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
STUDY ON RAPID MANUFACTURING TRAINING NEEDS IN THE EUROPEAN CONTEXT
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.
THIN TPO FILM OVERMOLDING FOR VEHICLES INTERIORS DECORATION
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
EXPANDED INJECTED PP SYSTEM TO MAKE 25% LIGHTER ESTHETICAL
INSTRUMENT PANEL
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
PRODUCTION OF POLYPROPYLENE (PP) FOAMS FROM A CONVENTIONAL PP
GRADE. ANALYSIS OF CELLULAR STRUCTURE AND MECHANICAL
PROPERTIES.
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.
ADHESION BETWEEN POLYPROPYLENE AND STEEL BY OVER MOULDING
In this work, a hybrid polypropylene (PP)/steel car
part (Traverse leg) was created by over moulding. PP was
modified with 10%wt. of PP-g-Ma coupling agent.
Different surface treatments were applied to the steel
determining its influence on adhesion. Best peel strength
was reached when the steel was sanded. Etching and shot
peened plates showed similar but lower levels of
adhesion. In all cases, the application of torch heating was
necessary to create a thin layer of iron oxide strongly
bonded to the steel and by reaction to the PP-g-Ma. To
create adhesion a minimum steel temperature of 120ºC
was necessary.
T.I.I.P.: A TRAINING AND RESEARCH GROUP IN INJECTION MOLDING
Created from University of Zaragoza, the group T.I.I.P. has developed its activities since 1989 around injection molding. This team has always worked as near as possible to the industry (its name includes “workshop”, not “laboratory") and, in its aims, it promotes the research work pushed from market demands. However, for an effective knowledge exchange, the members of the group T.I.I.P. have promoted hundreds of training courses teaching to all the injection´s actors, about how to arrange the whole process to improve final results. During these twenty years, fifteen doctoral theses and twenty friendly computer programs for training were made, closing the loop.
HALOGEN-FREE FLAME RETARDANT POLYOLEFIN FOAMS
FOR AUTOMOTIVE APPLICATIONS
A new type of materials has been produced by means of
creating a cellular structure in blends of LDPE/LLDPEg-
MAH/ATH. The presence of the aluminium hydroxide
(ATH) in a polymer blend, both as flame retardant and
reinforcement, significantly increases the density of the
end product. The aim of this work is to achieve a cellular
structure by foaming these materials, when high loading
levels up to 60wt% of ATH are included. As a result, a
density reduction of 50% has been obtained together
with excellent mechanical and flame retardant
properties. A comparison of these properties between
solid and foamed materials is included.
DEVELOPMENT OF MODIFIED POLYLACTIDE (PLA)
Polylactide (PLA) and other bio-based plastics have been attracting much attention for environment problems. In this report, modified PLA resin have been developed and based on “Technology of Nano-Modification for Polymer”, such as control of softening and of crystallization in nano size. Two types of modified PLA of which one is clear and soft PLA for extrusion molding and another one is high moldability PLA for injection molding have been developed. These modified PLA have been applied as alternative plastics of PP and ABS to stationery, packaging, convenience goods, electrical appliance and so on. Performances and technologies will be presented.
EFFECT OF PHYSICAL AGING ON ENTHALPY RELAXATION AND
EMBRITTLEMENT OF ELASTOMER THERMOPLASTIC BIODEGRADABLE
POLY (L-LACTIDE/ ε-CAPROLACTONE)
In the design of new polymeric materials the longterm
stability and durability are matters of considerable
importance. It is known that during physical aging volume
contraction and densification of polymers occur and
therefore physical properties such as mechanical or
crystallization behavior of amorphous polymers may be
affected. In this work the impact that physical aging has on
two biodegradable poly(L-lactide/ε-caprolactone) (PLCL)
copolymers differing on their randomness character was
studied. Their thermal behavior has been evaluated by
specific aging strategies using Differential Scanning
Calorimetry (DSC).
