By Jan H. Schut
New technologies at ANTEC 2016, the Society of Plastics Engineers Annual Technical Conference, held this year in Indianapolis, IN May 23-25 (www.4spe.org), include an array of unusual functional structures created in plastics and composites by means as different as chicken feathers, plasma, and micro fibrillation. New machine processes include two new multi-screw extruders from Chinese technical universities and a new chaotic melt mastication process from the University of Massachusetts in Amherst (www.polysci.umass.edu).
Guangdong Industry Polytechnic (www.gdqy.edu.cn) introduced its non-identical twin and triple screw extruder for the first time with two papers reporting better mixing, finer dispersions and less breakage of fibers. South China University of Technology (www.gdqy.edu.cn) presented a physically foamed and structured terpolymer with solid domains of PS in a matrix of biodegradable PPC with in situ PTFE micro fibers that increase viscosity over 1500%. The terpolymer is made on its triple-screw extruder with vibration on the middle screw, introduced at ANTEC 2013 (see blog May 10, 2013).
The title of each highlighted paper is followed by bracketed information on when and where it was given, i.e., M, T or W indicate Monday, Tuesday or Wednesday followed by the session title and time. People who didn’t attend ANTEC can purchase a link to download all papers from the SPE (www.4spe.org) for $250 to members and $300 to non-members. Plenary speeches, New Technology Forums, and undergraduate student posters aren’t on the link.
MIXING AND COMPOUNDING NEWS
The Mixing of Flame Retardant Polymer Materials in a Novel Co-Rotating Non-Twin Screw Extruder [M/Extrusion-Reaction&Mixing I, 10:00] by Bai-Ping Xu, professor, Guangdong Industry Polytechnic, Guangzhou, China (www.gdqy.edu.cn), presents an unusual “self-made” co-rotating non–uniform twin screw extruder for the first time in the U.S. These “fraternal” twin screws can reportedly mix compounds more efficiently than conventional identical twins. A paper published last year in “Fibers and Polymers” (SpringerLink) also describes the non-twin screw extruder mixing immiscible polymers with finer dispersed phases and fibers with less breakage than identical twins. Patented non-twin-screw technology (U.S. Pat. # 9174380) can apply to twin- or triple-screw extruders.
Morphology of HDPE/PS Blends along the Axial Position in a Novel Co-Rotating Non-Twin Screw Extruder [T/Alloys&Blends Compatibilization, 3:30] by Bai-Ping Xu, professor, Guangdong Industry Polytechnic, Guangzhou, China (www.gdqy.edu.cn), describes using the novel non-twin screws in a clamshell barrel, mixing an 80/20 wt% blend of immiscible HDPE and PS. The material was processed at different screw speeds and observed with the barrel open, showing smaller droplet size and narrower size distribution at higher screw speeds.
Melt Mastication: A New Rheological Process to Generate High Performance Parts from Semi-Crystalline Polymers [T/Engineering Properties&Structure, 8:30] by Alan Lesser, professor, University of Massachusetts, Amherst, describes using a modified, heated static mixer for “chaotic mixing” or mastication of a semi-crystalline polymer at a temperature between its melting point and melt crystallization temperature. This new process significantly increases crystallization and gives conventional isotactic PP the strength of glass-filled PP. Patented “Melt Mastication” (U.S. Pat. # 9284388) was first mentioned at the SPE Automotive Composites conference in 2013, but ANTEC is the first presentation on how it enhances polymer stiffness, strength and toughness.
STRUCTURE & COMPOSITES NEWS
Preparation of PPC/PS/PTFE Composites with In-situ Fibrillated PTFE Monofibrillar Network and Their Supercritical Carbon Dioxide Extrusion Foaming Properties [T/Thermoplastic Materials&Foams, 9:00] by Hao-Yang Mi, professor, South China University of Technology, Guangzhou, China (en.scut.edu.cn), is done using SCUT’s triple-screw compounding extruder with vibration in the middle screw (see blog, May 10, 2013). The triple-screw creates a multi-phase composite with PTFE nano fibers created in situ in a PPC/PS matrix. Rigid PS domains and PTFE nano fibers increase PPC’s viscosity by 1576%, allowing composite foam with four times higher cell density than PPC alone. SCUT’s triple screw extruder is built commercially by POTOP Experimental Analysis Instrument Co. also in Guangzhou (www.potop-lab.com).
Three-Dimensional Hierarchical Materials by Memory-Based, Sequential Wrinkling [T/New Technology Forum-Surface Engineering, 2:00] by Teri Odom, professor, Northwestern University, Evanston, IL (www.chemgroups.northwestern.edu/odom) creates super hydrophobic 3D surface patterns on PS sheets. Pre-strained, biaxially oriented PS sheet is plasma treated to deposit a soft fluorocarbon (CFx) polymer skin. Then the strain is relaxed to create surface wrinkles. This repeatable, tunable process applies robust wrinkle patterns that can withstand subsequent bending and stretching. Oxygen treatment traps oxygen in the wrinkles to create different levels of hydrophobicity for a range of potential applications.
Fabrication of Hybrid Polymeric-Metallic Foams as Scaffolds for Bone Tissue Engineering [M/Thermoplastics Materials&Foams, 1:30] by Anil Mahapatro, assistant professor, Wichita State University in Kansas (www.wichita.edu), creates an unusual foam structure by electro-depositing magnesium onto PU foams. PU is a representative example of a polymeric foam used as a bone graft material. Magnesium gives mechanical strength for bone support while improving bone binding and regrowth.
