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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Understanding the Effects of a Compounding Process on the Production of Co-Extruded Vinyl through the Utilization of Design of Experiments (Part II)
There are many ways to add color to the windows of your home. For many window companies, a weatherable PVC is used on the outside of the window to provide for a durable, low maintenance, and weatherable exterior. The market demands a variety of different colors within a short time; thus an understanding of rapid adaptability to the market demand is needed. This paper is a continuation of a project presented last year. This paper will discuss the results of a Designed Experiment (DOE) conducted to determine the variables for successfully developing a process window model. This model can be used for current and future colors; thus shortening the development time.
Using a Hierarchical Model of Cognition to Enhance Polymer Education
A hierarchical model of mental growth can be used as the basis for developing critical thinking skills in polymer science and engineering undergraduates. Specifically, mental growth constitutes a progression through a hierarchy of cognition. The critical thinking and judgment required of scientists and engineers lies at an upper level in the hierarchy, and to reach high levels, an individual must master cognitive skills and reorganize knowledge gained at lower levels. Teaching and learning devices that exercise low-level cognitive skills and that support effective development of critical thinking are presented. Assessment instruments that monitor student growth and evaluate the effectiveness of these teaching and learning devices are also described.
An Innovative Alternative for Plastics Training & Certification
Training and certification have been hot topics in the plastics industry for a number of years, but we have had little success in establishing a relevant certification strategy or making major improvements in the way we train employees. We all seem to recognize the need for a welltrained and highly skilled workforce in order to compete in today’s knowledge-based economy but our approach to training hasn’t changed much over the years.This paper presents a new competency-based training and certification model which can provide a framework that leverages the collective knowledge of the industry and empowers the learner to clearly identify their own learning needs. This unique approach also ensures that learning takes place within the work context of the learner, ensuring maximum retention and application on the job.It will review the work that has gone into the development of this model including the completion of an in-depth industry needs assessment and a Master’s degree in advanced educational techniques and technologies. Individuals who have a stake in ensuring we have a well-trained workforce will find this session of great interest. Copies of the original thesis, which expands on the points brought forward here, is available by email request.
How to Tell when the Emperor is Naked
A near-fad mentality to source in China has developed in buyers of plastic products. Major company senior managements are declaring that sourcing should only be done in China in a near-total absence of strategic comparison data that is relevant to their products. Their employees then stop thinking critically and do as they are told regardless of the impact. Many of these off-shore sourcing decisions are inappropriate and very costly both for the buyer and for the North American suppliers they didn't but probably should have used. A review of case studies permits some understanding of the key elements that both suppliers and buyers need to assess in making intelligent sourcing decisions. Further strategic assessment reveals some specific differences in strategy and methods that should be considered by mold builders, molders, and buyers to know when the emperor is naked.
Critical Chain Project Management
The ability to execute projects is of critical importance to the success of today's organizations. Unfortunately out-of-control projects that overstress people, organizations, and budgets are the rule rather than the exception. Several years ago a new project management methodology called Critical Chain Project Management (CCPM), was introduced by Eliyahu Goldratt, promising substantial gains in the ability to monitor and manage projects, along with a potentially dramatic reduction in overall project duration. This paper presents an overview of CCPM and discusses the benefits and hurdles the author encountered implementing it in his organization.
The Impact of Biotechnology and Nanotechnology on the Chemical and Plastics Industries
Nanotechnology, Biotechnology and an increased awareness of the environment are generating new and emerging technologies that could have a disruptive effect on various segments of the plastics industry.This paper will discuss the areas where the greatest disruption will occur and how. For these emerging technologies to be adopted in the mainstream they will need to demonstrate performance advantages as well as total cost performance benefits. This transition is beginning to occur. Taking the time to understand where these new technologies could change the way we do business will keep us ahead of the competition and help us determine the opportunities which are available to us.
Plastics in the Twenties
Plastics are to continue their growth in the next twenty years and beyond, from 160 million tons in 2000 to 550 million tons in 2020.The general quantitative forecasts, however, show varying rates of growth, with:Population growth tapering and average income fast growing, Faster growing areas, outside the traditional Triad, USA, Europe, Japan, Faster growing applications, in structural and durables, New plastics coming, high performance, alloys, composites, silica based, And, maybe, entirely new paradigms for the next 25 years, with the decline of fossil fuels as energy The paper is divided into three parts:The world economic scene and forecastsPlastics end-uses, markets and applicationsWorld plastics consumption and forecasts
Effects of Heat Aging on the Properties of Rigid Medical Packaging Materials
Retention of physical, thermal and optical properties at an elevated temperature of 50°C was monitored in a heat aging study of two materials, following conditions of ASTM D-3045. XT® polymer acrylicbased multipolymer compounds were stable through 24 weeks of aging, with only minor optical changes. In contrast, EASTAR 6763 copolyester suffered significant property changes, notably embrittlement and higher glass transition enthalpy. Ethylene Oxide (EtO) sterilization further widened the performance gap. Retained strength of rigid medical packages is important for adequate protection through the rigors of storage and transportation.