MECHANICAL PROPERTIES OF LACTIDE BASED SCAFFOLDS FILLED WITH
INORGANIC BIOACTIVE PARTICLES
The mechanical properties of highly porous scaffolds
have been investigated. Scaffolds of poly(Llactide)(
PLLA) and poly(L-lactide/ε-caprolactone)(PLCL)
filled with 5, 10 and 15 vol.% of Bioglass® (BG) and
hydroxyapatite (HA) particles were prepared by a solvent
casting/particulate leaching procedure. The thermal
properties of the scaffolds were determined using
differential scanning calorimetry (DSC) and thermogravimetric
analysis (TGA), while the morphology was
characterized by scanning electron microscopy (SEM). All
scaffolds presented a highly porous structure (≈90%
porosity) and well-interconnected pores. Tensile test
results revealed that the addition of bioactive particles
increases the modulus and decreases the relative
elongation at break.
DEVELOPMENT OF NANOSCALE INTERFACIAL MORPHOLOGY IN POLYMER-BASED NANO-CARBON HYBRID STRUCTURES FOR STRESS TRANSFER IMPROVEMENT
Composites based on carbonaceous materials and polymers have been researched since the production of carbon fibers in the 1960s, leading to disruptive technological changes in the field of materials science. Today micro- and nano-scale carbon materials have opened new directions within this field to produce composites for high-performance applications. This work outlines in-situ analysis of the POLYMER-NANO interfacial zones in the composite as a function of nano-carbon structures. Stress transfer analysis of the composite interface couples nano-carbon structure with morphology and mechanical performance. This work addresses fundamental issues for materials design toward commercialization of polymer-based nano-composites meant for high-performance technologies.
REACTIVE EXTRUSION OF POLY(LACTIC ACID) WITH STYRENE-ACRYLICGLYCIDIL
METHACRYLATE
In this paper are discussed the rheological changes
observed in PLA by one-step reactive extrusioncalandering
(REX) using as a chain extender (CE) an
oligomeric copolymer styrene-acrylic multifunctional
expoxide. Dymamic rheological experiments and gel
permeation chromatography tests were used to
characterize the architectural modifications of two grades
of PLA, with different D-enantiomer content. According
to the results, an increase on D-enantiomer content seems
to reduce the CE coupling reactions. At the extrusion
conditions used high level of chain modification is
obtained as could be revealed by the increase on low
frequency complex viscosity as well as in the storage
modulus (G’) (associated to the melt elasticity).
The Effect of Carbon Nanotubes on the Rheology and Electrical Resistivity
of Polymer Blends
Different mixing protocols were used to incorporate
Carbon Nanotubes (CNT) into Polyamide 12 (PA)/ High
Density Polyethylene (PE) blends. At a composition of
75PA/25PE/0.75wt.% CNT, interface localization of CNT
promoted by predispersing CNT in the PE phase, resulted
in five decades lower resistivty compared to other mixing
protocols. Melt storgae modulus (G’) was also found to be
affected by interface localization in this case with over
20% higher G’ compared to the other protocols. Specific
CNT localization is explained in terms of preferential
interaction between PA and CNT on the one hand, and
kinetic restrictions arrising from the mixing protocol on
the other.
THE EFFECTS OF COMBINING NANOCLAY AND STEEL WIRES MULTISCALAR
REINFORCEMENTS ON THE STRUCTURE AND PROPERTIES OF
POLYURETHANE FOAMS
In this paper we prepared and characterized several
polyurethane composite foams by combining variable
concentrations of organophilic clay (montmorillonite) and
metal reinforcement, with the objective of developing
novel multi-scalar multifunctional rigid foams. The
addition of montmorillonite clay promoted foaming and
the formation of finer and more homogeneous cellular
structures, resulting in foams with compressive elastic
moduli and collapse stresses lower than that of the
unfilled polyurethane foams. However, a comparative
analysis versus the foams’ relative density demonstrated
that both mechanical properties follow one single trend
for the two materials. The combination of montmorillonite
and metal reinforcement further reduced the cell size of
foams, ultimately resulting in foams with similar
mechanical properties for considerably lower relative
densities. Although no important differences in thermal
conductivity were found for the polyurethane foams with
adding montmorillonite, the incorporation of the metal
reinforcement led to considerably higher thermal
conductivities, its value increasing with increasing
relative density.
