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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A.Maragiannis | D. Papageorgiou | C. Medrea | Stasinopouloi-Uddeholm, November 2011
Tyres consist of synthetic rubber | metals and linen.
Tyre waste decomposes after hundreds of years | and its
presence is detrimental for the environment. Standing
water | trapped into tires may be a permanent pollution
source | while tyre waste next to a forest increases the
possibility of fire. European legislation imposes the
recycling of tyre waste | which includes the following
three steps: shredding in strips | cutting strips in small
pieces | and powder production from the pieces. At the
last stage magnets remove the metallic pieces | while
centrifugal screens remove the linen. Metals are sold to
the steel industry as scrap | linen is used in limekiln as a
combustion material and the rubber flakes are used in
numerous applications (e.g. road surface construction,
concrete additives | mouse pads | etc.).
Shokoh Fatahi | Abdellah Ajji | Pierre G. Lafleur, November 2011
A wide range of PE materials | including LLDPE,
HDPEs and LDPE were used for preparation of the blown
films. By changing processing conditions | different
structures for these blown films were produced and their
structural parameters investigated. Establishing
fundamental /structural model between structural
parameters and tensile modulus of blown films was the
objective of this work. A model for the tensile modulus
was proposed and correlated to some structural
parameters including crystallinity | orientation factors for
crystalline c-axis and amorphous phase | lamellar
thickness and crystal size. The measured modulus and
calculated one were compared and a reasonable
agreement was found between them.
D. Olivier | J.A. Travieso | S. Borrós | G. Reyes, November 2011
Plastic Laminated Object Manufacturing has not been
assessed from the flexural properties point of view. The
deflection range in parts manufactured by this technique is
wider than in parts fabricated by other additive
manufacturing methods like SLS or FDM. This fact has
increased the interest on the final application of these parts
rather than restricted to Rapid Prototyping applications. In
this study it will be compared the impact of building
orientation and geometric features of parts over the
flexural properties. Through optical observation it will be
studied the failure mechanism
Jorge Aisa | Javier Castany | Angel Fernández, November 2011
New injection processes have been developed last decades, improving the designer freedom in order to launch attractive functionalities. All these procedures should be carefully analysed before to decide their use, because it is necessary to understand their natural restrictions, cost and operation requirements and rheological implications in the tools construction. This contribution presents a wide study made in the T.I.I.P., research group from the University of Zaragoza, which gives simulation results and experimental values about sequential injection moulding, and some practical considerations for designers and toolmakers, in order to get successfully results.
Saleh A. Jabarin | Sirisha R. Kesaboina, November 2011
The Kinetics of acetaldehyde (AA) stripping from PET pellets were determined at different temperatures, along with the determination of the residual concentrations of other less volatile compounds such as 2-methyl-1,3-dioxolane (2MD). The rate constants for the polymerization and AA diffusivity coefficients were determined at different temperatures of air stripping of PET. The air stripping of AA from PET is shown to involve chemical reactions and physical changes including polymerization, diffusion and generation of AA, 2MD, EG and water. This paper discusses the mechanisms of the chemical reactions and the formation of the by-products. The techniques used to elucidate the mechanism include gas chromatography (GC), intrinsic viscosity (IV), and density.
Hande Celebi | Goknur Bayram | Aydın Dogan, November 2011
In this study, composites were obtained by
introducing the zinc oxide (ZnO) fillers into the block
copolymers of poly(butylene terephthalate) (PBT) and
poly(tetramethylene oxide) (PTMO) by melt
compounding method. The thermal conductivity and
coefficient of thermal expansion of composites were
investigated as a function of ZnO size and concentration.
It was found that addition of ZnO increased thermal
stability, while it decreased coefficient of thermal
expansion of the composites at low temperatures (55 to 70
°C).
