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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
John Moalli, Steven Kurtz, Robert Sire, Sanjeev Srivastav, Ming Wu, May 2000
In recent years, the advance of high speed processors in personal computers has placed the capability of sophisticated analytical methods on nearly every desktop. In the plastics industry, codes are readily available to model, among other things, stresses, thermal characteristics and flow. Without proper input, however, such analyses are subjected to the Garbage In, Garbage Out (GIGO) syndrome and can produce misleading results. This paper discusses an approach to analytical modeling that includes experimentation for model input and constitutive model development, as well as the use of experimentation for verification of numerical modeling results.
Silvia E. Barbosa, José M. Kenny, Numa J. Capiati, May 2000
The incorporation of glass fibers in a thermoplastic matrix improves its tensile properties but decreases the impact strength. The addition of a third component such as an elastomer generates a new material with improved impact resistance but poor mechanical properties. In this work, a rubber phase was added to a glass short fiber reinforced polypropylenes to obtain a material with balanced tensile and impact properties. Two different types of rubber was used and analyzed. Some composites with different concentration rubber/FV/PP was prepared and molded by injection. Its mechanical an impact behavior was studied and the processing window was analyzed.
Ana C. Eulálio, Numa J. Capiati, Silvia E. Barbosa, May 2000
The recovery and recycling with profit of municipal plastic waste (MPW) is still an unsolved problem. Only in the developed countries a small portion of their MPW is used with profit. The major part of the plastic residue is disposed of landfilling. This work analyses the existing methodologies for recycling and assesses their potential application to MPW. Also, a comparative study of incineration, in terms of energy saving and contamination risks, is performed. The energy required for recycling and the energy obtained for controlled incineration is calculated, and the maximum energy opportunity is obtained. On the other hand, the energy needed to recycle either commingled or separated plastic residues was compared, taking into account the final properties obtained and the compatibilization step.
Claudia A. Fonseca, Kenneth E. Strawhecker, Evangelos Manias, Ian R. Harrison, May 2000
Poly(vinyl alcohol) / Sodium Montmorillonite hybrids of various compositions formed from water solution have been characterized utilizing X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC). Compositions with polymer concentration lower than 60 wt% formed intercalated hybrids predominantly, whereas higher concentrations of poly(vinyl alcohol) resulted in exfoliation of the clay layers in the polymer matrix. Furthermore, montmorillonite acted as a nucleating agent resulting in polymer crystallizing at higher temperatures for the hybrids compared to bulk polymer. It has also been observed that the presence of clay seems to induce a change in the polymer structure that is normally obtained through the annealing of poly(vinyl alcohol).
The technique of inverse gas chromatography has been used to investigate the thermodynamics of blend of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) at three different concentrations and four elevated temperatures. The measured polymer-polymer Flory-Huggins interaction parameters, c23, suggest that the well-known probe dependence problem cannot be solved by simply satisfying the zero Dc criterion. The problem is mainly attributed to the use of different reference volumes in the calculations of c12, c13, and c1(23) for different solvents. By selecting a common reference volume, probe independent c23 values were obtained.
Maria Dulce, L.V. Silveira, Phillip Choi, May 2000
The technique of inverse gas chromatography (IGC) has been used to study the miscibility of low-density polyethylene (LDPE) with six linear low-density polyethylene (LLDPE) with different solid state density, molecular weight averages, and molecular weight distribution. In particular, the Hildebrand solubility parameters of the pure polymers were measured and used to calculate the corresponding interaction parameters ?LDPE-LLDPE at four elevated temperatures. Our results suggest that the two types of polyethylene are thermodynamically miscible in the chosen temperature range. And the miscibility behavior of LDPE/LLDPE blends seems to be insensitive to the properties of LLDPE.
A comparative analysis of the shear-induced crystallization of metallocene and Ziegler-Natta based isotactic polypropylenes (i-PP's) was carried out. Numerous injection molding runs were performed and the effect of the shear-induced crystallization on the moldings was elucidated. The simulation of the injection molding process was performed using our unified crystallization model proposed earlier. The gapwise distributions of birefringence, crystallinity, spherulite size and thickness of the shear-induced crystallization layer in moldings were measured along with the mechanical properties of the moldings. The effects of processing conditions on these properties were determined. The measured values of crystallinity, spherulite size and thickness of the shear-induced crystallization layer were compared with the results obtained from the simulation of the injection molding process.
Non-conductive plastics are transparent for electromagnetic radiation. This can prevent the use of plastics in housings for electronic devices. A solution to this problem is to apply a conductive coating, or to make the plastic itself conductive by adding conductive fillers. We have proven that stainless steel fibres are an excellent means to make plastic conductive for EMI (Electro Magnetic Interference) shielding purposes. Electrically insulating polymers can cause electrostatic charging/discharging (ESD) problems in some applications. Integration of stainless steel fibres in the polymer can overcome these problems by preventing charge build-up and/or by providing a safe path for discharge currents. Stainless steel fibres can be mixed in thermoplastics (injection moulding), epoxy and poly-urethane (conductive floors), paint, elastomer, rubber, ...
