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.
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Conference Proceedings
ASSESSING THE THERMOFORMABILITY OF HIGH-PERFORMANCE POLYMERS FOR USE IN MEDICAL PACKAGING APPLICATIONS
A considerable number of polymers are available for usein medical and pharmaceutical packaging applications.Polymers such as polypropylene glycol modifiedpoly(ethylene terephthalate) polyacrylonitrile cyclicolefin copolymer and polychlorotrifluoroethylene exhibitdifferent mechanical and thermal properties therebyrequiring different processing conditions. Thethermoformability of these different polymers can beassessed in order to establish relative performance metricsprior to full scale production trials. This paper presentsmethods and analyses for assessing thermoformability.
THE ROLE OF GRAFTING DEGREE IN THE DISPERSION OF SILICA/POLYACRYLATE NANOCOMPOSITE PARTICLES INTO POLYACRYLATE MATRIX
A series of ‘guava-like’ silica/polyacrylate
nanocomposite particles with different grafting degrees
were prepared via mini-emulsion polymerization. The
silica/polyacrylate composite particles were melt-mixed
with unfilled polyacrylate resin to prepare the
corresponding silica/polyacrylate molded composites and
the dispersion mechanism of these silica particles from
the ‘guava-like’ composite particles into polyacrylate
matrix was studied by the section transmission electron
microscope (TEM) micrographs of silica/polyacrylate
molded composites. It was found that the grafting degree
of silica particles played a crucial role in the dispersion of
silica/polyacrylate composite particles into the
polyacrylate matrix.
THE ROLE OF GRAFTING DEGREE IN THE DISPERSION OF GUAVA-LIKE SLICE/POLYACRYLATE MATRIX
A series of guava-like silica/polyacrylate nanocomposite particles with different grafting degrees were prepared via mini-emulsion polymerization. The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate resin to prepare the corresponding silica/polyacrylate molded composites, and the dispersion mechanism of these silica particles from the ƒ??guava-likeƒ?? composite particles into polyacrylate matrix was studied by the section transmission electron microscope (TEM) micrographs of silica/polyacrylate molded composites. It was found that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix.
NEW PERSPECTIVE ON HEAT DEFLECTION TEMPERATURE OF GLASSY POLYCARBONATE
For polycarbonate the HDT values can vary over 20±C.
Many factors a®ect the test results. Among these ther-
mal dilatation and creep were discussed in detail. Quan-
titatively the contribution from thermal dilatation to
HDT values varies little with physical aging time but the
contribution from creep to HDT values changes greatly.
When creep is insigni¯cant the HDT values can be cal-
culated from an elastic beam de°ection equation and are
close to the Tg values. This paper qualitatively disputes
the claims of the e®ect of residual stress on HDT values.
It is argued that changes in residual stress level and HDT
values with physical aging are symptoms of the structural
relaxation but no causal e®ect exists between these two
symptoms. As a test method for amorphous polymers
Vicat or Tg can provide more reliable results than HDT.
NEW PERSPECTIVE ON HEAT DEFLECTION TEMPERATURE OF GLASSY POLYCARBONATE
For polycarbonate, the HDT values can vary over 20?øC. Many factors affect the test results. Among these, thermal dilatation and creep were discussed in detail. Quantitatively, the contribution from thermal dilatation to HDT values varies little with physical aging time, but the contribution from creep to HDT values changes greatly. When creep is insignificant, the HDT values can be calculated from an elastic beam deflection equation and are close to the Tg values. This paper qualitatively disputes the claims of the effect of residual stress on HDT values. It is argued that changes in residual stress level and HDT values with physical aging are symptoms of the structural relaxation, but no causal effect exists between these two symptoms. As a test method for amorphous polymers, Vicat or Tg can provide more reliable results than HDT.
POLYMER-POLYMER INTERFACIAL SLIP MEASUREMENTS IN MULTILAYERED FILM
Significant slip can occur during flow of twoimmiscible polymers due to reduced entanglements at theirinterface. The slip is of practical importance because of itseffect on morphology and adhesion of these multi-phasematerials such as disordered two-phase blends andmultilayer films. Using rheological technique we studiedthe interfacial slip in co-extruded multilayer films. Theviscosity drop of a multilayer sample below the averageviscosity of two neat components was observed for bothpolypropylene/polystyrene and polyethylene/fluoropolymer systems indicating interfacial slip.Furthermore the viscosity drop of a multilayer sampleincreased with the number of layers.
POLYMER-POLYMER INTERFACIAL SLIP MEASUREMENTS
IN MULTILAYERED FILM
Significant slip can occur during flow of two
immiscible polymers due to reduced entanglements at their
interface. The slip is of practical importance because of its
effect on morphology and adhesion of these multi-phase
materials, such as disordered two-phase blends and
multilayer films. Using rheological technique, we studied
the interfacial slip in co-extruded multilayer films. The
viscosity drop of a multilayer sample below the average
viscosity of two neat components was observed for both
polypropylene/polystyrene and polyethylene
/fluoropolymer systems, indicating interfacial slip.