FIRE BEHAVIOUR OF FLAME-RETARDANT RIGID POLYPROPYLENE FOAMS
It is well known the growing industry interest in
reducing the high flammability of polymers, as it limits
their suitability in a wide variety of applications where
fire retardancy is required, at the same time maintaining
some of the advantages related to their lightness. With
that in mind, this work presents the development of new
rigid polypropylene composite foams filled with high
amounts of flame-retardant systems based on hydrated
magnesium carbonate. Particularly, interesting flameretardancy
synergistic effects were observed in the
polypropylene composite foams by means of cone
calorimetry by combining the hydrated magnesium
carbonate with an intumescent formulation and layered
nanoparticles.
BISPHENOL-A FREE DENTAL POLYMER COMPOSITES
Bisphenol-A (BPA) is suspected to be an endocrine disrupter. Current polymeric dental materials are based on BPA derivatives, e.g. Bisphenol-A Diglycidylether Methacrylate (Bis-GMA) which may leach out unreacted monomers and its degradation products. Consequently, the present work deals with BPA-free alternatives, for potential use in dental polymers and composites.
Experimental results indicated that BPA-free monomers from natural and synthetic sources can replace Bis - GMA without sacrificing physical and mechanical properties of the final dental polymeric adhesives and composites.
OPTIMUM FLOURPLAST: CREATING NEW OPPORTUNITIES FOR THE BIOPLASTIC INDUSTRY. PROCESS STRUCTURE PROPERTY RELATIONSHIPS OF A NOVEL BIOPLASTIC POLYMER COMPOUNDING SYSTEM
This paper describes an outline of the structural features (using SEM, WAXS and other advances techniques) and various properties of products containing compatibilised thermoplastic flour (i.e. Optimum FlourPlast). Grain or cereal flour or even purified starches are them self not thermoplastic materials [1]. The thermoplastic flour (TPF) is made from an unique combination of natural based grain (by-) products and a novel compatibilising polymer system making it a thermoplastic material, which can be processed on standard plastic processing machines. The TPF is as such shown to be highly compatible with natural or petrochemical based biodegradable aliphatic (co-) polyesters and various polyolefins such as polypropylene. In such combinations it is shown that it improves processing conditions and enhances the properties of the end formulation (compounds). By making different combinations of the various grades of the TPF (i.e. building block system of precompounds) with other polymers it will be shown that it is possible to obtain a range of products with different properties and good functionality. This made it possible to process the components into products suitable for various applications such as injection molding, extrusion and thermoforming, and film blowing and casting.
New Processes for large scale automotive production of composite applications
In conventional manufacturing processes, composite structures
are formed in multistage, costly process chains and
joined in additional process steps (e.g. gluing or welding).
In terms of process engineering, the biggest savings in
mass production can be achieved by minimizing cycle
time. Jacob has developed new processes, FIT Hybrid
(JEC Award 2011) and SpriForm which combine molding,
forming and joining processes of thermoplastic composites
in a single, cost-effective, large scale process. The
key benefit of the invention is that, in addition to the
lightweight potential of composites, this process offers the
extraordinary potential of lightweight construction due to
the combination with structural design.
VISCOELASTIC CHARACTERIZATION OF SPORTS SURFACES AND ITS RELATION WITH FORCE REDUCTION MEASUREMENTS
The present paper describes the activity carried out to
investigate the dependence of the force reduction
measure of sport surfaces on the material’s viscoelastic
dynamic properties and on the geometry of the sample.
The study was carried out by means of lab tests with an
artificial athlete apparatus and by dynamic-mechanical
analysis. Seven different sport surfaces were tested with
the artificial athlete and their viscoelastic properties
analyzed. Other
polymeric materials were studied besides
the sport surfaces, in order to explore a wider range of
properties. The results show a marked effect of sample
thickness on the force reduction measure, and a method
to correlate them with intrinsic properties of the material
is proposed.
FUNDAMENTALS AND PRACTICE OF PLASTICS FAILURE ANALYSIS
It usually comes as a surprise when a plastic product fails. Plastics are made to succeed, not to fail. Sometimes the financial liability can be high, such as a waterline break that is not detected and causes major property damage. If there is a fatality due to plastics failure, criminal charges may be brought. A company can be forced into bankruptcy by plastics failure. So answering the question "why do some plastics fail and others don't" is of major importance. The answer involves choices of material (chemical composition, molecular weight and intermolecular order), design, processing and service conditions.
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