Prasanna Godbole, Joe White, Greg Hamblin, May 2000
Computer Aided Engineering (CAE) tools are able to provide powerful solutions to complex product design issues. A certain level of confidence in these solutions is assumed. However, the solutions provided are a function of several parameters: • Solver algorithm • Boundary conditions • Material properties • Fabrication process • Mesh size and type. How confident can we be in solutions from software that is performing an approximation of a real world condition based on all these variables? This paper will examine the effects of mesh size and solver method on the analysis accuracy when compared to the physical testing. To increase our confidence in these solutions, we wanted to understand the relationship between the key parameters and physical testing results. We compared various Finite Element meshing methodologies and analysis codes (structural and moldfilling) to lab tests of a Ford Ranger Pickup truck tailgate handle. Lab tests consisted of a tensile machine pulling directly on the back face of the ranger handle, which was injection molded in Nylon 6 polymer with 15% glass and 25% mineral fillings. Since material properties change with water absorption for nylon resins, all tests were conducted on dry as molded samples. Displacements and load values were documented for each test. The solutions provided from the analysis codes (while modifying element type and mesh size) were compared to the physical test results. Additional analytical lab testing was completed on the molded samples to confirm part composition, physical properties and glass orientation. Conclusions and recommendations were based on how closely the solutions matched the physical tests.
The ability to cut time and cost from a molding program is a significant advantage for injection molders operating in an increasingly competitive marketplace. Warpage and other defects that show up in molded plastics parts, as well as inefficiencies in production are unacceptable. Innovation, productivity, and dedication to quality are crucial for suppliers of injection molded parts. CAE simulation software offers a competitive advantage to those who wish to eliminate inefficiencies in their operations - advantages such as shortened time to market, efficiency improvements in the use of raw materials, reduced cycle times, and optimized production efficiency and product quality.
Lynnette M. Dehnke, Jose M. Castro, Ming Li, L. James Lee, May 2000
Current processes used to manufacture electronic pre-pregs and laminates use solvent based systems. Solvents are environmentally unfriendly and add no value to the final product. We are developing a new solventless process, based on the concept of continuous Resin Transfer Molding or Injection Pultrusion. The first step in designing the process is to select a suitable chemical system. The viscosity of the system should be such that it allows proper impregnation at a temperature at which not much reaction takes place. To predict the required pulling force, the friction at the wall as the material solidifies needs to be truly understood. A potential resin system has been identified and its chemo-rheology and structure formation will be discussed.
This paper deals with the gas absorption behavior of polymer systems. The emphasis is on the difference between filled and unfilled polymers to explain heterogeneous nucleation in filled polymers. A Foaming process simulator has been built to study the gas absorption. It consists of a test chamber that holds the polymer samples. The chamber can be pressurized with gas up to 5,000 psi and heated up to 450°F. The gas pressure is monitored by a high-accuracy pressure transducer and recorded by a data acquisition. The amount of gas absorbed by a polymer is determined from the pressure change. A rotor applies shear to the polymer melt to investigate the shear effects. Two polymer systems were tested, HDPE with/without talc, and PVC with/without calcium carbonate. It was found that the filled polymers absorbed more gas compared to the unfilled ones. It is suggested that there is a certain amount of gas accumulated in the filler-polymer interface. This accumulated gas helps to create nucleation sites during the foaming process.
This work concerns the initial stage of bubble growth during the foaming process for filled and unfilled polymers. It was found that a certain amount of gas accumulates in the polymer/filler interface (1), and that this has a significant impact on the initial cell growth. A model was developed to describe the initial cell growth. It was found that owing to the gas accumulation at the filler-polymer interface, the gas requirement for nucleation is much lower in a filled system than in an unfilled system. This gives rise to a smaller cell size for the filled system during the initial cell growth period.
Since the introduction of Trimellitic Anhydride by Amoco Chemicals in the late 1960s trimellitates have found their place in applications requiring greater permanence than what commercial phthalate plasticizers could bring. Trimellitate plasticizers offer today's vinyl compounder a unique combination of properties not attainable with polymeric or other monomeric plasticizers1,2. Phthalate plasticizers, long the workhorse of the industry, are efficient, process easily, impart good low temperature properties, and are well-suited for general use. Unfortunately, the phthalates can be volatile and lack the permanence needed for high temperature applications. The polymerics, which have the permanence necessary for high temperature applications, are often inefficient, difficult to process, have poor low temperature properties, and are expensive. The data presented here will demonstrate how trimellitate plasticizers bridge the performance gap between the phthalate and the polymeric plasticizers, combining the easy processing and low temperature properties of the phthalates with the low volatility and permanence of the polymerics. Compounds directed at two markets will be looked at: UL 105 °C Wire and refrigerator gasketing compound.
