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Conference Proceedings
AN EXPERIMENTAL INVESTIGATION INTO MELT PUMP PERFORMANCE
Melt pump performance and efficiencies will vary according to the viscosity of the resin being pumped, and the discharge pressure that the melt pump will need to overcome. Resin melt temperature differences and power requirements of the pump, will vary according to the resin, and conditions that the pump will operate under. This paper will explore the processing differences in (3) resins on gear pump performance at (4) different pump speeds, at three different discharge pressures. Discharge pressures on the pump will be varied keeping the suction pressure constant, thus increasing the change in pressure across the pump. Melt temperature, and pump efficiency. melt pump motor amperage, and total output, (kg/hr) will then be measured and recorded.
EFFECT OF ALUMINA NANOPARTICLES ON THE PROPERTIES OF LOW-VISCOSITY CYANATE ESTER ADHESIVES FOR COMPOSITE REPAIR
Polymer matrix composites (PMCs) are susceptible to microcracks and delaminations from impacts and thermal/mechanical loadings that greatly reduce their mechanical integrity. This is especially a problem for high-temperature PMCs because current repair resins have low glass transition temperatures (Tg's) that stem from the low prepolymer viscosities required of injectable resins. Bisphenol E cyanate ester has both a high cured Tg and low prepolymer viscosity, ideal for the injection repair of high-temperature PMCs. Alumina nanoparticles were incorporated to improve adhesive strength and engineer prepolymer viscosity. Lap shear tests were performed to evaluate the effects of alumina nanoparticles on the adhesive strength of the resin.
TRANSIENT RHEOLOGY OF A POLYPROPYLENE MELT REINFORCED WITH LONG GLASS FIBERS
The purpose of this research is to
understand fiber orientation of long glass fibers
(> 1mm) in polymer melts and the associated
rheology in well-defined simple shear flow.
Specifically, we are interested in associating the
rheological behavior of glass fiber reinforced
polypropylene with the transient evolution of
fiber orientation in simple shear in an effort to
ultimately model fiber orientation in complex
flow. A sliding plate rheometer was designed
to measure stress growth in the startup and
cessation of steady shear flow. Results were
confirmed by independent measurements on
another sliding plate rheometer13. A fiber
orientation model that accounts for the
flexibility of long fibers, as opposed to rigid rod
models commonly used for short fibers, was
investigated and results are compared with
experimentally measured values of orientation.
The accuracy of this model, when used with the
stress tensor predictions of Lipscomb, is
evaluated by comparing against experimental
stress growth data. Samples were prepared with
random initial orientation and were sheared at
different rates. Results show that fiber
flexibility has the effect of retarding transient
fiber orientation evolution. Additionally, it is
shown that the stress growth measurements
provide results that are not fully explained by
the chosen models.
CHALLENGING THE PARADIGM OF MICROCELLULAR FOAMS: MECHANICAL PROPERTIES OF LOW-DENSITY CYCLO-OLEFIN COPOLYMER FOAMS
Low-density foams of ethylene-norbornene
copolymers were produced and their mechanical properties
in compression investigated. Microcellular morphologies
were observed with mean cell diameters lower than
20 ?m. Although the cyclo-olefin copolymer (COC) resin
shares similar mechanical properties with polystyrene
elastic modulus and compressive strength of the
microcellular COC foams were much lower than the values
for standard PS foam having larger cells (100-200 ?mrange)
comparison made at the same density i.e. in the 50-
100 kg/m3 range. This goes against the usually accepted
paradigm of enhanced properties with microcellular foams.
Mechanisms for such unexpected behavior are proposed.
CHALLENGING THE PARADIGM OF MICROCELLULAR FOAMS:
MECHANICAL PROPERTIES OF LOW-DENSITY CYCLO-OLEFIN COPOLYMER FOAMS
Low-density foams of ethylene-norbornene copolymers were produced and their mechanical properties in compression investigated. Microcellular morphologies were observed, with mean cell diameters lower than 20 ?¬m. Although the cyclo-olefin copolymer (COC) resin shares similar mechanical properties with polystyrene, elastic modulus and compressive strength of the microcellular COC foams were much lower than the values for standard PS foam having larger cells (100-200 ?¬m range), comparison made at the same density, i.e. in the 50- 100 kg/m3 range. This goes against the usually accepted paradigm of enhanced properties with microcellular foams. Mechanisms for such unexpected behavior are proposed.
MICROMOLDING FOR QUARTZ GLASS/POLYMER COMPOSITES
Micromolding with microscale surface features and thin-wall plates of the quartz glass/polymers composites were performed to fabricate a new micro-fluidic plate with glass. Effects of process parameters on processability
and surface replication of the molded parts were evaluated.
The replication ratio and internal morphology of molded
green and sintered microparts were analyzed using SEM
and a confocal laser scanning microscope. During
sintering processes, the green molded composites shrank
with removal of binder polymer. The internal morphology
affected shrinkage of green molded composites. The
surface replication ratio of molded and sintered parts
showed high values. Sintered molded parts were produced
with a high aspect ratio of 3.4 and 10 ?¬m micro-line width.
