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
Gloss Control in Rigid PVC-Part II: Effect of Processing Variables on Gloss of Rigid PVC Profiles
Elvira Rabinovitch, Deanna Harshbarger, May 2000
This paper describes the results of the study on the effect of extrusion conditions on gloss of rigid PVC profile. Extrusion variables investigated in this study are: extrusion melt temperature, extruder temperature settings, extrusion rate and the die/sizer metal surface condition. It is hoped that this information will help PVC profile manufacturers to optimize their process for achieving desirable gloss.
Gloss Control in Rigid PVC-Part I: Techniques for Gloss Assessment of Rigid PVC Profiles
Elvira Rabinovitch, Deanna Harshbarger, James Isner, May 2000
This paper describes various techniques for assessing gloss of PVC extrusion. It discusses the effect of the incident light angle on measured gloss values and test sensitivity for PVC extrudates. It also describes the relationship between surface gloss and extrudate roughness, analyzed by scanning electron and optical microscopy. Finally, this paper provides recommendations on the most suitable methods for assessing gloss of PVC extrudates.
Role of Thermal Degradation of Polyethylene under Natural Weathering Conditions
Syed Halim Hamid, May 2000
UV-B portion of solar radiation adversely affects the physical, chemical, and mechanical properties of exposed plastics and thus their lifetimes are reduced. Mostly polymers used in outdoor applications have UV-stabilizers incorporated in their formulations. The crucial role of temperature on the weathering of polyethylene (PE) was studied. In this paper, polyethylene film samples were exposed to the outdoor weather of Dhahran, Saudi Arabia as well as in low temperature set up maintained at 15°C at all times. The combined effect of high temperature and UV-B radiation on the polyethylene film sample was evaluated in terms of drop in tensile properties and increase in carbonyl absorbance. Higher UV-B together with high temperatures encountered in this region cause faster degradation of polymeric materials.
Design Sequential Gating for Family Mold
A. Pipino, G. Boero, G. Bertacchi, May 2000
The paper illustrates the results of the first phase of a project investigating the area of major interest for sequentially operated valve gates, followed by the developments of a procedure for their implementation in family molds applied to very dissimilar parts. The activity covered the use of computer simulation to determine location, dimension and actuation time of gates during filling and holding phases. Some results are checked by molding on a specially designed mold. The methodology can exploit the potential of this technology to reduce tooling and molding costs with the added benefit of the best color matches of molded parts.
Fractography of Metals and Plastics
Ronald J. Parrington, May 2000
Fractography is critical to failure analysis of metals and plastics. Fractography of plastics is a relatively new field with many similarities to metals. Utilizing case histories, various aspects of failure analysis and fractography are compared and contrasted. Common failure modes include ductile overload, brittle fracture, impact and fatigue. Analogies can also be drawn between stress corrosion cracking (SCC)/stress cracking, corrosion/ chemical aging, dealloying/scission, residual stress/frozen-in stress, and welds/knit lines. Stress raisers, microstructure, material defects, and thermo-mechanical history play important roles in both cases. Key fractographic features for metals and plastics are described.
PEEK / Carbon Fiber Composites: An Evaluation of Particle Size and Processing Method on Composite Properties
T.A. Bullions, J. Morin, R.H. Mehta, A.C. Loos, May 2000
This study examines the effects of particle size on the consolidation quality and mechanical performance of carbon fiber-reinforced composites fabricated from dry powder coated carbon fiber tow (towpreg). Poly(ether ether ketone) (PEEK) powder was sieved to produce three different particle size distributions; a minimal polymer powder deposition system was used to coat carbon fiber tow with these distributions and unsieved polymer. Unidirectional composite panels were manufactured from these four batches of towpreg and APC-2 (PEEK / AS4) prepreg using an identical processing schedule. Poor consolidation quality of some panels limited conclusions. However, these results did bring forward several questions concerning the effects of powder particle size distribution on the processing of composites from PEEK/G30-500 towpreg that may be addressed in future studies.
