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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We studied the barrier properties of films produced from eleven different HDPE resins as a function of film thickness. The gauge-normalized water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) depend on film thickness for samples with a larger z-average molecular weight, and the gauge-normalized WVTR and OTR are independent of film thickness for samples with a smaller z-average molecular weight. We also find that WVTR tracks with the average degree of crystallinity of the film as determined by DSC, and that the dependence of film crystallinity on film thickness apparently accounts for the dependence of WVTR on film thickness.
H. Potente, V. Schöppner, R. Hoffschlag, S. Gövert, J. Schnieders, May 2010
This paper looks into the initial steps of the development of a self-optimizing hot-tool welding machine. By employing a new machine concept, it is possible to ensure displacement speeds counter to the direction of joining. This then allows the strength of the weld to be assessed while it is still in the molten state. To be able to use this data for self-optimization, it was necessary to establish a correlation between the short-time strength of the parts in the cooled state and their shorttime strength in the still molten state. Taking these correlations, a systematic approach can be worked out to allow the welding machine to find an optimum processing window with just a few test welds. The results show that the optimum of the joining displacement to the melt layer thickness ratio (sF/L0) can be established for the parameter setting by measuring the tear forces on the welding machine, even without knowing the short-time strength in the cooled state. The same applies for the ratio of the melt layer thicknesses to the wall thickness. Based on these results, the next steps are now to develop a means of selfoptimization and quality assurance during the running hottool welding process.
H. Potente , V. Schöppner , R. Hoffschlag , S. Gövert , J. Schnieders, May 2010
This paper looks into the initial steps of the
development of a self-optimizing hot-tool welding
machine. By employing a new machine concept it is
possible to ensure displacement speeds counter to the
direction of joining. This then allows the strength of the
weld to be assessed while it is still in the molten state. To
be able to use this data for self-optimization it was
necessary to establish a correlation between the short-time
strength of the parts in the cooled state and their shorttime
strength in the still molten state. Taking these
correlations a systematic approach can be worked out to
allow the welding machine to find an optimum processing
window with just a few test welds. The results show that
the optimum of the joining displacement to the melt layer
thickness ratio (sF/L0) can be established for the parameter
setting by measuring the tear forces on the welding
machine even without knowing the short-time strength in
the cooled state. The same applies for the ratio of the melt
layer thicknesses to the wall thickness. Based on these
results the next steps are now to develop a means of selfoptimization
and quality assurance during the running hottool
welding process.
H. Potente , V. Schöppner , R. Hoffschlag , S. Gövert , J. Schnieders, May 2010
This paper looks into the initial steps of thedevelopment of a self-optimizing hot-tool weldingmachine. By employing a new machine concept, it ispossible to ensure displacement speeds counter to thedirection of joining. This then allows the strength of theweld to be assessed while it is still in the molten state. Tobe able to use this data for self-optimization, it wasnecessary to establish a correlation between the short-timestrength of the parts in the cooled state and their shorttimestrength in the still molten state. Taking thesecorrelations, a systematic approach can be worked out toallow the welding machine to find an optimum processingwindow with just a few test welds. The results show thatthe optimum of the joining displacement to the melt layerthickness ratio (sF/L0) can be established for the parametersetting by measuring the tear forces on the weldingmachine, even without knowing the short-time strength inthe cooled state. The same applies for the ratio of the meltlayer thicknesses to the wall thickness. Based on theseresults, the next steps are now to develop a means of selfoptimizationand quality assurance during the running hottoolwelding process.
Understanding the mechanical behavior of nanostructured polymers is of great academic and practical interest. We used Atomic Force Microscopy (AFM) nanoindentation to measure mechanical properties of such materials. While AFM is generally acknowledged as a high-resolution imaging tool, accurate quantification of AFM nanoindentation results is a challenge.We report significant accuracy improvements for modulus measurements of polymeric materials when special large end-radius tips are used for indentation and viscoelastic contact models are applied for data analysis. Using these tips results in only minor loss of imaging resolution so that very small regions of interest can be identified and indented for mechanical analysis. We show AFM results for nine polymers and two polymer blends and a comparison with instrumented indenter results.
Polypropylene impact copolymers are widely used in
automotive applications. They are required to comply
with many criteria. Customers demand high-performance
materials which also exhibit good aesthetical properties.
