SPE Library

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.

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Conference Proceedings

Study on Worm Melt Fracture of Blow Molding Process Using Capillary Rheometer

Yongwoo Inn, Ashish M. Sukhadia, William M. Whitte, May 2015

During the blow molding process of large size drums, string-like defects, which are called worm melt fracture, can be observed on the extrudate surface. Such string-like defects are observed in the capillary extrusion at high shear rate range after the slip-stick transition. It is proposed that the cohesive slip layer which is a failure within the polymer melts inside the die could emerge out as the sting-like defects on the extrudates. The resin having more small chains and lower plateau modulus can be easier to have such an internal failure and consequently exhibit more ?worm? defects.

Modelling the Rheolgocial Behavior of Blowing Agent Laden Melts That Simulates the Foam Injection Molding Process

Christian Hopmann, Daniel Sander, May 2015

Currently a new approach for simulating the foam injection molding process is being developed at the Institute of Plastics Processing (IKV) Aachen, Germany. As existing simulation software for foam injection molding works with restrictions and assumptions, especially for the nucleation phase of the foam injection molding. Simulation results often do not correspond with practical tests at the injection molding machine.
In the new approach the influence of the blowing agent on the PVT- and rheological behavior is measured with two injection molds directly on the injection molding machine. The characterization of the material behavior is than prepared as input data to the injection molding simulation software.
In this paper the approach for modeling the rheological behavior of blowing agent loaded melts for simulating the foam injection molding process is described. Step one is to measure the effect of a blowing agent on the viscosity of a polymer melt at different melt temperatures and blowing agent concentrations through an online rheometer. Afterwards the measured data is adjusted, optimized and inputted into the injection molding simulation software.

Split Peel Seal System for Flexible Medical Device Packaging

Patrick Thomas, May 2015

Flexible medical device packaging systems typically include heat sealing a forming web to a breathable lidding substrate material in order to allow for ethylene oxide sterilization. Design for Six Sigma methodology and Stage-Gate Project Management were used in an effort to efficiently and effectively demonstrate the feasibility of developing a multilayer film structure and formulation that provides a ?split? peal seal bond to uncoated nylon reinforced medical grade paper. This peel seal system offers a cost/performance alternative between costly spunbonded polyolefin and paper lidding materials.

Preparation of Micro and Nanocellular Tpu-Graphene Nanocomposite Foam by Supercritical Co2 Foaming

Ying-Ru Chen, Sheng-Ping Peng, Shu-Kai Yeh, Chien-Chia Chu, Wen-Jeng Guo, May 2015

Thermoplastic polyurethane (TPU) possesses many special characteristics. The flexibility, rigidity, and elasticity can be adjusted by controlling the ratio of soft and hard segments. Additionally, the chemical properties of TPU can be varied by using different starting monomers. Due to its versatile physical and chemical properties, TPU is commonly used in transportation, construction, and biomaterials. The technique of foaming TPU by CO2 is still under investigation. To avoid the effect of additives that are found in commercially available polymer, we synthesized TPU ourselves using a pre-polymer method. In addition, graphene was added as the nucleation agent. The synthesized TPU was foamed by batch foaming using super critical CO2 as the blowing agent, and the effect of saturation temperature on the cell morphology of TPU foam was examined. The average cell size of TPU foam decreased from 1.8 ?m to 800 nm, after only 0.1 wt% of graphene being added.

Health Product Declarations-The Good, The Bad and The Ugly

Marty Sweeney, May 2015

Today, your products may be excluded from a project simply because you do not have an HPD (Health Product Declaration). This presentation will not advocate for, or against, Health Product Declarations (HPDs) and/or other instruments for demonstrating ingredient transparency. Rather, the goal of this presentation is to examine the evolution of Health Product Declarations, determine the true impact these mechanisms are having on buying decisions today, and discuss the likely impact in the future. Most importantly, we will discuss the ?as is? of ingredient transparency initiatives and the relative merits of defending and/ or embracing these initiatives, for building material manufacturers and raw material suppliers

Topics will include:
What is a Health Product Declaration?
Growing influence of green building rating systems (such as LEED) and how this is changing product development
Who?s on board? Who are the stakeholders driving change?
Ingredient Disclosure: Hazardous Chemical lists vs. Risk & Exposure Assessment
How do I decide if an HPD is right for my company?
Now that you?ve decided?what?s next?

