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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Wentao Zhai , Siu N. Leung , Hani E. Naguib , Chul B. Park, May 2010
In the past three decades there has been great
advancement in preparing microcellular thermoplastic
polymer foam. However little attention is paid to
thermoplastic elastomer. In this study microcellular
poly(ethylene-co-octene) (PEOc) rubber foams with a cell
density of 2.9×1010 cells/cm3 and cell size of 1.9 ?m are
successfully prepared by using CO2 as the physical
blowing agent with a batch foaming process. Microcellular
PEOc foams exhibit a well defined closed cell structure
uniform cell size distribution and formation of unfoamed
skin at low foaming temperatures. Their difference from
thermoplastic foam is the foam shrinkage in the
atmosphere due to the elasticity of polymer matrix. The
effect of melt flow rates on the cell growth process is
investigated by changing the foaming conditions.
Wentao Zhai , Siu N. Leung , Hani E. Naguib , Chul B. Park, May 2010
In the past three decades, there has been great advancement in preparing microcellular thermoplastic polymer foam. However, little attention is paid to thermoplastic elastomer. In this study, microcellular poly(ethylene-co-octene) (PEOc) rubber foams with a cell density of 2.9??1010 cells/cm3 and cell size of 1.9 ?¬m are successfully prepared by using CO2 as the physical blowing agent with a batch foaming process. Microcellular PEOc foams exhibit a well defined closed cell structure, uniform cell size distribution, and formation of unfoamed skin at low foaming temperatures. Their difference from thermoplastic foam is the foam shrinkage in the atmosphere due to the elasticity of polymer matrix. The effect of melt flow rates on the cell growth process is investigated by changing the foaming conditions.
Nanocomposites comprising a high percentage of inorganic layers and a low percentage of organic binder have been reported to exhibit remarkable physical properties due to high levels of organization, connectivity and phase morphology. We report the preparation and characterization of a system of this type consisting of montmorillonite layers and thermoplastic polyurethane (TPU) binder. Transparent sheets were prepared and characterized via SEM for structure, TGA and DSC for thermal properties, and DMA for mechanical response. These materials are stable, robust, and exhibit interesting combinations of stiffness and damping capacity.
C. Abeykoon, M. McAfee, K. Li, A. L. Kelly, E. C. Brown, May 2010
Delivery of a melt which is homogenous in
composition and temperature is paramount for achieving
high quality extruded products. However, melting
stability can be difficult to determine via typical melt
pressure and thermocouple instrumentation. This can
result in inefficient operation through non-optimized
operating conditions or extruder screw geometry. In this
work, melt temperature homogeneity in a single screw
extruder is investigated experimentally using a
thermocouple mesh technique. The effect of barrel
temperature settings and screw speed on die melt
temperature homogeneity is investigated. Inferential
methods of determining melting stability in-process are
investigated with the aim of developing modeling and
control techniques to improve process quality and
efficiency.
Michel F. Champagne , Richard Gendron , Jacques Tatibouët, May 2010
Manufacturing of extruded polystyrene (XPS) foam insulation boards is currently based on weak ozone depleting gases. Mixtures of blowing agents are actually seen as one of the most promising solutions to ozonedepleting substances phase-out. This paper investigates various blowing agent formulations based on mixtures of hydrofluorocarbons HFC-134a (1,1,1,2-tetrafluoroethane) and HFC-32 (difluoromethane). The study focuses on the rheological (plasticization) and degassing (solubility) behaviors of the formulations, as measured on-line during foam extrusion. Rules of mixing for such blends of HFCs are proposed based on the relative contribution of each component to the overall processing behavior.
Michel F. Champagne , Sashka Dimitrievska , Richard Gendron , Martin N. Bureau, May 2010
Massively invasive surgery is often the only cure for the worst cases of cartilage-related diseases. In an effort to physiologically mimic human joints, 4 biomedical thermoplastic polyurethanes (TPU) differing in glass transition temperature, modulus and wettability were foamed using a CO2-based solid-state process. Human cartilage mechanical behavior was closely matched by low density foams of the softest TPU investigated. In vitro osteoblastic studies showed improved cell differentiation, activity and proliferation; all suggestive of TPU foans potential osteointegration. The superior bioactivity and cartilage-matching mechanics make the TPU foam a promising cartilage replacement.
Peng Xiang-fang, Peng Jun, Xie Xiao-li, Turng Lih-Sheng, May 2010
The topography of the inner surface of small bore extruded tubes used in fluid handling applications can affect flow rates, fluid turbulence and biofilm adherence. Quantitative surface roughness analysis of tubes manufactured from different polymers has shown that the inner surface topography is related to the polymer molecular variables, rheological properties and extrusion processing conditions. Surface energy analysis of these surfaces has also been shown to be related to polymer type as well as surface roughness.