Microcellular Foam Molding: Advantages and Application Examples
Kai Jacobsen, David Pierick, May 2000
The MuCell® molding technology is a proprietary manufacturing process for producing microcellular foamed plastics. The microcellular foam process uses supercritical fluids (SCFs) of atmospheric gases to create evenly distributed and uniformly sized microscopic cells throughout a polymer. Suitable for injection molding, this breakthrough foam process enhances product design, improves processing efficiency, and reduces product costs. This foam process does not require chemical blowing agents (CBAs), hydrocarbon-based physical blowing agents, nucleating agents, or reactive components. The microcellular foam molding technology permits molders to reduce raw material consumption while producing strong, lightweight products, extending considerably the applications of foamed polymers. This paper describes those benefits, shows the effect of processing conditions on cellular structure and reviews some successful applications of the technology.
Laminated Protein Films
H.V. Pol, A.A. Ogale, P.L. Dawson, May 2000
The properties of laminated films made from soy protein isolate and corn-zein are investigated. Plasticized corn-zein protein mixture was laminated on one side of a preformed soy protein film to modify the moisture barrier properties. The 250 ?m thick laminated films were dark-yellow, translucent, and somewhat brittle. The water vapor permeability values of these laminates were lower than those of the single component soy protein films. The tensile strength of these laminates was about 5 MPa. Continuous hot-roll film extrusion was also conducted and the process is being refined.
Development of Polypropylene Plank Foam Products
Chung P. Park, Gerald A. Garcia, May 2000
Low-density plank foam products were developed from both conventional and high melt strength (HMS) polypropylene resins. Bubble stability was achieved by making the foam density low and the cell size small. The use of a multiple-orifice die with an optional use of forming yielded a plank foam product with a large cross-sectional size.
Evaluating the Cutting Behavior of Amorphous Poly(Ethylene Terephthalate) Sheet Using Steel Rule Dies
Eric Moskala, Dennis Barr, May 2000
A technique for measuring the cutting properties of thermoplastic sheet using steel rule dies is presented. This technique can be used to evaluate the roles of die hardness, point size, temperature, and bevel as well as sheet thickness and temperature on cutting efficiency. The technique is demonstrated using oriented polystyrene and amorphous polyesters such as PET and PETG. The cutting mechanisms for these materials are examined by controlling the penetration depth of the steel rule die in order to create a series of partial cuts.
Survival of the Fittest: Utilizing E-Commerce as an Integral Part of Your Marketing Plan
Margaret H. Baumann, May 2000
Business-to-Business e-commerce has even greater potential than consumer focused e-commerce. We currently are in a transition from the Industrial Age to the Information Age. E-commerce is introducing new business models in many industries. This paper will describe how and why that is as well as how you can harness the power of the Internet as part of your marketing strategy and business development tools for the next decade.
Model-Based Techniques for Improving Part Development
A. Attar, L. Pecora, R. DiRaddo, N. Bhuiyan, V. Thomson, May 2000
In this work, optimization strategies that employ model-based technologies are developed for minimising the overall weight and improving thickness distribution of an extruded blow moulded part. The part studied is a plastic dumbbell for the recreational sector. Process simulations and preliminary experimental trials are simultaneously performed to assist in the development of the part. Once the numerical modelling methodology is functional, one can perform a process optimization based on a desired objective function, such as uniform part thickness distribution and/or minimal part weight. The optimization is performed in two sequential steps (weight optimization followed by thickness optimization) by the systematic manipulation of the operating conditions, such as the parison dimensions. Furthermore, a commercial procedure modelling technology (i.e. FirstSTEP™) is employed for demonstrating the reduction in the part development time with the new model-based approach.
Anisotropic Electrical Percolation and Electrostatic Dissipation in Chaotically Mixed Carbon Black Filled Polyethylene Composites
S.G. Kasliwal, A.A. Ogale, D.A. Zumbrunnen, May 2000
The electrical resistivity and electrostatic charge dissipation characteristics of carbon black (CB) filled low-density polyethylene (LDPE) thermoplastic composites processed by three-dimensional chaotic mixing were investigated. These properties are reported as a function of carbon black concentration and are related to novel microstructures that have been shown to reduce percolation thresholds. Microscopic analysis of emerging structures is correlated to electrical properties of the composite. Electrical conductivity exhibited anisotropy indicating preferred orientation of aggregates formed in situ.