Paul G. Andersen | Frank Lechner | Maria Hoelzel | Thorsten Stirner, November 2011
Effectively feeding low bulk density material into a
co-rotating twin-screw extruder has always been a
challenge. However with the introduction of even finer
particle size fillers (sub-micron in some cases) as well as
new generations of polymer reactor resins, the issue has
become even more problematic. Additionally as bulk
density decreases, the materials tend to fluidize more
easily. Fluidization lowers the “effective” bulk density
even further and exacerbates feeding issues. Typical unit
operations within the compounding process where
material is more susceptible to fluidization are: transfer
from storage vessel to feeders, from feeder to twin-screw
extruder and within the feed zone conveying section of the
twin-screw extruder. While there are methods to minimize
the potential for fluidization such as dense phase
conveying from storage to feeder, minimization of the
feeder height above the extruder feed opening,
incorporating a vent into the feed hopper, extending the
length of the conveying zone in the extruder feed section,
the process eventually reaches a feed volume limitation,
which more often than not is well below an economically
viable production rate. This paper will review a new Feed
Enhancement Technology (FET) that provides significant
improvement for the introduction of fine particle / low
bulk density materials into the extruder.
The co-rotating fully intermeshing twin-screw
extruder is the primary production unit for compounding
of polymer based materials. It also has had a long term
presence in processing material in the chemical and food
industry and more recently in pharmaceuticals. While this
equipment celebrated its 50th anniversary several years
ago and might be considered a “mature” technology, it has
not experienced a decline in new developments as might
be expected, but rather a significant number of
advancements continue to evolve. This paper will
highlight several significant developments of the past 10
to 15 years. These are the implementation of high torque
(power) designs, the use of increased rpm in conjunction
with high torque for improved operating flexibility and
productivity, and finally a technology breakthrough for
feeding difficult to handle low bulk density materials.
John Vlachopoulos | Nickolas Polychronopoulos | Shinichiro Tanifuji, November 2011
The methodology is based on some conventional
models for flow in the hopper, solids bed and melting
zone. In the melt pumping zone the Hele – Shaw
approximation is applied, which describes spreading flow
in two dimensions. The momentum and energy equations
are solved layer – by – layer starting from the barrel wall.
This methodology enables significant reduction of
computer time required for simulation of extruders with
complex screw geometry, over the fully 3D approach.
Good agreement was obtained with some available
experimental data and further evaluations of predictive
capabilities are currently underway.
Shih-Po Sun | Lyndon Charles | Fei Peng | James R. Olson | Montgomery T. Shaw | Mei Wei, November 2011
Orthopedic procedures often require repair materials
that can carry large loads without excessive deformation or
failure. To this end, we designed composites using two
biocompatible/bioabsorbable polymers, poly(L-lactic acid)
(PLLA) and polycaprolactone (PCL). The latter was filled
with nano-needles of hydroxyapatite (HA), while the
PLLA was used in long-fiber form. Theory advises that
the HA nano-needles must be of high aspect ratio and be
aligned in the matrix to gain sufficient stiffness. We have
explored several processing techniques for accomplishing
this task, and have successfully made composites in the 8-
to 10-GPa range. Variations of this structure will also be
described.
J. Escudero | J. Tirado | M.A. Rodriguez-Perez | J.A. de Saja | D. Rosa | J.A. Vazquez, November 2011
This paper presents a novel technology to produce
plastic parts called “Stages Moulding”. The patented
technology allows producing plastic parts with complex
shapes, from a wide variety of polymers, with excellent
surface quality, reduced thermal and mechanical stresses
and possibility to produce parts with reduced weights.
This novel process uses cheaper moulds and equipments
than those used in injection moulding. The specific
characteristics previously mentioned make this
technology very promising for the production of plastic
parts for different markets. The paper explains the main
characteristics of this technology presenting some real
examples of parts produced.
A. Lopez-Gil | M.A. Rodriguez-Perez | J.A. De Saja | F.S. Bellucci | M. Ardanuy, November 2011
This research work develops new methods to
produce biodegradable starch-based trays for the
purpose of replacing expanded polystyrene in the food
packaging market. The starch based biopolymers
present several drawbacks like poor mechanical
properties and very high density. In order to overcome
these drawbacks two research lines have been set up:
blending thermoplastic starch with biobased
reinforcements from agricultural wastes like barley
straw and grape wastes, and testing the foamability of
these materials with a Microwave-foaming method.
David Arencón | Antonio B. Martínez | Pablo Moreno | Ana García, November 2011
The traditional sharpening through the razor blade
method employed in the fracture characterization of
polymers creates plastic deformation at the notch tip,
which affects the fracture toughness values. Recently it
has been applied a technique based on femtosecond
pulsed laser ablation, which removes material with almost
no heat dissipation, preventing melting and thermal
deformation of the surrounding area and without plastic
deformation at the crack tip. In this work, the fracture
toughness of polycarbonate was studied using the Linear
Elastic Fracture Mechanics testing procedure at impact
velocity, evaluating the influence of crack sharpening by
femtolaser or razor blade sliding.
