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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Nucleation and Crystallisation of PLA
Unless it can be properly crystallized, the field of applications for poly(lactic acid) will be limited by its low glass transition temperature. This paper discusses different strategies that can lead to partial crystallization within typical polymer processing conditions. X-ray techniques and DSC analysis are used to access the crystalline content developed in various molding and extrusion conditions and as a function of plasticizer and nucleating agent content.
Grooves in Scratch Testing
For a number of polymers with different chemical structures and different properties, we have determined scratch resistance and sliding wear. We have determined cross section areas of the grooves including the groove and side top-ridge areas. The nanohardness of the polymers was also determined using nanoindentation testing both inside and outside the grooves. A relationship between the hardness and the groove areas has emerged.
Interaction of HALS and Colorants
A series of colorants including yellows, reds, blues and greens have been evaluated when processed with monomeric and oligomeric HALS in PP and HDPE. Comparisons have been done in masstone and tint looking at effects on color shift and strength.
Development of a Composite Thermal Barrier Coating
A comparison between commercially available and a newly developed thermal management coating applied to steel substrates is presented. A successful coating must protect a thin 76 by 152 mm steel plate during a direct flame test and withstand low temperature flexural tests without cracking or delaminating. The only coating to meet both requirements is the newly formulated composite consisting of fiberglass in a silicone matrix.
Advances in Vibration Welding Techniques Allow Welding Multipiece Console Assembly
Advances in vibration welding tooling and machinery will offer manufacturers of center consoles a cost effective alternative to current methods. This concept will offer improved manufacturing flexibility and enhance overall performance. We will discuss the tooling and machine concept. This concept is the first of its kind and addresses the issues associated with welding multiple thermoplastic parts in a single operation using the vibration welding process. The tooling and concept are patent pending.
Interfacial Interactions in Polymer Thin Films and Polymer Nanocomposites
Polystyrene (PS) thin films were spun-coat on graphite and silicon oxide surfaces to resemble the polymer-substrate interface in carbon and organoclay based nanocomposites. The film thickness was varied and the apparent glass transition temperature (Tg,a) were investigated by using nanoparticles embedding technique. The PS on these substrates shows different Tg,a profiles, depending on the polymer-substrate interactions. These results will provide valuable guides for rational design of new polymer nanocomposites.
Sharkskin and Melt Fracture of Some Biodegradable Polymers
Sharkskin and melt fracture phenomena have been investigated in two commercial biodegradable polyesters– aliphatic-aromatic co-polyester (AAC), poly(lactic acid) (PLA) and their blends. The study was conducted in a two bore capillary rheometer. It was observed that at high shear rates and stresses PLA exhibits sharkskin and gross melt fracture, while AAC exhibits only gross melt fracture. Experiments indicate that the blends exhibit both phenomena and that blending is beneficial for postponing the onset of flow instabilities to higher shear stresses.
Application of Tapping Mode Atomic Force Microscopy for Measuring Relative Interface Thickness in Multilayer Polyolefin Films
In any polymer blend system, the nature and thickness of the polymer interface can have a significant influence on the overall performance of the blend. AFM in tapping mode (TMAFM) was employed to establish a systematic methodology to quantitatively measure the relative interface thickness in coextruded multilayer films.
Wettability of Photografted Deep-Groove Polypropylene Fibers
This paper presents photografting as a surface modification method to provide permanent wettability improvement to deep-groove polypropylene (PP) fibers. We also describe approaches to evaluate the wettability of these fibers and the wicking performance of fiber bundles when polyacrylamide (PAAm) was grafted onto the fibers. In this study, the concentration of the monomer and the UV-exposure time were altered to examine the effects of those variables on fiber hydrophilicity. Results showed lower water contact angle and improved wicking capacity upon modification with PAAm.
Stabilizer Additives R&D for Polyesters: Their Incorporation Inpolymerization Versus Downstream Compounding
The development and incorporation of stabilizer additives for bottle resin polyesters is increasingly more challenging and sophisticated. The diversity of polyester production processes and applications provide many possible insertion points for new additive technologies (1-3). Depending on the polyester problem it may be more effective to incorporate an additive in-polymerization (‘upstream’) versus (‘downstream’) compounding or converting. This paper discusses strategies for protecting polyester properties like color & thermal stability.
