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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Effect of Varaible Fiber Orientation on Material Properties in Extruded Polymer Composties with Multi-Scale Additives
In this experiment, carbon microfibers and multi-walled carbon nanotubes were compounded into a poly-butylene terephthalate polymer matrix. PBT-based composites were compounded in a co-rotating non-intermeshing twin-screw extruder with various fractions of carbon microfiber and multi walled carbon nanotubes additives. In addition, two dies ? straight and divergent ? were used to explore differences in physical properties.
Mechanical and thermal properties were tested and the results compared for straight and divergent dies. Optical images were analyzed to study the behavior of microfibers in flows through straight and divergent channels. A correlation was shown between the die type, the structure in the optical images and the physical properties.
Degradation Analysis for Polyethylene of Raised Temperature Resistance after Long-Term Hot Water Immerssion and Hot Air Exposure Tests
Polyethylene is widely used as a lifeline pipe for water and hot water supply plumbing in domestics. Recently, plastic pipes are required the performance of not only long service life but also recyclability. Non cross-linked polyethylene with durability and recyclability are beginning to use for heating pipes, for instance the polyethylene of raised temperature resistance (PE-RT).It is meaningful that the degradation of the PE-RT mechanism at high temperature is revealed for developing higher durability pipes and diagnosing used pipe?s deteriorations
In this study, as non-cross-linked polyethylene acceleration testing of PE-RT test piece was performed for long term under hot water and air condition to clarify the degradation state chemically compared with mechanical and anti-oxidation properties. FT-IR and Raman mapping method was used to examine the distribution of oxidation state, anti-oxidant additives quantity and crystallinity.
The oxidations of polyethylene were not found, but anti-oxidant additives were remarkably reduced, which coincided with oxidation induction time (OIT) decrease. It was found particularly in about 80 ?m from the surface of only hot water test samples, the reduction was accelerated because of the elution to hot water. The tensile strengths were increased compared with initial and almost the same regardless of test times. The heat of fusion varied similarly with the tensile strength, which means thermal crystallization. On the other hand, tensile elongations at break were slightly reduced at long time. It was found the dispersion degree of crystallinity was bigger over test time from the analysis of Raman peak intensity ratio (crystal to amorphous) and the dispersion in hot air are remarkable. This inhomogeneous crystallinity is assumed to decrease the elongation by deformation or defects in micro region.
Modified Soybean Oil Plasticizer in Carbon Black Filled Sbr
Soybean oil (SO) was modified through the reaction with dicyclopentadiene (DCPD) at a pressure of 0.14-0.21 MPa and a temperature of 240øC. Carbon double bonds in the soybean oil molecules were converted into norbornyl groups of different ratios. SBR compounds with 60 phr of carbon black (CB), 30 phr of different extender oils including SO, modified SO (MSO) and naphthenic oil (NO) were prepared. The gel fraction, crosslink density, curing behavior, mechanical and dynamic properties and reactions between the SO, MSO and curatives were investigated. It was found that with an increase of the modification level, the gel fraction of the SBR/MSO vulcanizates slightly increased while the crosslink density decreased. The SBR/MSO compounds exhibited faster curing. Their vulcanizates showed lower modulus and higher elongation at break and tensile strength in comparison with the SBR/NO vulcanizates. The tire performance predictors based on the dynamic mechanical analysis indicated that the use of SBR/MSO compounds in tire tread expected to improve traction but increase rolling resistance compared to the SBR/NO compounds. After adjusting the curative recipe, the tensile properties and abrasion resistance of the SBR/MSO vulcanizates were tremendously improved. Use of this recipe is expected to achieve similar traction and lower rolling resistance compared to the SBR/NO recipe. The addition of MSO to SBR showed improved mechanical properties and had a promising possibility to replace petroleum oils in the rubber improving safety in tire production.
Correlating the Melting of Semi-Crystalline Polymers to the Shrink Wrapping Process in Shrink-Film Packaging Applications
Thermal collation shrink packaging technology involves the release of polymer orientation in the film upon heat exposure in the collation shrink heat tunnel. The selection of the resin, coextruded structure design, the extrusion film line design, and the process parameters all affect the polymer orientation and subsequent release to form the shrink package. In the typical shrink wrap process; the oven temperature and conveyor speed provide the required thermal exposure to release the polymer orientation causing the film to shrink.
