1:30 pm – 6:30 pm:
TH17-Thermoplastic Materials and Foams-Room S320G
1:30 pm – 2:00 pm:
Influence of the Compounding Process Parameters on the Dispersion and Material Properties of Graphene-based PP Composites Using a Twin-screw Extruder Under Industry Related Conditions
Maximilian Adamy, IKV Aachen
Ideal graphene has excellent mechanical, electrical and thermal properties and is therefore potentially suitable as a functional filler in thermoplastics. Laboratory tests have already shown that very low filler contents are sufficient to achieve a significant improvement of the material properties. However, the investigations carried out so far have been based on experiments on the laboratory scale. These results cannot be transferred to an industrial scale. This is mainly due to the changed geometric conditions as well as the different shear energy inputs and residence times. Therefore, the focus of this work is on the influence of manufacturing conditions on the dispersion and the resulting material properties of graphene-based composites, which are produced by the use of a co-rotating twin screw extruder under near-industrial conditions. The results show that the processing of graphene-based composites in industrial scale is possible. Nevertheless, the effect of graphene on the mechanical properties is less pronounced compared to the properties of graphene-based composites that are produced in laboratory scale, due to a low degree of dispersion. The investigations concerning the influence of the machine parameters throughput, speed, screw configuration and the addition position of the graphene on the properties of graphene-based PP composites demonstrate that the mentioned machine parameters have a significant influence on the process parameters specific mechanical energy input (SME), melt temperature and the residence time of the melt in the twin screw extruder. The quality of the graphene dispersion is generally improved by long residence times and high shear energy inputs, which are achieved by low throughputs and high screw rotation speeds or by the use of a screw configuration with a high energy input. However, the differences in the degree of dispersion shown do not lead to significant differences in the mechanical properties of the nanocomposites. It can be concluded that the residence times and SME are not sufficient to achieve an adequate dispersing quality in the melt mixing process using a twin-screw extruder under near-industrial conditions to achieve significant property improvements.
2:00 pm – 2:30 pm:
Open-cell Foaming of PP/PTFE Fibrillated Composites
Yuhui Qiao, Mr
In the study, PP/PTFE composites with different degree of fibrillation are prepared. Crystallization and rheology behavior are investigated. PTFE is easily deformed into fiber during compounding. The presence of PTFE fiber enhances the kinetics of isothermal crystallization of PP. The second modulus plateau at the low ω and a tan δ peak indicate the existence of a three dimensional networks. Extrusion foaming results show a 2 orders increase in cell density and 10-fold decrease in expansion ratio due to addition of PTFE compared to that of PP. With PTFE nanofiber, open-cell content of the composites is increased.
2:30 pm – 3:00 pm:
An Application of Thermoplastic Polyurethane Foaming in Handrail Extrusion
Qingping Guo, EHC Canada
This study investigated an application of making thermoplastic polyurethane (TPU) foam using Expancel® microspheres  as blowing agent in handrail production at EHC Canada, Inc. The optimized Expancel® content was found and all properties (especially the mechanical properties) of the foamed handrail were tested. The results reveal that the current extrusion processing parameters do not need to be changed for producing the new foamed handrails with Expancel® microspheres. All foamed handrails passed mechanical tests. This foaming of handrail material resulted in 14% reduction in use of that TPU material and a 10% saving in its cost.
