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

Flame Retardant Polypropylene Copolymer and EVA Blends Filled with Micro- and Nanoparticles of Magnesium Hydroxide

Oliverio Rodríguez-Fernández, Carlos Espinoza-González, Graciela Morales, Isaura Yañez-Flores, Mika Paajanen, Satu Pasanen, JoséBocanegra, Ricardo Benavides, Carlos Tena, May 2014

Magnesium hydroxide (MDH) is an inexpensive inorganic flame retardant agent that has been increasingly used to replace conventional halogen-containing flame retardants in polymers. In this work, the effects of combination of micro-sized MDH particles (mMDH) with different morphologies and nano-sized MDH particles (nMDH) on flame retardant and mechanical properties of random polypropylene copolymer /EVA blends were studied. The results demonstrated that the morphology of mMDH particles also plays an important role on flame retardant properties mechanisms of the polymer. Issues concerning with the initial endothermic decomposition stage of the mMDH particles are crucial in the final flame retardant property of the composites.

Impact Modified PBT-PC Blends with Improved Ageing Characteristics

Kaushal Gandhi, Tianhua Ding, May 2014

Molded in color weatherable Xenoy™ PBT-PC blends have been widely used in automotive, transportation, and leisure vehicles exteriors applications because these products offer a good balance of mechanical properties as well as weatherability. SABIC recently commercialized a Xenoy™ grade with improved property retention after heat and hydro ageing. While the initial impact strength of the new grade was similar to other existing weatherable Xenoy™ grades the property retention after heat and hydro ageing showed a significant improvement. Color retention under the SAE J1960 protocol of weathering was comparable to other existing grades in chromatic colors. Some of these blend properties shall be discussed in the paper.

Spectrophotometric Assessment: The Challenges of 0/45-45/0 in a D8 World

Rex W. Petterson, May 2014

Determining the acceptability of automotive interior has typically been accomplished through visual consensus and spectrophotometric analysis. As many have experienced in this all too subjective pursuit, not only can three or more separate sets of eyes discern three or more totally diverse variations in color acceptability, our benchmark instruments of choice can offer distinctly different opinions also. Diversity in devices, innumerable surface-variation characteristics of the sample and inherent human imperfection in the repeatability of the manual “reading” process are all contributing factors to spurious spectrophotometric results. We will discuss what instrumental options we have available in order to have our electronic results correlate with what we see.

Crystallization Characterization of Injection Molded Parts Using Ultrasonic Technology

Peng Zhao, Jianzhong Fu, Lih-Sheng Turng, May 2014

A method based on ultrasonic technology to study the crystallization characteristics of injection molded parts has been proposed. A new method for calculating the ultrasonic velocity and attenuation is presented. The ultrasonic velocity and attenuation signals, together with differential scanning calorimetry (DSC) measurements, were used to characterize injection molded polylactic acid (PLA) speci-mens annealed at 80 °C for different periods of time. Experimental results show that the ultrasonic velocity and the ultrasonic attenuation increased with the degree of crystallinity in the annealed specimens. This suggests that the non-destructive ultrasonic technology could be an effective tool in characterizing or monitoring the crystallization of injection molded parts during or after injection molding.

Glass Fiber Reinforced POM with Superior Mechanical Properties– Hostaform® XGC Series

Kirsten Markgraf, Lowell Larson, May 2014

Celanese has developed a new series of glass fiber reinforced polyoxymethylene (POM) co-polymers, - Hostaform® XGC (“Xtreme Glass Coupled”). Glass Fibers are commonly used to enhance stiffness and strength in thermoplastics. The adhesion between the fiber and the polymer matrix plays a predominant role governing the characteristics of the resulting reinforced plastics. Application of a specific coupling technology, together with the modification of the polymer backbone , leads to a unique mechanical property profile. The advantages of these products are a combination of improved strength and impact performance.

