Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session Q19: Invited Session: Industry Day: Rheology and Processing for Additive Manufacturing |
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Sponsoring Units: FIAP Chair: Tirtha Chatterjee, The Dow Chemical Company Room: Mission Room 103B |
Wednesday, March 4, 2015 2:30PM - 3:06PM |
Q19.00001: Polymer Physics as a Key to Advanced Manufacturing at Dow Invited Speaker: Florian Schattenmann Dow combines the power of science and technology to passionately innovate what is essential to human progress. The Company is driving innovations that extract value from the intersection of chemical, physical and biological sciences to help address many of the world's most challenging problems such as the need for clean water, clean energy generation and conservation, and increasing agricultural productivity. Dow's integrated, market-driven, industry-leading portfolio of specialty chemical, advanced materials, agrosciences and plastics businesses delivers a broad range of technology-based products and solutions to customers in approximately 180 countries and in high growth sectors such as packaging, electronics, water, coatings and agriculture. In 2013, Dow had annual sales of more than {\$}57 billion with more than 6,000 products manufactured at 201 sites in 36 countries across the globe. Given the large scale of Dow's manufacturing footprint and broad range of industries, markets and applications Dow serves, a wide range of advanced manufacturing technologies are being developed. The presentation will give an overview of select manufacturing technologies and how polymer physics, modelling, analytical techniques and experimental validation are being employed to drive world leading innovation. We will discuss examples from several product technologies including composites, adhesives and polymers synthesis. [Preview Abstract] |
Wednesday, March 4, 2015 3:06PM - 3:42PM |
Q19.00002: New insights on cellulosic ether hydrogels Invited Speaker: Robert Sammler Aqueous hydroxypropylmethylcellulose materials (HPMC) often have much lower hot gel moduli (\textless 10 Pa) relative to those (3,000 Pa) of aqueous methylcellulose materials (MC) at end-use conditions (\textless 2 wt.{\%}, 90 $^{\circ}$C), and these lower moduli limit their use in applications. The origin of their lower moduli is suspected to arise from the order of two thermal transitions when warming. One transition, thought to involve a chain conformation transition, is referred to here as chain collapse. Another, thought to involve the self-assembly of chains into a three-dimensional physical network, is referred to as gelation. Often, chain collapse is thought to proceed gelation when slowly warming aqueous commercial HPMC materials from 5 to 90 $^{\circ}$C at 1 $^{\circ}$C/min, while the opposite order is thought to occur for many aqueous commercial MC materials. Chain collapse is identified as a sharp drop in the solution viscosity at pre-gel temperatures as $T$ rises. The insensitivity of the chain collapse temperature to HPMC concentration is used to argue that this thermal event is distinct from gelation. These concepts are supported with the preparation of two developmental HPMC materials with similar \textit{MW} and substitution levels (\textit{DS} and \textit{MS}). One HPMC material, prepared by a unique process, is designed to reverse order of the thermal transitions. This HPMC material is found to exhibit high hot gel moduli similar to those of aqueous MC materials; moreover, its gel is able to form synerese fluid as it contracts in size when warmed. The gel contraction is thought to be a manifestation of chain collape. [Preview Abstract] |
Wednesday, March 4, 2015 3:42PM - 4:18PM |
Q19.00003: Particle laden interfaces and dispersions: Enabling high performance and multifunctional materials Invited Speaker: Ravi Sharma Particles at interfaces are finding increasing use in Pickering emulsions due to their superior stability compared to surfactant-stabilized emulsions. In this presentation we present an overview of particle laden interfaces and particle concepts for development of high performance materials, some of which could be used to address current materials problems in additive manufacturing. [Preview Abstract] |
Wednesday, March 4, 2015 4:18PM - 4:54PM |
Q19.00004: Modifying polymer rheology by using nanofillers: applications in additive manufacturing Invited Speaker: Dilip Gersappe The ability to control the flow properties of polymers is critical to developing materials that can be used for additive manufacturing. In this talk, I discuss the effect of adding nanofillers in polymeric matrices on the flow and rheological properties. We use Molecular Dynamics simulations to examine the role nanofillers have on polymer melts and polymer blends. In homopolymer systems, our results indicate that above a critical concentration of filler particles, the network structure formed between the fillers and the polymers strongly affects the dynamics of the nanocomposite under shear. However, we also find that low concentrations of filler particles leads to a large increase in chain orientation (relative to the pure polymer case) when shear is applied. Our results indicate that the ability of fillers to maintain the network during shear results in the enhancement of the shear thinning effect at high concentrations of filler particles, while the ability of fillers to induce high degrees of orientation in polymer chains results in shear thinning being present even at lower concentrations of fillers. In polymer blends, we show that the nanofillers can reduce the slip at the interface between the two components. We also examine the role of the aspect ratio of the nanofiller on the rheological properties of polymer nanocomposites. [Preview Abstract] |
Wednesday, March 4, 2015 4:54PM - 5:30PM |
Q19.00005: Rheology and Flow-Induced Crystallization of Polyolefins Invited Speaker: Antonios Doufas This talk will give an overview of melt rheology in shear and extensional flow kinematics as well as flow-induced crystallization (FIC) behavior of polyolefin systems relevant to polymer processing. Examples for both polypropylene (PP) and polyethylene (PE) systems will be discussed. The effect of shear on FIC of several PP resins of various microstructures is studied using parallel-plate and capillary rheometry. Generally, an increase in strain and strain rate or decrease of temperature is found to decrease the thermodynamic barrier for crystal formation enhancing the crystallization kinetics at temperatures between the melting and crystallization points. FIC kinetics were enhanced with increased PP molecular weight indicating the importance of the high-end tail of the MWD on FIC. Various dies of different contraction angle and different length-to-diameter (L/D) ratios were used to investigate the effect of flow (mainly extensional kinematics in die entrance) on FIC. Extensional strain is found to be a key parameter influencing FIC. The effect of different molecular structures (from linear to long chain branched) on melt rheology and FIC response of several PE systems will be discussed. The melt rheology and FIC characteristics of thermoplastic materials are important for their processability performance in conventional and advanced fabrication processes such as Additive Manufacturing. [Preview Abstract] |
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