SPE Library
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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
Not an SPE member? Join today!
| = Members Only |
|
Categories
|
Conference Proceedings
Fluidized Bed Degasification for Removing Unreacted Monomers in Continuous Mass Polymerization
The feasibility of a fluidized bed degasifier design where removal of polymer residuals to low levels as expected by the regulatory agencies is evaluated. Mass transfer models are needed to quantiate the devolatilization efficiency. The relative importance of the diffusive and convective transport mechanism varies as a function of the flow physics in the fluidized bed degasifier. The conditions of operation suggested are sub glass transition temperature of the polymer and subatmospheric vacuum pressures.
Spreadsheets and Simulation in Polymer-Polymer Phase Diagrams
The compositional window of miscibility of two terpolymers can be calculated using a spreadsheet. The results are presented as a function of the compositional mismatch. The @RAND key was used to demark the miscible regions from the immiscible ones in the entire compositional range (n x m x k x 1 or n4) of the terpolymer. The computations were completed in cN or n time. The spinodal for miscible systems can be constructed and the LCST and UCST behavior captured.
Failure Analysis Models for Polyacetyl Molded Fittings in Plumbing Systems
Plumbing fittings molded from polyacetal resins have been studied after removal from service. Methods of failure analysis will be reviewed and failures will be correlated with time in service and water chemistry. The progression of failure will be described and related to the calculated stresses in the fittings.
New Twin Screw Element Design for Elastomer Compounding
A new mixing element design reduces the shear heat buildup normally seen with elastomer based compounds. This enables mixing these formulations at rates not achievable with standard design elements. The geometry of this element retains the general self-wiping characteristics usually found with fully intermeshing, co-rotating twin screw compounders, yet reduces the maximum pressure seen in the apex area. Process examples demonstrate the different responses seen with these mixing elements versus standard design elements.
Analysis of Halo Effects on Injection Molded Parts
The problem of a specific type of surface defect called tiger stripes" or "halos" on the injection molded parts of the thermoplastic olefin blend is investigated. First the method to reproduce such defects on the small parts is described and then the results of a rheological method to predict materials prone to producing tiger stripes are presented. Results indicate that both the molecular weight and relaxation behavior are critical determinants. Materials with large molecular weights as predicted by very high melt viscosity at zero shear rate and short relaxation time tend to form less tiger stripes."
Analysis of Halo Effects on Injection Molded Parts
The problem of a specific type of surface defect called tiger stripes" or "halos" on the injection molded parts of the thermoplastic olefin blend is investigated. First the method to reproduce such defects on the small parts is described and then the results of a rheological method to predict materials prone to producing tiger stripes are presented. Results indicate that both the molecular weight and relaxation behavior are critical determinants. Materials with large molecular weights as predicted by very high melt viscosity at zero shear rate and short relaxation time tend to form less tiger stripes."
Processing Variables and the Scaling Parameters in Blown Film Extrusion
Five critical blown film extrusion variables to the formation of morphology of blown film and thus, mechanical/physical properties were identified. For the identified critical processing variables, mathematical expressions of scaling parameters were derived in terms of scaling factors. The scaling factors ?, ?, q, and z are the ratios of die radii, die gaps, output rates, and frost line heights, respectively, of two different blown film extrusion lines. It was found that the scaling parameters should satisfy the following conditions to ensure a proper scaling from one film extrusion line to another.
Synchrotron Studies of Polymers: An Industrial Perspective
The advantages inherent in synchrotron radiation from an insertion device for studies of oriented polymers are discussed. The relevance of these capabilities for industrially related R&D studies is examined. Increased intensity over lab sources makes possible real-time studies under conditions similar to those encountered during processing. Applications resulting from the highly collimated radiation include mapping spatial variations of structure in films or injection molded plaques. Control over the incident energy provides further advantages. Some illustrative examples are provided.
Electrical Properties of Carbon Black(CB)-Filled Polypropylene/Ultra-High Molecular Weight Polyethylene Composites
Carbon black(CB)-filled polypropylene(PP) /ultra-high molecular weight polyethylene (UHMWPE) composites were prepared by the conventional melt-mixing method. The electrical resistivity, positive temperature coefficient(PTC) effect, and morphology of the composites were elucidated in detail. CB particles were found to be selectively localized at the interface between PP matrix and UHMWPE particles or in the PP matrix due to the extremely high viscosity of UHMWPE. Double-PTC effects were also observed and discussed.
Solid State FTIR Analysis of Hydrogen-Bonded Domains in Synthetic Biopolymer Hybrid Silk-Like Materials
Novel silk-like hybrid-peptide polymers containing either parallel or anti-parallel ?-sheets templated by either phenoxathiin or xanthene derivatives have been prepared. Solid state FTIR spectroscopic studies confirm the presence of ?-sheets in the polymers. Building blocks that do not contain the rigid templates do not readily form the sheet structures.