It has been our experience in dealing with various customers in the Packaging industry that there exists a wide variation in the understanding of the relationship between polymer material science and the shrink process. We believe that bridging this gap would enable practitioners in the industry both design, as well as operate their shrink processes optimally.
This paper addresses the relationship between the melting processes of semi-crystalline polymers used for shrink film packaging application to the shrink process.
Development of Green Polymer Blends Made from Carbon Dioxide Based Polyol and Poly (Lactic Acid)
Poly(lactic acid) (PLA) and Poly(propylene carbonate) (PPC) polyol were melt-compounded to fabricate a novel polymer blend with balanced mechanical properties (tensile strength and ductility). Blend with 90wt.% PLA/10wt.% PPC polyol and 70wt.% PLA/30wt.% PPC polyol were prepared and evaluated in terms of mechanical performance. As for the blend with 30wt.% PPC polyol, two residence time have been applied (1min and 2min). It was found that 10wt.% loading of PPC polyol has an adverse effect on both tensile strength and elongation at break of the blend. Overall mechanical performance deteriorated with only 10wt.% PPC polyol. Major finding was that with incorporating 30wt.% PPC polyol in the polymer blend system, the ductility (elongation at break) of the blend significantly improved by 5000%. However, the tensile strength decreased drastically. The morphology of the blend was investigated through scanning electron microscopy (SEM).
Stimuli Responsive and Biomineralized Scaffold: An Implant for Bone-Tissue Engineering
Development of bioactive and stimuli responsive materials in the form of implant/scaffold is the urgent need that mimics the natural bone structure and function. To achieve such novel smart biomaterials ?PVP-CMC-CaCO3? scaffold was prepared using PVP-CMC hydrogel as a matrix, following the biomimetic mineralization process i.e. simple liquid diffusion technique. The main concern of this study is to establish its stimuli responsive nature as it is one of the important factor of biomaterials. The swelling-deswelling capacity of ?PVP-CMC-CaCO3? scaffold was carried out at 37oC using physiological solution. The morphological changes which occurred in the biomineralized scaffold during swelling-deswelling-reswelling and deswelling steps were confirmed using scanning electron microscopy. The obtained results concerning shape-size and thickness indicated that PVP-CMC-CaCO3, a hydrogel based scaffold is a true stimuli responsive biomaterial.
Rheo-Kinetic Study of a Model TPU System for Reactive Extrusion
Bulk polymerization of thermoplastic polyurethanes (TPU) in reactive extrusion is a very complicated topic. Understanding how to efficiently produce TPUs is dependent upon the relationship between the extrusion process and the polymerization. The goal of this study was to determine the response of the polymerization kinetics to both composition and shear rates. Rheological measurements were taken while concurrently collecting in situ Fourier transform infrared (FT-IR) spectra. The results indicated that polymerization kinetics were sensitive to both the hard segment (HS) composition of the system and the shear rate imposed on the system.
Environmental Qualification of Cables to IEEE Standards and End-User Specifictions
General Cable Corporation recently committed to a multi-year effort on development and qualification of 60-year life Class 1E cables. The major milestones achieved in the development include (a) Introduction of 60-year life nuclear cables in the industry (b) Approval of 60-year cables for service in the new nuclear power stations (Vogtle site and V.C. Summer site) and (c) Use in a new generation nuclear reactor power plant AP1000 designed and sold by Westinghouse Electric Company. Cable constructions tested were 600V cables, 2 kV cables and 15kV MV power cables. This paper presents the scope of overall qualification program and test results conducted per IEEE standards and end-user specifications. The cable testing will be discussed in relation to thermal aging and radiation exposure followed by DBE (Design Basis Event) accident conditions.
Fractographic Examination and Tensile Property Evaluation of 3D Printed Acrylonitrile Butadiene Styrene (ABS)
Acrylonitrile butadiene styrene (ABS) tensile specimens produced by 3D printing in two different orientations, injection molding, and subtractive machining were fractured by tensile overload in accordance with ASTM D638. In this study, the tensile properties and fracture surfaces of the different manufacturing methods are compared and contrasted using optical microscopy, computed tomography (CT) and scanning electron microscopy (SEM). CT reconstructions of the pre-failed tensile bars and images (optical and SEM) of the fracture surfaces are provided and discussed.
