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.
Maleic anhydride modified polypropylene was compounded with commercially available surface modified montmorillonite in an extruder. Re-compounding ensured the removal of visible tactoids from extrudate but TEM and XRD techniques showed non-uniform dispersion of clay platelets. In this study, we investigated the mechanical and fracture properties of nanoclay-filled polypropylene. Tensile strength and stiffness increased steadily with nanoclay content. The J-integral fracture resistance was also attempted on this novel material.
Monosandwich, overmolding and push-pull are special injection molding methods by which parts composed of two different materials can be produced. While the first two techniques yield structures in which the core material is totally encapsulated (monosandwich) or side surrounded (overmolding), the parts obtained via push-pull exhibit multiple oriented layers of the two materials. A comparison of the morphological developments and the flexural and impact properties induced by the three methods is made.
The origins of elasticity in thermoplastic vulcanizates have been debated for the past decade. Previous modeling attempts provide numerical solutions that make assessment of constituent concentration and interactions unclear. A microcellular modeling approach is proposed and evaluated herein to describe the steady-state deformation behavior of dynamically vulcanized blends of ethylene-propylene-diene monomer (EPDM) and isotactic polypropylene (iPP). This approach provides an analytic result including terms for composition and cure state.
We have measured the state of molecular orientation in extruded polyethylene sheet using reversion tests. This state gives rise to anisotropy in stress-deformation behaviour. A novel constitutive relation, consisting of an established large deformation, rate dependent model into which is incorporated a preoriented Gaussian network, is used to model this effect. It has been implemented within the finite element package ABAQUS and applied to large extensions of specimens at various angles to the extrusion direction.
Modification of two types of Cloisite 30B and Na+ montmorillonite clays is made by its intercalation with polyvinylchloride (PVC) plasticizers, both low molecular and high molecular. Plate like filler particles are generated by compounding the modified clay with PVC. Plasticized PVC sheets without haze can be obtained. Morphology of such composites is evaluated with XRD and the scanning electron microscopy. The PVC nanocomposites were tested for abrasion resistance, E-modulus and flame resistance.
Density and deformation of ethylene-propylene copolymers are investigated in terms of composition and morphology. The morphology, crystallization kinetics and basic mechanical behavior are examined as a function of sample age in a previous study (1). Initial density appears to be dictated by composition and not crystallinity while changes in density are due to hexagonal crystal formation. Ductility is dependent on branching density and appears to be controlled by selective strain-induced crystallization.
Chaotic mixing produces self-similar mixing structures through repeated stretching and folding of materials interfaces, which can be exploited in processing of polymers to produce morphologies unachievable in conventional single and twin screw extrusion processes. In this study, the self similar mixing process is idealized by baker's cut, whereby materials are affinely stretched and folded or stretched, cut, and stacked. The process is repeated to produce morphology in the blending of immiscible polymer systems of polypropylene (PP) and polystyrene (PS).
On a worldwide scale, no commercial or scientific method is available for reliable, non-destructive rating of vibration welds. Industrial production depends on mechanical spot checks and statistical methods. Therefore an innovative quality concept (fundamentals: process knowledge, artificial intelligence) was developed. Since being presented at ANTEC '93 (1), it has been optimized and tested with simple specimen and complex applications. The system now enables reproducible joint strength classification, just by analyzing the vibration welding process.
In this paper we report about a research on innovative exploitation of agricultural resources.Thermoplastic biopolymers such as PLA or MaterBi can be derived from vegetal carbohydrates. Properties of biopolymers are similar to those of commodity resins; to improve their performance they can be compounded with vegetable fibers. Biocomposites are pelletized and injection molded or produced in form of mats suitable for compression molding. Possible applications in automotive field are investigated through the production of car part prototypes.
Creep properties are shown by applying a constant stress to a plastic specimen and measuring the strain as a function of time. The flexural creep of a material is related to temperature and stress effects. This study measures the effect, constant temperature has on creep properties of polycarbonate (PC) while different stresses are applied. Specifically, a heat deflection temperature testing apparatus is used to provide a constant temperature when a fixed amount of pressure is applied to the plastic.