LFT and GMT
Glass mat thermoplastics (GMT) are currently state-of-the-art materials for compression molding, with still hugh potentials. In Europe their unique position is attacked through the use of Long fibre thermoplastic (LFT) materials which are processed through the use of extrusion compression molding. Although raw and semi-finished product producers are fighting a media battle, it will be discussed how both materials can nicely exist alongside from the viewpoint of a finished product producer.
Time Dependent Crack Growth in Polyethylene with Emphasis on Environmental Attack
This research seeks to determine the effect of chlorinated hot water on slow crack growth resistance in polyethylene using a test methodology that is quick and inexpensive. This will be done through the use of three point bend tests on specimens completely immersed in a bath of chlorinated hot water. The results will then be compared with results from the same test run without chlorinated hot water. Comparative data will be used to determine chlorine's effect.
Crystallization Behavior and Crystal Morphology of HDPE-Molecular Weight Dependence
A series of high density polyethylene (HDPE) fractions with molecular weight ranges from 1,600 to 325,000 g/mol have been investigated. The results of overall crystallization kinetics study by DSC indicate that the crystallization rate and the Avrami exponent (n) vary with molecular weight and undercooling (?T). Basically, the fraction with a lower molecular weight shows a higher crystallization rate. PLM, TEM and x-ray scattering technique were used to study the crystal morphology under different ?T's. Typical spherulites, axialites and asymmetrically shaped single crystals were observed.
Fatigue Stress-Life Characterization Approach for Continuous Glass Fiber/Thermoplastic Composites
The long-term mechanical behavior of continuous glass fiber/thermoplastic composites has been addressed in terms of flexural fatigue stress - life curves. Contrary to other engineering materials submitted to cyclic loading, generally showing a significant stiffness reduction near the end of their fatigue life, the fatigue response of continuous glass fiber/polypropylene (PP) composites shows a progressive damage accumulation that must be considered when fatigue stress - life curves are reported. A fatigue life characterization methodology is proposed.
Vibration Molding of Thermoplastic Composites
VIM (Vibrational Microlamination) is a new technology in the physical sciences. In VIM development, the physical, the chemical, and engineering technologies have been combined to contribute effective new knowledge.
Effects of Molecular Structure on Macroscopic Mechanical Properties of an Advanced Polymer (LARC™-SI)
Mechanical testing of an advanced polymer resin with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The elastic properties, inelastic elongation behavior, and notched tensile strength all as a function of molecular weight and test temperature were determined. It was shown that notched tensile strength is a strong function of both temperature and molecular weight, whereas stiffness is only a strong function of temperature.
Structure-Mechanical & Dynamic Mechanical Properties Relationship in Polyamide Based Thermoplastic Elastomeric Blends and Blocks
Dynamic mechanical and mechanical properties of segmented polyamides composed of polyether and polyamide structural units of varying block lengths and thermoplastic elastomeric reactive blends of polyamide and acrylic rubber of varying interactions have been studied. The results are explained on the basis of the chemical structure and morphology of the systems.
Choosing a New Future - A Look at the Current Polystyrene Industry from Global and Market Perspectives and Opportunities for Stronger Growth
In a highly uncertain international business environment, the polystyrene industry still has attractive opportunities and needs to plan now to take advantage of the next turnaround when economic conditions improve. The industry has the power to choose its future by taking the right steps now to prepare for the opportunities that will emerge with the upturn.
Prediction of Complex Dynamic Behavior from Simple Deformations
Many researchers have noted that characterizations based on sinusoidal tests alone provide misleading information regarding materials used in non-sinusoidal periodic applications. However, availability of commercial instruments that can evaluate materials in complex periodic deformations is rare. To address this problem, various nonsinusoidal periodic deformations are applied to a nitrile elastomer using a torsional rheometer and suitable modeling is employed to predict the behavior. Also it is shown that complex dynamic behavior can be predicted from simple deformations.
Capturing PVT Behavior of Injection-Molded Parts Using Hybrid Methods
Polymer crystallization is the primary mechanism for shrinkage in semi-crystalline molded parts. Injection molding CAE utilizes PVT data to provide information about crystallization. Conventional PVT measurements do not reflect the true shrinkage behavior of the plastic because they do not subject the polymer to the same kind of thermal history as seen in the actual molding process. We introduce a novel hybrid technique to characterize the PVT relationship of molded parts, which accounts for cooling rate effects.
|
This item is only available to members
Click here to log in
If you are not currently a member,
you can click here to fill out a member
application.
We're sorry, but your current web site security status does not grant you access to the resource you are attempting to view.
.jpg)
.jpg)
.jpg)
.jpg)
