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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How Important Is the Volumetric Absorption Concept? Part 2 - LPM
In part 1 of this series, I defined the equations and parameters for the subject. In Part 2, I examine how volumetric absorption influences time dependent heating rates for PE and PS in three thin-gauge thicknesses. I also compare these results to the effect of heater and sheet emissivities.
A Journey Toward Packaging Sustainability
Packaging sustainability has many contributing factors including: renewable materials; reduced package weight; recyclable materials; reduced food waste (for food packaging); and reduced packaging waste. These factors and interactions among them are described, along with examples of implementation.
Modelling Mechanical Behaviour of Amorphous Poly (L-Lactic Acid) under Biaxial Stretch at Temperatures above Glass Transition
Stretch blow moulding process has been applied to manufacture of bioresorbable vascular scaffold (BVS) made by poly (l-lactic acid) (PLLA) improve the mechanical properties of product. Biaxial stretching test was conducted to obtain the mechanical properties of amorphous PLLA materials at temperatures above glass transition. The glass-rubber (GR) constitutive model was adopted to model the mechanical behaviour and can be used for the simulation for the forming process.
Determining Stretch Properties from Purely Shear Data for Polymer Fluids
In this paper, we describe a methodology for determining elastic stretch properties of polymer fluids from purely shear data. The theory is founded on the basis of decoupled rubber elasticity and relaxation, to uncover the rubber elasticity portion of contribution to viscoelasticity. This would not only produce a means for linking shear with extension, but potentially would also provide a new paradigm for studying the relation between structure and deformation for dissipative materials. A case study is presented to emphasize the potential applicability of the methodology when only partial data is available.
Effects of Process Parameters on Cell Morphology of Microcellular Injection Molded Parts
A Taguchi DOE method was employed to investigate the effects of injection molding process parameters on cell morphology of microcellular foams. Melt temperature, mold temperature, super critical fluid (SCF) concentration, and shot size were considered. It was found that the cell size depended strongly on shot size. The results are helpful for designers to optimize the process conditions to achieve high quality microcellular part.
Novel Peek with High Flowability
Injection molding is a widely used processing technique for fabrication of high volume polyether ether ketone (PEEK) parts. The processing of PEEK at high melt temperatures with viscous resins can be challenging. A novel high flow PEEK with low melt viscosity (MV) has been developed to improve processability while retaining PEEK’s thermo-mechanical behavior. This article showcases high flow PEEK’s balance of properties in comparison to that of conventional PEEK and the processing advantages and the part performance benefits for injection molders and end-customers.
Ultrasonic Processing of Epoxy/CNT Nanopaper Composites
This work presents a novel ultrasonic infiltration approach for epoxy and multiwall carbon nanotube (MWCNT) nanopaper prepreg. The prepared prepregs and their nanocomposites demonstrated promising performance in processing flexibility, abrasion resistance, scratch resistance, EMI shielding, and thermal transfer properties for potential applications in wind energy, electronics, and automotive industries.
Creep and Recovery of Polylactic Acid and its Clay Nano-Composite
This work focuses on exploring the long-term rheological behavior of polylactic acid and its nano-composites containing 3% clay. Creep and recovery experiments were performed at 160°C for the neat PLA and its composite. Zero-shear rate viscosity was determined and used to determine the terminal relaxation time. Also, the continuous retardation spectra were calculated from the creep data and found to be consistent with those from the oscillatory data.
Innovations in Automotive Plastics "Applications"
SPE Automotive Innovation Awards
Innovations in Automotive Plastics "Materials and Processes/Enabling Technologies"
SPE Automotive Innovation Awards
The Study of Polyolefin Elastomer Effect on Soiling Resistance
Soiling resistance has been issued in automotive industry, which is a measure of soiling or dirt pick-up such as mud on the surface for the interior and exterior of automotive. In this study, the effect of thermoplastic olefin (TPO) composition on soiling resistance was investigated, which is widely used for those applications, and the design guide of polyolefin elastomer (POE) in the polypropylene (PP) compounds for the automotive parts was suggested.
Advancements in Nanocellulose Biomaterials: Opportunities for the Plastics Sector
• Types of Nanocellulose • Production Methods • Physical Characteristics • Surface Modification • Ongoing Research Areas • Case Study – Reinforced Plastics
Effectiveness of Silver Based Antimicrobial Immersed in a Universal Masterbatch
Healthcare Associated Infections (HAI’s) are a critical problem in hospitals as well as other healthcare delivery institutions. The Centers for Disease Control and Prevention (CDC) reports that on any given day about one in every 25 hospital patients has at least one hospital associated infection. These incidences of HAI’s at the least raise the patients healthcare costs and time in the healthcare delivery institution and, at worst, cause death to affected patients. The battle to prevent HAI’s in healthcare delivery institutions is carried on via many different methods including sterilization of devices, disinfectant cleansing of hospital surfaces, UV lamps in patient rooms, surface engineering of polymers, as well as functionalizing polymers that are used in medical devices and medical substrates with an antimicrobial additive. Silver based antimicrobial additives have an excellent history regarding the prevention of HAI’s in the medical market. The silver additive can be added straight into the polymer melt stream as it is being compounded or it can be incorporated into a carrier masterbatch that is added into the polymer melt stream. The use of a “universal” masterbatch carrier that the silver antimicrobial is employed into can be an efficient and effective method for functionalization of a polymer to make it antimicrobial. This presentation will focus on the effectiveness and efficiency of a silver based antimicrobial additive employed into a universal masterbatch for deployment into a polymer melt stream. It will present testing, test methodology, and test results regarding silver release testing, ash testing, efficacy testing in ABS, polycarbonate, and TPU.
