The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
Ballistic clay is used as a backing material for standards-based ballistic resistance tests for the purposes of providing a measure of the energy transferred to the body when a threat is defeated. However, this material exhibits complex thermomechanical behavior under actual usage conditions. In this work, we characterize rheological properties of the standard backing clay material, Roma Plastilina No. 1, used for body armor testing, using a rubber process analyzer. Test methods employed include oscillatory strain sweep, frequency sweep, and oscillatory strain ramp. The results show that the material is highly nonlinear, thermorheologically complex, and thixotropic. The modulus decreases under dynamic deformation and partially recovers when the deformation is discontinued. Experimental protocols developed in this study can be applied for the characterization of other synthetic clay systems.
Sean Teller, Jorgen S. Bergström, Gregory R. Freeburn, May 2017
Finite element analysis plays a crucial role in modern engineering problems, enabling engineers to predict the response of designed parts at any point in the design process. Specifying a constitutive model that accurately captures the mechanical response of a polymer material is paramount to obtaining useful results. In order to understand the capabilities of commercial FE packages used to simulate problems involving polymers, we have tested the uniaxial response of polyamide in tension and compression over six decades of strain rate. We then calibrated four constitutive models to the experimental data: an Abaqus Parallel Rheological Framework model, the LS-DYNA SAMP-1 model, the ANSYS Bergström-Boyce model, and the PolyUMod Three Network model. We compared the performance of the four models in predicting the experimental data; the Three Network model had the lowest error. Additionally, we compared the runtime of a simple test case for each model; the ANSYS Bergström-Boyce model being the fastest.
Mark D. Wetzel, John C. Howe, Michael T. Sterling, Gregory A. Campbell, May 2017
Highly filled polymer compounds can present processing challenges, including high screw shaft torque, energy consumption, die pressure and melt temperature rise. Previous theoretical development and experimental evaluations of highly filled polymer melts showed that the rheology can be described with a percolation model [1-4]. This paper re-evaluates a batch mixer characterization method used to measure the effects of filler concentration on melt processing. The experimental results are compared with capillary rheometer measurements using several low-density polyethylene resins, calcium carbonate and titanium dioxide. The theoretical treatment of the rheology as a particulate percolating system with power-law behavior is used to analyze rheometer and batch mixer data. The effects of resin molecular weight, filler type and size on rheology and melt processing are described.
Masayuki Yamaguchi, Tomoki Itoh, Jiraporn Seemork, May 2017
The effect of mixing condition on flow instability at capillary extrusion was studied using linear low-density polyethylene (LLDPE) blends. Two types of LLDPE with different molecular weights were blended by various mixing devices and conditions. It was found that the onset of flow instability is sensitive to the mixing method even though their linear viscoelastic properties are almost identical. The blend obtained by poor mixing conditions shows shark-skin failure even at a low shear stress, although the blend prepared by intensive mixing provides smooth surface at the same shear stress. This is attributed to the low onset shear stress of shark-skin failure for the blend prepared by poor mixing. Furthermore, a blend by poor mixing is found to show a significantly low value of the maximum draw ratio at hot-stretching. The result suggests the existence of mechanically-weak points, which leads to cohesive failure at strand surface by the abrupt stretching at the die exit, i.e., the shark-skin failure.
Thermal inhomogeneities in spiral mandrel dies, which occur especially in the pre-distributor, can lead to an uneven flow distribution despite a rheologically optimized design of the die. Against this background an integrative thermal and rheological flow simulation has been developed at the IKV, in which the whole pre-distributor can be modelled non-isothermally. The simulation takes both the non-linear flow behavior of the melt and the thermal phenomena in the die material into account. In this contribution, the developed simulation model is used to evaluate and compare the temperature influence on the melt distribution in three different types of pre-distributors. These are a 23-pre-distributor of a radial spiral mandrel die, a 24-pre-distributor of an axial spiral mandrel die and a star pre-distributor with vertical redirection. The simulations show that in case of the 23- and 24-pre-distributor, both the external tempering of the die and the dissipative shear heating lead to an uneven temperature distribution in the melt and thus cause an inhomogeneous melt pre-distribution. In case of the star pre-distributor, the die tempering has no significant effect on the flow distribution. However, the dissipation leads to an uneven heat-up of the melt in the area of the redirection, which results in an uneven melt flow at the outlets of the pre-distributor. In the next step, thermal design measures are introduced into the pre-distributors in order to homogenize the flow rate distribution at the outlets of the pre-distributors. By integrating heater cartridges, brass inserts and insulating gaps into the die, a more homogeneous flow rate distribution at the outlet of each pre-distributor can be achieved.
