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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New Scientific Approaches for the Integration of the Statistical Design of Experiments for the Validation of Injection Molding Processes in Medical Technology
The qualification of injection molds for the manufacture of medical products is a requirement of the GMP (Good Manufacturing Practice) and an elementary component of the quality management in medical technology. The individual steps of the Design Qualification (DQ), Installation Qualification (IQ), Operational Qualification (OQ) and Performance Qualification (PQ) are described in detail. The first-time compilation outlines comprehensively the qualification process. The contents have been adapted especially to the requirements of the injection molding process and implemented with new scientific approaches for the statistical tool of Design of Experiments.
New Approach to Electromagnetic Interference (EMI) Shielding of Plastic Parts Using In Mold Coated (IMC) Nanopaper
EMI shielding refers to the reflection/adsorption of electromagnetic radiation by electrically conductive materials, usually metal, or polymer composites. However, metal coatings do corrode and acceptable shielding levels are difficult to achieve using conductive fillers in a thermoplastic matrix. This study presents a new approach to EMI shielding of plastic parts using in mold coated nanoparticle thin films or nanopapers to create a highly conductive top layer. EMI shielding effectiveness (SE) and electrical conductivity were measured.
Effect of Incorporating Nanoparticles into Fiber Reinforced Epoxy Composites
The addition of nanoparticles to polymeric matrices has shown great promise for improving mechanical and thermal properties. In this study, an Advantex® glass fiber(GF) mat was sprayed with carbon nanofibers (CNF) on both sides and an epoxy resin was infused through this mat via vacuum assisted resin transfer molding. Mechanical properties of the CNF composites, sand erosion resistance and permeability were measured. With the addition of 0.5% CNF, mechanical properties improved while permeability decreased. The effect on sand erosion was negligible; we show that if sand erosion resistance is desired, a better alternative is to use a CNF thin film nanopaper on the surface.
Drilling of Composites
Composites have become a more common material choice in many of today’s components; however, little investigation has been done regarding the effects of machining, especially drilling, on the mechanical properties of composites. This has lead to much debate about which combination of variables yields optimal results by causing the least amount of change in the mechanical properties of a laminate. This paper will focus on the effects of drilling open holes into composites in the presence of coolant and utilizing drill bits with varying point angles. Unfortunately, data collected during this experiment does not suggest that point angle has a significant effect on either tensile strength or modulus of carbon fiber and epoxy composite. Only the presence of a hole which forms a stress concentration was found to have an effect. Point angle of the drill bit was, however, found to have a 95% confident statistically significant effect on the delamination caused by drilling into the composite. Also the presence of an oil-based coolant during drilling was found to have a 95% confident statistically significant effect on the flexural modulus of the composite as tested using the 3-pt bend test.
PVC or a Power Plant
Conservation of energy and environment is the call of the day. Every human being is aware of the terrifying rate at which the natural resources are being depleted and very well knows the difficulties in replenishing them, leave alone replenishing them at the same rate. The demand supply gap in the electricity is resulting in load shedding not only in residential areas but also in the industrial sector. On the other hand, serious efforts are being made to augment forest cover by adding to the ‘artificial forest’ with the tree plantation drive across the country, yet the natural forest coverage in India is actually on the decline. Scarce natural resource like wood and energy dependent metals - being major components of construction sector, need of the hour is to select alternatives which are more environment friendly and energy efficient. PVC – well established in the Western Hemisphere and finding increasing acceptance in the developing countries as well - is one such wonderful alternative to many of the conventional materials in the building and construction sector. This has resulted in this material getting designated as “Construction Polymer” – very rightly so! Owing to its excellent inherent resin characteristics and adaptability to numerous compounding ingredients, PVC can be formulated in various ways to meet different end use requirements. Further, technological advancements in processing have also given means to make this commodity polymer meet the ‘engineering’ requirements. A polymer which consumes much lesser energy and creates much lesser environmental impact compared to many of the traditional construction materials and even some of the major polymers during its entire life cycle, PVC has established itself in significant end use applications in the construction sector. This paper makes an honest attempt to critically evaluate the advantages of PVC Pipes & windows in saving energy and environment in a typical house over the cradle to grave co
An Experimental investigation of the Plasticating and Friction behavior of PET chips
An experimental study of the plasticating and frictional behavior of dried and preheated PET chips on a moving, steel surface has been conducted using an experimental apparatus called the Screw Simulator. The Screw Simulator has been specifically designed to reproduce the primary plasticating [melting] and solid conveying mechanisms of single screw extruders. The screw simulator permits the direct observation and measurement of a materials melting and frictional properties. The PET resin plasticating and frictional properties were studied as a function of metal surface temperature, surface velocity, sample width and applied load. In addition the materials bulk density as a function of pressure at several preheating temperatures was measured. These experimental findings have important implications in the design and scale up of single screw designs.