Furthermore, the viscosity drop of a multilayer sample
increased with the number of layers.
STUDY OF TAKE-UP VELOCITY IN ENHANCING TENSILE PROPERTIES OF ALIGNED ELECTROSPUN NYLON 6 FIBERS
The variation of both the tensile properties and the thermal properties of aligned electrospun fibers with the take-up velocity (TUV) of disc collector have not been widely investigated due to the difficulty of handling aligned nanofibers and measuring low loads. In this paper 25% of nylon 6 solution was electrospun into fibers and the fibers were aligned using a rotating disc collector. We evaluated both the mechanical and the thermal properties of aligned electrospun nylon 6 nanofibers having a diameter less than 200 nm as a function of the TUV based on a disc collector. It was determined that by increasing the TUV from 14.2 m/s to 21.4 m/s the tensile properties showed a substantial increase including the elastic modulus the strain energy density and the tensile strength which increased by 108% 100% and 75% respectively. Meanwhile the melting temperature remained the same compared to the bulk material.
STUDY OF TAKE-UP VELOCITY IN ENHANCING TENSILE PROPERTIES OF ALIGNED ELECTROSPUN NYLON 6 FIBERS
The variation of both the tensile properties and the thermal properties of aligned electrospun fibers with the take-up velocity (TUV) of disc collector have not been widely investigated due to the difficulty of handling aligned nanofibers and measuring low loads. In this paper, 25% of nylon 6 solution was electrospun into fibers and the fibers were aligned using a rotating disc collector. We evaluated both the mechanical and the thermal properties of aligned electrospun nylon 6 nanofibers, having a diameter less than 200 nm, as a function of the TUV based on a disc collector. It was determined that by increasing the TUV from 14.2 m/s to 21.4 m/s, the tensile properties showed a substantial increase including the elastic modulus, the strain energy density, and the tensile strength which increased by 108%, 100%, and 75%, respectively. Meanwhile, the melting temperature remained the same compared to the bulk material.
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELYINTERMESHING
TWIN SCREW EXTRUDERS: A SCALE-UP ANALYSIS
The peroxide-initiated degradation of polypropylene in
fully-filled screw elements of closely intermeshing twinscrew
extruders is being analyzed. For this purpose threedimensional
simulations are being implemented to
describe this reactive flow in screw elements of two
different size extruders. The effects of the initial peroxide
concentration mass throughput and especially extruder
size on the final weight-average molecular weight and
poly-dispersity index of the product are studied. In
relation to the later the temperature of reaction resulting
from the specified processing conditions is discussed.
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELYINTERMESHING
TWIN SCREW EXTRUDERS: A SCALE-UP ANALYSIS
The peroxide-initiated degradation of polypropylene in fully-filled screw elements of closely intermeshing twinscrew extruders is being analyzed. For this purpose, threedimensional simulations are being implemented to describe this reactive flow in screw elements of two different size extruders. The effects of the initial peroxide concentration, mass throughput, and, especially, extruder size on the final weight-average molecular weight and poly-dispersity index of the product are studied. In relation to the later, the temperature of reaction resulting from the specified processing conditions is discussed.
DESIGN AND EVALUATION OF AN INTERBODY FUSION CAGE MOLD
The main goal of this project was to design evaluate and
validate an interbody fusion cage (IFC) and its injection
mold by means of CAE/CAD and finite elements tools
(Pro-ENGINEER C-MOLD and ANSYS). IFC is
employed as a supplement in the lumbar fusion. PEEK was
chosen for IFC manufacture. Based on the interbody cage
design two cavities and a double opening ejection system
were used in the mold. Molds with different cooling and
feeding systems were designed and evaluated using
modelator and simulation software (C-MOLD). Results
indicate that the best mold has only one standard lateral
gate and four cooling channels in each cavity. The cycle
time was less than 36 sec. After a financial study this
project represents a feasible solution for Venezuelan
patients.
DESIGN AND EVALUATION OF AN INTERBODY FUSION CAGE MOLD
The main goal of this project was to design, evaluate and validate an interbody fusion cage (IFC) and its injection mold by means of CAE/CAD and finite elements tools (Pro-ENGINEER, C-MOLD and ANSYS). IFC is employed as a supplement in the lumbar fusion. PEEK was chosen for IFC manufacture. Based on the interbody cage design, two cavities and a double opening ejection system were used in the mold. Molds with different cooling and feeding systems were designed and evaluated using modelator and simulation software (C-MOLD). Results indicate that the best mold has only one standard lateral gate and four cooling channels in each cavity. The cycle time was less than 36 sec. After a financial study, this project represents a feasible solution for Venezuelan patients.
