10:00 am – 10:30 am:
Macromolecular Spectroscopy for Determining Mechanical Properties of Polydimethylsiloxane (PDMS)
In this study, vacuum assisted bubble free casting was used to prepare and test Polydimethylsiloxane (PDMS) with varying crosslinking densities. Tensile tests and Shore D hardness tests were performed to determine tensile strength and hardness of PDMS. PDMS with concentrations of 2.5:1, 5:1, 7.5:1, and 10:1 wt/wt silicone resin to curing agent were fabricated for uniaxial tensile testing and hardness testing. Fourier transform infrared (FTIR) spectroscopic analysis revealed that there is a strong correlation between tensile strength and hardness with respect to absorbance spectra of carbon Silicone-Oxygen-Silicone (Si-O-Si) bonds.
10:30 am – 11:00 am:
Flow Problems That Could Arise From Adding Biomass Materials to Plastics
Carrie Hartford, Jenike & Johanson
In an effort to become more “green” in the plastics world, engineers are developing unique products by adding biomass materials to create bio-friendly plastics. The biomass additives may have a different aspect ratio, size, compressibility or density than the pellets and powders but they all must come together in a uniform, consistent, reliable flow into the extruder. Understanding the implications to the handling of adding a new biomass material to a blend is critical for the success of the product. Taking a scientific approach to understanding the flowability of a component and blend is critical to ensuring a successful outcome. Often, this approach results in either making a change to the equipment that the material is handled in to support the new blend, or to making a change in the material or blend (or the conditions at which it is handled) to flow through the existing equipment.
11:00 am – 11:30 am:
Rotomolding Processes for Poly (Aryl Ketones) and Other High Temperature Polymers
Manuel Garcia-Leiner, Exponent
High temperature thermoplastic polymers are continuously evaluated as options in a multitude of applications, including aerospace, medical, oil and gas exploration, and other high demanding applications. The fundamental understanding of their structure and its effect on their expected performance in critical environments is of high importance for the development of new technologies and complex processing techniques. Commercial efforts have recently focused on the development of high performance materials for specialized and highly demanding applications. In this regard, due to their superior properties, poly(aryl ketones) or PAEKs have gained significant attention. Their exceptional behavior at high temperatures, along with their superior chemical resistance, mechanical properties, excellent abrasion resistance, and natural flame retardancy make them suitable for a multitude of growing applications and markets. Among the PAEK family, poly(etherketoneketone) (PEKK) offers a unique chemical structure, favoring precise manipulation of its polymer microstructure and key properties. PEKK resins offer very high melting and glass transition temperatures, a wide range of crystallization rates and degrees of crystallinity, superior mechanical properties, chemical resistance and low flammability. Because of their extremely high thermal properties and polymorphic crystalline nature, PEKK polymers offer also clear advantages in powder applications over traditional high-performance thermoplastics and other aromatic polyketones [1-3]. This study provides a detailed evaluation of the performance of PEKK polymers in rotomolding applications. The results presented here offer a general overview of the changes in physical properties and macroscopic morphology observed in PEKK parts when processed at elevated temperatures. This study also describes the development of an optimized rotomolding process to produce parts with improved performance capable of satisfying highly demanding requirements for specialized applications such as aerospace, medical, and oil and gas exploration among others.
8:00 am – 11:30 am:
(Moderator: Kevin Laux)-Room S320F
8:00 am – 8:30 am:
Further Improvements in Processing of Semi-crystalline and Amorphous Polymers for Thermoforming Sheet in Multiple NIP Systems
Peter Rieg, Battenfeld-Cincinnati
With the development of high-speed extruders, the cooling capacity of conventional roll stacks reached its limit. Wider lines or bigger roll diameters were possible solutions, but often lead to lower quality or required more space. Therefore, a new roll stack concept was developed to ensure even cooling and low sheet tolerances thus saving material and enabling uninterrupted processing of the sheet in thermoformers. The new roll stacks work with three principles to achieve flat, stress-free sheet and higher transparency and surface gloss: • Uniform cooling of top and bottom side of the sheet • Thin-walled rolls for better cooling properties • Multiple nips for optimal heat transfer In the past years, this concept has been further refined, for higher outputs, lower sheet tolerances and better end product properties.