1:30 pm – 6:00 pm:
W14-Engineering Properties and Structure: Physical Properties of Polymers III
(Moderators: Luyi Sun and Pavan Valavala)-Room S320B
1:30 pm – 2:00 pm:
Thermal Conductivity Enhancement Through Stretching of Polyethylene-graphene Nanocomposites
Brian Grady, University of Oklahoma
The effect of simultaneous alignment of polyethylene (PE) lamellae and graphene nanoplatelets (GnP) on thermal conductivity of PE-GnP nanocomposites is investigated. Such alignment is achieved by subjecting the composite to mechanical strain. Alignment of PE lamellae is quantified using wide-angle X-ray scattering measurements while graphene nanoplatelet alignment is quantified via polarized Raman spectroscopy. Measurements reveal that thermal conductivity (k) of the composite increases at a faster rate with applied strain compared to pure PE pointing to the beneficial effect of GNP alignment on k enhancement. At the maximum applied strain of 400% and using 10 wt% GnPs, a composite thermal conductivity of 5.9 W/mK is achieved representing an enhancement of ~12-fold over the unoriented pure polymer (k~0.5 W/mK), a ~4-fold increase over the unstretched filled polymer (1.5 W/mK) and a ~1.75-fold increase over the unfilled oriented polymer (3.5 W/mK)
2:00 pm – 2:30 pm:
Processing Parameters Effect on Barrier Properties of Nitrile Based Nanocomposite Membrane
Mohamed Zemzem, École de Technologie Supérieure
The influence of processing parameters on barrier properties of nanocomposites was investigated. Elastomer nanocomposites consisting of nitrile rubber latex and clay nanoparticles were prepared by three techniques: Chemical dissolution, melt-mixing in an internal mixer and extrusion. Resistance to methanol were assessed using gravimetric method. It was observed that extruded material exhibited the highest chemical resistance. Small-angle X-ray scattering patterns indicated that this improvement was due to nanoparticle orientation in the structure. With the other techniques, a neat enhancement of solubility was spotted over the pure rubber. X-ray diffraction results related this aspect to the delamination of the clay nanoparticles. Moreover, when melt-mixing was adopted, improvements were also recorded proportionally to the increase of the torque as well as the residence time inside the mixer.
2:30 pm – 3:00 pm:
Characterization of Scratch Behaviors of Multilayer Automotive Coatings for Various Scratch Conditions
Sung Wook Moon, Korea University
Vehicles confront damages and breakdown caused by various factors under working condition. The most common type of the failure is scratch. External particles such as small pebbles pop up and cause physical damages on the surface of the vehicle. It is not desirable in the aesthetic point of view. Clear-coat layer, which is on the top of the painted surface, is directly affected by scratch. To evaluate the scratch characteristics of the coatings of passenger vehicles, we conducted scratch tests using ASTM D7027 standard. Through the experiments, we obtained scratch properties of various coatings. Using the results, scratch-resistant clear-coat will be developed.
3:00 pm – 3:30 pm:
Biomimetic Nanocoatings with Exceptional Mechanical, Barrier, and Flame Retardant Properties from Large Scale One-Step Co-assembly
Luyi Sun, Associate Professor, University of Connecticut
Large-scale biomimetic organic/inorganic hybrid nanocoatings with a nacre-like microstructure were prepared via a facile co-assembly process. Different from conventional polymer nanocomposites, such nanocoatings contain a high concentration of nanosheets, which can be well aligned along the substrate surface. Moreover, the nanosheets and polymer matrix can be chemically co-crosslinked. As a result, the nanocoatings exhibit exceptional mechanical properties (high stiffness and strength), barrier properties (to both oxygen and water vapor), and flame retardancy, but meanwhile, they are highly transparent (maintaining more than 85% of their original transmittance to visible light). The nanocoatings can be applied to various substrates and regular or irregular surfaces (e.g., films as well as foams). Because of their excellent performance and high versatility, such nanocoatings are expected to find widespread application.
3:30 pm – 4:00 pm:
Architecture of Micro- and Nano-layer Structure and its Functional Propertes of Polymers
Shaoyun GUO, Polymer Research Institute of Sichuan University
Addition of functional components into polymers is the important route for preparing polymer functional composites. For economic cost increase and mechanical properties decrease in the presence of functional fillers, we are all exploring the good functional performance at the lowest content of fillers. Here tailoring the structure morphology of the composites will play the important role. Laminating is one of preferred structures. In general, the polymer composites with multilayer structure have good balance of toughness, stiffness and strength. In this paper, the morphology development of polymer in the confined space of micro- and nano-layers and layer interfacial contribution to properties enhancement will be reported. We can develop a series high damping and sound-proofing polymer composites through multi-layer structure : high damping materials, high noise shielding, high electromagnetic waves shielding materials, high flame retardant materials and high conductive materials.
4:00 pm – 4:30 pm:
Exploiting Capillary Forces in Filled Plastics: Electronically Conductive Plastics by Bonding Copper Filler with Molten Solder
Derrick Amoabeng, Ph.D Candidate, University of Pittsburgh, Chemical Engineering Dept.