Thermal Imaging Your Process - No Guesswork
Samuel L. Belcher, May 2000
Blow molding is a thermal process involving heat and plastic resin. The blow molding machine heats the plastic pellets to a uniform temperature, through the function of heater bands and the friction of the screw, thus forming a homogenous melt that is shaped to a circular tube called the parison. The parison is then placed in a female blow mold that is cooled or heated via a turbulent fluid. Too much heat or too little heat, or too much cooling/heating at the wrong place or the lack of uniformity of heat/cool will cause many production problems. The machine plus the mold continuously strive to maintain these heats/cooling functions, but it is a precarious struggle. Unfortunately, you cannot see the thermal energy, only its effects. Thermal energy radiates in the infrared spectrum, outside the spectrum of visible light, which we rely upon in our daily lives and of course our blow molding environment.
Devolatilization of Polymers by Diffusion and Foaming
Ingo Gestring, Dieter Mewes, May 2000
Devolatilization is a key-step in polymer processing. Low-molecular-weight components are removed from a polymeric system. The transport of these components takes place by diffusion and in some cases by foaming. In this study the different transport phenomena are investigated independently from each other in a special designed apparatus. The transport in thin films and rotating pools with surface renewal is measured for different parameters. For the diffusive transport a high surface renewal rate and thick films enhance the mass transfer. For foam devolatilization the conditions for bubble nucleation and foam formation are investigated. The bubble nucleation takes place in the rotating pool in the area of high shear velocity.
Wonder Injection Molding with Momentary Mold Surface Heating Process (MsSH Process)
Myung-Ho Kang, Dong-Hak Kim, Y.H. Chun, May 2000
Momentary Mold Surface Heated Process is a invention which heats only the mold surface over 400°C in few seconds with gas flame and cool it down very quickly again. Practically it was tried to produce a shiny surface of 98% light reflecting of the injection molded article of 30% glass fiber reinforced Polycarbonate. And it was carried out successfully with a simple attached equipment and specially designed mold so called MmSH Mold which is to supply the gas fuel and air between the two parts of mold. The results and method of wonder injection molding with MmSH Process was reviewed in this paper.
Design of an Injection Mold with Removable Plates Using CAE
S. Villarroel, R.A. Morales, H. Rojas, May 2000
The objective of this work was to design a mold of normalized test specimen to evaluate mechanical polymer properties with removable plates to inject each specimen independently using computed-aided engineering (CAE). The design was validated through simulation program of the injection process C-MOLD. Four cooling systems, the position of the entrance and the percentage of shrinkage were evaluated. There were no differences between the cooling systems studied. The maximum shrinkage was less than 2% and no part warpage was observed
Design of an Injection Mold Using C-MOLD Software
H.B. León, R.A. Morales, O. González, May 2000
The purpose of this paper was to design a security cap and its injection mold using CAD/CAE tools. C-MOLD and Pro/ENGINEER softwares and the Concurrent Engineering Method were applied. The part and its mold were successfully designed in only 20 weeks.
Dynamic Rheological Properties of HDPE/Ethylene-Alpha-Olefin Copolymer Blends
R.A. Morales, J.J. Sánchez, A.J. Müller, May 2000
The blends of linear and branched polyethylenes have received much attention in recent years. Many studies have been carried out to evaluate the miscibility of these mixtures and its influence on the final properties. There still some degree of controversy on the issue of melt miscibility even though partial co-crystallization has been demonstrated for some of these systems.
Surface Delamination of an Injection Molded Medical Device Using Flexible PVC
Tahua Yang, Sherwin Shang, John Booras, Michael T.K. Ling, Henk Blom, Lecon Woo, Ho-Seon Jin, Dan Marcquenski, May 2000
An autoclavable medical device was designed using flexible PVC. The device was injection molded and subsequently was exposed to steam autoclaving. Surface delamination was observed in the adjacent area of the gate. Investigations on material properties, pigment dispersion, and residual stresses were conducted. It appeared that by simply controlling the molded-in stresses, the defect could be minimized. In a Design of Experiment (DOE) study, the key molding parameters were identified.
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