Morphology and Properties of Nylon-6/Epoxy Composites
An innovative approach to process epoxy/nylon-6 composite is demonstrated in this article. Firstly, the solution polymerization of nylon-6 was successfully carried out in N-methylpyrollidone (NMP) as solvent. The structure and morphology of nylon-6 precipitated from NMP was studied. Then several films were prepared from blend by varying the amount of nylon-6 in epoxy resin without Curing agent. All films were fully characterized for thermal and dynamic mechanical properties using Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analyzer (DMA). The addition of nylon-6 showed a plasticizing effect on epoxy. The growth of nylon-6 crystals in epoxy matrix lead to unique spherultic multiphase morphology as observed under Scanning Electron Microscopy.
Halogen-Free Organic Pigments: Considerations for Selecting a Colorant
Certain organic pigments contain aryl?halides and alkyl halides as part of the chromophore structure and in some cases unintentional halogenated byproducts from the manufacturing process. Halogenated compounds can be sources for persistent and bioaccumulative dioxins depending on end?of?life cycle processing and are the subject of certain electronic industry standards. Requests for non?halogenated pigments are also trending in the pigments industry. CI or CAS chemical structures provide an expedient way to determine if an organic pigment contains halogen atoms. Analytical testing is required to parenthetically characterize any organic pigment as halogen?free in accordance with established electronic industry standards. This paper does not provide any original work or experimental findings but is rather intended to provide the reader considerations for organic pigments in view of industry initiatives and legislation aimed at protecting the environment.
Enhancement of Induction Heating Efficiency on Mold Surface Using Ferrite Materials
Mold temperature plays a significant role to the quality of injection molding process. A high mold temperature setting is feasible to enhance the molding quality but prolongs the cooling time. Use of induction heating to heat the mold surface only seems to provide a feasible solution without scarifying the molding cycle. Still, there exist some problems to be resolved in induction heating such as proximity effect. The proximity effect is the sudden interaction of magnetic fields that are generated because of two nearby coils with inverse current directions, affecting the change of flux. It causes significant decrease of heating efficiency and thereby generates non-uniform heating. To eliminate its drawback, this study proposes a novel magnetic shielding induction heating method by employing ferrite materials to enhance both the heat efficiency and uniformity. Comparing to conventional magnetic concentrator, experimental results depict that the proposed method can efficiently improve the influence of proximity effect; thus increases heating rate and obtains more uniform temperature distribution.
Adhesion Improvements of Nanocomposite Interfaces
Attention has recently become focused on the performance advantages of nanocomposites, and particularly polymerbased nanocomposites with respect to incumbent “neat” polymers or metallic materials for lightweighting initiatives. In the interest of sustainability, the specific use of bio-reinforced nanocomposite parts and nanostructured coatings within automotive, aerospace, construction, medical and packaging applications is accelerating. These “green” nanocomposites can provide high mechanical strength at low density, low weight, and low cost while generating low carbon dioxide emissions. However, there are interfacial surface adhesion challenges with these and other nanocomposites, in addition to particle distribution and stability issues, which can inhibit full realization of their mechanical performance advantages. This paper will profile polymeric nanocomposites and nanocoatings, as well as define surface modification protocols using atmospheric pressure plasma technologies to optimize interfacial adhesion to similar and dissimilar materials.