ADVANCES IN PLASTICS JOINING TECHNOLOGIES FOR THE ASSEMBLY OF
MEDICAL DEVICES
With demand for the use of plastics in Medical
Devices expected to continue growing there is also
a growing demand for improved control and analysis
of related assembly processes. Additionally there is
a growing demand to use plastics in MEMS and
Micro-fluidics for analytical and drug delivery
devices. Therefore manufacturers are increasingly
looking for joining technologies that are particulate
free and will not occlude miniature channels. These
trends have led to the introduction of several new
methods to control monitor and analyze the
assembly process as well as led to the use of new
plastics joining technologies such as Laser and Infra
Red Welding.
ADVANCES IN PLASTICS JOINING TECHNOLOGIES FOR THE ASSEMBLY OF MEDICAL DEVICES
With demand for the use of plastics in Medical Devices expected to continue growing, there is also a growing demand for improved control and analysis of related assembly processes. Additionally there is a growing demand to use plastics in MEMS and Micro-fluidics for analytical and drug delivery devices. Therefore manufacturers are increasingly looking for joining technologies that are particulate free and will not occlude miniature channels. These trends have led to the introduction of several new methods to control, monitor and analyze the assembly process as well as led to the use of new plastics joining technologies such as Laser and Infra Red Welding.
HYPERELASTIC MODELING OF ENHANCED MECHANICAL PROPERTIES OF
ELECTROSPUN POLY(?-CAPROLACTONE) FIBERS
Little is understood on the deformation of electrospun
nanofibers. This study aims to evaluate the electrospun
nanofiber deformation in both macroscopic and nanometer
length scales using the classical hyperelastic models. The
Mooney-Rivlin models are used to evaluate the tensile
properties of poly(?-caprolactone) (PCL) made by the
electrospinning technique. The stress-strain relationships of
single fibers are reported. This study also provides
comparative analyses among Mooney-Rivlin models.
Analytical calculations illustrate the importance of
understanding crystallinity and molecular orientations of
nanofibers.
HYPERELASTIC MODELING OF ENHANCED MECHANICAL PROPERTIES OF ELECTROSPUN POLY(?æ-CAPROLACTONE) FIBERS
Little is understood on the deformation of electrospun nanofibers. This study aims to evaluate the electrospun nanofiber deformation in both macroscopic and nanometer length scales using the classical hyperelastic models. The Mooney-Rivlin models are used to evaluate the tensile properties of poly(?æ-caprolactone) (PCL) made by the electrospinning technique. The stress-strain relationships of single fibers are reported. This study also provides comparative analyses among Mooney-Rivlin models.Analytical calculations illustrate the importance of understanding crystallinity and molecular orientations of nanofibers.
THE EFFECT OF UV IRRADIATION ON MELTING AND CRYSTALLIZATION
BEHAVIOR OF POLY(1-BUTENE)
The work directs attention towards the influence of
natural weathering and accelerated UV degradation on
thermal behavior and subsequent transformation behavior
of isotactic poly(1-butene) (PB-1). For these purposes two
different commercial-available grades of PB-1 were
chosen. Specimens prepared by compression molding were
UV irradiated for 0 to 40 hours and naturally weathered up
to 63 days. Significant changes were consequently
observed in crystallization and melting behavior as well as
in the phase transformation mechanism.
THE EFFECT OF UV IRRADIATION ON MELTING AND CRYSTALLIZATION BEHAVIOR OF POLY(1-BUTENE)
The work directs attention towards the influence of natural weathering and accelerated UV degradation on thermal behavior and subsequent transformation behavior of isotactic poly(1-butene) (PB-1). For these purposes, two different commercial-available grades of PB-1 were chosen. Specimens prepared by compression molding were UV irradiated for 0 to 40 hours and naturally weathered up to 63 days. Significant changes were consequently observed in crystallization and melting behavior as well as in the phase transformation mechanism.
NEW LOW GLOSS POLYCARBONATE BLENDS FOR AUTOMOTIVE
APPLICATIONS
Automotive original equipment manufacturers are
consistently looking for low-gloss materials for interior
applications that can stand up to years of wear and tear and
environmental exposure yet maintain aesthetic quality
without painting. Bayblend® LGX 300 resin is specifically
developed for automotive interior applications requiring a
material that is inherently low in gloss with extra
flowability good weathering and good scratch and mar
resistance. Another important attribute of Bayblend LGX
300 is its low-emission characteristic which is particularly
important as automotive manufacturers strive to reduce the
levels of VOCs in their automobiles to improve the interior
environment and meet federal regulations. Because LGX
300 resin is a low gloss high-flow polycarbonate (PC)
blend with good heat and impact performance; thin-wall
part design can be achieved without painting.
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