Antimicrobial Effects of Polymer Blended Triazole Derivatives

Vicki Flaris, Ipsita A. Banerjee, Jared Hannah, Craig G. Casazza, Henry Siccardi, Joseph Hartnett, May 2014

In this work, we have synthesized an amino acid conjugate of the triazole derivative 2-Amino-5-propyl [1,2,4] triazol [1,5-a] pyrimidin-7-(4H)-one (Triaz). The amino acid utilized is arginine due to its basic properties, thus rendering the final synthesized conjugate a positive charge. It is well known that cationic peptide conjugates show enhanced antimicrobial activity. Thus, we have examined the antimicrobial activity of the conjugate in the presence of the fungus Rhizopus. Further, fungal growth was monitored in a range of hydrophobic and hydrophilic environments by blending the conjugate with polymers such as polyethyleneglycol diacrylate (PEGDA), t-butyl acrylate (TBA) and diethylene glycol (DEG). Our results indicate that addition of PEGDA reduced antimicrobial growth, while DEG showed enhanced growth when Triaz was not conjugated with the amino acid. Thus the conjugate-polymer composites may have potent antimicrobial activity.

Acoustic Behavior of Open-Cell Foams Backed with an Air-Gap

Davoud Jahani, Raymond K. Chu, Aboutaleb Ameli, Mehdi Saniei, Chul B. Park, Hani Naguib, May 2014

Open-cell thermoplastic based materials have elicited much interest in the field of sound absorption due to its recyclability and high capabilities in airborne dissipation. In this work, open-cell material with high density polyethylene (HDPE) is fabricated and used in the construction of multi-layer sound absorption systems for lower frequencies. The preliminary study results show that a combination of air gap with high open-cell material can significantly improve the low frequency absorption of open-cell materials. In the application of this concept, the requirement for thick materials to obtain the required sound absorption coefficient may be eliminated. This paper discusses two multi-layer sound absorption systems constructed with open-cell HDPE material and an air gap.

Bioepoxy / Glass Fiber Composites

Johannes Möller, Christopher Kuncho, Daniel F. Schmidt, Emmanuelle Reynaud, May 2014

The present study focuses on the development of bioderived epoxies and their composites. Epoxidized linseed oil has been cured using both amine and anhydride hardeners, with curing time and temperature adjusted to maximize Shore D Hardness in the neat resin. Both resins were then used to manufacture glass fiber composite coupons that were tested in flexure. The properties of the anhydride cured bioepoxy composite were significantly better than the amine cured equivalent, and approached those of a composite based on a high performance petroleum derived anhydride cured epoxy.

Burn Mark Prediction in Injection Molding

Gabriel A. Mendible, Alyssa L. Santiago, Carol Barry, Stephen Johnston, May 2014

Defects in injection molded parts are undesirable with increasing part quality. The root cause for burn marks (dieseling) is the rapid compression of trapped air in the mold. An approach for estimating the air temperature in the cavity is presented that allows the prediction of burn marks. The approach uses screw position signals coming from the machine to estimate the temperature increase due to compression, the heat transfer to the mold and the heat transfer to the melt front. Effects of the injection rate, melt temperature and mold temperature were experimentally compared to analysis results. The estimation technique provided the correct trends for most effects. The analysis offers a potential opportunity to incorporate on-line determination of burn marks for quality control.

A Study on the Acoustic Behavior of Micro Perforated Panels: Experiment and Modeling

Davoud Jahani, Aboutaleb Ameli, Lun Howe Mark, Nemat Hossieny, Chul B. Park, Hani Naguib, May 2014

Solid and foam 1mm-thick polypropylene injection molded parts were produced using the advanced structural foam injection molding machine. Relatively uniform cell morphology was obtained when the polymer melt was injected with relatively high pressure and high flow rate. Foam samples with 75%, 4E8 cell/cc, and 10?m of void fraction, cell density, and cell size respectively were produced. The samples were perforated with 500?m, 400?m, 300?m, and 200?m in size considering a 1% perforation ratio for all the samples. Solid and foam micro perforated panels (MPPs) for sound insulation were developed. The foam MPPs showed 6% to 35% higher absorption coefficient than solid MPPs when a 6mm air-gap was considered.