The challenge is to balance properties as high impact
strength, good flow ability and absence of surface defects,
like tiger stripes.
It is known that peroxide modification whilst
increasing the flow ability of polypropylene impact
copolymers deteriorates the basic mechanical and
aesthetical properties.
Work was performed in which a PP-impact
copolymer was subjected to peroxide aided chain-scission
under simultaneous presence of the co-agent 1,4-
butanedioldimethacrylate (1,4-BDDMA). Results show
that samples made with 1,4- BDDMA exhibit superior
cold impact resistance and tiger stripe performance
compared to the materials made with only peroxide. In
addition, morphology, molecular weight distribution, and
rheological behaviour of the continuous and dispersed
phases of the modified PP impact copolymer were
studied.
Polypropylene impact copolymers are widely used in automotive applications. They are required to comply with many criteria. Customers demand high-performance materials which also exhibit good aesthetical properties. The challenge is to balance properties as high impact strength, good flow ability and absence of surface defects, like tiger stripes. It is known that peroxide modification whilst increasing the flow ability of polypropylene impact copolymers deteriorates the basic mechanical and aesthetical properties. Work was performed in which a PP-impact copolymer was subjected to peroxide aided chain-scission under simultaneous presence of the co-agent 1,4-butanedioldimethacrylate (1,4-BDDMA). Results show that samples made with 1,4- BDDMA exhibit superior cold impact resistance and tiger stripe performance compared to the materials made with only peroxide. In addition, morphology, molecular weight distribution, and rheological behaviour of the continuous and dispersed phases of the modified PP impact copolymer were studied.
Joseph Samaniuk, David Litchfield, Donald Baird, May 2010
Processors who process mono or multilayer films on blown or cast film plants need to optimize the performance in terms of Low Seal Initiation Temperature (SIT), Hot Tack Strength and Heat Seal Strength. Masterbatches of terpolymer & polybutene-1 were prepared and added to skin layers of three layer polypropylene cast film. The results indicate lower SIT and higher Heat Seal & Hot Tack Strength.
Polypropylene based terpolymers along with Polybutene-1 offer wider choice to film manufacturers to tailor-made films with properties. This paper will provide path for processors on tailor-making the properties as desired by end users.
Joseph Samaniuk , David Litchfield , Donald Baird, May 2010
A novel technique for improving the exfoliation of organically modified layered silicate (OMLS) in a PET matrix using super critical carbon dioxide (scCO2) is compared to traditional direct melt blending. The process relies on the rapid expansion of a sc-CO2/OMLS mixture into the second stage of a single screw extruder where it is subsequently melt blended with the PET matrix. The simple environmentally benign process results in a more highly exfoliated system than direct melt compounding.X-ray diffraction analysis and mechanical testing are used to reveal improved clay exfoliation and the resulting mechanical properties.
For mass production of hybrid plastic/metal components to be fully realized, novel joining technologies without the use of bonding agents need to be developed. A hybrid-bonding technology based on conductive heating of the metal part is presented. Once the metal surface reaches a predetermined temperature, pressure is applied to the components to promote matching of the faying surfaces. Contact of metal and plastic components is achieved. Once the thermoplastic part melts the pressure induced flow promotes mechanical bonding between the two components with controlled cooling. The influence of welding parameters on the bond strength is examined. In addition an investigation of various materials and surface modifications was studied.
The objective of a laboratory test method is to define the approach that will permit an operator to obtain meaningful reliable data. As materials and decoration techniques evolve commonly used test methods to measure abrasion resistance of decorated plastics may no longer be sufficient. To ensure a robust product it is essential that you understand how to recreate and measure ƒ??real-worldƒ? damage. This paper presents a process to develop (or improve) test methods intended to quantify the resistance of surface wear on decorated plastics.Emphasis is placed on reducing common sources of test procedure variation and advanced techniques to interpret and quantify the results.
Polyethylene/montmorillonite nanocomposites based on LDPE, HDPE and LLDPE of similar rheological properties were prepared and mechanically tested in tension mode. It was shown that nanocomposites based on LLDPE exhibit a very peculiar behavior, with a significant improvement in toughness (elongation at break). The microstructural features of the various nanocomposites were investigated through scanning and/or transmission electron microscopy. Based on those observations, an explanation for the deformation and fracture mechanisms in LLDPE/montmorillonite nanocomposites was proposed.
Extrusion embossing is an economic and fast process
for the production of large quantities of structured films.