Galip Yilmaz, Thomas Ellingham, Lih-Sheng Turng, May 2017
Ultra-high molecular weight polyethylene (UHMW-PE) was injection molded using a microcellular injection molding (MIM) process to introduce supercritical nitrogen (SC-N2) into the melt to decrease the viscosity of the polymer and improve processability while reducing degradation. Solid and foamed parts were produced. Rheological tests indicated that a viscosity reduction during processing decreased the material’s tendency to degrade during injection molding. Although the SC-N2 processing did not improve the tensile strength of the molded parts, it significantly improved the processability of UHMW-PE via injection molding. Micro-computed tomography (µCT) images illustrated the internal structures of the parts and revealed sink marks in the solid formed SC-N2 processed samples, even when packing pressure was applied.
Martin Zatloukal, Wannes Sambaer1, Dusan Kimmer2, May 2017
Full 3D polydisperse particle filtration modeling at low pressures has been performed for a polyurethane nanofiber based filter prepared via electrospinning process in order to more deeply understand the filter clogging and the cake formation. In this work, realistic SEM image based 3D filter model, transition/free molecular flow regime, Brownian diffusion, aerodynamic slip, particle-fiber and particle-particle interactions together with a Euclidian distance map based methodology to calculate the pressure drop have been utilized. Model predictions have been compared with relevant experimental data in order to validate the used assumptions, methodologies and numerical scheme. The effect of particle-particle as well as particle-fiber interactions on the nanofiber based filter efficiency, pressure drop and the quality factor during the filter clogging has been investigated in more detail.
Martin Zatloukal, Tomas Barborik, Costas Tzoganakis, May 2017
In this work, viscoelastic, isothermal extrusion film casting modeling utilizing 1D membrane model and modified Leonov model was performed in order to understand the role of planar and uniaxial extensional viscosities, extensional strain hardening, Deborah number and die exit stress state (captured here via the second to first normal stress difference ratio –N2/N1). It has been found that the neck-in can be expressed via simple set of dimensionless analytical equations utilizing all above mentioned variables, and thus providing detail view into complicated relationship between polymer melt rheology, die design, process conditions and unwanted neck-in phenomenon.
This work combined the grafting maleic anhydride(MAH) onto polypropylene (PP) and the coupling reaction between diamine and MAH grafted PP (PP-g-MAH) into a single step through a twin screw extruder. Detailed molecular weight analysis, rheological characterization and foaming tests were conducted subsequently. The investigation indicated that the concentration of reagents plays a key role in control of the chain structure. By the combination of SEC and rheological analysis, the optimum amount of MAH and diamine for preparing LCB-PPs is decided. However, the optimum peroxide loading during branching modification is not clear and need further evidence. To solve this problem, a foaming test was carried out to assess the performance of the modified PP with different peroxide loading. The results demonstrate that an intermediate level of modification (peroxide concentration, 0.2-0.4 wt%) is already sufficient for the optimization of foaming process.
Jinchuan Zhao, Guilong Wang, Qingliang Zhao, Chul B. Park, May 2017
Polypropylene (PP) foams with a low thermal conductivity (less than 40 mW/m·K) and a low density (0.1-0.2 g/cm3) were fabricated by the foam injection molding technology with mold opening while using CO2 as a blowing agent. PTFE fibrils manufactured by in-situ fibrillation using a co-rotating twin screw extruder were used to improve the melt strength and the strain hardening property. The crystallization behavior and the rheological properties were studied, to demonstrate that the dispersed PTFE fibrils effectively enhanced the crystallinity and, thereby, increased the melt strength, and induced a strain hardening behavior. When foamed in injection molding, the fibrillated PTFE containing PP showed much more improved foaming behavior. The thermal conductivity mainly depended on the expansion ratio of foam, although the quality of the cells (i.e., the size and uniformity) also influenced those properties.
The objective of this work is to study the rheological characteristics of the compound of polycarbonate resins with different melt flow indexes and the affects of the processing parameters PC1 content (30wt%-pph) of MFI (25gm/10mins) and PC2 content (70 wt. %-pph) of MFI (6.5gm/10mins). By understanding the relationship between shear rate and viscosity, it becomes possible to define the viscosity model and exact color shifts. The temperature was varied at three stages (230°C, 255°C and 280°C) to study its effect on rheological characteristics, colour differences (dE*), pigment size distribution and dispersions.
Zhanhu Guo , Xingru Yan , Wenqing Yang , Xuan-Lun Wang, April 2017
Glycidyl methacrylate-grafted high-density polyethylene improved the compatibility of polyoxymethylene and polyolefin elastomer, in turn enhancing the properties of polyoxymethylene.