Defining Mechanical Performance Requirements for Flexible Packaging Utilized in Military Rations

Danielle Froio, Shari Dangel, Corey Hauver, Jo Ann Ratto, Steven Jackson, May 2014

The objective of this study is to determine which material properties are critical for package survival during rough handling studies, which simulate the stresses and rigors that military rations are subjected to throughout the logistics cycle. Three polyolefin films with varying degrees of mechanical performance were converted into pouches, filled with either food or a simulated food item and packed into the military’s existing individual ration, the Meal, Ready to Eat™ (MRE™). Twenty four cases, each containing twelve MRE™ meals, were subjected to a rough handling sequence that included vibration and drop testing at ambient conditions. Upon completion of rough handling the rations were opened and pouches were inspected for mode of failure and failure rates. Failure rates of the three polymeric pouches and current foil based pouches were recorded and compared to selected film and package properties, such as Young’s modulus, tensile strength, tear strength, puncture resistance, impact resistance, seal strength, and burst resistance. It was found that puncture and impact resistance showed the highest degree of correlation with failure rates.

Gas-Assist Injection Molding of PLA for Foaming Applications

Lun Howe Mark, Raymond K. Chu, Aboutaleb Ameli, Davoud Jahani, Peter Jung, Chul B. Park, May 2014

The integration of gas-assist with foaming technologies was recently unveiled as a new technological development for microcellular foam injection molding. This work investigates the effect gas-assist processing on the final cellular structure of foam injection molded products. Typical gas-assist parameters including the holding pressure, holding time, ramping and start delay were examined. It was found that the application of gas-assist can improve or deteriorate the cellular structure depending on the processing parameters.

Modeling Polymer Failure under Creep Loading through Simulation of Crack Growth

Hanxiao Ge, Haiyan Li, Susan C. Mantell, May 2014

Plastics used for structural applications are often subjected to creep loading and component lifetime will be limited by crack propagation. A finite element model of crack growth in plastics subjected to creep loading is developed. The model is comprised of a viscoplastic model of the bulk material and a cohesive zone model for tracking crack growth. Model parameters are found by curve fit to experimental data for polyethylene sheet samples. Model predictions for creep behavior and time to failure under creep loading conditions are compared to published data for HDPE. The model predicts the trends observed in the published data.

Processing of Biomass Fillers and Reinforcements at Entitled Capacity on Co-Rotating Twin Screw Extruders

Jatin Panchal, Dr. Babu Padmanabhan, Robert Roden, May 2014

Polymers are increasingly being combined with renewable biomass fillers and reinforcements to improve product performance, reduce cost, reduce product density, improve aesthetics and/or reduce the carbon footprint typically associated with plastics. The use of renewable materials for fillers and reinforcements in plastics has existed for several decades, however, their acceptance is rapidly expanding due to increasing plastics costs and environmental concerns. Unfortunately, a common property most of these materials share - sensitivity to heat and shear, limits their availability to be mass produced in an efficient manner in order to be cost competitive with commodity plastics and thermoplastic composites. However, a better understanding of the physical mechanisms that contribute to the onset of thermal degradation and of the technologies available to prevent such can enable significant capacity enhancements when processing biocomposites using co-rotating twin screw extruders. Another characteristic of many of these materials is that they possess a low bulk density, making them difficult to transport into the extruder at a high throughput. Technologies have recently emerged that can effectively improve the conveying efficiency of “difficult-to-feed” fillers and reinforcements.

Residual Stress Analysis of Compression-Molded Poly(Ether Ether Ketone) Cylindrical Parts

Lin Jin, Jeet Sengupta, Tim Bremner, Hung-Jue Sue, May 2014

Cylindrical parts were compression-molded using polyetheretherketone (PEEK) fine powder. Post-molding thermal stress relief was executed through systematic variations in time and temperature cycles. Following stress relief, washers were cut from the cylindrical stock shapes and used in the analysis of residual stress. Quantitative determination of the residual stresses along the circumferential direction was carried out based on displacement data obtained by a ring slitting and layer removal method. Thermal and morphological properties of the material were characterized, and their relationship with the residual stress distribution in the material is discussed.

Chemical Resistance of Pigments in a Plastic Substrate

Inga Lesko, Roger A. Reinicker, May 2014

Plastics are used in numerous applications where they come into contact with acids, bases and chlorine containing chemicals, for example common bleach. These include packaging of all sorts, home and garden uses, and building and construction applications, for example. Chromatic pigments used to color these polyolefins may or may not be durable over time depending upon how the chemical penetrates the substrate and how resistant the pigments are to the chemical agent. One application of particular interest is also what colorants can be used in conjunction with recreational pools and pool chemicals. This paper will present data on the color change of pigments exposed in such situations. Emphasis will be on polyolefins, but data from synthetic fiber testing can also be illuminating. An attempt will be made to understand the results on the basis of pigment chemistry, concentration, and particle size.

