SPE Library
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
Optimization of Nanocomposites Injection Molding by design of Experiments
Design of experiments (DOE) is a systematic method based on designed experimental rums used to evaluate the effects of selected variables on the final product properties. The method is especially useful when materials are expensive and/or scarce and only small quantities are available for experimentation, such as with carbon nanotubes (CNT). The effects of injection molding on the properties of Polycarbonate and Polybutylene Terephthalate multi-wall CNT composites were studied using DOE. Results demonstrated that although only a small number of experimental runs were used, a significant effect of the injection molding parameters on the properties of the nanocomposites was detected.
PHYSICOCHEMICAL PROPERTIES OF PLASMA POLYMERIZED ACRYLIC
ACID, ε-CAPROLACTONE AND LACTIC ACID FILMS
The physicochemical properties of plasma
polymerized films were investigated by means of X-Ray
photoelectron spectroscopy (XPS), Fourier Transform
infrared spectrophotometry (FTIR), ellipsometry and
Water Contact Angle. Three different monomers (acrylic
acid, ε-caprolactone and lactic acid) were polymerized in
a Plasma Polymerization System for different times (7, 15
and 30 min) and power conditions (80 and 120 W). While
plasma polymerized acrylic acid and ε-caprolactone
shared a strong similarity with the conventional polymers,
lactic acid did not bear any resemblance to the
conventional polymer.
PVC – Moving Up to the Next Level
The papers from the most recent IOM3
conference, PVC 2011, are used as the basis
for this paper.
The PVC market is reviewed on the basis
of Europe’s environmental challenges with
management options being reshaped by global
megatrends.
The cost competitiveness of PVC
products, energy saving from using PVC
products and increasing recognition of our
sustainable development progress can only
serve our industry well into the future.
The Voluntary Commitments of the past
ten years (Vinyl 2010) and the next ten years
(VinylPlus) are reviewed.
Examples of educational initiatives in the
UK to improve perceptions are also
highlighted.
MECHANICAL AND THERMAL PROPERTIES OF SUPERCRITICAL CARBON
DIOXIDE PROCESSED EPOXY SILICONE BLENDS
Mechanical and thermal properties of epoxy have
been modified through blending of diglycidylether
of bisphenol A (0.1 mol) with polydimethylsiloxane
(PDMS) at concentration ranging 1.0 to
3.0 phr of resin at 1400 psi and 90±10C for 1hr in
supercritical carbon dioxide (scCO2), followed by
curing with triethylenetetramine (10 phr) at
40±10C.The formation of synthesized epoxy
silicone blends (ESBs) has been ascertained
through ultraviolet –visible (Uv-vis), Fourier
transformed infrared (FT-IR), X-ray diffraction
(XRD) spectra and microscopy. With PDMS
concentration, the compressive, tensile strength,
Rockwell hardness (R scale), fringe values and
crystallinity of ESBs were decreased with
simultaneous increase in their impact strength,
resistance against wear and thermal stability.
Key words: Supercritical carbon dioxide, Polymer
blends, Spectra, Morphology, Mechanical and
thermal properties.
COMPLEX INVESTIGATION OF INJECTION MOULD FILLING
Thin wall injection moulding is a difficult process. High viscosity polymeric material is injected into a mould by high speed and high pressure. A special instrumented injection mould was designed for the investigation of the cavity filling of injection mould. Rheological measurement can be carried out with different wall thickness slit die inserts. The pressure can be measured during the filling, the packing and the cooling stages as well. The pressure drop during the filling can be used for determination the flow properties of the material. The measured cavity pressure of the injection cycle is proper for the validation if thin wall injection moulding simulation. The filling of the dies was simulated by Moldex3D software.
SYNTHESIS OF POLYPYRROLE / POLYTHIOPHENE COPOLYMERS IN
SUPERCRITICAL CARBON DIOXIDE
Chemical oxidative copolymerization of pyrrole with
thiophene was conducted using ferric chloride initiator at 90
°C, 1200 psi over 24 hours in supercritical carbon dioxide
(scCO2). Polymerizations were conducted with different
concentration ratios of pyrrole to thiophene 1:0, 0:1, 1:1 and
1:2 in a 100 mL high-pressure batch reactor. Polymerization
yield which was up to 56.7 % in homopolymerizations was
found to decrease in copolymerizations at molar ratio of
pyrrole to thiophene 1:1 .The polymers were characterized
by ultraviolet visible (Uv-vis), Fourier transformed infrared
(FT-IR) spectra, elemental analysis, gel permeation
chromatography (GPC), simultaneous thermogravimetricdifferential
thermal analysis-differential thermogravimetry
(TG-DTA-DTG), electrical conductivity and atomic force
microscopy (AFM).
Key words: Supercritical carbon dioxide, Polymerization,
Polypyrrole, Polythiophene, Copolymers, Characterization.
Evaluation of tribological behavior of amorphous and crystalline thermoplastic compounds under high pressure, velocity and temperature conditions
In the present study, the friction and wear properties of two high temperature resistant polymers, an amorphous polyetherimide (PEI) and a crystalline 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 wear properties. Lubricated and lubricated-reinforced compounds showed excellent wear properties compared to pristine resins throughout all PV conditions.