Hybrid TPEs: Combining the Strengths of Olefin Block Copolymers with SEBS
Olefin Block Copolymers (OBCs) are used in a broad range of applications and markets, including soft compounds. Recently, a new grade, INFUSE™ 9010 OBC, was introduced specifically for use in oil- extended compounds. The benefits of this OBC grade on the properties of oil-extended thermoplastic elastomers (TPEs) have been presented previously . Styrenic block copolymers, such as poly(styreneethylene/ butylene-styrene) (SEBS), are frequently used in TPEs with a broad range hardness and other physical properties. The focus of this paper is on the physical and rheological properties that can be obtained in TPEs formulated using both OBC and SEBS elastomers. In general, these hybrid TPE compounds have properties intermediate between that of TPEs formulated with OBC or SEBS alone.
Excellent properties of a novel composite ?-nucleating agent for isotactic polypropylene
The thermal behaviors and mechanical properties of isotactic polypropylene (iPP) with a composite ?- nucleating agent VP-101T has been investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and polarized optical microscopy (POM) and mechanical measurements. The crystallization temperature did not increase with the further addition of nucleating agent. The relative ?- form content and the total crystallinity increase a lot. By adding VP-101T, the impact strength could be increased by 3~4 times. The heat deflection temperatures are increased as well. With the increasing concentration of VP-101T, the morphologies of ?-crystals change from to cluster of crystalline. The optimal concentration of VP-101T is 0.2%.
Effects of Clay Loading on the Structures, Mechanical, Rheological Properties of Microcellular Foams of PLA/MMT Nanocomposites
This study investigated the effect of clay loading on the properties of conventional/microcellular injection molded Poly-Lactic-Acid (PLA) nanocomposites. The results showed that addition of MMT decreases the tensile/impact strength of PLA/Clay nanocomposites. The XRD results showed that with the addition of clay which increased the crystallinity of the PLA/MMT nanocomposites. The thermal properties results showed with the addition of clay which increased melting temperature, degradation temperature and thermal conductivity of the nanocomposites. The clay helps the nanocomposites on having small size cell on the foamed nanocomposites. For the rheological test, with addition of clay into PLA which decrease the viscosity of the nanocomposites. The decreased tensile strength and viscosity is caused by the degradation of the PLA/MMT nanocomposites.
Preparation And Characterization Of LDPE/ Clay Nanocomposites
Low Density Polyethylene/clay nanocomposite is a thermoplastic polymer matrix, that has nanometer scaled organoclay fillers dispersed in it. The characteristic structure of the material enhances its properties. This work therefore reports the preparation of Low density polyethylene filled with nanometer scaled octadecylamine modified Ghanaian clay particles, and determines the structure of the material formed. Commonly known clay samples from Mfensi community in the Ashanti Region of Ghana was used. Octadecylamine modified clays were incorporated into the LDPE matrix by melt mixing route. Structure of the LDPE/ clay nanocomposites was determined by Fourier Transform Infrared spectroscopy, (FTIR), x-ray diffractometry (XRD) and crosslinking density determination. Swelling index measurement was employed in the crosslinking density determination. Complete dispersion of clay fillers in LDPE matrix were best observed at very low modified clay loadings. The low density polyethylene molecules did not intercalate into the clay galleries. Modified clay contents increased the C-H vibrational motions of the LDPE/ clay nanocomposites. Also crosslinking densities of the nanocomposites decreased with increasing clay contents. We believe that dispersion of the polymer, (LDPE) in the clay matrix can be increased by applying high shear. Improving the dispersion will lead to increase of the LDPE loading in the clay composite.
Homogenization of Film Thickness in the Stretching of Polycarbonate
In order to study the homogenization of film thickness in the production of self-reinforced polycarbonate through stretching, it is first of all necessary to find appropriate methods for characterizing this homogenization. Different means of doing this are analyzed in this paper, and initial results presented. One way of characterizing the homogenization of the film thickness is through a double logarithmic plot of the true stress over the stretching ratio. Polycarbonate films are deformed in stretching investigations, employing different stretching ratios, stretching temperatures and stretching speeds and, in the course of this, the force versus the deformation is recorded. It is seen here that the degree of hardening is highest for the lowest stretching temperature in each case, and only at this temperature does homogenization of the film thickness occur that is independent of the stretching rate and the stretching ratio. This is also clear from the initial modeling results. The homogenization of the film thickness through deformation can be depicted by the finite difference method. Optical analyses using the 3D laser microscope allow the surface quality of the polycarbonate films to be analyzed before and after stretching.