We test whether the electrical conductivity of copper-polystyrene composites can be improved by adding a metal solder alloy during blending. Copper-in-polystyrene composites prepared by melt-blending have poor electrical conductivity. Addition of a flux (a compound commonly used in soldering) during blending is found significantly to improve the conductivity. A further large increase in conductivity was obtained by adding molten solder during composite preparation. The mechanism of this improvement is that the solder bonded the copper particles together into large aggregates that percolated throughout the sample. We examined the effects of the volume ratio of solder to copper particles on electrical conductivity and the composite morphology. If sufficient solder was added, the copper particles become welded together by the solder to form a self-supporting metal network, and a conductivity of ~500 S/m was realized at a metal loading of only 20 vol%. With insufficient solder, large but non-percolating structures of solder-bound copper particles appeared, and the corresponding blends had lower conductivity. While most of the samples were prepared by hand-blending, we verify that the same approach of improving conductivity can be applied using a Brabender batch mixer.
4:30 pm – 5:00 pm:
Microcapillary Film Membranes Based on Polyvinylidene Fluoride
Gerald Billovits, The Dow Chemical Company
Microcapillary film (MCF) membranes offer a promising new media configuration for water purification devices. A 50 mm wide microcapillary film die was designed and constructed, allowing a fluid to be injected at 42 separate locations within a molten polymeric film as it exited the die. MCF membranes were prepared using this die by profile extrusion of a polyvinylidene fluoride (PVDF) based formulation, which was rendered microporous via Thermally Induced Phase Separation (TIPS) and dissolution of a dispersed nano-calcium carbonate porogen. Air was used as the bore fluid to form the microcapillaries. Analysis of the membranes prepared by this technique using scanning electron microscopy showed surface porosity and an interconnected, porous interior morphology that was uniform from the outside surface to the capillaries on the interior. These MCF membranes can be formed into spiral wound modules, useful for ultrafiltration applications or, when coated with an ion-rejecting top layer, for desalination of aqueous feed streams.
5:00 pm – 5:30 pm:
Numerical Modelling of Complex Parison and Sheet Formation in Blow Molding Processes using BlowView Software
Zohir Benrabah, National Research Council Canada
BlowView is an engineering 2.5D finite element simulation software, developed at NRC, dedicated to simulate conventional extrusion blow molding, twin-sheet extrusion blow molding, stretch blow molding and thermoforming processes. This versatile blow molding simulation software is highly automated, flexible and user-friendly, yet allows users in-depth analysis capabilities for a wide range of materials, including optimization and permeability. Extrusion blow molding, and twin-sheet extrusion blow molding, are extensively used in manufacturing automotive plastic fuel tanks (PFT). These processes consist of three main phases: parison/sheet formation, inflation and part cooling and solidification. The parison/sheet formation is the most critical stage, as the final dimensions and mechanical performance of the PFT is directly related to the initial extrudate shape, which often requires the use of advanced die shaping technologies such as: Vertical Wall Distribution System (VWDS), Partial Wall Distribution System (PWDS), Die Slide Motion (DSM), and/or a combination of all three. These technologies are all available in the BlowView software, and can be handled simultaniously and synchronized with the machine programming points. In order to predict the extrusion with sag and swell, BlowView uses a hybrid approach that couples fluid mechanics to represent the die flow, with solid mechanics to represent the parison/sheet behavior outside the die, and a phenomenological swell model to capture the die geometry effect. This approach permits avoiding instability issues encountered by traditional fluid mechanics, especially at high Weissenberg numbers. After extrusion, the parison/sheet inflation is predicted tacking into account all mold components and their respective position and displacements. The modelling capabilities of NRC’s BlowView software will be presented based on using an industrial case study of a PFT. Permeability and optimization results will be also illustrated.
5:30 pm – 6:00 pm:
How Polymer Rheology Impacts the Extrusion Blow Molding Process
David Kababik, The Dow Chemical Company
6:00 pm – 6:30 pm:
Synergistic Reinforcing and Toughening High Density Polyethylene by introducing Dynamic Shear Force Field and Ultrahigh Molecular Weight Polyethylene
Tong Liu, South China University of Technology
In this work, simultaneously strengthened and toughened high density polyethylene (HDPE) composites were successfully prepared by the self-designed loop oscillating push-pull molding (LOPPM) machine. A series of related characterization methods were used to investigated the properties of resulted samples. The tensile strength, impact strength and Young’s modulus of LOPPM samples was dramatic increased compared to the CIM samples due to the existence of aligned shish-kebab, demonstrating a simultaneously reinforced and toughen HDPE-based sample was obtained. SEM and 2D-WAXD results indicated that the incorporation of complex dynamic shear force field and UHMWPE induced the highly crystal orientation and thus regular shish-kebab was observed. According to the relationship of structure and properties, the mechanism of simultaneously strengthened and toughened was discussed and provide a controlled way to manipulate the congregated structure of crystalline polymer via external dynamic force field.
6:30 pm – 7:00 pm:
Effects of Extruder Screw Configuration on Thermal Properties of Glass Fiber Reinforced Polyamide 6 Composites Throughout the Direct Long-Fiber-Reinforced Thermoplastics Process
Takashi Kuboki, University of Western Ontario
This study investigates the effects of screw configuration of the second extruder on the thermal properties of glass fiber reinforced polyamide 6 (PA6) composites throughout the direct long-fiber reinforced thermoplastic (D-LFT) process. Two screw configurations, which generate low and high shear stress in composite melts, were applied to the second twin-screw extruder in the D-LFT process. Thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) analyses were performed on samples taken from different locations along the D-LFT process. TGA results showed that thermal stability of the final products can be improved by decreasing shear stress in composite melts in the second extruder. Non-isothermal DSC crystallization analysis revealed no substantial changes to the material’s degree of crystallinity with the variations in screw configuration. Isothermal DSC crystallization analysis also showed that the screw configurations had little effect on crystallization half-time of the final products.