Low density polyethylene (LDPE) thin films are produced by blown film extrusion. The control of key variables during processing is important in the development of optimized microstructure and mechanical properties. Joining several extruded film pieces by thermal welding is common in industry to produce finished products. It has been reported in the literature that the welding process impacts the cold brittleness temperature of a film and weld system. This observation is confirmed in this work. There have also been reports in the literature of changes in polymer microstructure and properties adjacent to thermal welds in non-film applications such as pipe welding. This Heat Affected Zone (HAZ) has been observed here for the first time in the thin films. The size of the HAZ is shown to scale with welding temperature. Evidence correlating the size of the observed HAZ to the degree of change in cold brittleness temperature is also presented.
The Plastics Resources for Educators Program (PREP) was developed as part of the National Science Foundation's Advanced Technology Education (ATE) project. The funded project was entitled, Advanced Technological Education in Plastics Engineering Technology". The PREP program aims to help establish the educational infrastructure necessary to insure the U.S. plastics industry remains internationally competitive. There are three major outcomes associated with PREP. The first outcome is the development of instructional materials including plastic processing simulators virtual laboratory instruments and an electronic textbook. The second outcome is the development of the summer plastics educators institute at UMass-Lowell. The third outcome is establishing a communication forum that will facilitate exchange between plastics and polymer educators nationally. An overview of PREP and the structure of the program will be discussed. Examples of materials available to plastics and polymer educators via the PREP Internet WebPages will also be demonstrated."
Teresa P. Karjala, Steve M. Hoenig, Martin J. Guest, Y. Wilson Cheung, Malcolm P. Finlayson, Brian W. Walther, Jeff R. Montanye, May 2000
Ethylene/styrene Interpolymers produced via INSITE* Technology exhibit compatibility with a wide range of polymers due to their inherent combination of olefinic and styrenic functionality. Blends of Interpolymers with polyethylene and polystyrene are discussed in terms of rheology, morphology, and observations from injection molded products. Dispersion of the minor phase is predicted by a rheological model, and these predictions are compared with the morphology of the blends.
Recent developments have shown that non-invasive, focused, microwave heating of the enlarged prostate condition termed BPH or benign prostatic hyperplasia can give patients immediate and painless relief without the need for surgery and the prolonged recovery time associated with it1. This paper will describe how a urinary catheter was developed with a uniquely designed size-limiting balloon that both protects the urethra during heat treatment while also forming a biological stent. This stent opens what was swollen shut by the BPH condition and allows relief to the patient immediately after the completion of treatment rather than after a long recovery time.
The kinetics of crosslinking polymerizations entail a complex combination of behaviors such as diffusion-controlled propagation, reaction diffusion controlled termination, volume relaxation, heterogeneous network formation, and non-constant initiator efficiency, chain depropagation and precipitation. One would like to be able to predict the mechanical properties of a material from the conditions used during the polymerization, or alternatively one would like to be able to create materials with specific properties purely through an understanding of the kinetics. A more complete understanding of the polymerization process is required before this can be achieved. We use Monte Carlo simulations to understand the characteristics such as a predisposition to hydrogen abstraction, chain length, and the ability of the system to exhibit some level of microscopic ordering, as in urethaneacrylate networks. Specifically, the effect of initiation rate on the rate of polymerization and correspondingly, the propagation and termination kinetics has been studied and aspects of the termination kinetics such as when, if ever, reaction diffusion controlled termination becomes the dominant termination mechanism have also been explored. The reaction time and yield curve generated by Monte Carlo simulations was com pared with the experimental values reported in the literature for the continuous mass polymerization of HIPS and ABS. The crosslinked polybutadiene is influential in the determination of the impact strength gloss balance.
The design of a single processing method to produce transparent nanocomposite is presented. This will enable the weight of the transparent armor systems to be reduced by at least 35 % against armor piercing threats relative to present systems. Transparent armors currently in use consist of soda-lime glass or borosilicate glass laminated to polycarbonate. Fabrication of large sized materials is a new feature of the new design. The chosen fabrication route is by using a twin screw non intermeshing co-rotating extruder. The cost analysis to determine production costs for 100 panels per annum is presented. The processing parameters and their effect on the strength, thermal conductivity, thermal expansion, as well as transmittance in the visual and Infra-red spectrums. The transmit wavelengths to the ratio of the particle size is used to evaluate the haze formation in the material.
84 countries and 60k+ 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.
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.
.jpg)
.jpg)
.jpg)
.jpg)