Development of novel Wood Plastic Composites (WPC) using as natural filler wood from the recycling of leisure sailing ships
Plastic Wood Composites, or commonly known as WPC, are a novel and interesting alternative to the usage of wood in certain applications, improving the properties of the final products thanks to the polymers intrinsic properties. However, compatibilization between the polymer matrix and the wood fibers or particles is a key factor that must be taken into consideration. Hydrophilic fibers are not compatible with hydrophobic polymer matrices, such as polyethylene or polypropylene (the main used polymers due to their processing temperatures and the low degradation temperature wood possess).
The present research aimed to develop WPC using as the natural fiber recycled wood obtained from out-of-use leisure sailing ships. The objectives of the research presented and added new challenges on the development of such natural composites, posed by the state of the wood to be used, usually contaminated with salt, rests of minerals and rests of organic matter, so an excellent decontaminating process was a must. Once the wood conditioning processes were completed, a conventional extrusion process was carried out to obtain the WPC. The polymers used as polymer matrix were Low Density Polyethylene (LDPE) and Polypropylene (PP). Four different concentrations of wood fibers were used (10%, 20%, 30%, 40%) in order to determine their properties according to the fiber concentration. Also, two different compatibilizers for wood and polymers were used to check their behavior, as well as composites without compatibilizers were obtained.
Finally, characterization techniques, including SEM microscopy, mechanical and impact properties and aging tests were carried out for all the developed WPC composites. Results indicate which were the best wood concentration on the composites as well as the best compatibilizer and its concentration on the final composite.
MECHANICAL TESTING OF POLYPROPYLENE MATERIALS IN SHEAR ANALYSED BY DIGITAL IMAGE CORRELATION
Three polypropylene-based materials (two talc-filled compounds and one unfilled homopolymer) were tested with two in-plane shear test methods (Iosipescu and V-notched rail). The three materials behaved differently in the shear tests. Most notably, cracks developed in tension near the notches for the particle-filled materials, while the unfilled homopolymer did not fracture. There were also differences between the materials regarding strain localisation between the notches, and thickness change in the sheared section. The stress-strain curves obtained with the two shear tests were quite similar.
MATERIAL MODELLING FOR SIMULATING IMPACT LOADING OF INJECTION-MOULDED POLYPROPYLENE PARTS
This paper describes the calibration and verification of a material model used in the numerical simulation of mechanical loading of plastic parts. The material model features strain rate dependent yield stress, pressure dependent yield stress, plastic dilatation and damage. The model was calibrated with data from tests in uniaxial tension, shear and uniaxial compression, utilising 3D digital image correlation for full-field displacement measurements. Two load cases were simulated; centrally loaded clamped plates and three-point bending of bars. The predictions of force vs. deflection were good to fair. The results are discussed in terms of deficiencies of the calibration data, heterogeneity and anisotropy of the injection-moulded components, and shortcomings of the model.
EVALUATING THE REACTIVE BLENDING OF PET/PEN IN A TWIN-SCREW
EXTRUDER: AXIAL DISPERSION MODEL
The transesterification of PET and PEN in a twin-screw
extruder (TSE) was investigated. A theoretical model, able
to predict the extent of transesterification reaction (X) and
degree of randomness (RD) against processing parameters
along the screw axis is presented. PET/PEN blends were
prepared via the melt mixing process. The axial dispersion
model (ADM) was developed for modeling the twin screw
extruder. Extent of transesterification reaction and degree
of randomness was examined via Nuclear Magnetic
Resonance Spectroscopy (H-NMR). Theoretical and
experimental results were in good agreement, allows the
prediction of the X and RD as a function of processing
parameters such as time, temperature and composition.
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.
POLY(LACTIC ACID) – INVESTIGATION AND MODIFICATION OF MECHANICAL BEHAVIOR
Both industrial and scientific interest in poly(lactic acid) (PLA) increased in recent years for various reasons; hopes are rising that this material may represent an alternative to commodity polymers. In order to answer these expectations, thorough characterization and modification of poly(lactic acid) is necessary. The actual presentation focuses on the mechanical properties, especially the impact resistance of PLA. Attempts were made to improve this characteristic by blending with both rigid and elastomeric polymer grades. The blends were characterized with various techniques in order to compare toughening methods in these systems, and enlighten the relationship between interactions, structure and macroscopic properties.
CHEMICAL DEGRADATION DRIVEN CRACKING IN PE PIPES
Stress corrosion cracking (SCC) in polyolefin pipes
usually starts as a microcrack colony within a degraded
layer adjacent to the pipe surface exposed to combine
action of mechanical stress and chemically aggressive
environment. One can distinguish four stages of SCC: 1)
microcracks initiate within the degraded polymer; 2) slow
growth of individual cracks; 3) strong interaction of cracks
and formation of clusters; and 4) clusters growth and
crack/or cluster instability leading to the ultimate failure.
