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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
CALCULATION AND ANALYSIS OF MOLD COST FOR INJECTION MOLDING VIA A MOLD DESIGN NAVIGATION SYSTEM
Low cost and quality are essential demands in mold
and molding manufacturing. Mold cost calculations can
be classified into four parts: material manufacture
overhead and profit. This research develops a navigation
system that can provide a calculation and analysis of mold
prices. The difference between the actual sample price
and the calculated price is roughly 6%. Via the mold price
navigation system customer and mold vendor engaged in
detailed discussions and obtain a good mold price
estimate. The system not only greatly helps the
inexperienced designer but also provides a feasible mold
price calculation conception and a collaborative
environment for the design process.
CALCULATION AND ANALYSIS OF MOLD COST FOR INJECTION MOLDING VIA A MOLD DESIGN NAVIGATION SYSTEM
Low cost and quality are essential demands in mold and molding manufacturing. Mold cost calculations can be classified into four parts: material, manufacture, overhead, and profit. This research develops a navigation system that can provide a calculation and analysis of mold prices. The difference between the actual sample price and the calculated price is roughly 6%. Via the mold price navigation system, customer and mold vendor engaged in detailed discussions and obtain a good mold price estimate. The system not only greatly helps the inexperienced designer but also provides a feasible mold price calculation conception and a collaborative environment for the design process.
PROCESSING AND PROPERTIES OF ELECTRO-CONDUCTIVE CARBON NANOTUBE COMPOSITES IN HIGH PERFORMANCE ENGINEERING POLYMERS
Development of electro-conductive polyamide 4.6 (PA4.6) and polyamide 4.6/poly(phenylene sulfide) blend (PA4.6/PPS) incorporating multiwall carbon nanotube (CNT) were first reported in this work. PPS/CNT was also investigated. The CNT composites exhibited electrical conductivity at remarkably low CNT content, displayed a volume electrical percolation threshold at < 0.9 wt% CNT. At only 1 wt%, all the three composites would already register 103 Ohm?úcm volume resistivity. The required surface electrical percolation to reach 107 Ohm ?ú sq-1 for the PA4.6, PPS and PA4.6/PPS blend was 1.4, 2.0 and 0.9 wt% respectively. A co-continuous morphology observed for the PA4.6/PPS blend would explain for its extremely low percolation.
The melt crystallisation behavior of the polymers altered appreciably in the presence of CNT. PA4.6 crystallised at some 12 ?øC higher, from 257.5 ?øC to 269.5 ?øC. The full crystallisation half-time of PPS was reduced by nearly 2/3 from 110s to 38s, while its peak crystallising temperature was raised by some 46 ?øC from 188.5 ?øC to 235 ?øC. The small doublet melting peak of the virgin PA 4.6/PPS blend would merge into single peak in its composite that could indicate the blend compatibility was more improved in the presence of CNT. Furthermore, the PA4.6/PPS/CNT blend showed least mould shrinkage and smoothest injection moulded surface among all the composites investigated.
THREE DIMENSIONAL NANO IMPRINT LITHOGRAPHY USING PHOTO-CURABLE RESIN
Three dimensional (3D) Nanoimprint Lithography (NIL) was carried out using photo-curable resin. NIL process was as follows: first, a fabricated NIL mold was coated with an anti-sticking layer. Then, a ultraviolet (UV) photo-curable resin was dispensed onto cleaned glass slides or polyethylene terephthalate (PET) films. Next, the mold was pressed against the resin on the substrate. The photo-curable resin was then exposed of UV light. The mold was then retracted, leaving behind a replica of its pattern. Using 3D mold with markedly uneven, evaluation of photo-curable resin was possible and it was found that weaker intermolecular force monomers improved transfer and release properties.
STUDY ON PACKING EFFECTS ON THE PART SHRINKAGE MOLDED BY
EXTERNAL GAS-ASSISTED INJECTION MOLDING PROCESS
External gas-assisted injection molding (EGAIM) has been receiving attention for its improvement of surface quality. However, compared with gas-assisted injection with gas penetration into the melt core, the packing effects of EGAIM on the pressure variation within the mold cavity and the part shrinkage have not been investigated. In this study, the pressure differential between core and cavity is about 3.04 bar. In addition, the required gas packing pressure (90 bar) is much lower than that of conventional packing pressure (1000 bar) in achieving identical shrinkage. With increased gas packing pressure and gas packing time, the shrinkage can be further reduced. However, the gas delay time for shrinkage is related to the pressure inside the mold.