Nanomechanical and Nanotack Properties of Polymer Composites
Joining and adhesive properties of polymeric composites are of critical importance for emerging applications in the aeronautical, aerospace and marine industries. Traditional macroscopic adhesion testing techniques evaluate macroscopic properties of materials, with limited information on the molecular level processes that control actual performance. Nanomechanical and nanotack evaluations utilizing advanced nanoprobe techniques of polymer/fiber composites reveal differences in performance at the molecular level.
Shear Rheology of Highly Filled Polymeric Suspension
Highly filled polymeric materials exhibit complex rheological properties. In this study the rheological characteristics of highly filled suspension based on ethylene octane copolymer binder and Dechlorane filler were studied. Steady shear and thixotropic behaviors are discussed.
Multiphysics Based Progressive Failure Analysis for Cryogenic Composite Fuel Tank Design
Thermal residual stresses, internal fuel pressure and acceleration stresses during launch stage were evaluated and quantified for cryogenic composite fuel tank design. Fuel leakage induced temperature variation through laminate thickness after initial cracking was applied to a progressive failure analysis. Comparison of the results with conventional failure analyses was performed. Critical temperature and pressure conditions for failure initiation and whole laminate cracking were found based on the failure analysis.
Luminance of Injection Molded V-Groove Light Guide Plate
The luminance of an injection molded V-groove light-guide plate (LGP) was found to be affected by the depth of melt filling of the grooves. Imperfections in filling are influenced by local pressure and temperature histories. The measurements of the depth of melt filling were carried out at different locations using two optical grade polycarbonate (PC) moldings obtained at various processing conditions.
Cavity Temperature Control during the Cooling Cycle in an Injection Molding Machine Using a Predictive Controller
An approach to controlling the cavity temperature of the molded part during the cooling cycle of an injection molding machine is developed. The controlled variable is chosen as the average cavity temperature which is used during the cooling cycle. The coolant flow rate in the mold is used as the manipulated variable. An adaptive predictive controller is used to maintain a given average cavity temperature setpoint with existing disturbances. The control strategy was simulated and tested in an industrial scale injection molding machine.
Surface and Interfacial Studies of Plant Biopolymers
The outermost surfaces of plants are covered by a cuticular membrane which modulates the interactions of the plant with its environment and provides a protective barrier to pathogens. As this interface is a composed primarily of a biopolymer, physical methodologies for their study of polymer mechanical behavior and chemical make-up can provide molecular level details of these systems. In this paper we will briefly describe so important questions in plant biology and the methodologies needed to address these problems which can be found in polymer and physical chemistry.
Effects of Drying Conditions on the Morphology and Performance of Sulfonated Poly(Arylene Ether Sulfone) Copolymer Films for Proton Exchange Membranes
Sulfonated poly (arylene ether sulfone) copolymer has been shown to be a promising material for proton exchange membranes for fuel cell via a lab-scale batch solution casting followed by a mild radiation drying. The effects of the conditions of intense forced convection air on the morphology and performance of this copolymer film have been investigated for industrial production.
Industrial Applications of Heat Sealing Modeling
A mathematical model and computer simulation describing the constant heat sealing process for linear, semi-crystalline polymer films has been applied to heat sealing process optimization. Among the applications explored are the identification of a sealant resin melt index range that ensures maximum heat strength achievement for a prescribed dwell time, the development of sealing conditions for controlled frangibility seals, and heat sealing equipment specification and selection.
Continuous Film Casting and Evaluation of Novel Polymer Membranes for Fuel Cells
A continuous solution film casting process was studied for manufacturing novel polymer membranes for PEM fuel cells. A lab reverse roll casting machine was built and used to cast membranes with typical thickness of 25 micron to 50 micron. Investigation was made to establish the casting and drying conditions to produce voids-free, uniform membranes with desired thickness. The proton conductivity, mechanical properties and morphology of the membranes were evaluated.
Permeability of Flake-Filled Barrier Membranes: A Numerical Evaluation
Direct numerical simulations are conducted in two dimensions to compute the permeability of membranes filled with aligned flakes. The effects of flake aspect ratio, volume fraction, spatial distribution and size dispersion are examined. Lots of simulations have been carried out using a fast multipole-accelerated boundary element method, and the results are compared to some of the existing models.
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