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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There are many influential factors and processing variables that can impact the mechanical and aesthetic properties of a rotomolded part. One of the main variables is the resin being processed and its associated rheological properties. The manner by which the polymer powder sinters and fuses together needs to be understood to ensure the correct processing cycle is used to obtain an optimum cured part. The influence of bubbles that form during the sintering phase and the melt index of the material, contribute to the quality of the part being produced.
In an attempt to prepare our students better for the challenges after their University study, the Departments of Chemical and Mechanical Engineering at the University of New Brunswick are continuously seeking new ways to expose the students to state-of-the-art real world technologies. The authors present an approach for introducing the students to various aspects of plastics processing and training on an example of their senior design course.
The trade show is a vital component to the plastics industry. As we depend more and more on e-mail, the internet and conference calls, we have become removed from each other. The opportunities to speak face to face, and business to business with so many companies under one roof, is unique to the trade show setting. In this presentation several suggestions and tips" will be discussed which will help you optimize your trade show experience."
A thermoplastic rifle stock for a new rifle was developed. Initial wooden models were shaped to meet market demands. CAD models were produced both manually and using digitizing with little difference in outcome. CAD models should include manufacturing process related geometry issues such as draft allowance and gate vestige size and location. Examples of methods to prevent problems are outlined throughout the development process. Ultimately, a successful new product was delivered to the marketplace with both prototype and production tooling.
Since it is known that cross-linked Polyethylene can be welded, it is clear that the acting mechanisms in the interior of a welded joint are not adequately explained yet. There are several criterion, hypotheses and models that try to describe what happens in a welded joint. In this paper two new promising hypotheses, the Mixed Crystal Hypothesis and the Nexus Hypothesis, are introduced. The Mixed Crystal Hypothesis can be proven by the help of several different examination methods. Other examinations support the Nexus Hypothesis.
This presentation is concerned with the development of process simulators for the analysis of compounding operations in modular corotating intermeshing twin-screw extruders. Approximate flow and heat transfer models are presented and implemented in a personal computer based software package for the fast simulation of the processing behavior in realistic settings.
Coextrusion with three or more layers is commonly used to produce end products that have properties with a good mix of the individual components. Layer multiplying technology allows for coextruded samples to be multiplied into tens or even thousands of layers, producing microlayers. In this manner, a wide variety of polymers can be combined intimately with minimal mixing. Microlayers have several distinct advantages as both a research tool and as a method of producing end products with enhanced properties. The effect of large interfacial area and of scaling is discussed with several example systems.
Adhesive bonding typically produces slow strength build. Accelerating processes are used to heat the adhesive rapidly. Two approaches are used: heat the adherends, which transfers heat to the adhesive, or heat the adhesive directly using added susceptor material. In this paper, the relative merits of both approaches are examined using induction and microwave heating as examples. Each approach is discussed along with the importance of curing kinetics at temperature.
To design an extruder screw for a given polymer, the barrel length for melting is needed for a given flow rate and speed. The melting rate needed for calculating the length is given through the conservation laws in cylindrical coordinates based on defined fundamental average parameters. Extrusion machine data are used to calculate the functions of the parameters. Results based on polyethylene data are given.
M.N. Ichazo, J. González, C. Albano, B. Díaz, May 1999
This article describes the surface modification of CaCO3 filler with three titanate and one zirconate coupling agents and its effects on the properties of the PP/HDPE blends. CaCO3 was coated with these coupling agents of varying concentration (0.3-1 wt. %). The best performance in terms of tensile modulus was observed in blends having 0.7% titanate coupling agent (LICA 12). SEM microgrhaps indicated better dispersion and decreased agglomeration of the smaller CaCO3 particles.
C. Albano, M.N. Ichazo, J. González, K. Molina, L. Espejo, May 1999
The effect of the filler size and composition on the mechanical properties of wood flour-PP composites was studied. The blends were prepared in an intermeshing co-rotating twin screw extruder and injection molded. The best properties (elastic modulus and tensile strength) were obtained for the 40 wt. % wood flour composites for all filler sizes employed. PP/HDPE blends (80/20 wt. %) were prepared based on the higher wood flour content of the composites tested previously.