Understanding Processability of PA11 via Rheology

Chuanchom Aumnate, John Puentes, Tim A. Osswald, Steve Schick, Jake Mulligan, C. Herrild, K. Smith, May 2014

Polymers are continuously being introduced in applications where metals have been traditionally utilized. For example, PA11 is now being used in the oil and gas industry in underwater flexible pipelines. There are some challenges that are presented when using these nontraditional materials of construction, and likewise, there are interesting challenges that arise during processing. Due to molecular weight growth from shearing and thermal history, the rheological behavior of this resin is a function of time. The molecular weight increase leads to viscosity increase, which reduces sag after extrusion, but hinders flow inside the die. These competing mechanisms must be controlled during processing. This experimental study will help in the understanding of the rheological changes during processing by showing the influence of time, temperature, thermal history and moisture content on the rheology of PA11. Modeling the change in viscosity, which affects production parameters and throughput in extrusion processes, is part of the future work of this study. Beside the temperature-shifting factor, the thermal history and moisture content were identified as playing a critical role in processing tuning. Conventional shear thinning models fail to predict the behavior of this type of material. It is necessary to investigate modeling strategies to assess the appropriate processing conditions of PA11.

High Temperature Flexible PPS Products for Harsh Environments

Rong Luo, Kent Miller, Xiaoyan Tu, Xinyu Zhao, May 2014

There has been an increasing interest for high temperature flexible materials for growing market applications, such as deep ocean extraction in oil and gas industry, and under the hood fuel handling in automotive industry. This trend has prompted the search for a material that can operate above 130 °C and often in harsh chemical environment. A series of flexible polyphenylene sulfide (PPS) products were developed to enable high temperature tubing/piping applications in oil & gas and automotive industry. These new flexible PPS materials demonstrated superior heat resistance up to 165 °C and low temperature impact resistance down to -40°C. The flexible PPS materials also showed excellent chemical resistance to fuels, oils and variety of automotive fluids. More importantly, these material can be processed into parts, tubes, pipes, tanks, wires, films and sheets using injection molding, extrusion, blow molding and wire coating.

Thickness Measurement Methods Aiding Lightweighting of PET Bottles

Masoud Allahkarami, Reaj U. Ahmed, Sudheer Bandla, Jay C. Hanan, May 2014

The aim of lightweighting PET bottles is to reduce waste in material use by optimizing the design and manufacture process. Efficient lightweighting development requires adapting robust techniques for thickness measurements. Knowledge of the final thickness distribution at different locations of the bottle is essential for identifying critical locations that could be modified in the preform or mold. X-ray tomography, IR-based thickness measurements, and Hall Effect techniques have been demonstrated as nondestructive tools for thickness measurement. Some methods are slow or expensive. Here, a low cost method for thickness measurement of PET bottles based on cross section measurement also was demonstrated using an optical scanner.

Lightweight Polypropylene-Carbon Nanotube Foams with Low Filler Content, High Permittivity and Low Dielectric Loss for Charge Storage Applications

Aboutaleb Ameli, Davoud Jahani, Mohammadreza Nofar, Chul B. Park, Petra Pötschke, Ghaus Rizvi, May 2014

Microcellular polypropylene-multiwalled carbon nanotube (MWCNT) composites with low filler content exhibiting high dielectric permittivity, and low dielectric loss are reported. Nanocomposites were prepared by melt compounding and foamed using supercritical carbon dioxide in a batch process. The introduction of cellular structure decreased the dielectric loss of the nanocomposites up to five orders of magnitude, while the decrease in dielectric permittivity was only 2-4 times. Thus, microcellular composites containing only ~ 0.34 vol.% MWCNT presented a frequency-independent high dielectric permittivity (~ 30) and very low dielectric loss (~ 0.06). The improvement in dielectric loss was explained in terms of the formation of effective nano-capacitors caused by foaming action (biaxial stretching and uniaxial compression) and volume exclusion. The results of this work reveal that high dielectric nanocomposites can be developed using foaming technologies for charge storage applications.