The stage of crack initiation is primarily controlled by
chemical degradation, and the second stage is strongly
related with the effect of mechano-chemical degradation at
process zone. The interaction of multiple cracks and
clusters are typically observed after the many cracks grow
individually. In this paper, the mechanism of crack
initiation and growth due to mechano-chemical
degradation is addressed and modeled.
AUTOMOTIVE SUNROOF SYSTEMS AND FRAMES IN XIRAN® SMA/ABS
Automotive Sunroof Systems, which have become a must have for the added comfort and styling to today s cars, increasingly rely on engineering plastics functionalities to replace metals. Structural and semi-structural Sunroof module components, Sunroof frames in particular, typically need to meet a wide range of technical requirements, with a clear focus on integration of functions, safety, cost and weight reduction. The glass-reinforced materials, thermoplastics and thermosets, currently used for Sunroof frames are mostly based on PBT/ASA, PBT, PA, PP and unsaturated polyester SMC. These products are not a perfect match for the application needs of today and the future. Glass-reinforced SMA/ABS on the other hand offers an ideal, unique combination of properties required in Sunroof frames and systems. SMA/ABS-GF compounds such as Polyscope s Xiran® SG grades have clear technical and commercial benefits: • high dimensional stability and precision • very low warpage, compliance to mold cavity shape • good performance at low wall thicknesses • high creep resistance • excellent adhesion without surface treatment • low density, high economic value • good chemical resistance • easy recyclablility with efficient waste streams.
CARBON FIBRE REINFORCED LLDPE DEVELOPED FOR LIGHTWEIGHT
APPLICATIONS BY TREATING THE FIBRES WITH A NEW TYPE OF
COUPLING AGENT
Scope of our work has been development
of a new type of coupling agent by which
processing of long carbon fibre reinforced
composites by injection moulding will be
possible since hindering the fibres from
breakage and simultaneously improving
the mechanical properties. Resistance of
LLDPE of 1-10% carbon fibres against
tensile and flexure stresses has been
investigated. Tensile strength has increased
by 30% and flexure strength has gained
90% related to the neat polymer.
Fibre/matrix interaction has been studied
on SEM graphs and a polymer layer has
been observed to be connected to the fibre
in additive treated fibre containing
composites.
Ultraprecision Grinding of Aspheric Cemented Carbide Lens Mold
for Plastic Injection Molding
To cope with increasing demands on ultraprecision
profiling and finishing of aspheric lens molds, we have
implemented an ultra nanoprecision aspheric grinding
system to be mounted with an ELID(ELectrolytic Inprocess
Dressing)-capability and on-line feedback
capability of profile accuracy. A cemented carbide mold
has successfully ground and finished to be with several
nanometric surface smoothness and with ultraprecise
profile accuracy by just grinding process with ELID
mechanism. Some specific conditions have been
investigated to achieve better accuracy and quality on
molds. This paper presentation introduce those R&D
activities and also discuss on the latest achievements on
this topics, with showing injected aspheric lenses by the
molds.
ACOUSTIC TRANSMISSION PROPERTIES OF PLASTICS COMPOUNDS
Acoustic properties of polymer compounds are an important consideration for many applications. Currently there is a standard test method for the determination of the sound impedance and absorption properties of materials but there is no such test for the property of sound transmission loss (STL). The equipment used for the impedance and absorption standard test can, however, be adapted to measure the sound transmission property. The objective of this project was, therefore, to assess this testing method for STL and to carry out an initial investigation on the relationship between the structure of plastic compounds and their acoustic transmission property.
MICROWAVE ENHANCED FOAMING OF SELECTED POLYMERIC MATERIALS
Microwave heating has a number of advantages in comparison to the conventional method due to the ability to heat a part of polymeric material directly through specific interaction of electromagnetic radiation with selected types of materials. Most thermoplastics are relatively transparent for microwave irradiation and they do not absorb microwaves to a sufficient extent to be heated. In such case, enhanced microwave heating can result from the use of fillers such as carbon black.
In this paper, the ability of different thermoplastic polymers as polyurethane, poly(vinyl chloride) and carbon black filled polypropylene to absorb microwave irradiation and to be foamed using chemical blowing agents is discussed. The temperature changes of such materials as the heating effect under microwave irradiation with various power were investigated. Selected polymeric materials with additive of chemical blowing agents were foamed under microwave irradiation and the influence of foaming conditions on cell structure and apparent density of porous products was analyzed.
UPGRADING PERFORMANCE OF RECYCLED POLYAMIDE WITH ZEMAC®
Polyamides are widely used in many applications. There is a vast amount of recycled polyamide coming from the carpet and textile and other industries. Due to degradation and loss of viscosity, this recycled polyamide has reduced performance and limited its use. The unique chemistry of alternating copolymers of ethylene and maleic anhydride provide several advantages for upgrading recycled polyamide. This paper discusses the results obtained with compounding prime grade polyamide as well as recycled polyamide with the addition of small quantities of this copolymer and specific property improvements for applications in injection molded compounds.
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