Soy- and Biochar-Based Fertilizer
Compounds of soy flour, biochar and a polymer matrix, such as PLA, have proven to be effective fertilizers comparable to commercial products. Prototype composites achieved NPK values of 2.85, 0.20, 0.49 and 3.08, 0.21, 0.48 %, respectively for PLA- and PHA-based composites. These composites only leached a fraction of nitrogen compared to a commercially available synthetic fertilizer. Low leachate values, as compared to commercial fertilizers, may be associated to the absorption and releasing of nutrients by biochar. The nitrogen within the soy is also not readily water soluble and is released over time by microbial action.
Study on the Relationship between the Degree of Crystallinity and the Ultrasonic Velocity for Poly(Lactic Acid) (PLA) Parts
The relationship between the degree of crystallinity and the ultrasonic velocity was analyzed in this study for injection molded poly(lactic acid) (PLA) parts undergoing an annealing process. An annealing process was first employed to produce PLA parts with different degrees of crystallinity. Next, a novel ultrasonic water immersion method was presented for calculating the ultrasonic velo?cities of these annealed PLA parts. Then, the ultrasonic velocity results were plotted with the crystallization re?sults from differential scanning calorimeter (DSC) mea?sure?ments for analysis. Experimental results show that the inverse effective ultrasonic velocity versus the degree of crystallinity over the whole crystallinity range for three different annealing temperatures show good linearity, with a correlation coefficient of around 99%. The linear rela?tionship observed in this study might provide a novel method for investigating the degree of crystallinity of semi-crystalline polymers in practical production.
Novel Porous Nano-Graphene/Polyimide Composite as Electrode Material
In this work, we have studied the electrochemical behavior of non-porous and porous nano-graphene/polyimide composite films fabricated by the thermal degradation of grafted flexible acrylic acid on polyamic acid backbone. It is observed that pore size distribution has a significant effect on specific capacitance and bulk resistance of the composite material. BET and Electrochemical impedance spectroscopy (EIS) data reveal a complex pore distribution for the materials. As the porosity of the composite material increased, its bulk resistance decreased by up to 400% and the specific capacitance increased by up to 200%. Ionic diffusion resistance associated with the pore structure for the porous composite decreased due to easy access of electrolyte ions through the pore length of the material. Specific capacitance of up to 34,240mF/g was obtained for the composite system at a scan rate of 50mV/s which remained fairly stable through the 50 cycle runs. Potassium hexaflorophosphate (KPF6) dissolved in propylene carbonate was used as electrolyte for all the electrochemical techniques.
Time Temperature Superposition Principle for Predicting Long-Term Response of Fique-Fiber Reinforced Polyethylene- Aluminum Composites
In order to design and manufacture natural fiber-polymer composites as structural components in existing and novel technological applications, the long term viscoelastic behavior of the materials must be understood. In order to do that, the time?temperature superposition principle (TTSP), is used to predict long-term viscoelastic behavior from short-term experimental data. Dynamic?mechanical analysis (DMA), was used to study the viscoelastic properties of composites made from fique mats and low-density polyethylene?aluminium (LDPE?Al) obtained from recycled long-life Tetra Pak packages. This paper reviews the effect in using Chemical treatments such as alkalinization with NaOH, silanization, and polyethylene impregnation treatments for composites, understanding the interaction mechanisms between natural fibers and the LDPE-Al; and presents the effects of treatments on the viscoelastic behavior. Fractographic evaluations in the scanning electron microscope (SEM) confirm the quantitative characterization obtained from DMA.
Study of the thermoelectric performance of GNP/PVDF and MWCNT/PVDF composites fabricated via melt blending method
Polymer based thermoelectric materials were usually fabricated using solvent casting methods in the past. However, such processes may involve the usage of highly toxic solvents and solutions. In this paper, we present the results of thermoelectric performance of poly(vinylidene fluoride) (PVDF) based thermoelectric material with graphene nano-platelets (GNP) and multiwall carbon nanotube (MWCNT) as fillers. The samples were fabricated though melt blending method, which is a cheaper, simpler process and can be easily scaled up to industrial level for mass production. Our results indicated that melt blending process can produce either similar or superior results compare to the traditional solvent casting methods. For GNP/PVDF samples, we have found a superior Seebeck coefficient approximately 200% higher compared to the value reported from previous studies, while the electrical and thermal conductivity show similar values. In addition, our melt blended MWCNT/PVDF samples showed a similar trend comparing to solvent casted samples that were reported in literature.
