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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The studies used to determine what chemicals (and how much of them) can move in some way from a source material (usually polymeric in nature) to another sink (food, pharmaceutical, the body, the air) falls into the general category of what is termed ƒ??extractablesƒ? and ƒ??leachablesƒ? studies. The reasons the studies are done are to meet regulatory guidelines and to aid risk professionals (toxicologists) in assessing a given products safety. In practice, it is the analytical methods used to detect, identify, and quantify the chemicals that migrate out of the base material that poses the most significant obstacle in helping risk assessors make a determination as to the risk posed by a given product.
Rajendra K. Krishnaswamy , Jason Baird , John P. Christiano, May 2010
The complex time and temperature dependent melt rheology of Poly (Hydroxy Butanoic Acid) or PHB copolymers is an important consideration for their extrusion. In this effort, we report the influence of temperature profile and screw design on the process stability, melt temperature, melt pressure, output rate and molecular weight retention using highly-instrumented commercial-scale extruders with smooth-bore feed sections. One important outcome of this investigation is screw design guidelines for the extrusion of PHB copolymers.
The understanding of the coating process by fluoropolymer processing aids has been of great importance to the removal of sharkskin phenomena. The current work examines the effect of fluoropolymer domain size, shear rate and viscosity ratio. Previous work demonstrated the superior performance of large-particle processing aids and the deposition in the region of the die exit, using in-sit measurements. The current work expands those findings by presenting 1) the effect of the viscosity ratio on the deposition rate on the wall, 2) the reduction of sharkskin, and 3) the reduction of the pressure drop.
Jun Tian, Sung Dug Kim, Shreyas Chakravarti, May 2010
There is an increasing trend towards the use of Thermoplastic Polyolefins (TPO) in the marketplace particularly in the automotive sector due to the desirable mechanical properties. In order to achieve adhesion of coatings to TPO, automotive manufacturers have traditionally used solvent based chemical adhesion promoters or other forms of surface pretreatment to overcome the lack of bonding sites on this low surface energy substrate. Each of these pretreatment methods has their own drawbacks and all add an extra step to the coating process. A water based direct to plastics (DTP) coating for TPO is therefore very desirable due to the lack of flammable, environmentally detrimental solvent as well as the elimination of the pretreatment step. The barriers to achieving adhesion to TPO with a water based coating include the inability to wet out water over such a low surface tension substrate and the lack of bonding sites on the substrate. Once the barriers to adhesion are overcome, the coating must still meet the performance requirements of the finished coating.
This paper explores a water based DTP coating and the role that adhesion promoters, surface tension modifiers, and resin systems play in the adhesion and overall performance of the coating on TPO. The study indicates that the selection and concentration of each of these is very important in overcoming the barriers to applying a water based DTP coating to TPO and achieving the overall performance required. In addition, the curing schedule for the coating systems examined plays a critical role in achieving the desired results.
Jun Tian , Sung Dug Kim , Shreyas Chakravarti, May 2010
Polymer blends provide an efficient way of making new materials with improved properties. The miscibility of poly(resorcinol phthalate-block-carbonate)(RPC) and poly(ethylene terephthalate )(PET) blends is examined by differential scanning calorimetry and dynamical mechanical analysis. When the resorcinol phthalate level in RPC copolymers is as low as 20mol%, the blends show limited miscibility. As the resorcinol phthalate level increases from 40 to 80mol%, the blends go from being partially miscible to completely miscible. Understanding this phase behavior change in the context of the classical Flory-Huggin's theory is attempted.
Yong Min, Bin Zhu, Cailiang Zhang, L. James Lee, May 2010
Polyaniline-clay (PANI-MMT) nanocomposites were synthesized through in-situ polymerization of polyaniline with various dopants. Those nanocomposites were used to blend with polystyrene (PS) to form an expandable composite resin, which will significantly impact the foaming process using a CO2 blowing agent. The material composition and foam morphologies were characterized through various analytical techniques, such as, X-Ray diffraction (XRD), SEM, dielectric measurement, UV/vis, and FTIR. Based on our experimental results, we are proposing that the de-doped base form" of Pani-MMT nanocomposites and both "inorganic and organic salt-form" Pani-MMT nanocomposites will act as a "molecular CO2 reservoir" to control the CO2 releasing during the foaming. The selection and optimization on those compounds will be enormously important for developing a new inexpensive and environmental friendly blowing agent for the foam industry to achieve the final goal of replacing the existing CFCs /HCFCs /HFCs blowing agents!"