EFFICACY OF SATURATED DESIGN OF EXPERIMENTS IN MULTIVARIATE PROCESS CHARACTERIZATION
Process characterization provides a model of process responses as a function of process factors, which is useful for process optimization and quality control. In this paper, four Design of Experiments (DOE) are implemented for a thin wall molding process, including two fractional factorial designs, a D-optimal design, and a supersaturated fractional factorial design. The capability of the DOEs are subsequently analyzed with respect to the estimated main effects and defect prediction capabilities. The results indicate that fully saturated designs are satisfactory for process characterization, but all critical process factors should be investigated. Experimental designs having confounded process factors were found preferable to experimental designs of similar size that were not confounded, but investigated fewer factors.
REPLICATION PROPERTIES AND STRUCTURE IN MICROMOLDING WITH HEAT INSULATOR MOLD
Micromolding with microscale surface features and thin-wall plates was performed to fabricate zirconia with heat-insulated molds. Effects of process parameters on processability and surface replication of the molded optical parts such as a diffraction grating and anti-reflective plates were evaluated. The replication ratio and higher-order structure of molded parts were analyzed using SEM and a polarizing optical microscope. Using an insulated mold, the flow length and surface replication ratio of molded parts increased. The molecular orientation of molded parts decreased using this mold, as it did in molding conditions of higher mold temperatures and injection temperatures.
ABRASION TESTING OF PACKAGING FILMS
When packaging sterilized medical devices or products, the integrity of the film is essential to ensure sterility of the device until usage. With competitive forces prompting the use of thinner gauge films, the risk of abrasion-induced failures increases dramatically. Until recently, there have been no effective means for packaging engineers to quantify which films would be most suitable for final applications. The Flexible Material Abrasion Kit allows engineers to perform a controlled laboratory test and analyze the variables that may influence the abrasion resistance of packaging films. This paper presents the concept behind the device and describes an actual case study.
MULTIVARIATE ROBUSTNESS MEASUREMENT
Multivariate modeling methods such as Principle Components Analysis are increasingly being used for quality control. The capability of such PCA models are traditionally verified by changing the process settings on an individual basis until a process fault is encountered. While such an approach is valid it is inefficient and does not consider interactions between multiple process settings. In this paper a design of experiments (DOE) is applied to more effectively identify process constraints with greater precision than the traditional fault identification approach. The method is demonstrated with the production of short shots and indicates significant differences between univariate and multivariate analyses with respect to yield predictions.
MULTIVARIATE ROBUSTNESS MEASUREMENT
Multivariate modeling methods such as Principle Components Analysis are increasingly being used for quality control. The capability of such PCA models are traditionally verified by changing the process settings on an individual basis until a process fault is encountered. While such an approach is valid, it is inefficient and does not consider interactions between multiple process settings. In this paper, a design of experiments (DOE) is applied to more effectively identify process constraints with greater precision than the traditional fault identification approach. The method is demonstrated with the production of short shots, and indicates significant differences between univariate and multivariate analyses with respect to yield predictions.
IN-SITU REINFORCED THERMOSET COMPOSITES USING CRYSTALLIZABLE
SOLVENTS
This study demonstrates an approach to generate
reinforcement in thermosetting polymers through crystal
growth of low molecular weight crystallizable solvents.
Phase separation and crystallization in blends of
dimethylsulfone (DMS) and diglycidyl ether of bisphenol-
A monomer were investigated via small angle laser
scattering and optical microscopy at different isothermal
conditions along with crosslinked mixtures using 1 3-
Phenylenediamine. Reaction conditions which lead to
suitable reinforcements were identified. It is also shown
that DMS crystals grow anisotropically to form faceted
geometries that resemble chopped-fiber-like morphologies
as well as show unique ways of anchoring to the matrix.
IN-SITU REINFORCED THERMOSET COMPOSITES USING CRYSTALLIZABLE SOLVENTS
This study demonstrates an approach to generate reinforcement in thermosetting polymers through crystal growth of low molecular weight crystallizable solvents. Phase separation and crystallization in blends of dimethylsulfone (DMS) and diglycidyl ether of bisphenol- A monomer were investigated via small angle laser scattering and optical microscopy at different isothermal conditions along with crosslinked mixtures using 1,3- Phenylenediamine. Reaction conditions which lead to suitable reinforcements were identified. It is also shown that DMS crystals grow anisotropically to form faceted geometries that resemble chopped-fiber-like morphologies as well as show unique ways of anchoring to the matrix.
THE USE OF RHEOLOGICAL AND THERMAL FRACTIONATION METHODS FOR THE ASSESSMENT OF NUCLEATING AGENT EFFICIENCY IN POLYPROPYLENE
The increasing diversity of commercial polypropylene products in recent years, related to the increase in the production volumes of PP, has led to a high number of studies dealing with structure-specific nucleating agents (NAƒ??s). Experiments on sorbitol-based NAƒ??s suggest that the nucleation function of this group of nucleating agents is a result of hydrogen bonding and self-assembly. So far, nucleation studies have been conducted in an indiscriminate manner with little reference to the exact effect of PP structure on nucleating behaviour of NAƒ??s. However, given the variety of commercial PP structures produced today, the question on the existence of synergy between polypropylene structure and nucleating efficiency of NAƒ??s remains open. The SIST (Stepwise Isothermal Segregation Technique) has been used in this study as a fast and efficient method to characterize a group of random PPƒ??s having different structures, giving the lamellar thickness distribution. In addition, temperature sweep measurements were performed to study the effect of flow on the interaction between NA and PP. In this way, small discrepancies between different materials can be pointed out to assess the nucleating efficiency of the nucleating agent.