Simplifying Failure Analysis for Adhesive Joining Operations
Troubleshooting a failure in an adhesively bonded joint can be a daunting task due to the wide variety of processing and performance variables that can affect joint performance. Fortunately most failures can be attributed to one of four causes: No/Poor Cure of the Adhesive; Poor Bond Strength to a Substrate; Insufficient Adhesive for the Joint; or Wrong Adhesive for the Application. In this paper, techniques for identifying these causes of joint failure and solutions will be described.The adhesive families most commonly used for bonding plastics on medical devices are cyanoacrylates and light cure acrylics. This paper will provide background on both chemistries, give a detailed review of the potential causes of each of the main failure modes associated with these adhesives and potential solutions. It is hoped that this will aid the reader in applying the same failure mode analysis to other adhesives that are not covered in this paper. To help illustrate these concepts, some real life examples of adhesive failures and the steps in the process used to resolve them will be discussed.
Electron Beam Compatible Polymers
An overview of electron beam systems provides a summary of system configurations and significance of important energy measurements related to systems capabilities. The overview includes the benefits of direct vs. indirect systems, horizontal vs. vertical beam sources, and the importance of power and energy values to throughput and penetration of systems.The radiation effects on polymers are described and the mechanisms of these changes are defined. The responses of a number of polymers important to the medical industry are summarized. A few key guidelines for polymer selection are:Selection of the highest molecular weight polymer to help reduce any effects of degradation.Aromatic polymers exhibit better radiation resistance than aliphatic polymers.Antioxidants can often be added to improve radiation stability.Less oxygen dissolved in the polymer and surrounding the polymers will help reduce oxidative degradation.The material properties required for radiation resistance and suitability for electron beam sterilization are delineated and discussed.
Superior Stabilization of Polypropylene for Radiation Sterilized Medical Devices and Packages
Hindered amine light stabilizers (HALS) have been used for decades as some of the principal stabilizers for the protection of polypropylene from the effects of sterilizing doses of high-energy radiation. ExxonMobil Chemical Company has now found proprietary (HALS) additive packages that provide superior stabilization to radiation-sterilized polypropylene. When further improved by blending with small amounts of metallocene-catalyzed, ethylene-based plastomers, these formulations are highly resistant to degradation after irradiation and useful for a broad range of medical device and packaging applications.
Micro Molding Challenges
As miniature molded parts approach micro or nano in size, several challenges exist to molding them in a production environment.This paper explores some of these challenges such as polymer property changes induced by shear stress through near micron-sized gates, humidity control for extremely small shot sizes, and integrating macro to micro technologies to produce near micron level geometry in precision, micro mold components.New mold manufacturing technologies exist to remove variation from micromolded features and further work is being done with scientific micromolding process control, both of which are critical to long-term micromolding process capability. ANTEC
Plastic Bio-MEMS Sensors
A novel method for the production of polymer microcantilevers is described, along with the characterization (i.e., determination of stiffness and resonant frequency) of parts produced with said method. The manufacturing method consists of casting a polymersolvent solution upon a glass base, gold-coating and precision cutting of the produced film, and mounting of the cut film pieces onto injection-molded bases for characterization in a commercial atomic force microscope (AFM). The technique is repeatable and has produced polymeric beams of micron thickness, with lengths up to 25 mm and widths down to 25 microns. With this wide size range, production of polymeric beams with stiffnesses commensurate with those of probes used in atomic force microscopy is possible, and indeed the stiffnesses of the beams produced for this work range from roughly 0.001 N/meter to 0.1 N/meter.
TekFlow Processing for Miniature and Micro-Size Applications for Medical Plastics
The number of micro-sized medical applications is increasing each year due to advances in equipment used for medical / pharmaceutical testing and also as components in new minimally invasive surgical devices. These applications involve miniature and micro-size devices which rely the processor's ability to fabricate smaller plastic parts, parts with thinner walls, parts with micro features (like holes, channels, or posts) or even micro-surface textures. Unfortunately, most engineering grade plastic materials also exhibit low flow characteristics and are processed at higher temperatures. The result is that it is difficult to fill thin wall sections and small features with molten plastic. Even when the plastic does fill these thin, small sections, often it shrinks so much afterward that the dimensional stability is compromised and the tolerances are unacceptable. The purpose of this presentation is to discuss the benefits to micro-processing which are proposed by TekFlow Processing, a disentanglement technology which reduces the processing temperatures and pressures normally required, thereby assisting the fabricator/ processor to create challenging miniature and micro shapes and tolerances. The lower processing temperatures and pressures also allow the processor the option of using thermally or pressure sensitive inserts or additives.