Tuning Thermal Property of a Thermoplastic Polycarbonate-Based Polyurethane by Means of Post-Extrusion, Solid State Annealing

Xiaoping Guo, May 2015

The tubes melt-extruded of a commercially-available segmented polyurethane block copolymer based on the soft segment chemistry of poly(1,6-hexyl 1,2-ethyl carbonate) diol (namely BionateTM 75D) were found to exhibit structural relaxation and phase demixing (or ?cold crystallization?) phenomena upon thermal exposure at low temperatures. To prevent these phenomena for practical engineering applications, a series of post-extrusion annealing experiments were conducted at temperatures from 50 to 150 øC within durations from 15 to 240 min. To reveal the correlative process-structure-property relationships, the annealed tube samples were then analyzed using differential scanning calorimetry (DSC) methods. It was observed that despite initial morphological states of the extruded tubes, their thermal properties are largely tunable via solid-state annealing processes. Dependent of annealing conditions, the extruded tubes could be renewed to a desirable phase-separated morphology exhibiting the desirable thermal properties that are deemed to be thermally stable.

A Study on the Relationship between the Size of the Company and It?s Sustainability Spending in the Plastics Industry

Bonnie J. Bachman, Shikhar P. Acharya, Shristy Bashyal, Margaret H. Baumann, May 2015

Business corporations? emphasis on sustainability is ever increasing which is evident by the increase in sustainability spending. Each year, companies are spending more on sustainability. This research is an attempt to understand if the sustainability spending depends upon the size of the company as measured by its revenue. Moreover, the paper focuses on the relationship between sustainability spending and size of the company in plastic industry. The study is the second survey of its kind and is based on the global inquiry with the members of the Society of Plastics Engineers (SPE). Based on the results of Chi-square test for independence, we found that there is no relationship between sustainability spending and the size of the company.

Effect of Brightness, Color and Transparency on Scratch and Mar Visibility in Polymers

Marquen Hamdi, Hung-Jue Sue, Drew Manica, May 2015

Scratch and mar damages can critically impact the aesthetics of polymeric surfaces. Improving scratch and mar visibility resistance of polymers is of big interest for academic and especially industrial arenas. In this paper, we investigate the influence of surface brightness, color and transparency on scratch and mar visibility resistance in polymers. A new psychophysical test based on Multidimensional Scaling (MDS) statistical method was utilized to determine mar visibility resistance onset. It has been found that scratch visibility resistance decreases with greener, lower brightness and higher transparency samples. Preliminary results show that MDS is a powerful tool to disseminate the psychophysical evaluation of mar damage. This research paves the way for a standardized methodology to reliably quantify scratch and mar visibility resistance in polymers.

CAE Verification on Gas-Counter Pressure Mechanism in Gas-Assisted Injection Molding

Wen-Ren Jong, Shyh-Shin Hwang, Shia-Chung Cheng, Chien-Chou Wu, Chi-Hung Kao, Yan-Mao Huang, Song-Hong Hong, May 2015

The tradition packing way is that the injection unit holds the high pressure in a few seconds, which is highly energy-consuming. Gas Assisted Injection Molding (GAIM) refers to injecting gas into the short shot melt in the packing stage, the compressed gas is used as the medium to push melt and maintain pressure, which can save the material and energy. Therefore, the hollow area and penetration length are mostly required in end product quality. This study visualizes molding flow, and uses gas counter pressure mechanism in the gas assisted molding process, the melt flow behavior is influenced by controlling the counter pressure, so as to discuss the effect of counter pressure mechanism on the hollow area and the penetration of gas assisted molded articles. This study designs in-mold visible mold, and uses clip-shape cavity for experiment on gas assisted injection molding with counter pressure mechanism. The flow field of two phase fluid and fountain effect in different counter pressure conditions are observed by high-speed photography and adding particles, the relationships among the penetration length of finished product, hollowed evenness and molding parameters are analyzed by mold flow analysis software, and the database of gas assisted injection molding under counter pressure mechanism is created. The experimental results show that the gas counter pressure is applied to gas assisted molding, the hollow area is reduced and the penetration length of finished product can be increased, so as to uniform the hollow quality. And the result of mold flow analysis software will verify the experiment.

Non-Destructive Monitoring of Damage in CFRP using Ultrasonic Birefringence

Peter Fey, Daniel Michaelis, Peter Middendorf, Gerhard Busse, Marc Kreutzbruck, May 2015

A non-destructive testing method ? ultrasonic birefringence ? employing ultrasonic transverse waves and their polarization dependent velocity and attenuation is proposed to monitor fatigue damage in laminated CFRP and damage induced by tensile loading of braided CFRP. A calculation approach is presented to predict the measurement results in laminated CFRP. The method exploits the inherent elastic anisotropy of fiber reinforced plastics to characterize damage. The increase in attenuation and decrease in velocity which is induced by the transverse matrix cracks in fatigued laminated CFRP is matched with simulated results to estimate the shear moduli of each fiber direction in the laminated CFRP and hence characterize the fatigue state in each fiber direction. In the braided CFRP case the method is used in a preliminary attempt to demonstrate the anisotropy of damage induced during tensile testing.