Cecilia Duran-Valencia, Simon Lopez-Ramirez, Fernando Barragan-Aroche, Luis Cervantes-Montejano, Gerardo Pineda-Torres, April 2017
Understanding the structure-function relationship in polymeric materials enables the development of stable products to optimize hydrocarbon recovery under harsh conditions.
Prapol Chivapornthip , Erik L. J. Bohez, December 2016
Uniaxial compression experiments show that the bulk viscosity has a higher magnitude than shear viscosity and should therefore not be neglected during flow analysis of the injection-molding process.
A fully biobased composite material, composed of bamboo fibers and a nanoparticle-reinforced bio-epoxy matrix, exhibits improved mechanical properties.
Kim McLoughlin Senior Research Engineer, Global Materials Science Braskem
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Kim drives technology programs at Braskem to develop advanced polyolefins with improved recyclability and sustainability. As Principal Investigator on a REMADE-funded collaboration, Kim leads a diverse industry-academic team that is developing a process to recycle elastomers as secondary feedstock. Kim has a PhD in Chemical Engineering from Cornell. She is an inventor on more than 25 patents and applications for novel polyolefin technologies. Kim is on the Board of Directors of SPE’s Thermoplastic Materials & Foams Division, where she has served as Education Chair and Councilor.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Gamini has a BS and PhD from Purdue University in Materials Engineering and Sustainability. He joined Penn State as a Post Doctorate Scholar in 2020 prior to his professorship appointment. He works closely with PA plastics manufacturers to implement sustainability programs in their plants.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Tom Giovannetti holds a Degree in Mechanical Engineering from The University of Tulsa and for the last 26 years has worked for Chevron Phillips Chemical Company. Tom started his plastics career by designing various injection molded products for the chemical industry including explosion proof plugs and receptacles, panel boards and detonation arrestors for 24 inch pipelines. Tom also holds a patent for design of a polyphenylene sulfide sleeve in a nylon coolant cross-over of an air intake manifold and is a Certified Plastic Technologist through the Society of Plastic Engineers. Tom serves on the Oklahoma Section Board as Councilor, is also the past president of the local Oklahoma SPE Section, and as well serves on the SPE Injection Molding Division board.
Joseph Lawrence, Ph.D. Senior Director and Research Professor University of Toledo
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Dr. Joseph Lawrence is a Research Professor and Senior Director of the Polymer Institute and the Center for Materials and Sensor Characterization at the University of Toledo. He is a Chemical Engineer by training and after working in the process industry, he has been engaged in polymers and composites research for 18+ years. In the Polymer Institute he leads research on renewably sourced polymers, plastics recycling, and additive manufacturing. He is also the lead investigator of the Polyesters and Barrier Materials Research Consortium funded by industry. Dr. Lawrence has advised 20 graduate students, mentored 8 staff scientists and several undergraduate students. He is a peer reviewer in several journals, has authored 30+ peer-reviewed publications and serves on the board of the Injection Molding Division of SPE.
Matt Hammernik Northeast Account Manager Hasco America
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Matt Hammernik serves as Hasco America’s Northeast Area Account Manager covering the states Michigan, Ohio, Indiana, and Kentucky. He started with Hasco America at the beginning of March 2022. Matt started in the Injection Mold Industry roughly 10 years ago as an estimator quoting injection mold base steel, components and machining. He advanced into outside sales and has been serving molders, mold builders and mold makers for about 7 years.
84 countries and 85.6k+ stakeholders strong, SPE
unites
plastics professionals worldwide – helping them succeed and strengthening their skills
through
networking, events, training, and knowledge sharing.
No matter where you work in the plastics industry
value
chain-whether you're a scientist, engineer, technical personnel or a senior executive-nor
what your
background is, education, gender, culture or age-we are here to serve you.
Our members needs are our passion. We work hard so
that we
can ensure that everyone has the tools necessary to meet her or his personal & professional
goals.
Need help from SPE Headquarters?
SPE HQ provides a range of services to Chapters. If you are a chapter and need HQ services (i.e.,
event registration - full list of HQ services can be found here), please fill out and submit the HQ services request form found
here: www.4spe.org/HQservices.
IMPORTANT! If you are simply looking to post your
event on SPE's calendar, please click the "Submit an Event" button below. All events
submitted for inclusion in the SPE calendar are subject to approval.
Going to a SPE event?
If you are going to a SPE event and need a Visa invitation letter, please submit your request for a Visa Invitation letter.
SPE Members receive discounted rates on all event registrations. Not a member of SPE? Join today!
How to reference articles from the SPE Library:
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers, ISBN: 123-0-1234567-8-9, pp. 000-000.
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
