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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
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.
STRESS-INDUCED CRYSTALLIZATION OF A METALLOCENE HIGHDENSITY
POLYETHYLENE
The final mechanical properties of a plastic product
which is made of semi-crystalline polymers depend
significantly on the molecular properties and the applied
processing conditions. Particularly, the formation of flow
induced structures via polymer crystallization plays a
major role in defining the final attributes of the product.
In this paper, the effects of shearing, uniaxial extension
and temperature on the flow induced crystallization of a
high-density polyethylene (HDPE) are examined using
rheometry. Extensional flow found to be a stronger
stimulus for polymer crystallization compared with that of
simple shear. Generally, strain and strain rate found to
enhance crystallization in both simple shear and
elongation at temperatures around the meting point. At
temperatures well above the melting point, polymer
crystallized under elongational flow while there was no
crystallization under simple shear flows.
SOLUTIONS WITH UV-CURING PAINT TECHNOLOGY FOR DIFFERENT
BUSINESS UNITS
UV-curing paint technology is known since many years
e.g. in the field of wood application or in the area of
plates and blanks. Today it is also getting more and more
common for automotive and decorative applications
starting with new improved technologies also to paint 3-
D parts.
The new Dual-cure paint system of PETER-LACKE
combines the advantages of the very fast drying and
excellent scratch resistance of a UV-curing paint system
with the 3-D painting ability and physical properties of a
conventional thermal cured PU-paint system. A dual-cure
piano black system was launched e.g. for the new Audi
A8 Interior.
The UV-Mono-cure systems – just cured by UV-light –
give additional to the very short cure time of just a few
seconds the advantage of very low or no emissions. Many
colours and effects are possible in both UV paint systems
and can be used on various plastics as well as on metal or
glass.
COATINGS ON TRANSPARENT PLASTICS FOR AUTOMOTIVE APPLICATIONS
Transparent thermoplastic polymers hold an
important position as materials for optics as well as for
automotive glazing. However, soft plastic parts need to be
protected by coatings. For optical applications especially
antireflective coatings are inevitable. A presently wellestablished
coating system for plastics is plasma ionassisted
deposition. Special efforts are essential to find out
the best coating conditions for each type of plastic. A
comprehensive understanding of complex interactions
between the plasma and the different polymer materials is
a key factor for the development of coating strategies.
Some coatings on polycarbonate for automotive
applications will be discussed for example.
Surface Modification Techniques for
Optimizing Adhesion to Automotive
Plastics
Automotive plastics with a low polarity, such as PE,
PP, TPO, POM, PUR and PTFE typically require
surface treatment when decoration is required.
Metallic surfaces may also require cleaning to
remove low molecular weight organic materials
prior to decoration. Once the above-mentioned
interior and exterior grades of substrate surfaces are
cleaned and activated, printing, gluing and painting
are possible without the use of adhesion-promoting
primers. This paper describes the latest innovations
in three-dimensional surface treating technology for
plastics finishing which address the need to advance
adhesion properties, increase product quality, and
achieve environmental objectives within the
automotive industry. These innovations include
advanced thermal and non-thermal discharge
treatment processes for raising the polarity of
surfaces to be painted, bonded, decorated,
laminated, printed, or to have tape applied.
LIFETIME PREDICTION IN ENGINEERING PLASTICS - LIMITATIONS OF SHORT-TERM TEST EXTRAPOLATIONS
Using short term tests to predict future outcomes of any long term process is common in extrapolation techniques in Science, Social science and Engineering. However, in every process it is important to ascertain some sort of criterion before extrapolation techniques are employed. The criteria for predicting lifetime of an engineering plastics for the specific application must include the requirements of the test to (a) reproduce the mechanisms of field failures and (b) have a technically sound procedure for extrapolation of a the relatively short test data. We will finally propose a quantitative modeling approach as an alternative to “empirical” extrapolation.
Interlaminar Fracture Toughness
Of Carbon Fabric Reinforced Epoxy Composites
The Mode I and Mode II fracture behaviour of three carbon-epoxy composite laminates with different fabric reinforcement and different matrices was investigated. Standard Double Cantilever Beam (DCB) and End Notched Flexure (ENF) delamination tests were performed to determine initiation toughness and to asses the subsequent crack propagation behaviour. Various toughening mechanism, acting at the microscopic level and responsible for the stick-slip propagation behaviour observed, have been identified. The effect of temperature in a range from -60° to 165 °C was investigated.
A COMPREHENSIVE STUDY OF LOW-DENSITY POLYETHYLENE
IN CAPILLARY FLOW
The capillary flow of a commercial LDPE melt was studied both experimentally and numerically. The excess pressure drop due to entry (Bagley correction), the compressibility, the effect of pressure on viscosity and the possible slip effects on the capillary data analysis have been examined. Using a series of capillary dies having different diameters, D and length-to-diameter L/D ratios, a full rheological characterization has been carried out, and the experimental data have been fitted both with a viscous model (Carreau-Yasuda) and a viscoelastic one (K-BKZ/PSM model). Particular emphasis has been given on the pressure-dependence of viscosity, with a pressure-dependent coefficient βp. For the viscous model, the viscosity is a function of both temperature and pressure. For the viscoelastic K-BKZ model, the time-temperature shifting concept has been used for the non-isothermal calculations, while the time-pressure shifting concept has been used to shift the relaxation moduli for the pressure-dependence effect. It was found that only the viscoelastic simulations were capable of reproducing the experimental data well, while any viscous modeling always underestimates the pressures, especially at the higher apparent shear rates and L/D ratios.
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