Comprehensive Sterilization Study of Multiple Polystyrene Grades and Other Polymers

Laren Shoup, May 2015

There are no ?all encompassing? sterilization studies which combine all available sterilization methods at varying intensities comparing polystyrene to other polymers commonly used in medical packaging and devices. This paper will show physical property data over a two year time span using multiple general purpose polystyrene (GPPS) and high impact polystyrene (HIPS) grades, comparing them to seven other polymers, including high density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET), copolyester (PETG), acrylonitrile butadiene styrene (ABS), impact acrylic (PMMA), and styrene butadiene copolymer (SBC). The sterilization methods used include two intensities each of Gamma, E-Beam, and Ethylene Oxide (EO or EtO).

Color Transfer from Point a to Point B: A Review and Examination of, Crocking, Rub-Off, Bleeding, Blooming, Blushing, Transfer, Migration, Extraction, Sublimation, Exudation, Plate Out, Diffusion and

James E. Rediske, May 2015

Virtually any industry that makes use of colored thermoplastic compounds whether made from master batch or compound has the potential to be negatively impacted by the movement of color from the manufactured item to the surrounding environment, eg; hands, clothing, or other objects. Industries where this may be of critical importance include but are not limited to fiber (clothing, upholstery and carpet), food packaging, toys, automotive, and household appliances. No one appreciates the color of their new clothing transferring to their couch, or the color of a child?s new favorite toy transferring to their face because they fell asleep laying on it. This paper attempts to review the above phenomenon, many of which have similar definitions, but may indeed have different mechanisms. In some of the above instances mechanisms for their occurrence are proposed and methods hypothesized as to how to predict and therefore how to mitigate their presence.

The Effect of Matrix Viscosity and Compounding Parameters on the Morphology and Electrical Conductivity of PP-CNTs/PS Blends

Kejing Yu, Amir Ameli, Yasamin Kazemi, Sai Wang, Chul. B. Park, May 2015

Co-continuous polypropylene (PP)/polystyrene (PS)=53/47 vol% blends containing 0.7 vol% multi-walled carbon nanotubes (CNTs) were obtained by melt-mixing in a conical twin-screw micro-compounder. To study the influence of melt viscosity ratio, PS with different viscosities were selected. With decreasing viscosity ratio, the better uniform co-continuous structure and higher electrical conductivity could be obtained. The compounding parameters, including the mixing time and the sequence of incorporation have been investigated. The results indicated that high melt viscosity ratio could not hinder the migration of CNTs from PP into PS phase. Higher rotation speed, mixing simultaneously and shorter mixing time lead to the better uniform co-continuous morphology and higher electrical conductivity

Foaming Behavior and Control of Polypropylene/Nitrogen System in Microcellular Foam Injection Molding

Guilong Wang, Lun Howe Mark, Vahid Shaayegan, Chul. B. Park, May 2015

Foaming behavior of polypropylene/nitrogen system in microcellular foam injection molding was investigated by using a 50-ton injection molding machine equipped with Mucell? gas injection unit. The evolution process of cell morphology was obtained by regulating the filling ratio. Both the filling ratio and the injection velocity have significant effects on cell morphology. To maximize the cell density, lower injection velocity should be used and the filling ratio should be controlled in the reasonable level of about 80%. With an extremely large filling ratio, cells formed in filling stage can be dissolved back into polymer melt and the special cell morphology with longitudinal cells can be obtained.

Solid-State Thermoplastic Nanofoams via a Novel Low-Temperature Saturation Pathway

Huimin Guo, Vipin Kumar, May 2015

A low-temperature saturation pathway to create thermoplastic nanofoams is presented. We conducted saturation by CO2 to a temperature as low as -30 øC and successfully fabricated PC nanofoams (cell size 20-30 nm, void fraction up to 60%), PMMA nanofoams (cell size 30-40 nm, void fraction up to 86%), and PSU nanofoams (cell size 20-30 nm, void fraction up to 48%). Cell nucleation densities exceeding 1015 cells/cm3 were achieved.
Lowering the saturation temperature results in a significant increase in solubility, which is essential for creating nanofoams. Cell nucleation density increases with CO2 concentration and average cell size decreases with CO2 concentration. All three polymers exhibit very similar behaviors. At sufficiently high CO2 concentrations, cell nucleation densities reach the range of 1012 - 1015 cells/cm3, and corresponding cell sizes fall below 1 æm into the nanometer range. The CO2 concentration for generating nanofoams is above 18.9%, 32.6%, and 12.3% for PC, PMMA, and PSU, respectively. Representative processing conditions for creating nanofoams with cells below 100 nm are presented. The method of lowering saturation temperature can be applied to create nanofoams in other polymers, polymer blends, copolymers, and polymer nanocomposites.