W.L. Zhu, J. Wang, C.B. Park, R. Pop-Iliev, J. Randall, May 2010
The interface fracture process of most layered or bonded structures is commonly under the control of mixed mode cracking where the interface shear and normal fracture components exist simultaneously when the hybrid joints are bonded with different adherend materials. In this work, a simple and novel method is proposed to realize and characterize the pure mode I interface fracture for the hybrid joints with dissimilar substrates. The theoretical and experimental results indicate that the present method may be considered as a standard test method for the characterization of hybrid joints with dissimilar materials.
W.L. Zhu , J. Wang , C.B. Park , R. Pop-Iliev , J. Randall, May 2010
In this work, polylactide (PLA) foams were prepared via a batch foaming system by using CO2 as a blowing agent. The foamability of four PLA grades were compared and the effect of chain branching on cell morphology was investigated. The thermal properties of PLA were analyzed by thermogravimetry and differential scanning calorimetry (DSC). The extensional viscosity of PLA was measured by using a rheometer with an extensional viscosity fixture (EVF). The relationship between the chain architecture, cold crystallization phenomenon, extensional viscosity and foamability of various linear and branched PLAs are explained in the conclusion.
Traditionally automotive Thermoplastic Polyolefins (TPOs) have been made by compounding processes. The mixing of components at the molding press (At-Press) greatly reduces compounding cost while providing flexibility to dial in dimensional and mechanical performance. This technology also offers cost savings via inventory consolidation and simplified logistics. This paper presents results from Dow's INSPIRETM At- Press approach, which is designed to meet high end OEM specifications. The formulations are designed for mixing at the molding machine and delivering excellent talc and elastomer dispersion under the breadth of typical fabrication conditions. Part results validate good dispersion and distribution and equivalent properties to compounded TPOs. Consistency of At-Press process was demonstrated to be at the same level as compounded TPO. In this paper, At-Press blending is shown to be a very viable technology.
Paul Andersen, Chi-Kai Shih, Mark A. Spalding, Mark D. Wetzel, Timothy W. Womer, May 2010
Constant-temperature embossing experiments were performed on supercooled amorphous PET films. The process was designed to achieve isothermal embossing so that cooling can be eliminated. Rather than using a conventional cooling process for solidification, the supercooled PET films, after rubbery softening, were hardened by crystallization at the same embossing temperature. The resulting cycle time is on the order of the characteristic crystallization time, approximately 1 min or shorter for supercooled PET in a large processing temperature window centered at 180?øC. In the testing experiments, parallel microtrenches of 20 ?¬m width and aspect ratio 2 were faithfully replicated from a silicon master onto the PET film without the cooling stage. The time and temperature dependent thermomechanical behavior of the supercooled PET film was studied to understand the underlying principle of this novel embossing process.
Paul Andersen , Chi-Kai Shih , Mark A. Spalding , Mark D. Wetzel , Timothy W. Womer, May 2010
Vast improvements in polymer extrusion processinghave been achieved through innovations in machinery,screw and barrel designs, functional operations,monitoring and controls, resins, and fundamentals.Selected examples are given to illustrate the breakthroughmachinery inventions that occurred in the past 50 years inthis field. These inventions and their technical andindustrial significance will be discussed. Selectedexamples include the conception of the single and twinscrewextruders, and the vast functional improvements thataffected market demand of extruded products withconsistent quality at ever higher production rates. Storiesbehind some of the breakthrough inventions will also bepresented.
Peter J. Martin, Hui Leng Choo, Chin Yong Cheong, Eileen Harkin-Jones, May 2010
Extrusion experiments were performed on three Cyclic Block Copolymer (CBC) resins using a highly instrumented single-screw extruder. These materials are substantially fully hydrogenated styrenic block copolymer and they represent a class of optical polymers with excellent light transmittance and unique birefringence properties. The data collected indicate that a screw designed with a compression ratio near 3.0 and a compression rate of no more than 0.0045 mm/mm should work well for the targeted application. These experiments also revealed that CBC extrusion behavior is more sensitive to block copolymer composition than molecular weight across the ranges studied.
Peter J. Martin , Hui Leng Choo , Chin Yong Cheong , Eileen Harkin-Jones, May 2010
The plug-assisted thermoforming process is the largest and most important industrial thermoforming process. The main aim of this study was to investigate the interaction between the properties of the plug and the polymer sheet in thermoforming. Non-isothermal plug only thermoforming tests were carried out using identical plug designs for various combinations of plug and sheet materials. It was hoped that this study would help to improve the understanding of friction and heat transfer effects during the thermoforming process. The plug materials used included: Hytac-B1X (thermoplastic syntactic foam), Hytac-WFT (epoxy syntactic foam with added Teflon), Blue Nylon, and POM (polyoxymethylene). The sheet materials included aPET and polystyrene (HIPS). It was found that the magnitude of slip during plug contact was much higher with aPET than with HIPS and that this reduced as the temperature of the plug was increased. Different plug materials produced significantly different wall thickness distributions in the preforms. It was concluded that friction was the dominant effect during contact.