3:00 pm – 3:30 pm:
Flexural Testing of PET-NanoFiber and PP Foamed Composites
Lun Howe Mark, University of Toronto
In this work, in-situ nanofibrillated PET is used to reinforcing a PP matrix to enhance the final mechanical properties and foam structure quality of an injection molded sample. Although there have been many approaches to reinforce a polymer matrix to increase the melt strength of PP. Long-chain branching, micro- and nano-scale additives and crosslinking approaches each have their own separate drawbacks. However, the use of nanofibrillated composites is a highly efficient and effective method for foam processing. By fibrillating the PET nanofibers (NF) within the PP matrix, fiber breakage from compounding processes can be avoided. To create the PET-NF, PET and PP were first mixed in a twin-screw extruder to disperse the PET as small spherical domains. Afterwards, this blend of spherical PET in PP is melt drawn through a fiber spinning machine to stretch the PET into fibrils with nanoscale diameters and high aspect ratios. As the PET and PP are melt spun together, the nanofibers are well dispersed in the matrix material and ready to be used as a masterbatch. The PET-NF masterbatch is then diluted from 5% to 0.5 and 0.5%, and used in an injection molding (IM) machine. Using foam injection molding (FIM) with mold-opening (MO), foams of various thicknesses and expansion ratios were created with and without the PET. When high-pressure FIM was compared, the foam quality with the PET-NF was higher than the neat PP matrix. The presence of the PET-NF acted as cell nucleating agents which lowered the energy barrier to nucleation by affecting the interfacial energies and inducing local pressure variations. In addition, the PET-NF likely acted as crystal nucleating agents. With use of MO-FIM, the PET-NF showed a three to four magnitude improvement in the cell density. When the flexural properties of the solid and foamed, with and without PET-NF, samples were compared, the PET-NF samples demonstrated higher flexural strength and toughness. Using PET-NF to reinforce the PP matrix increased the both the solid flexural strength and the flexural modulus of the samples by 5 to 10%. However, when HP-FIM is included, the stiffness decreased as toughness increased, which is typical for most foamed samples. Between the foamed PET-NF samples and neat PP, the foamed samples exhibited an increase of up to 40% for both the flexural modulus and strength. When MO-FIM was used, the results showed that the PET-NF increased the flexural modulus between 23 to 46% and the flexural strength between 15 and 25%. This work demonstrated that PET can effectively be fibrillated in a PP matrix. Using injection molding, the PET nanofibers were effective in increasing both the cell density of the final composites. In addition, the PET nanofibers reinforced the PP matrix to increase the flexural strength and modulus.
3:30 pm – 4:00 pm:
Protected Biofilm Growth in Macroporous Polyvinilidene Fluoride Carriers for Biological Organic Temoval From Municipal Wastewater
Pardis Ghahramani, York University
Attached growth bioreactor process provides surface area to support the growth and attachment of bacteria, and thereby a means to biologically remove organics from wastewater. In this work, an open-cellular polyvinylidene fluoride (PVDF) foams consisted of macroporous structures were designed and fabricated to promote the efficiency of existing biofilm carriers for wastewater treatment. A manufacturing approach that integrated compression molding and particulate leaching was employed to fabricate the PVDF foams. Different contents of salt were used as leaching agent to fabricate PVDF foams with macroporous structures of different total protected surface areas. Experimental studies were conducted to elucidate the structure-to-performance relationships of these macroporous PVDF carriers in terms of bacteria-to-carrier interaction and organic removal efficiency.
4:00 pm – 4:30 pm:
Impact Management and Protection for Playing Surfaces using Expanded Polyolefin Particle Foam – New Materials and Designs
Steven Sopher, JSP International
This paper provides details on the topic of impact management and injury mitigation for playing surfaces, including Football Fields, Soccer Fields, Playgrounds and other playing surfaces both indoors and outdoors and the use of Expanded Polyolefin Particle Foam in their design and construction. The design and construction of sports surfaces plays an important role in playability, performance, injury reduction, and overall impact management and shock mitigation. Expanded Polyolefin Particle foams are being used to fulfill this role. The properties of Expanded Polyolefin Particle Foams allow for designs which take advantage of the isotropic nature of particle (bead) foams, the highly efficient energy management properties, and the ability to manage energy and mitigate impact with a combination of compression, flex and tension. The ability to shape mold the material allows for the most efficient three-dimensional and multi-axis design for energy management. It also allows further performance optimization through changes in geometry and changes in density. This paper will present recent sports surface design innovations and provide case studies vs. competitive technology. Other benefits of Expanded Polyolefin Particle Foam will be presented including 100% recyclability, water-resistance, chemical resistance, long term performance, and the ability to meet the ever increasing rigorous standards for restricted chemicals. This paper will also explore the latest development in the area of soft bead foam technology. New materials beyond the existing Expanded Polypropylene (EPP) such as advanced thermoplastic polyolefins, elastomers, vulcanizates, and polyurethanes are now being used to manufacture expanded particle foam which provide enhanced benefits in the area of energy management and safety. The benefits of these new materials, which include Expanded Thermoplastic Olefins (ETPO), Expanded Thermoplastic Urethanes (ETPU), Expanded Thermoplastic Elastomers (ETPE), Expanded Thermoplastic Vulcanizates (ETPV), and other expanded material blends will also be shown.