Radiation Grafting for Surface Modification of Nano-Fibers
The performance of polymeric materials in a particular application depends to a great extent on the properties of the interface or interphase between the polymer and the applied environment. Grafting is a useful technique for modifying polymer surface properties and for constructing materials whose bulk and surface properties are different. Radiation grafting provides significant advantages over chemical grafting methods. Radiation sources include electron beam (EB) ultraviolet light (UV) and plasma. The concept of using radiation grafting as a method for tailoring polymer surface properties has been applied to a wide variety of applications including bio-medical, textile, electrical, and membrane applications. In this work, we focus on applying radiation grafting technology to nanoscale polymer systems, specifically nanofibers produced by electrospinning polysulfone (PSF). Using EB, hydrophilic monomers such as acrylamide have been grafted on PSF fibers and the modified materials have been evaluated using surface analysis techniques including XPS, ATR-FTIR, ESEM, and contact angle measurements. Our results indicate that we have successfully grafted acrylamide onto polysulfone electrospun fibers while maintaining the fine fibrous structure in these systems.
The E-Beam Curing of Epoxy Resins
The electron beam curing of epoxies is actively explored for application in composites and adhesives. The dynamics of epoxy homopolymerization was studied at different doses of irradiation – from 0.05 to 17 Mrad. The results enabled estimation of the maximal uncured dose and minimal cured dose. These values are useful for repeatable electron beam processing, for example to ensure proper ply consolidation during Automated Tape Placement (ATP) with in-situ EB cure. DSC tests were used to study the dynamics of heat postcuring for preliminary irradiated resins and to estimate the values of residual exotherms of irradiated epoxies.
A Rapid, Nondestructive, In-Situ Analysis of Plastics for Heavy Metals with Portable X-Ray Flourescence Analyzer
Recently introduced regulations, such as European Community “Packaging Directive” - ECDirective 94/62/EEC (1), impose the maximum limit on total amount of metals such as Cd, Cr, Hg and Pb in plastic packaging materials to less than 100 mg/kg. Another EU Directive, 91/338/EC (2), sets the maximum allowable concentration of cadmium in plastics used for consumer goods at 100 mg/kg. In the US, the “Proposition 65” introduced in California banned cadmium from use.Effective enforcement of these regulations creates the need for analytical methods capable of rapid, accurate, nondestructive in-situ analysis of plastics. An X-ray Fluorescence Analysis (XRF for short) is very well suited for this task.In this paper we report on successful application of a small, portable X-ray fluorescence analyzer in analysis of plastic for metals. The analyzer can quantify heavy elements such as lead and cadmium in plastics down to 10 and 25 mg/kg, respectively, at a 120 sec. measurement time per sample.
Sustainable Polymers: From a Glorious Past to a Bright Future
In the coming decades it will become increasingly difficult to cheaply satisfy society's thirst for petroleum-based polymers. Additionally, the problems associated with disposal of non-renewable, non-degradable petroleum based polymers will drive the search for agriculture based plastics that do not sacrifice cost or performance. Although agriculture based plastics have been around for over a century, they were largely forgotten after the advent of synthetic, petroleum based polymers. This paper revisits the literature left to us by early twentieth century engineers who made protein based plastics from casein and soy protein on an industrial scale. In recent years, there has been a resurgence of interest in this type of material. This paper reviews current research on biopolymers such as casein and soy protein based plastics as well as polylactide acid, or PLA.
Use of Natural Fibre as Reinforcing Agent in Biodegradable Foamed Packaging Materials Made from Wheat Flour
The use of packaging materials is expected to increase annually on average by about 5 percent in the foreseeable future, but the technology for reusing and recycling of packaging waste is lagging behind. This paper considers the evaluation of an alternative packaging material, derived from renewable resources, which is economical to use, biodegradable and recyclable by composting. In this paper consideration will be given to the preparation, characterisation and properties of starch-based materials derived from wheat flour. A range of techniques, used to characterise these materials will be discussed, including image analysis, SEM, thermogravimetric analysis, compressive strength, impact and recovery measurements.
Melt Processing of Traditionally Solution-Processed Polymers with CO2
The effects of using near critical and supercritical carbon dioxide (CO2) to plasticize polymers that are difficult to melt process are studied, in particular acrylonitrile (AN) and methyl acrylate (MA) copolymers. Previous work with PAN/MA copolymers included differential scanning calorimetry (DSC), used to evaluate the resulting shift in the glass transition temperature (Tg) following plasticization, and pressurized capillary rheometry to evaluate the melt rheology and entry pressure effects prior to and after plasticization. A slit-die rheometer has been designed to allow the attachment of various nozzles to the exit to maintain high pressure and single-phase flow, suitable for measuring viscosity reduction with CO2 in a continuous process. Comparisons are made between capillary and slit die rheometry for quantifying the effect of CO2 plasticization on a model 65% AN, 25% MA, and 10% rubber copolymer.
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