The mixing performance of a co-rotating twin screw extruder during melt-melt blending of polypropylene was experimentally investigated using an interfacial reaction between reactive polymer tracers. The conversion was dependent on the formation of interfacial area between the two melt streams, and therefore, the distributive mixing performance was directly measured using this technique. The focus of the experiments was to determine the effects of machine parameters (screw design and operating conditions) on the mixing performance.
Polypropylene (PP) coated dies were used in an attempt to decrease the die pressure and eliminate surface melt fracture during the extrusion of linear low density polyethylene (LLDPE). The investigated coatings were: controlled-rheology PP, hydrosilylated PP, amorphous PP wax, and maleic anhydride grafted PP. Extrusion stability, die pressure, and extrudate appearance were used to compare the effectiveness of the different coatings.
Bill Fierens, Dan Fisher, Mark Shade, John Bozzelli, May 1999
The trend in the injection molding industry today is to measure and record machine specific process variables. The goal of this paper is to explain the concept behind measuring and recording process conditions rather than equipment setpoints. The purpose of doing so, will be to convince molders everywhere that a non-machine specific process sheet will enable the processor to produce identical parts from machine to machine. The benefits are numerous, especially when one considers ISO and QS certification and the financial investment that they bring.
Two transition metal-based catalytic systems for the homo and copolymerization of olefins will be discussed. The first encompasses palladium(II)-catalyzed alternating copolymerization of olefins with carbon monoxide. The polymers synthesized include chiral isotactic copolymers derived from both simple olefins, as well as those bearing a variety of functional groups. The second system involves palladium(II) catalyzed homopolymerization of norbornene derivatives and their copolymerization with acrylates.
Naba K. Dutta, N. Roy Choudhury, Janis Matisons, G.H. Edward, May 1999
A simplified numerical computational technique based on a Gaussian spectral distribution model developed by Dutta and Edward  has been used to describe the stress relaxation behavior of polystyrene (PS) and isotactic polypropylene (iPP) over a wide range of, time and temperature. An excellent fit between experimental data and the mathematical model is observed. The method may be applied generally for any linear viscoelastic property and for any polymer.
A Dynamic Mechanical Thermal Analyzer, DMTA, instrument can be used to study noise reduction of thermoplastic composites. In this study, a polyamide 66 matrix modified with impact modifier, impact modifier plus foaming agent, and 30% glass fibers have been studied. In this study, the addition of impact modifier enhances the noise damping of the composite material by a factor of two.
Mechanical Properties and adhesion strength of a thin polymer coating on a rigid substrate can be measured directly by two tests: (i) a one-dimensional V-peel (pull-off experiment); (ii) a central point load (shaft-loaded blister). In either case, it is found that G = ? (Fw0 / A) with ? a numerical constant depending on the ratio of bending to stretching stresses on the film. It is shown that delamination behavior depends strongly on the film thickness and the extent of deformation.
A new shaft-loaded blister test is used to directly measure the mechanical properties of thin polymeric films. The shaft tip is rounded to a hemispherical cap to avoid film puncture. An elastic solution is suggested for the applied load as a function of shaft displacement, which depends on the ratio of shaft radius to blister dimension. To avoid concentrated load, an alternative way of loading the blister is by a horizontal cylinder of finite radius.
Plastic bosses are fundamental components of many parts and assemblies. Due to the multiple functions and configurations, they can be difficult and time-consuming to properly design. Plastic type, size, and structural reinforcements are some of the design parameters that need to be determined. Current design methods follow set standards and produce inefficient designs for many applications. This paper explores the possibility of automating the boss design process given the needed clamping force, orientation, pullout force, torsion, and pressure configurations between the parts to be fastened.
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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
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.