AN APPROACH TO POLY(1,2-DICHLOROETHYLENE) SYNTHESIS VIA RING-OPENING METATHESIS POLYMERIZATION (ROMP)
The preparation of poly(1,2-dichloroethylene), an unknown material that is expected to be a superb engineering thermoplastic, was explored. The ROMP of cis-3,4-dichlorocyclobutene quantitatively yielded a white linear polymer with 'CHClCHClCH=CH' repeating units. However, its subsequent addition chlorination could not be made to occur to a detectable level. Steric hindrance and/or electronic deactivation due to the inductive effect of Cl apparently made the chlorination impossible. Furthermore, thermal degradation of a series of model compounds indicated that polymers containing (CHCl)n (n ' 3) structures would have low thermal stabilities.
DESIGN OF AN ADVANCED INJECTION MOLDING CONTROL SYSTEM
In injection molding, the control system plays a crucial role in quality consistency. Low-grade IMMs are manufactured in a large volume in Asia with low profit margin. Technology upgrade is the key to business success. An advanced control system has been designed in this paper to improve the performance of existing low-end IMMs with minimal modification. The control system architecture and advanced features are introduced. Experimental results show that with this controller, the performance of low-end machines can be comparable to that of the high cost and high performance machines, in term of repeatability and accuracy.
POLYETHERIMIDE-POLYESTERCARBONATE BLENDS WITH LOW HEAT RELEASE
Blends of polyetherimide (PEI) with polycarbonate (PC) form phase-separated mixtures. However replacement of polycarbonate bisphenol-A (BPA) derived linkages with resorcinol derived ester linkages to form isophthaloyl and terephthaloyl resorcinol polyestercarbonate (ITR-PC) exhibits surprising miscibility with PEI. Due to the flame retarding capability of ITR-PC versus PC the PEI + ITRPC blends also exhibit improved flame resistance in terms of lower heat release (HR) as measured by Ohio State Universityƒ??s (OSU) Heat Release test apparatus.Due to their lower heat release (< 65/65) these blends are compliant with US Federal Aviation Authority Regulation (FAR 25.853) and thus are acceptable for use in the fabrication of interior components for transportation industry. Due to their miscibility these PEI + ITR-PC blends can also be used in applications requiring transparency.
ADHESION OF BIODEGRADBLE PLASTICS WITH BONE: A COMPARATIVE
STUDY USING COMMERCIALLY AVAILABLE SCREW / PLATE SYSTEM AND
BIODEGRADABLE POLYMER MELT ADHESIVES
Biodegradable bone plates are commonly secured to
bone surfaces using screws in craniomaxillofacial
surgery. Using melt adhesives potentially replaces the
need for existing screws and the associated complex
techniques and equipment. Previously we have shown the
advantages of using biodegradable melt adhesives over
screw systems [1]. A time-based study comparing the
effect of using melt adhesives and screws to secure bone
implants to bone in a live goat model was performed. This
paper demonstrates and compares the impact of using
screws plates and melt adhesives on the healing of bone
and operative time.
ADHESION OF BIODEGRADABLE PLASTICS WITH BONE: A COMPARATIVE STUDY USING COMMERCIALLY AVAILABLE SCREW / PLATE SYSTEM AND BIODEGRADABLE POLYMER MELT ADHESIVES
Biodegradable bone plates are commonly secured to bone surfaces using screws in craniomaxillofacial surgery. Using melt adhesives potentially replaces the need for existing screws and the associated complex techniques and equipment. Previously we have shown the advantages of using biodegradable melt adhesives over screw systems. A time-based study comparing the effect of using melt adhesives and screws to secure bone implants to bone in a live goat model was performed. This paper demonstrates and compares the impact of using screws, plates, and melt adhesives on the healing of bone and operative time.
CELL STRUCTURE OF INJECTION MOLDED THERMOPLASTIC OLEFIN FOAMS
A linear and a branched polypropylene were blended with an ethylene ?ñ-olefin copolymer as the toughening elastomeric compound. A significant strain hardening behaviour was observed for the branched polypropylene (B-PP) as well as the branched polypropylene based TPO (B-TPO). The foamabilities of the compounded TPOs were investigated in a low pressure injection foaming process at an industrial scale. While linear polypropylene based TPO (L-TPO) exhibited no strain hardening behaviour, the cell density of the LTPO was significantly higher than that of the B-TPO.The results of injection foaming of neat polypropylenes, however, showed that the cell density of B-PP foam is almost 2 folds larger than that of the L-PP foam! These observations along with the morphological investigation of the unfoamed blends suggest that the foaming behavior of these TPOs is controlled by the interfacial properties and the blend micro-structure.
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