This one-step-process can be used for embossing of
macroscopic and microscopic structures as well. The
replication accuracy of microstructures can be increased
significantly using variothermal heating concepts for the
embossing rolls. Two variothermal heating concepts using
additional inductive or laser-based heating devices are
developed at the IKV. The achievable temperature curve
on the roll surface is determined in dependence of the
heating device and the time. Furthermore improvements in
replication accuracy by variothermal heating are
presented.
Extrusion embossing is an economic and fast process for the production of large quantities of structured films. This one-step-process can be used for embossing of macroscopic and microscopic structures as well. The replication accuracy of microstructures can be increased significantly using variothermal heating concepts for the embossing rolls. Two variothermal heating concepts using additional inductive or laser-based heating devices are developed at the IKV. The achievable temperature curve on the roll surface is determined in dependence of the heating device and the time. Furthermore improvements in replication accuracy by variothermal heating are presented.
Dimensional consistency is a critical attribute of molded part quality but is frequently only estimated from cavity pressure or part weight measurements. An in-mold shrinkage sensor having a deflectable diaphragm under melt pressure instrumented with strain gages connected in a full bridge circuit is designed and validated. Molded part shrinkage is then measured as the polymer melt solidifies, shrinks, and retracts from the mold wall. The results of a DOE conducted to validate the performance of the sensor indicate the sensor outperforms both cavity pressure transducers and regression models, and is able to measure the shrinkage to an absolute accuracy of 0.01 mm for a 2.5 mm thick part.
Yashpal J. Bhandari, Gurulingamurthy Haralur, Peter Catsman, May 2010
New OSU compliant, hard coated polycarbonate copolymer articles were formed by extrusion and injection molding processes followed by hard coating. These samples were prepared using a variety of hard coatings and processes to afford scratch resistant, low color, high transmission and low haze articles. These highly transparent, low color articles are the first in their class to be fully compliant to the OEMs and FAA (FAR25.853) aerospace flammability standards. The combination of coating and specific resin is needed to produce the excellent balance of flame resistance, durability and optical properties.
Liqiang Yang, Kristina Setyowati, An Li, Shaoqin Gong, Jian Chen, May 2010
In the Bepex process ground and washed post-consumer polyester packaging (rPET) flakes are efficiently decontaminated and polymerized for food contact packaging applications. The hot processed flakes may be directly extruded into the bottles, sheets or films thereby eliminating several energy, capital and labor intensive steps resulting in a cost-effective simplified process. Volatile contaminants in the polymer are removed by diffusion into the gas phase thereby purifying the polymer in the solid state under atmospheric pressure. The presence of small amounts of selected vapors in the gas enhances diffusion of the volatile components providing efficient decontamination without excessive molecular weight build-up.
Liqiang Yang , Kristina Setyowati , An Li , Shaoqin Gong , Jian Chen, May 2010
This paper reports the infrared (IR) actuation performance of a new family of single-wall carbon nanotube (SWNT)-nematic liquid crystalline elastomer (LCE) nanocomposites. A strong and instantaneous response (~30% strain) to the IR stimulus was observed in the SWNT-LCE nanocomposites due to the photon absorption of the SWNTs resulting in an increase in the nanocomposite film's temperature and thereby triggering a nematic-isotropic phase transition. The IR strain response of the SWNT-LCE nanocomposites increased with the SWNT loading level and the degree of hot-drawing but decreased with the photo-curing time.
Solid-state fabrication of polymer nanocomposites has advantages over conventional processing methods. Polypropylene-graphite nanocomposites were fabricated via two contrastive solid-state processes, batch-based cryogenic milling and continuous solid-state shear pulverization. The effects of filler loading and processing parameters such as pulverization time and harshness of pulverization were investigated. Composite morphology was characterized via XRD and SEM. The mechanical properties were measured via tensile and impact testing, while the thermal behavior was probed by DSC and TGA.
Weathering performance of a new carbon black pigmented high heat polycarbonate copolymer has been investigated. Superior retention of optical properties (e.g. color and gloss) is observed with the copolymer after 750hrs of weathering exposure in comparison with other commercial alternatives. Various surface characterization techniques are used to understand the mechanism & quantify the photodegradation effect. Morphology imaging through atomic force microscopy and Scanning Electron Microscope are used to explain the improved retention of gloss with the copolymer.
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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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