ADVANCED AEROSPACE COMPOSITES USING AN AROMATIC
THERMOSETTING COPOLYESTER MATRIX –
IMPROVED THERMAL FATIGUE
The potential superiority of ATSP (aromatic thermosetting
copolyester) matrices compared to conventional epoxies
for aerospace composites is discussed. Preparation and
characterization of carbon fiber/ATSP composites are
described. In this paper we demonstrate that ATSP
oligomers display liquid crystalline behavior which was
identified using optical microscopy with cross-polarizers.
We also describe how ATSP tailored to have a liquid
crystalline structure has reduced stresses at the
fiber/matrix interface and better thermal fatigue resistance
compared to epoxy.
ADVANCED AEROSPACE COMPOSITES USING AN AROMATIC THERMOSETTING COPOLYESTER MATRIX ƒ?? IMPROVED THERMAL FATIGUE
The potential superiority of ATSP (aromatic thermosetting copolyester) matrices compared to conventional epoxies for aerospace composites is discussed. Preparation and characterization of carbon fiber/ATSP composites are described. In this paper, we demonstrate that ATSP oligomers display liquid crystalline behavior which was identified using optical microscopy with cross-polarizers.We also describe how ATSP tailored to have a liquid crystalline structure has reduced stresses at the fiber/matrix interface and better thermal fatigue resistance compared to epoxy.
THE EFFECTS OF COMPATIBILIZERS IN INJECTION MOULDED WOOD PLASTIC COMPOSITES
The aim of this work was to investigate the various effects of compatibilizers on different aspects. The polypropylene based WPC, containing different compatibilizers, were produced via compounding and injection molding. Testing for tensile and impact strengths as well as for MFR and shrinkage was carried out subsequently.
We found, that the presence of a compatibilizer not only enhances tensile strength (up to 80%, depending on wood and compatibilizer concentration), but also influence other properties, e.g. shrinkage and MVR are increasing with increasing compatibilizer concentration.
Furthermore, with the help of a saturation model, the effects of different compatibilizer grades, exhibiting different maleic anhydride content as well as different viscosity, were evaluated to get deeper insight in the mechanisms.
PREPARATION OF MICROCELLULAR POLY(ETHYLENE-CO-OCTENE)
RUBBER FOAM USING SUPERCRITICAL CO2 TECHNOLOGY
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.
PREPARATION OF MICROCELLULAR POLY(ETHYLENE-CO-OCTENE) RUBBER FOAM USING SUPERCRITICAL CO2 TECHNOLOGY
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.
STIFF, HIGHLY DAMPING THERMOPLASTIC POLYURETHANE
NANOCOMPOSITES VIA SIMPLE, SCALABLE PROCESSING
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.
MONITORING THE EFFECT OF OPERATING CONDITIONS ON MELT TEMPERATURE HOMOGENEITY IN SINGLE-SCREW EXTRUSION
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.
PS FOAMS BLOWN FROM HFC-134a/HFC-32 BLENDS: PROCESSING BEHAVIOR
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.
SOFT POLYURETHANE FOAMS AS CARTILAGE REPLACEMENT: PROCESSING BEHAVIOR AND BIOCOMPATIBILITY
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.
EFFECT OF ORGANOCLAY ON THE MECHANICAL PROPERTIES AND
CRYSTALLIZATION BEHAVIORS OF INJECTION-MOLDED PP/ ABS/
MONTMORILLONITE NANOCOMPOSITES
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.
EFFECT OF ORGANOCLAY ON THE MECHANICAL PROPERTIES AND CRYSTALLIZATION BEHAVIORS OF INJECTION-MOLDED PP/ ABS/MONTMORILLONITE NANOCOMPOSITES
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.
AUTOMATED OPTIMIZATION OF INJECTION MOLD COOLING CIRCUIT WITH OPTIMIZATION TOOL PIANO
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.
PLASTICS INDUSTRY INNOVATION: HOW TO SURVIVE AND THRIVE IN A RECESSION
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.
POLYMER DYNAMICS IN SINGLE-WALLED CARBON NANOTUBE POLYMER
COMPOSITES
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.
POLYMER DYNAMICS IN SINGLE-WALLED CARBON NANOTUBE POLYMER COMPOSITES
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.
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