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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Prediction of Mechanical Properties of Injection Molded Plastics Components – A Systems Approach
Research objective is to establish manufacturing-related design rules and procedures for engineering design of injection molded thermoplastics parts, and to investigate application of novel materials to support development of design for sustainability. Thorough analysis of a large number of mechanical test results has led to a better understanding of factors influencing mechanical performance in tensile and tensile-impact. Among the noteworthy conclusions is the importance of shear rates and temperature gradients in the surface layers during molding.
Structural Plastics- Design for Function
A methodology in producing highly functional designs is discussed. The family of injection molding processes referred to as Structural Plastics offers product designers more design liberty with net-shape moldings with highly functional and value added features. Functionality determines which process and resin should be specified through cost/benefit analysis.
Hedge Strategies for Plastics Part Design
Risk is inherent in the production of any molded part stemming from, for example, changes in production quantities, uncertainty in molding behavior, redefined product specifications, failures in equipment, and abandoned supplier relationships, and other causes. This paper provides several strategies for hedging these risks by considering the cost of the changes to correct different failure modes in the design. The objective is to improve product performance while reducing time to market and risk.
The Role of Material Selection in Product Failure
According to one major industry study, 45% of all field failures involving parts fabricated from plastic materials can be attributed, at least in part, to an incorrect material selection. This paper will highlight several case studies involving failures due to improper material specification and will discuss solutions to these failures.
Failures Due to Compositional Factors
Failures generally are due to problems of design, composition or processing. In this paper, examples are given in which failure was due primarily to composition. In some cases, components of the known formulation were at fault. In others, contaminants introduced externally were the cause of failure. Among the types of failure were odor, color, materials sticking together unintentionally and other problems resulting from transfer of formulation components to other materials.
Constitutive Model for Non-Linear Behaviour of SMC
In the present paper an approach for modelling SMC material as visco-elastic damageable is presented. Damage theory by Chow and Wang is used in combination with linear visco-elasticity. The model is exemplified through application to uniaxial creep test with material of different damage states. Simultaneous testing and simulations on a modern SMC material is performed with good accuracy, especially at moderate damage levels.
Fracture Analysis of Polypropylene Montmorillonite Nanocomposites
Samples of polypropylene (PP) and PP nanocomposites with 1, 2, 3, and 5 % of Montmorillonite layered silicate (MLS) were tested in three-point bending conditions. Techniques of crack tip opening displacement (CTOD) and J-integral are used to determine the influence of MLS on this feature of the material. Fracture toughness was obtained for each one of the systems mentioned. It was found out that the addition of 5 % MLS reported the highest impact on the properties.
Scratch Behaviors of Moldings
Scratch behaviors in several types of plastics have been investigated in order to develop scratch test method for plastics. The effects of scratch conditions such as scratch speed and normal load on the strength reduction have been discussed on the basis of absorbed energy obtained by carrying out the Charpy impact test after scratching (CAS for short). The effect of scratch has been studied by comparing the absorbed energy of CAS with that of Charpy impact test using both notched specimens and un-notched specimens. It is noted that scratches led to strength reduction in several plastics.
New Thermoplastic Vulcanizates (TPVs) with Improved UV Resistance and Fogging Properties
A new line of thermoplastic vulcanizates (5700B) has been developed by DSM Thermoplastic Elastomers for automotive sealing system applications as well as other applications where UV resistance is critical. This new line of products, consisting of many different grades with hardness ranging from 58 shore A to 40 shore D in black color, shows superior processability, consistent quality, and balanced properties meeting automotive material and performance specifications. In this paper, we will discuss some of the features associated with this new line of products.
Long-Term Aging of New Heat and Oil Resistant Thermoplastic Vulcanizates (TPV)
Thermoplastic vulcanizates (TPVs) afford many advantages in terms of part design, processing, and part cost. Due to temperature and oil resistance limitations, current generation TPVs (e.g., EPDM//polypropylene) and copolyesters have had only limited applicability in underhood automotive applications.A new class of heat- and oil-resistant TPVs has been recently introduced1. A representative polyacrylate / /polyamide TPV from this class will be shown to exhibit superior physical property retention after 2000h air and oil (SF105) exposure to temperatures between 100° and 150°C.