High Temperature and High Energy Density Nanolayer Film Capacitors [T/Electrical&Electronics, 3:00] by Deepak Langhe, technology director, PolymerPlus LLC, Valley View, Ohio (www.polymerplus.net), shows the latest development from PolymerPlus, a spin-off from Case Western Reserves’ high multi-layer film lab (www.stc-clips.org) in 2010 (see blog July 6, 2012). Polymer Plus’s patented developmental nanolayer co-ex film capacitors (U.S. Pat. # 8611068) with up to 257 layers offer higher energy density, higher temperature performance, and lower energy loss than current metalized and laminated capacitors. PolymerPlus also makes optic lenses with over 800,000 nanolayers (U.S. Pat. # 7002754).
Production of in situ Microfibrillar Composites as a Novel Approach Towards Improved Bio-Based Polymeric Products [W/Bioplastics, 8:30] by Chul Park, professor, University of Toronto, Ontario, Canada (www.utoronto.ca), first extrudes strands of an immiscible blend of 97/3 PLA/PA6, then draws the strands to create 200 nm PA6 micro fibrils in the PLA matrix, improving melt strength, elasticity and foamability. Strands are then chopped and molded at below the melt temperature of PA6 to retain the micro fibers. The research was published last year in the American Chemical Society’s “Biomacromolecules,” but this is its first presentation to a plastics audience.
Capillary Coextrusion: a New Process for Creating Small-Scale Coextruded Films [M/Flexible Packaging, 9:30] by Patrick Lee, assistant professor, University of Vermont, Burlington (www.uvm.edu), describes a clever device to test layer adhesion in coex films more accurately than testing cast or laminated film layers. Lee attaches a small (10 mm) coex die to a dual-bore capillary rheometer to coextrude 8-9 mm test films continuously.
Green Plastics: Utilizing Chicken Feather Keratin to Improve the Thermo-Mechanical Properties of PU Composites [M/Composites-Natural/Bio, 9:30] by Firoozeh Pourjavaheri, PhD candidate, RMIT University, Melbourne, Australia (www.rmit.edu.au), enhances thermo-mechanical properties of TPU composites by adding 10% and 20% purified keratin fibers from waste feathers, mixed with urethane using solvent casting and evaporation. The resulting composites show lower glass transition temperature, % strain recovery, and mass loss of the composite than neat TPU, but higher elastic modulus, storage modulus and heat resistance, indicated by the % char.
Soy Protein Isolate Films with Improved Mechanical Properties via Bio-Based Dialdehyde Carboxymethyl Cellulose Crosslinking [M/Bioplastics 8:30] by Ting Zheng, graduate student, Clemson University, Clemson, SC (www.clemson.edu), reports new glycerol-based soy protein films cross-linked with DCMC for an astonishing 218% improvement in tensile strength. So called “edible films” for meat and poultry packaging have been a hot research topic on technical programs for decades without being commercialized because of poor strength, so a property enhancement of this magnitude could be significant.
Improvement of the Extrusion Foaming Properties of Externally Plasticized Cellulose Acetate by Reactive Melt Mixing Using a Multifunctional Reactive Oligomer [M/Extrusion-Forming I, 9:30] by Sven Hendriks, scientific research assistant, Institute of Plastics Processing at RWTH University, Aachen, Germany (www.ikv.rwth-aachen.de), uses a reactive oligomer as a chain extender to foam fine-celled cellulose acetate sheets or boards with 1,3,3,3-tetra-fluoropropene (HFO 1234ze) as physical blowing agent. The IKV has partnered with the Fraunhofer UMSICHT, Oberhausen, Germany (www.umsicht.fraunhofer.de); FKuR Kunststoff GmbH, Willich, Germany (www.fkur.de); Inde Plastik Betriebsgesellschaft mbH (www.indeplastik.de); and Jackon Insulation GmbH, Mechau, Germany (www.jackon-insulation.com), for several years foaming cellulose acetate, but this is the first mention of chain extenders.
INJECTION MOLDING & THERMOFORMING NEWS
High Precision and Repeatability in Micro Injection Molding Using the Inverse Screw [T/Injection Molding-Emerging Tech, 3:00] by Torben Fischer, chief engineer, Institute of Plastics Processing at RWTH University, Aachen, Germany (www.ikv-aachen.de), reports the first test results on the repeatability of this unusual threaded barrel/smooth shaft micro molding machine using different thermoplastics including POM, PC, PMMA, PP and 30% glass-fiber-reinforced PP. The inverse screw micro molding machine was introduced in Germany in 2013 and in the U.S. at ANTEC 2014 (see blog Nov. 11, 2014).
Development of an In-Line Plasma Treatment during the Injection Molding Process [W/Injection Molding Troubleshooting, 11:30] by Timo Nordmeyer, scientific employee, University of Paderborn in Germany (www.ktp.uni-paderborn.de), describes integrating a stationary atmospheric plasma jet inline into an injection molding process. The target is injection molding of technical parts of polymers with low surface energy like fiber-reinforced PP for automotive housings. The patent pending process was developed with Plasmatreat GmbH, Steinhagen, Germany (www.plasmatreat.com).
Cycle Time Reduction by Water Spray Cooling in Thermoforming [M/Extrusion-Forming I, 10:00] by Jonathan Martens, research assistant, Institute of Plastics Processing at RWTH University, Aachen, Germany (www.ikv.rwth-aachen.de), reports 5% faster cycle time vacuum-forming a 400-ml beaker in a female mold with atomized water mist sprayed onto the formed sheet on the open side away from the mold. Water spray cooling is used in industrial thermoforming for large parts with different stretch ratios, but not in packaging. The trick is to use just enough water to cool without leaving water residue on parts after unmolding.