Peng Xiang-fang , Peng Jun , Xie Xiao-li, May 2010
The mechanical properties and crystallization
behaviors of PP/acrylonitrile-butadiene-styrene/organic
montmorillonite nanocomposites (PP/ABS/OMMT)
were studied. It was shown that compatilizer
PP-g-MAH not only improved the compatibility of
PP/ABS but also promoted the dispersity of OMMT
particles in continuous phase PP and dispersed phase
ABS. In addition PP was reinforced and toughened by
both layered silicate OMMT nanoparticles and ABS.
The blend weight ratio of PP/ABS/OMMT which was
85/15/2 wt % had a concerted effect on toughening.
OMMT nanoparticles also increased crystallization
temperature and crystallinity.
Peng Xiang-fang , Peng Jun , Xie Xiao-li , Turng Lih-Sheng, May 2010
The mechanical properties and crystallization behaviors of PP/acrylonitrile-butadiene-styrene/organic montmorillonite nanocomposites (PP/ABS/OMMT) were studied. It was shown that, compatilizer PP-g-MAH not only improved the compatibility of PP/ABS, but also promoted the dispersity of OMMT particles in continuous phase PP and dispersed phase ABS. In addition, PP was reinforced and toughened by both layered silicate OMMT nanoparticles and ABS.The blend weight ratio of PP/ABS/OMMT, which was 85/15/2 wt %, had a concerted effect on toughening.OMMT nanoparticles also increased crystallization temperature and crystallinity.
In order to assure the part quality in the part design
step, it is desirable to optimize the cooling circuit prior to
the mold design step. In the environment of frequent
design changes, a way to optimize automatically the
cooling circuit in a short period of time is necessary. In
this work, an automated optimization of the cooling
circuit was examined with a commercial optimization
tool, PIAnO. The optimization technique is useful largely
for large parts such as instrument panels and bumpers.
The objective function is the deviation of temperature
difference from a target mold surface temperature.
Brian P. Grady, Abhijit Paul, Warren T. Ford, May 2010
In this paper, we will discuss several companies who
have not seen recessions as a deterrent to innovation but an
opportunity.
Using a case study format, we will discuss four
companies that have innovated in a recessionary
environment. We will derive the lessons learned and offer
some recommendations as to ƒ??how toƒ? look for the silver
lining in an economic downturn.
The objective of this paper is to present examples of
companies that re-positioned for growth during an
economic downturn. In two of the cases, an innovative
business grew out of adversity. The third is a new
company that was able to identify a technology developed
earlier but eventually abandoned due to a lack of a market.
The last invested while its competitors contracted.
Due to the poor economy, most of us are experiencing
a drop in our business and are looking for ways to reposition
our businesses. Our businesses are down as much
as 50% from prior years. We have cut our costs, reduced
our payrollsƒ??what do we do nowƒ??
The following four companies are examples of what
can be done to innovate in a recessionary environment.
The following table shows the types of business
segmentation opportunities.
Brian P. Grady , Abhijit Paul , Warren T. Ford, May 2010
A 100 000 g/mol polyethylene molecule has a crosssection
of about 0.5 nm and a contour length of about 0.9
?m. A typical single-walled carbon nanotube (SWCNT)
has a cross-section of about 1 nm and a contour length of
about 1 ?m. The critical difference from a physics
perspective between these two molecules is that the
persistence length of the former is about 0.6 nm and the
persistence length of the latter is reported as ? 30 ?m.1
One can make a similar comparison between SWCNTs
and liquid crystalline polymer molecules; in this case the
key difference is that the length of the former is much
larger than the length of the latter. This paper presents
what is believed to be a synergistic type of behavior that is
possibly related to the similarity in size of the two high
aspect-ratio materials the fact that single-walled carbon
nanotubes can increase the jump in heat capacity at the
glass transition. Other measurements involving the
behavior of fictive temperatures and activation energies
measured from calorimetric studies are also given.
Brian P. Grady , Abhijit Paul , Warren T. Ford, May 2010
A 100,000 g/mol polyethylene molecule has a crosssection of about 0.5 nm and a contour length of about 0.9 ?¬m. A typical single-walled carbon nanotube (SWCNT) has a cross-section of about 1 nm and a contour length of about 1 ?¬m. The critical difference from a physics perspective between these two molecules is that the persistence length of the former is about 0.6 nm and the persistence length of the latter is reported as ƒ?? 30 ?¬m.1 One can make a similar comparison between SWCNTs and liquid crystalline polymer molecules; in this case the key difference is that the length of the former is much larger than the length of the latter. This paper presents what is believed to be a synergistic type of behavior that is possibly related to the similarity in size of the two high aspect-ratio materials, the fact that single-walled carbon nanotubes can increase the jump in heat capacity at the glass transition. Other measurements involving the behavior of fictive temperatures and activation energies measured from calorimetric studies are also given.