Kurt A. Koppi, Berend Hoek, Jack Little, Weijun Zhou, May 2010
Thin-wall injection molding experiments and mold filling analysis were performed on four Cyclic Block Copolymer (CBC) resins. These materials are substantially fully hydrogenated styrenic block copolymer and they represent a class of optical polymers with excellent light transmittance and unique birefringence properties. These resins are currently under development for various optical applications including injection molded light guide panels and lenses. The thinwall injection molding behavior and impact performance of the four CBC resins was compared to a competitive polymethylmethacrylate (PMMA) resin.
R. A. Pearson , L. N. Bacigalupo , Y.L. Liang , B. T.-Marouf , R. K. Oldak, May 2010
A poly(styrene ' butadiene ' methyl methacrylate) triblock copolymer (SBM) and a poly(methyl methacrylate ' butylacrylate ' methyl methacrylate) triblock copolymer were investigated as a toughening agents for a ductile epoxy resin. A carboxyl acid terminated copolymer of butadiene-acrylonitrile (CTBN) was used as a control (conventional toughening agent).The use of CTBN resulted in micron-size rubber particles (c.a. 3 microns diameter) and the use of SBM and MAM resulted in spherical, nanometer size rubber particles (c.a 40 nanometers in diameter). Interestingly, the SBM modifiers were found to be more effective toughening agents at high rubber contents. Scanning electron microscopy attributes the increase in toughness due to extensive matrix dilation and transmission optical microscopy suggests that more energy is dissipated per unit volume for the SBM modified epoxy.
This paper presents the redesign of two polymer processing lines involving, in the first case, a 90 mm screw design with a barrier zone and an elongational mixing unit for the manufacturing ofPP double wall sheet. A new flat die geometry was also required. The new components needed to solve homogeneity problems and grammage variations.
In the second case, a 50.8 mm- screw design with a barrier zone and a removable mixer was required for the production of thin wall containers using a 150 ton injection molding machine. A ring non-return valve was designed to assure parts reproducibility and to avoid leakages.
Sunny Modi , Kurt koelling , Yael Vodovotz, May 2010
PHB (Poly (3-hydroxybutyrate) families of naturally occurring polymers are extracted from micro-organisms.PHB behaves similarly to conventional thermoplastics, yet are fully biodegradable in common composting conditions.To improve flexibility for potential food packaging applications, PHB can be synthesized with various copolymers such as 3-hydroxyvalerate (HV). The objective of this study was to characterize the thermal and rheological properties of PHB synthesized with various valerate contents and relate these findings to potential food packaging applications.
M. Umar, L. Mulvaney-Johnson, R. Speight, P. Brincat, A. Bakharev, P. D. Coates, May 2010
Urethane based thermoplastic elastomers (TPU) have an impressive range of performance characteristics such as outstanding scratch/abrasion resistance, excellent oil resistance and high tensile and tear strengths. However, application of TPUs is limited when low hardness (<70 A) is required. Soft TPU materials with low level of hard segment are difficult to process. Commercially, low hardness products are produced by adding phthalate plasticizers, which are not desirable in some applications. The objective of this project is to study TPU hardness modification using styrenic block copolymers to achieve soft TPU alloys without significantly sacrificing other physical properties.
M. Umar , L. Mulvaney-Johnson , R. Speight , P. Brincat , A. Bakharev , P. D. Coates, May 2010
A methodology is presented for determining moulded part mass from a combination of continuous process measurement and known polymer material pressure-specific volume-temperature (pvT) characteristics. The methodology determines the mass of melt that has been delivered to the mould cavity through the swept volume of the injection screw, but taking into account melt compressibility. The screw position is continually monitored by a computerized system along with the melt pressure and temperature. Results show a good correlation between the predicted and measured specimen mass over a range of processing conditions.
The plastics industry has been under heavy criticism from environmentalists for contributing to pollution and litter, exposing consumers to toxic matter, and using more than its fair share of energy resources. Are any of these accusations valid? If so, has our industry been responsive to these challenges in a meaningful way? Do the solutions offered by the environmentalists, to the problems they raise, have merit? This paper will attempt to address major environmental issues at they concern the plastics industry from an economic and scientific viewpoint and summarize what makes sense and what does not.
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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
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.