4:30 pm – 5:00 pm:
Ultra-low Density Foams of Nanocrystalline Cellulose Reinforced With Polyvinyl Alcohol
Nahal Aliheidari, Ph.D Student, Washington State University
Environmentally friendly thermal insulation and energy saving materials are in high demand for buildings, packaging, and other applications. Here, we report ultra-low density composite foam materials that are mainly composed of cellulose, an abundant degradable and recyclable green material. Nanocrystalline cellulose (NCC) was mixed with 0-20 wt.% polyvinyl alcohol (PVA) in an aqueous solution, followed by ice crystallization and freeze drying processes to fabricate the NCC/PVA cellular structures. Ultralight foams with densities as low as 0.026 g.cm-3 (porosities as large as 98.22%) were successfully prepared and their compression and thermal conductivity behaviors were characterized. The results revealed that the compressive stiffness and strength of NCC foams can be significantly enhanced (about an order of magnitude) by the introduction of 20 wt.% PVA as an elasticity enhancer. The thermal conductivity of NCC/PVA foams remained approximately unchanged with an increase in the PVA content and varied only between 0.037 and 0.041 W/mK, a range that is common for commercially available insulation materials. A relatively low thermal conductivity with enhanced mechanical properties of these NCC-based foams offers a potential bio-based material composition for insulation applications.
5:00 pm – 5:30 pm:
A System for Visualizing and Measuring Stress of Plastic Flows Under Shear Conditions
Taylor Ducharme, University of Vermont
Shear stress on polymers has been shown to have a strong effect on morphological and thus mechanical properties of the final structure. In this study, an in-situ visualization system was developed to i) visualize crystal nucleation and growth with high spatial and temporal resolutions and ii) have capability to measure the local shear stress and viscosity of a saturated polymer in isolated, simple shear. The system allows for easy control of experimental parameters: applied shear strain, shear strain rate, temperature, heating/cooling rate, pressure, polymer, and saturation gas. An early verification of the shear stress measuring capability was conducted of the This visualization/measuring system provides a reliable way of determining both rheological and optical properties of plastics simulated under dynamic conditions like that of industrial plastic processes.
5:30 pm – 6:00 pm:
Mining the Value from Oil Sands Tailings Ponds
Pavani Cherukupally, University of Toronto
In Canada, the cleaning cost of 340 billion gallons of oil sands tailings ponds is estimated to be over $27 billion. There is a need for cost-effective technologies for removal and recovery of oil from these ponds. Previously, we reported foams application for absorption and adsorption of crude oil from water. This works aims to develop effective method for foam reuse and oil recovery to improve the benefits of the treatment process. The polyester polyurethane (PESPU) foam with pH-responsive wetting properties and crude oil were used to assess the effectiveness of mechanical compression, pH-swing method, and chemical wash method. The mechanical compression is a simple, environmental friendly, and easy to implement method. This process was effective in recovery of the absorbed oil, where the oil uptake mechanism is reversible superhydrophobic forces and pore filling. However, for adsorbed oil recovery it was less effective. According to pseudo-second-order kinetic model, the oil droplets were adhered to the sponge surface by physical forces. As a result, mechanical forces were weak in shearing-off the thin oil film. Based on pH-responsive wetting property, the oil adsorption was effective at acidic conditions. Therefore, the oil recovery was performed at basic conditions by introducing new “pH-swing” technique. This method produced minimal waste and sustainable, but materials reusability declined to ~70% within three cycles. Finally, chemical wash method was applied to recover the adhered oil from the surface. According to surface chemical displacement principles, a solvent with appreciably low surface tension than the foam and similar molecular structure the crude oil was used to wash the sponge at ambient conditions. Due to enhanced solubility and flowability, the crude oil was readily recovered from the foam surface. The cleaned foam as well exhibited over 99% efficiency over multiple reuses. Our finding show that the foam is a promising solution to remediate detrimental oil sands tailings and for recovery of the residual crude oil from water leading to environmental and economic benefits.
6:00 pm – 6:30 pm:
Highly Viscous Polyamides Made of Cast Polyamide 6 Recyclates
Benjamino Rocco Formisano, Research Associate, Institut für Kunststofftechnik – University of Stuttgart
Cast polyamide 6 is anionically polymerized from ε-caprolactam. Its good properties are mainly caused by the higher molecular weights, compared to standard polyamide 6. Because of sprues and post-processing, a larger amount of scrap is produced. This scrap is typically incinerated without sufficient use of its high quality properties. However, cast polyamide 6 also offers great potential for material recycling, particularly if its high molecular weight can be retained. As cast polyamide decomposes during processing as well, it is necessary to add some additives during compounding. It is the aim of the presented work, to recycle cast polyamide to highly viscous materials. This is done by adding a polyester-modified wax and a carboxylic acid. It can be shown that it is possible to get materials having viscosities of up to two magnitudes higher compared to a typical extrusion polyamide. The high molecular weight of cast polyamide can be maintained or even outperformed. While Young’s modu-lus and tensile strength remain unchanged, the used wax causes some crosslinking of the polyamide and thus also leading to higher impact strength.