Conformal cooling channel could make the temperature
distribution in the mold uniform, reducing cycle time and
improving part quality. However, design principle for the
conformal cooling channel has not been established yet. In
this study, a constructal design principle was tried with
hexagonal cooling channel. The size and the depth of the
hexagonal cooling channel were optimized to minimize the
temperature deviation of the mold surface. Constraint was
pressure drop through the cooling channel limited by the
pumping capability. The CAE tool for mold cooling
analysis was Moldflow Cool.
A thermoplastic elastomer (TPE) blend of thermoplastic polyurethane (TPU) and polypropylene (PP) was sampled from extruded strands and injection molded plaques. Highly stretched strands of the PP phase are aligned parallel to each other along the extrusion direction in the extruded samples while in the injection-molded samples the PP phase is in ellipsoidal domains residing in the shear plane of the mold. Subjecting the samples to a tension load leads to rupture of the elongated strands, resulting in increased tensile set and reduced moduli. Annealing the extruded specimen at 150 oC for 30 min. can create cracks in the blend similar to those generated during tensile testing.
Oludolapo Shobanjo, Stuart Blackburn, Owen Draper, Richard Greenwood, May 2010
The foaming process of PMMA in specially
designed rotor system with screws and previously
designed rotor system without screw was studied
respectively. In this study, with supercritical carbon
dioxide (ScCO2) as a blowing agent, microcellular foam
of PMMA was made in traditional steady process and
dynamic vibration field respectively by using the
isobarical feeding equipment of supercritical carbon
dioxide and microcellular foaming simulator. The effects
of processing parameters such as pressure, time of
saturation, shear stress were investigated, in order to
study and analyze the effects of processing conditions on
PMMA microcellular plastics. Foamed samples with the
cell density of 78.7??107 cell/cm3, average cell size of
12.6 ?¬m have been produced by using the screw system.
Oludolapo Shobanjo , Stuart Blackburn , Owen Draper , Richard Greenwood, May 2010
Wax formulations prepared using paraffin wax (PW) and hydrogenated resin (HR) were studied to identify effects of temperature and composition on phase homogeneity. A phase diagram was constructed showing regions of PW/HR miscibility and tracking changes in PW crystallisation as HR is added. Polarised optical microscopy identified changes in nucleation and crystal growth mechanisms of the PW semi-crystalline phase promoted by HR. A simplified wax injection system was used to investigate conditions for defect formation. Results, to be validated using a ProCAST model, showed defects occurred by injecting blend compositions corresponding to regions of PW/HR phase separation as shown by the phase diagram.
Reema Sinha, Sangita Nandi, Arun Sikder, Radha Kamalakaran, Susanta Mitra
and Edward Kung*, May 2010
In the present study, the friction and wear properties of high temperature resistant polymers, Polyetherimide (PEI) and Polyetheretherketone (PEEK), have been investigated at specific combinations of high pressure, velocity and temperature against smooth steel counterparts. The effects of internal lubricant, polytetrafluoroethylene (PTFE) and PTFE with short fiber reinforcements (carbon fiber) are outlined. The tests were performed on a thrustwasher testing machine under dry sliding conditions. Different analytical techniques were employed to study the correlation between the transfer layer and friction properties. Lubricated and lubricated-reinforced compounds showed excellent wear resistance compared to pristine resins.
The mechanical properties and misconstrues of high impact polystyrene (HIPS) toughened by styrenebutadiene-styrene (SBS) were studied to find the Brittle-Ductile Transition Point. At the Brittle-Ductile Transition point, HIPS and SBS alloys were prepared using melt intercalation technique by blending HIPS and SBS while used acrylonitrile-styrene (AS) powder, gaining higher impact and tensile strength. Their microstructures near the Transition Point were characterized by scanning electron microscope (SEM) to investigate the toughening mechanism of HIPS/SBS/AS composites. The toughening mechanism is similar to the mechanism of RIF toughening rather than the cold-drawing theory which applied to ductile matrixes toughed by rigid organic filler (ROF).
Both polypropylene (PP) and polystyrene (PS) parts were molded by injection-compression molding. The Taguchi method was utilized to investigate the effects of six processing parameters including mold temperature compression speed compression time compression distance delay time and compression force on part shrinkage uniformity. Analyses of means and variance showed that the compression force is the most important parameter for part shrinkage uniformity of both parts. The compression distance is the second most significant parameter on shrinkage uniformity of PS part but not significant parameter on PP part. The optimal processing parameters for improving the shrinkage uniformity of both parts are found and verified experimentally.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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