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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Thermoplastic vulcanizates (TPVs) or dynamic vulcanizates are a special class of thermoplastic elastomers, produced by mixing and crosslinking of a rubber and a thermoplastic polymer simultaneously. In a previous study it was demonstrated that the use of dicumyl peroxide in combination with triallyl cyanurate as crosslinking agents provide a good overall balance of physical properties of PP/EPDM TPVs. Commonly used peroxides like dicumyl peroxide generally produce volatile decomposition products, which sometimes provide a typical smell or show a blooming effect. In this paper multifunctional peroxides are described, which reduce the above-mentioned problems. They consist of a peroxide and co-agent-functionality combined in a single molecule. The multifunctional peroxides provide properties of TPVs, which are comparable with commonly employed co-agent assisted peroxides. The solubility and kinetic aspects of the various peroxides are highlighted, as well as the decomposition products of the multifunctional peroxides with respect to the avoidance of smelly by-products. Particularly 2,4-diallyoxy-6-tertbutylperoxy- 1,3,5-triazine turns out for be a very good alternative to the dicumyl peroxide/triallyl cyanurate combination.
Srivatsan Srinivas, Sudhin Datta, George A. Racine, May 2004
ExxonMobil Chemical has introduced a family of Specialty Polyolefin Elastomers, a novel type of polyolefin with isotactic propylene crystallinity, under the trade name Vistamaxx™. These polymers contain a predominant amount of propylene (>80%) with isotactic crystallinity, the balance being ethylene and other ?- olefins. These elastomers are highly elastic, with excellent recovery from deformation even without vulcanization. These elastomers, unlike the related EPR polymers, share the processability of conventional plastics such as polyethylene and isotactic polypropylene and can, thus, be easily formed into articles such as films, fibers and nonwoven fabrics, which are highly elastic, using conventional plastic processing processes. In this paper, we discuss the details of the structure-property relationships in these polymers and emphasize the factors leading to the elastic character of these elastomers.
ExxonMobil Chemical has introduced a family of Specialty Polyolefin Elastomers, a novel type of polyolefin with isotactic propylene crystallinity. These polymers contain a predominant amount of propylene (>80%) with isotactic crystallinity, the balance being ethylene and other ?-olefins. Unlike the closely related EPR polymers, these polymers share the processibility of isotactic polypropylene and can thus be formed into fabricated articles using conventional processing equipment. In this paper we show SP elastomers combine an unusual and unexpected degree of elongation and elastic recovery without the need for crosslinking. These properties mimic those of crosslinked elastomers. We also show that the properties arise from the uniform introduction of small levels of crystallinity meso propylene residues.
Louis Freitas, Yundong Wang, Ryszard Brzoskowski, May 2004
Laser marking technology provides an alternative and effective route for printing on TPVs (Thermoplastic Vulcanizates). Natural color TPV materials containing laser sensitive additives can be easily laser marked using common Nd:YAG laser systems through a process and effect known as Color Change. Current black TPVs, however, have proven to be very difficult to laser mark, even with laser marking additives. Manufacturers have no choice other than to use pad printing techniques or some form of adhesive stickers to label their products. Recently introduced laser printable black grade offers all the benefits of current TPVs. This new grade can provide a high print definition and good contrast (yellow/tan on black) mark that is highly durable under a variety of environments.
Kevin G. Cai, Charles G. Reid, Satchit Srinivasan, Norbert Vennemann, May 2004
The elastomeric properties of polyolefin thermoplastic vulcanizates (TPV) have been characterized by compression set, recoverable strain after hysteresis, and thermal scanning stress relaxation (TSSR) analysis. Unlike a thermoset rubber, a TPV is a two-phase system with highly crosslinked fine rubber particles dispersed in a thermoplastic matrix. Compression set, which was originally designed to characterize the elastomeric properties of a thermoset rubber, does not truly characterize the unique elastomeric properties for a TPV. Compression set for a TPV is not only highly dependent on the crosslinking density and structure, but also very sensitive to the orientation of the two phases in the TPV. For the same TPV with a fully crosslinked rubber phase, the compression set value can vary substantially depending on sample preparation and thermal history. Elastomeric properties can be better characterized by the recoverable strain after hysteresis and TSSR stress-temperature curve. The thermal-mechanical properties or stress relaxation behaviors provides more useful information for designing and producing all-thermoplastic parts, such as automotive seals, from TPV.
Thermal and rheological properties of a poly(etherblock- amide) copolymer were characterized by means of differential scanning calorimetry (DSC) and dynamic rheological approaches. Based on the calorimetric and rheometric data, the microphase separation transition (MST) was studied, showing that upon heating the copolymer solid could be transformed into three different states: restructured solid, structured melt, and homogeneous melt. The driving force for the conversion among the three states is primarily due to crystal re-organization, crystallization, and melting. It is also found that different crystal structures in the solid state could be introduced by changing the conditions of cooling from a homogeneous molten state. The existence of a wide MST range and the conversion of the states imply a variety of proper process windows for various polymer processing operations. This knowledge is essential for understanding the processes and further assisting in rational process development.