A Model for Permeability Reduction in Polymer Nanocomposites
A simple theory that builds on the tortuous path concept is developed to quantitatively predict mass transport through a polymer containing dispersed nanoplatelets, and data are presented on polylactic acid (PLA)-matrix nanocomposites. PLA is a bioderived biodegradable polymer that is being employed in food packaging where the plastic is discarded after a single use. However, the poor water vapor barrier property of PLA limits its use in this regard, and it is of interest to reduce moisture permeability through this polymer. In the present work, Cloisite 30B, an organoclay that is compatible with PLA, was dispersed in the polymer via melt-mixing, and processing conditions were optimized to reduce platelet agglomeration. Nanocomposite morphology was characterized with transmission electron microscopy, and moisture permeability was measured as a function of clay content. There was good agreement with the proposed theory, and it was found that at a 5.3 vol% filler loading the water vapor permeability was reduced by almost 70%.
Synergistic Effects of Antioxidants (AO) on Properties of Homo Polypropylene
Antioxidants (AO) are used to protect the polymer from deterioration either during extrusion or after production. Probably two types of Antioxidants are used to protect polymer, primary antioxidant (phenol type) and secondary antioxidant (phosphate type). The performance ratio of both the antioxidants is depend on its process technology, processing conditions and its application. To understand the effect of each antioxidants on HomoPP, different samples at different AO dosage were extruded. Relevant product properties such as mechanical, physical and rheology were measured. The test result obtained elucidates that the polymer recipe is a balance of additives to meet the requisite end product properties under the employed processing conditions.
Lateral Torsional Buckling of Anisotropic Laminated Thin-Walled Rectangular Simply Supported Composite Beams Subjected to Pure Bending
In this paper, a generalized analytical approach for lateral-torsional buckling of simply supported anisotropic, thin-walled, rectangular beams under pure bending condition was developed using the classical laminated plate theory as a basis for the constitutive equations. Buckling of such type of members has not been addressed in the literature. A closed form buckling expression is derived in terms of the lateral, torsional and coupling stiffness coefficients of the overall composite. These coefficients are obtained through dimensional reduction by static condensation of the 6x6 constitutive matrix mapped into an effective 2x2 coupled weak axis bending-twisting relationship. The stability of the beam under different geometric and material parameters was investigated. The analytical formula is verified against finite element buckling solutions using ABAQUS for different lamination orientation showing excellent accuracy.
Analytical and Finite Element Buckling Solutions of Fixed-Fixed Anisotropic Laminated Composite Wide Plates under Axial Compression
Using Rayleigh-Ritz approximation, a generalized analytical buckling formula was developed of generally anisotropic laminated fixed-fixed composite plates. Using the generalized constitutive equation, the effective extensional, coupling, and flexural stiffness coefficients of the anisotropic layup are determined using dimensional reduction by static condensation of 6x6 composite stiffness matrix. The resulting explicit formula is expressed in terms of the flexural stiffness coefficients as well as the plate geometry. In order to decrease some of the discrepancy in some of the results, the coupling and extensional effect was considered through the substitution of the pre-buckling solution into the bifurcation expression to yield a new formula. The analytical results are verified against finite element Eigen value solutions for a wide range of anisotropic laminated layups yielding high accuracy. A parametric study is then conducted to examine the effect of ply orientations, material properties and type of element in FE analysis. Relevance of the numerical and analytical results is discussed for all these cases.
Optimizing Fused Deposition Modeling 3D Printing Process for Fracture Resistance
The quality of fused deposition modeling (FDM) 3D printed parts are primarily influenced by the process conditions and mesostructural features. This study aims to establish the relationships between the process parameters/mesostructural features and the fracture resistance of printed parts. Double cantilever beam specimens of ABS were printed at different nozzle and bed temperatures, and with different layer height and layer width and then fracture-tested to measure the fracture resistance using J-integral in a finite element model. The result indicated that nozzle temperature and layer height had the most significant effects on the fracture resistance. The fracture resistance increased by ~30% with 20°C increase in the nozzle temperature. The bed temperature and the layer width appeared to be less significant factors, compare to the nozzle temperature. The results of this work establish insight and guidance in the design of printed materials for structural and functional applications.
Method to Evaluate Biaxial Stretch Ratios in Stretch Blow Molding
The structural performance of poly (ethylene terephthalate) (PET) films depends on material distribution and microstructural changes in PET from stretching. Biaxial stretching during processes such as blow molding creates a specific thermomechanical history of the film, which determines material properties. The dependence of PET film crystallinity and the resulting mechanical properties on stretch ratios makes them a critical parameter in designing an efficient lightweight design. Therefore, it is important to have a method which can provide accurate material distribution information along with local stretch ratios. Such material efficiency can be applied to container design. In this work, we introduce a method to track material distribution from a “preform” to a “bottle” during a two-step injection stretch blow molding process and evaluate the stretch ratios.
Numerical and Experimental Analysis of Infill Rate on the Mechanical Properties of Fused Deposition Modelling Polylactic Acid Parts
Material characterization of 3D printed PLA parts with different infill rates was performed by standard tensile tests. Three-dimensional finite element simulations of the tensile tests were also performed. For the simulations, a method for reconstructing the CAD model of the printed parts with different infill rates was proposed and numerical simulations were conducted on the reconstructed models. A reasonable prediction of the experiments in terms of material behavior and the stress-strain characteristics for infill rate of 100% is obtained from the numerical analysis. Discrepancies between the numerical predictions and experimental results especially in the plastic deformation region for other infill rates are discussed in the paper.
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