APPLICATIONS

Dante Guerra, Jesse Guerra, Xilian Ouyang, Jose Castro, L. James Lee, May 2011

Fiber reinforced polymer composites are used in a wide variety of applications such as aerospace, military, defense, and wind energy industries. In many applications, solid particle erosion damage can be a critical issue. In this study, a novel method of fabricating low-cost nanoparticle thin films or nanopapers for use as a surface protective layer for fiber reinforced polymer composites was developed. Inclusion of these nanopapers through current manufacturing methods has shown increases in solid particle erosion protection of up to 7x. The nanopapers have also shown to increase surface electrical conductivity by as much as 16 orders of magnitude.

SYNTHESIS OF HIGH ION-EXCHANGE NANOPARTICLES BY EMULSION COPOLYMERIZATION OF QUATERNARY ALKYL AMMONIUM MODIFIED SULFONATED STYRENE AND DVB FOR COMPOSITE PEM APPLICATION

Emmanuel Pitia, Robert Weiss, Montgomery Shaw, May 2011

High ion-exchange capacity (IEC) crosslinked nanoparticles were synthesized by an emulsion copolymerization of divinylbenzene and sulfonated styrene (SS) for application as the proton conducting phase in composite proton exchange membranes. The effects of the counterion of the sulfonated styrene monomer, the surfactant and the crosslinking on the ability to stabilize the emulsion to high IEC were studied. Water-insoluble nanoparticles with IEC as high as 5.2 meq/g were achieved using sulfonated styrene with a quaternary alkyl ammonium cation, a non-ionic surfactant and a crosslinking agent in the emulsion formulation. Nanoparticles with diameters of 20 160 nm were achieved.

EVALUATION OF PROPERTY-PERFORMANCE RELATIONSHIPS OF POLYURETHANE FOAMS USED IN AUTOMOTIVE SEATING APPLICATIONS

Bernard Obi, Edwardo Leyva, Venkat Minnikanti, Parvinder Walia, David Bank, May 2011

High resiliency polyurethane foams are used to provide superior comfort in automotive seat designs. A modified Voigt viscoelastic model is used to simulate vibrational transmissivity (dynamic comfort) during ride. The model links dynamic comfort to foam parameters of dynamic modulus and damping. The results from the simulations show that low dynamic modulus coupled with high damping gives optimal comfort. The simulation results also confirm that thinner seating negatively affects dynamic comfort. A dynamic oscillatory hysteresis analysis is used to obtain both the dynamic modulus and damping parameter. There was reasonable agreement between experimentally measured and model predicted vibrational transmissivity.

REINFORCEMENT OF POLYPROPYLENE SPUN FIBERS BY POSS NANOPARTICLES

Sayantan Roy, Sadhan Jana, May 2011

The molecules of polyhedral oligomeric silsesquioxane (POSS) containing silanol functionalities interacted by hydrogen bonding with sorbitol nucleating agent and formed low viscosity liquid complex during melt processing and finally turned into cylindrical nanoparticles in spun fibers of isotactic polypropylene (iPP). It was found that at the optimum combination of POSS (typically 2-5 wt%) and sorbitol nucleating agent (typically 1 wt%), iPP compounds can be spun into fibers with 40% reduction in diameter compared to unfilled PP, 60% increase in tensile strength and modulus, and 100% increase in yield stress.

SEMICRYSTALLINE POLYAMIDE ENGINEERING THERMOPLASTICS BASED ON THE RENEWABLE MONOMER, 1,9-NONANE DIAMINE

Alex Kugel, Jie He, James Bahr, Mohammed Nasrullah, Bret Chisholm, May 2011

A series of poly(1,9-nonamethylene adipamide-co-1,9-nonamethylene terephthalamide) copolymers were produced using melt polymerization and the thermal properties and crystal structure characterized. The results obtained confirmed that the copolymers exhibit isomorphism. As expected, glass transition temperature and the apparent melting temperature increased with increasing terephthalmide content. Using the difference in the apparent melting temperature to the crystallization temperature as a measure of relative crystallization rate, it was observed that crystallization rate decreased as the terephthalamide content of the copolymer was increased from 0 to 50 mole percent but then sharply increased when increased beyond 50 mole percent.

THERMO-MECHANICAL PROPERTIES AND THERMAL DEGRADATION CONTROL OF POLY (LACTIC ACID) AND POLY (LACTIC ACID)/CLAY/WOOD NANOCOMPOSITES

Qingkai Meng, Marie-Claude Heuzey, Pierre Carreau, Daniel De Kee, May 2011

Poly (lactic acid) is an important biopolymer with suitable mechanical properties for construction and packaging applications. The mechanical and thermal properties of PLA can be tailored by compounding reinforcing fillers. PLA nanocomposites based on nanoclay and/or wood flour were prepared by melt extrusion of PLA. Three compatibilizers - maleated polyethylene, maleated polypropylene and maleated poly (lactic acid) were used in PLA/clay/wood nanocomposites. Approaches to control PLA thermal degradation during melt extrusion were examined. Residual catalyst deactivation and molecular weight control by chain extenders were believed to be the most effective and feasible methods.

DEVELOPMENT OF AN ANTIBACTERIAL FILM FOR APPLICATION IN THE FOOD INDUSTRY

Richard Silverwood, Abdellah Ajji, May 2011

In this study, the preparation of Low density polyethylene (LDPE)/ZnO nanocomposite and its antibacterial efficiency was analysed. The antibacterial property investigation was performed by colony count tests. Scanning electron microscopy (SEM) was performed to investigate the dispersion effect of LDPE-g-MAH copolymer. Two ZnO nanoparticles sizes were studied and their efficiency was first tested in water suspension. The results show that both an increase in mixing temperature and addition of copolymer improve the antibacterial efficiency of the polymer film.

PVC-CACO3 NANOCOMPOSITES PRODUCED BY IN-SITU COUPLING USING TITANATE COUPLING AGENT IN TWIN-SCREW EXTRUDER

Indra Kemel, Mark Hoffman, Tania Vodenitcharova, Robert Burford, Alan Whittle, May 2011

This study focused on the effect of titanate coupling agent to the mechanical and fracture properties of PVC nano-CaCO3 composites. The titanate coupling agent is introduced into the PVC nanocomposite through in-situ coupling technique, where the titanate mixed with PVC resin and nano-CaCO3 particles during dry mixing and relies on the high shear force during extrusion to induce coupling reactions and dispersions. This enabled the process to be transferred into existing PVC manufacturing technology. The composites morphology and mechanical properties are examined to understand the effect of titanate coupling agent to the PVC nanoCaCO3 composites.

EVOLUTION OF CARBON BLACK GRADES FROM RUBBER APPLICATIONS TO SPECIALTY PLASTIC APPLICATIONS

Daniel Callahan, May 2011

The different end use requirements of carbon black in rubber and plastics applications are discussed in this paper. Although the larger volume of carbon black is used in rubber applications, the critical requirements of these products are much different than the needs in plastics applications such as molding and fiber. It is recommended to evaluate the end use product requirements and manufacturing process when choosing a carbon black. Carbon black suppliers have developed specialty grades of carbon black to meet the needs of the plastics market.