Technology revolutions sometimes span such a long timeline of business realization that critical innovations along the way can become lost or hidden in commonplace commercial acceptance. An essential understanding or supporting technical advance developed at just the right time and which contributed important value to business success can go under-appreciated or even unrecognized.The development and commercialization of LLDPE created new catalyst, process, and product technologies and seeded the emergence of new, world scale competitors in the polyolefins industry. It was a revolutionary development.This paper describes market facing technology innovations that were instrumental to LLDPE business success. These developments have helped set the stage for another burst of innovation in the ongoing development and commercialization of metallocene and other single-site catalyzed polyolefins.The polymer molecular design capabilities of the new single-site catalysis have created whole new families of polyolefins and has launched a new technology revolution for our industry. This product revolution builds upon and extends some of the innovations from Z/N LLDPE commercialization.
Roman Cermák, Martin Obadal, Martina Polášková, Karel Stoklasa, May 2004
An influence of the mould temperature (MT) on structure and properties of the samples injection-moulded from pure and ? nucleated isotactic polypropylene (?-iPP) was investigated. Pure and 0,03 wt. % of nucleating agent NJ Star NU-100 doped iPP was isothermally solidified in the range of mould temperature 40-120 °C. Polymorphic composition studied by means of wide-angle X-ray scattering did not show significant sensitivity to MT. On the contrary, moulding temperature notably influenced mechanical behaviour of both pure and ?-iPP samples.
Christopher Rush, Joe Falque, Karen McRitchie, September 2003
This paper discusses how a process-based parametric cost model SEER-DFM is used to facilitate the real time cost impact assessment of composite and metallic design alternatives. The main purpose is to introduce the underlying cost model methodology and demonstrate its flexibility for developing trade studies. Readers are introduced to the model its premise and how engineers use it to obtain substantial cost savings through ‘real world’ examples.
Solid freeform rapid tooling technologies of various sorts have promised new conformal cooling advantages for
plastic tooling. In principle these technologies offer geometric design freedoms unavailable by machined or
EDMed approaches. In practice all solid freeform approaches are not equal. This paper will discuss opportunities and limitations on design freedoms and important issues associated with material properties; and will show that raster-scanned 3D Printing technology has matured to a point of delivering on the promise.
One of the biggest challenges facing molders of
automotive exterior body panels is the reduction
of paint pops. Minimizing or eliminating paint
pops would greatly reduce manufacturing costs
by minimizing rework painting and scrap
material.
A new SMC formulation has been developed
that is more resilient and durable than standard
Class A SMC. The material is more resistant to
micro cracking the primary source of paint
pops while maintaining the physical properties
and surface quality required for Class A exterior
body panels.
Decorative films laminated to plastic substrates have
been used for many years but the recent wave of
technological advances and increased competition offer
more variety in design colors materials and performance
properties than previously available. This offers part
designers and plastic processors the option to use
decorative laminate technology for more applications
while reducing costs eliminating environmental concerns
conversion from non-plastic materials and improving
product performance.
The past few years have witnessed a rapid growth in the use of glass reinforced thermoplastics for automotive applications. New developments in LFT's and GMT's are beginning to meet the industry's demands for complex modular components – such as front ends instrument panel carriers and underbody assemblies – with low-cost lightweight materials which have acceptable mechanical performance. However in terms of damage tolerance particularly resistance to heavy impacts and abrasion LFT's and GMT's are no match for the metals they are designed to replace. This paper will describe the use of a highly impact resistant self-reinforced polypropylene
composite to provide localized reinforcement in GMT and LFT components without increasing weight or compromising recyclability.
O. Khondker, U.S. Ishiaku, H. Hamada, September 2003
This paper submits investigation on the tensile and bending properties of the flat braided thermosetting composites made using jute yarns. Combining flat braided jute yarns (untreated and coated) and vinylester resin composite specimens were manufactured by hand lamination method. Tensile and 3 point bending tests were conducted. Test samples were polished and pre- and post-failure examinations were carried out using optical and
scanning electron microscopy in order to analyze the test results and their relationships to the state of resin impregnation into the fibre bundles fibre/matrix interfacial properties and the fracture and failure mechanisms. While tensile properties were slightly degraded due to coating treatments bending properties of the composite showed improvement when coated yarns were used. These variations in the mechanical properties were broadly related to the state of resin impregnation into the fibre bundles and/or fibre/matrix interfacial interactions.
Asami Nakai, Dai Nakaami, Tsutom Narita, Hiroyuki Hamada, Eisuke Fukui, September 2003
In this study multi-axial warp knitted thermoplastic composites were fabricated by our-developed Micro-braiding technique. Cross-sectional observation tensile test and 3 point bending test were performed. The composite with good impregnation state and high mechanical properties was obtained under appropriate molding conditions. The multi-axial warp knitted fabric composite without unimpregnated region had the
equivalent mechanical properties with unidirectional composite laminates. From these results continuous fiber
reinforced thermoplastic panel was realized by combining braiding and knitting technique.
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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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