S. Pardo-Alonso | S. Estravís | E. Solórzano | M.A. Rodríguez-Perez | J.A. de Saja, November 2011
X-ray radioscopy is a technique in which a series of
radiographies are acquired during an evolving process.
The present study aims to investigate the mechanisms
occurring during the reactive foaming process of rigid
polyurethane (PU) foams in its liquid state. The work
addresses a comparative study of in-situ pore growth
determination in PU foams with and without
nanoadditives (nanoclays), based on the mentioned
technique and thus providing a valid methodology to
investigate the foaming process in all its stages. The
results confirm that nanoparticles addition modify the
final pore size most probably based on a higher
nucleation rate at initial stages.
S. Estravís Sastre | M. A. Rodríguez Pérez, November 2011
Nanofillers are added to rigid PU foams to improve their mechanical properties, however this expected behaviour is not always found. A poor dispersion of the fillers is usually accepted as a possible explanation, but chemical interaction between matrix and fillers could also result in a reduction of the final foam properties. In this study, polyurethane rigid foams (with and without nanoclays) have been produced and characterized. Different dispersion techniques have been used. The experimental results suggested that chemical interaction between fillers and matrix plays a critical role in the mechanical behaviour of these type of systems.
Juan Lobos | Migue A. Rodriguez-Perez | Gemma Gasa | Miguel Muñoz, November 2011
This paper presents an investigation on the improvement
of the thermal conductivity of polystyrene foams by using
different types of carbon blacks as additives. Carbon
blacks with different morphologies were used as IRblockers.
To test the changes in the conductivity foams
with densities between 20 and 100 kg/m3 were produced
using the solid state foaming technique. The cellular
structure and thermal conductivity were analyzed in
detail. In addition the thermal conductivity was
analytically modeled to study the influence of the
different carbon black types on the heat flow by radiation.
The best morphology to reduce the thermal conductivity
has been detected.
Rapid Manufacturing (RM), as one of the most important emerging technologies, has a high potential as part of European industry, with a clear role in manufacturing process and economy. In this context, seven EU entities have proposed an e-learning program on these technologies, to increase its knowledge and use, with the aim of improving competitiveness in companies. Results on surveys prepared in this project with the aim of establishing the actual situation in Europe in this field and filled in by companies and training centres are presented in this communication, providing an overview of RM general knowledge and use.
Tu Le Ngo | Alain Choquet | Dominique Valligny, November 2011
Many vehicle manufacturers are aiming diversifying
their car interiors with more daring colours and textures
with limiting the amount of investment. For large
interior parts, like instrument or door panels, special
resins or painting technology was considered current
state of the art. A new technology, thin TPO film
overmoulding, could replace this current state of the art
technology.
The main paper objective of this paper is to describe the
advantages and the issues in using thin thermoplastic
olefin (TPO) foil overmolding as an alternative. This
paper presents the new generation of TPO “ready for
graining” soft foils and the innovative tooling & process
needed to laminate the foil during the PP direct injection
shot
Christian Bey | Alain Choquet | Dominique Valligny, November 2011
By the year 2025, carbon emissions levels will require for
the main vehicle in the world important weight
reductions. Plastics components can now be expanded
during injection keeping correct mechanical behavior to
design vehicle interiors. The paper presents the
instrument panel application and describes the
importance of the Polypropylene (PP) material, the
expansion technology and the related component,
injection press and tooling designs. The paper aims to
demonstrate how applications like visible instrument
topper panels or side trimmings could be designed in
purpose to respect esthetical and mechanical
specifications
C. Saiz-Arroyo | M.A. Rodríguez-Pérez | J.A. de Saja, November 2011
Foaming of polypropylene is not trivial due to its
weak melt strength and its semicristalline character. The
solutions proposed up to now are based in crosslinking
the polymeric matrix or in the use of special
polypropylene grades.
A collection of samples with relative densities in the
range of 0.3-0.6 have been produced using a conventional
PP grade. The improved compression moulding foaming
process which uses a chemical blowing agent was used to
produce the analyzed foams. The effect of chemical
composition on both cellular and mechanical properties
has been analyzed.
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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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