Effects of Processing Parameters on Experimental Fiber Orientation of Glass Fiber-Reinforced Injection Molded Composites

Rebecca Minnick, Donald G. Baird, May 2015

Effects of injection speed on the experimental orientation of long, semi-flexible glass fiber-reinforced polypropylene composites using an end-gated plaque geometry exhibiting a complex 3-dimentional flow field were quantified. Three injection speeds were considered with constant mold and screw temperatures. Samples were subsequently used to obtain experimental orientation and fiber length distribution data. Orientation data was obtained using a slightly modified version of the Method of Ellipses, which is used for rigid fibers. Injection speeds of 1, 2, and 4 seconds were used with a mold temperature of 79oC. Orientation data along the center plane and also images along the composite width were obtained and compared. Preliminary data suggests that the orientation at these injection speeds does not change considerably along the center plane from one mold fill time to another. More data is needed to conclude whether orientation is changing significantly along the width of the part.

A New Evaluation Method of O-Ring Rubber Seals by Compressive Load Test

Yuya Yokohama, Toru Hotta, Kazushi Yamada, Hiroyuki Nishimura, Hideo Kurokawa, Yuji Higuchi, Kazuhisa Igawa, Chihomi Takami, May 2015

O-ring Rubber seals are widely used for hot water pipes and various parts of residential gas appliances for water heating. Although there is much know-how on design, there are few researches on the durability of O-ring rubber products. Hence, it is very important to understand the mechanical properties and durability of O-ring for long-term usage in safety. In this study, we had immersed several kinds of commercial O-rings with the same size and different components into hot water with and without aqueous chlorine solution for up to 18,000 h. And we tried to apply a compressive load test for the O-ring rubber in order to evaluate the mechanical properties after the accelerated degradation test. From the result, it was found that the compressive load for the displacement of O-ring immersed into chlorine-containing hot water indicated severely degradation as compared with that of O-ring immersed into hot water. In addition, it was also found that the measurement result of compressive load sensitively indicated the same tendency with the result of compression set test.

Effect of Screw Geometry on Long Glass Fiber Breakage during Injection Molding

Ruggero Giusti, Giovanni Lucchetta, Irenko Dubrovich, May 2015

The aim of this work is to compare the effects of two different 40 mm screws on fiber breakage during plastication. A polypropylene, reinforced with 30% long glass fibers, was tested. A standard three zone screw and a special profile screw were compared. The special screw has low compression ratio, a dynamic mixer and it is tapered over the whole length. The pitch is variable, increasing from the feeding zone to the screw front; the combination of these features gives higher productivity with better melt homogeneity and a very consistent dosing time end cushion. The plastication was performed at two different process conditions and the screw pull-out technique was used. The fibers length was measured at different distances from the hopper after the matrix pyrolysis. The experiments show that the different geometry of the screws, within the selected conditions, did not affect the fiber breakage. Residence time and aspect ratio of pellet length to channel width and length were also considered. A procedure was developed and validated in order to allow an accurate comparative analysis of the fiber breakage progression during plastication.

Grain Development & Grain Repair on a 7,Xxx-Series Aluminum

David A. Okonski, Gavin G. Benedict, Lisa A. Benedict, David M. Duff, May 2015

Engineers at GM have been developing an injection mold tooling strategy based on the use of aluminum to meet low, medium, and high volume production part requirements. This scalable tooling strategy marries the appropriate aluminum with the appropriate tool construction to satisfy production demands while minimizing tooling capital investment and piece price. Implementation has required engineers to overcome both cultural prejudices against the use of aluminum and technical roadblocks like the ability to grain a part?s surface. This paper reviews the work accomplished by GM and Alcoa in regards to grain development and repair on a 7,XXX-series aluminum, QC-10.

Direct Fiber Feeding Injection Molding of Glass Fiber Reinforced Polyoxymethylene/Poly (Lactic Acid) Blend Composites

Suchalinee Mathurosemontri, Putinun Uawongsuwan, Satoshi Nagai, Hiroyuki Inoya, Hiroaki Ichikawa, Hiroyuki Hamada, May 2015

In this study, the short glass fiber reinforced POM, PLA and POM/PLA blend composites were fabricated by a direct fiber feeding injection molding. The glass fiber contents were controlled by the matrix feeding speed. The mechanical properties were investigated by tensile testing method. It was found that the tensile modulus of all composition increased with increasing glass fiber content by the results of POM/PLA blend composites indicated the intermediate value between PLA and POM composites. Tensile strength of POM/PLA blend increased nearly the same with POM composite at low glass fiber content. The critical fiber length that was calculated by modified Kelly and Tyson`s equation was used to calculate interfacial shear strength. The critical fiber length of them did not change significantly. However, PLA composite has a high interfacial shear strength even all of them revealed a fair interfacial adhesion between glass fiber and matrix that were observed by scanning electron microscope.