High Performance Clear Thermoplastics Elastomer
High performance clear TPE products are developed to replace silicone and PVC in various medical and personnel care applications. These are high clarity TPEs with high tensile and tear properties. They retain mechanical properties and dimensional stability after hours of testing in boiling water and repeated dishwasher cleaning cycles. These TPEs have good processability. They can be used in FDA and USP required applications.
New EPDM Rubber Concentrates for Making Thermoplastic Vulcanizates (TPVs) by Toll Compounding Process
EPDM rubber concentrates have been developed by DSM Thermoplastic Elastomers. This new line of products consists of three low durometer grades. These rubber concentrates are designed for toll compounders to make TPVs of different durometers (medium to high) and different properties by adding various amounts of polyolefin plastics, such as polypropylene (PP) and other ingredients, to the rubber concentrates on a twin screw extruder or on other mixing equipment with sufficient mixing capability.
Web Based Engineering Education
In an effort to develop better teaching approaches for engineering courses, academia is taking a look at alternative styles that implement advanced educational tools as an alternative to lecture-based courses. As the World Wide Web matures, multimedia and programming technologies are evolving to enable the development of instructional software containing significant depth and interactivity. This paper discusses the development and integration of web-based tools to support engineering courses.
Stretch Blow Molding Curriculum Development: Understanding PET-E Bottle Making from a Materials Viewpoint
Addition of Stretch Blow-Molding capability to the Plastics and Polymer Engineering Technology Program at Pennsylvania College of Technology is described. Through a grant from the National Science Foundation, process and analysis equipment was purchased to enhance courses in blow molding, process survey, and advanced processing courses. Copies of laboratory experiences are available nationally on a web site or through correspondence with the author.
Future Directions for Plastics Engineering Education: Technical, Business, and Human Concerns
Engineering practice in the plastics industry typically requires knowledge of materials science, mechanical design, and manufacturing processes. However, the traditional academic focus on these technical fundamentals may not be sufficient to satisfy recent trends in industry practice. This paper reflects on the current state of plastics engineering education and proactively suggests changes in the curriculum to address the needs of the global system of the plastics industry through the three domains of technical, business, and human concerns.
Organotin Stabilizers: Global Regulatory Review
There are many ongoing activities taking place in the regulatory arena regarding organotin stabilizers used in PVC. This paper will provide an overview of the activities, including who is involved and what the issues are. It will also describe how the stabilizer industry is dealing with these issues as part of their ongoing efforts to insure that the use of organotin stabilizers is approved and continues to be safe for people and the environment.
Effect of Extrusion Melt Temperature on Properties of Flexible PVC
This paper provides an insight on the relationship between the physical properties of the profiles extruded from flexible PVC compounds and the extrusion melt temperature. The properties include tear resistance, tensile properties, brittleness temperature and compression set. The effect of heat history on surface characteristics of the extrudate, such as surface roughness and gloss, and their relationship with the processing morphology is also discussed.
Characterization of Bimodal Impact Strength Distribution in PVC Using Instrumented Impact Testing
The ductile-to-brittle transition (DBT) is observed for PVC siding samples using an instrumented dart drop impact tester. Large numbers of test specimens from each sample were evaluated for impact strength to establish a clear indication of bimodality. For a particular sample, a DBT temperature determined from this method may be used to determine impact modifier efficiency, or as a robust quality control check for commercial siding producers.
Mechanism of Organotin Stabilization of Poly(Vinyl Chloride). 7. Association of Methyltin Alkyl Thioglycolates with PVC and its Implication in PVC Stabilization
The stabilization and degradation of PVC by methyltin alkyl thioglycolates was investigated by molecular orbital calculations of the most probable reactions responsible for them. Theoretical studies confirmed previously postulated mechanisms based on experimental results.
PVC Process Window as a Function of Lubricant Formulation
Extrusion responses including impact resistance (mean failure energy,MFE) of the extrudate as a function of extrusion conditions and ester lubricant formulation were evaluated. Mathematical models were calculated using experimental design software facilitating prediction of MFE and melt temperature responses for hypothetical extrusion conditions and lubricant packages. Extruder response predictions are then used to define a process window for hypothetical lubricant formulations where two or more extrusion responses must be balanced. Paraffin, ethylene bisstearamide, and ester based systems are compared.
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