Innovative thermoplastic vulcanizates (TPV) with high oil resistance will be described, consisting of thermoplastic polyurethanes (TPU) as matrix material and a dynamically crosslinked synthetic rubber phase. For the latter one ethylene-vinyl acetate copolymers (EVA) are used. The vulcanization step is realized by means of an organosilane crosslinking concept. For catalysis and water addition, necessary to accelerate hydrolysis- and condensation reaction, new catalyst (?Lewis acids) and water carrier systems are proposed and applied.
A three-dimensional finite element software is developed to simulate the incompressible, shear-thinning flow of thermosetting polymers coupled with thermal and curing effects. The SUPG method is used for upwind discretization of the energy equation. A control volume scheme with a fixed finite element mesh is employed to predict the fluid front advancement. The numerically predicted fluid front advancement in a microchip encapsulation cavity is compared with the experimental results.
A finite element method was used to simulate the polymeric fluid flow in multi-layer co-extrusion annular dies. New methods were proposed to update interface and node positions in the flow field during the interface updating procedure. The methods can be easily applied to the coextrusion process with no limitation on the extrusion layers. Examples are given to demonstrate the application of the updating methods. Discussions on the problems with finite element selection and path line method application are also presented.
Welding of plastic components has been playing a very essential role for system and subsystem integration of subcomponents. Ultrasonic welding process has been one of most popular welding processes for thermoplastic assembly. Effective usage of ultrasonic energy generated by the ultrasonic welding machine has been allowing various types of manufacturing processes such as welding, precision degating of molded parts, staking, seaming, embossing, ultrasonic molding, and so on. The most positive advantage of the process is the highly precise process control with a quick cycle time.
The rate of photo degradation of polystyrene in our society (Tropical Climate) has really limited its applications to mostly indoor use. This led to a wide range of research works on the effect of our Climatic condition on the photo degradation of polystyrene. Through studying and compilation of research findings and industrial informations, the primary causes, effect and factors affecting photo degradable in our society are discussed.
This paper reviews the evaluation of simultaneous through transmission infrared welding (STTIr) for joining selected under the hood applications." It was found that applications such as a brake fluid reservoirs could be effectively welded with STTIr without part marking or generation of particulates."
This keynote lecture discusses the use of biodegradable polymers as tissue engineering scaffolds. The basic principles of tissue engineering are addressed, going from scaffolds processing to some brief information on biological studies. These topics are introduced in a way that an audience composed by plastic engineers can easily became aware of the importance of the field and understands its complexity, as well as the role of biodegradable polymers on its success.
We will present a review of the world and US and Canada" demand for polyethylene and polypropylene from 2000 with a forecast to 2010. We will also look at the relative profitability of producing these resins in 2000. The polyethylene portion will be broken down into grades produced by the conventional high pressure process by the low pressure linear low density grades and high density grades.The paper will be based on 2000 data but the presentation at ANTEC will include some 2001 year end data."
The binary silica supported catalyst system comprising the Cp2ZrCl2 and SiMe2(Ind)2ZrCl2 metallocene compounds was prepared with different immobilization methods and evaluated at different propylene polymerization conditions. The homogeneous isolated catalysts and also the homogeneous catalyst mixture were also employed for comparison. High activities were obtained with the supported systems and the molecular weight of the produced polypropylene was invariably higher than the homogeneous precursor.
The heat seal strength of a flexible plastic package depends on the extent of molecular penetration at the seal interface, which in turn is a function of sealing jaw temperature, line speed and film thickness. Thinner films reach the maximum seal strength at lower jaw temperature or faster line speed than thicker films. A model is developed that combines heat transfer with molecular diffusion at the interface. The model points to how laboratory data may be used to predict the sealing performance of ionomers in high-speed packaging lines.
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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
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