Steel Treatment of Mold Components - the Knowledge Advantage
Heat Treatment is defined as the controlled heating and cooling, of metals, in order to alter their physical and mechanical properties.
First, before the mold is designed, the Engineering department reviews the quote then employs proven methods of design, material selection, and heat treatment.
This understanding is the key to selecting the best material, for a particular component. Additionally, the ability to specify this, to your outside services, will provide the end result you desire.
All Engineers do not have metallurgy knowledge, therefore, the heat treatment processes defined below will include some of the language used by a Metallurgist. This will help when specifying treatments, on mold design components, and to better relate to the processes used.
Mold Undercut Solutions - Data Driven Advantages
When designing injection molds, many decisions are made while quoting. Parts are examined for entrapment or details that cause them. Solving entrapment issues requires creative undercut solutions. There are many undercut solutions offered today. The designer needs to know how to quickly select the correct option for the most efficient molding and tool building.
This paper addresses methods of releasing threads, snaps, hooks, holes and anything that has a mechanical action that must take place before a part can be ejected and the mold opened. Often a certain method is used for a mold that is traditional, but with a fresh look at the part and current solutions, the design can be simplified. This can result in lowering molding time, manufacturing time and ultimately cost.
This informative guide addresses the most common undercut conditions with simple and long-lasting solutions. It compares traditional methods to non-traditional methods and explains the advantages and disadvantages.
Evaluation of Mechanical Properties of Cellulose Composite
Cellulose nanofiber (CeNF) is generally provided by micronizing a plant fiber to a nanometer-size in diameter. A CeNF reinforced thermoplastic composite is recently expected to indicate integrated high performance concerning light weight, thermal resistance and mechanical strength. It is important to disperse and defibrate CeNF uniformly in a resin in the extrusion process. In this study, various compounds of microcrystalline cellulose (MCC), CeNF, PLA, and PP were made using additives by the extrusion process. The mechanical properties were also evaluated.
Pigment Design in the Modern Age
Modern inorganic pigments are no longer just colorants for visual appeal; rather, they are functional colored materials exhibiting a wide range of properties. This distinction is important as pigments now provide specific physical and chemical advantages in addition to bright colors. It is therefor important to understand the fundamental correlations between crystal structure and physical properties when designing new pigments. New research pushes the boundaries of traditional metal oxide pigments by utilizing unusual host lattices, new elemental combinations, and unique synthetic methods. This paper will establish the basic considerations of modern pigment design and discuss the recent advancements in blue pigments, namely in the YIn1-xMnxO3 family.
Development of Eggshell Powder Masterbatch for Food Trays
In Japan, eggs are widely used in many food products on the market, and 200,000 tons of eggshells are annually discharged and most of them get discarded.
Re-use of discarded eggshells into food trays is one of the efficient ways to realize a recycling-oriented society.
Many food trays consist of polypropylene or polystyrene, and sometimes recycled products. Thus, it is possible to use biomass materials such as eggshells as a bulking agent. Eggshells need to be compounded into resin when used in food trays, but the egg?s unique sulfur smell is emitted when applying heat in the manufacturing process.
In order to solve this odor problem, we compounded under different conditions with polypropylene and eggshell to research ways to reduce odor.
The results suggested that molding temperatures exert significant influence on odor generation.
By molding at the lowest temperature that enables resin to mold, a possible countermeasure for odor reduction is created.
Evaluation of the High-Powered Machining Processes of Fiber-Reinforced Composites in Relation to the Method of Clamping and Process Design
Fiber-reinforced composites assume a key function in lightweight design. Due to high material and manufacturing costs, the objective is the near net shape manufacture of composite components via the forming processes. Subsequent cutting processes such as deburring are, however, still necessary. This post-processing leads to a reduction in the mechanical properties, not only through the cutting of the continuous fibres but also through potential production-related damage. The excellent durability properties of fiber-reinforced composites are thus lost. In this paper it is assumed that the production-related reduction in the mechanical properties of composites with thermoplastic matrix is not only caused and influenced by the design of the machining process but also through the method of clamping the parts which is necessary during the process. The qualitative evaluation is done through microscopical determination of the surface damage and the inter-laminar damage through ultrasonic inspection. Following an accelerated ageing process under the influence of bending loads, the determination of the flexural strength is carried out.
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