Effective Blending of Ultrahigh Molecular Weight Polyethylene with Polythylene Via Solid-State Shear Pulverization
Blending ultrahigh molecular weight polyethylene (UHMWPE) with high-density polyethylene (HDPE) via conventional processing methods is challenging; as a result of the vast viscosity mismatch between UHMWPE and HDPE, blends prepared via melt processing contain UHMWPE agglomerates dispersed in HDPE. We demonstrate the utility of solid-state shear pulverization to effectively blend 20 wt% UHMWPE with HDPE. Using rheology, differential scanning calorimetry, and tensile testing we studied the effect of UHMWPE composition on blend properties.
Post-Curing Effects on Thermo-Mechanical Properties of Injection Molded High Performance Phenolics
Constantly increasing temperature requirements for automotive applications take thermoplastic materials to their limits. Due to their excellent thermo-mechanical properties, which can be enhanced by an additional post curing step, injection moldable thermosets have a high potential as an alternative to high temperature thermoplastics or aluminum. In the scope of this paper the influence of post curing conditions on the thermo-mechanical properties, such as glass transition temperature as well as stiffness or tensile strength are examined.
Synthesis and Corrosion inhibition of polyurea-b-polyimide copolymer Coatings
A new class of polyurea-polyimide (PUI) block copolymer coatings has been successfully synthesized and formulated for corrosion protection of Al 2024-T3. The addition of polyurea leads to a remarkable enhancement in corrosion resistance and durability of PUI copolymer coatings, characterized by direct current polarization (DCP) in 3.5 wt% NaCl solution. In terms of chemical structure, the shielding of imide group by hydrogen bond (H-bond) self-assembly with polyurea effectively protects imide ring from hydrolysis. In terms of physical structure, the established H-bonds decrease the diffusivity of coatings, resulting in outstanding barrier property.
Scientifically Designed Barrier Screw
Single-screw extruders are most widely used in processing plastic materials for melting solid plastic into molten state, suitable for forming into desired shapes. The performance of an extruder basically depends on the geometrical feature of the screw. Among various types of special screws developed to improve the extruder performance, barrier screws utilizing a barrier flight have been most successful. The barrier flight divides the screw channel into a solid channel and a melt channel. Only molten plastic material can flow over the barrier flight from the solid channel into the melt channel. Many types of barrier screw with different geometries have been developed and successfully utilized in practice. Advances in machining screws now allow manufacturing of screws with complex geometries without difficulty. A novel barrier screw with a complex geometry is developed which confirms to the extrusion mechanisms along the screw, eliminating the shortcomings of previous barrier screws.
Effects of a Locally Inhomogeneous Atmospheric Pressure Plasma Treatment on the Adhesive Strength
To improve the adhesive strength of bonds for joining thermoplastic parts, atmospheric pressure plasmas are frequently used for pretreatment. To increase the width of the treatment, nozzle designs are deployed with an eccentric orifice rotating around the central axis of the nozzle. This rotating movement of the emerging plasma can result not only in inhomogeneous jet formation but also in uneven pretreatment. To examine the effects of inhomogeneous atmospheric pressure plasma treatment on the properties of the adhesive bonds, peel tests were performed with adhesives on pretreated thermoplastic substrates. Various locally inhomogeneous surface states were achieved by the pretreatment while varying some of the parameters such as the distance between orifice and substrate, velocity, and the position and diameter of the plasma orifice. To describe the intensity distribution of the plasma on the substrate surface, a mathematical model was developed and compared with the attained bonding properties. The results of the peel test correlate well with the modeled intensity distribution of the plasma treatment. In future, this model could be used to obtain a better description of the locally different adhesive properties after atmospheric pressure plasma treatment.
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