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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Siu Ning Sunny Leung, M. Omer Khan, Ellen Chan, Hani Naguib, Francis Dawson, Vincent Adinkrah, Laszlo Lakatos-Hayward, May 2011
This paper discusses the development and modeling of novel polymer composites that possess multifunctional properties demanded by electronic packaging applications. In this work, a thermal conductivity analyzer was designed and implemented to measure composites effective thermal conductivity (keff). An analytical model was established to predict keff of composites filled with spherical fillers. Using this model, together with experimentally-measured keff, a semi-empirical approach was developed to study the effects of polymer-filler interfacial properties on keff.
Kory Slye, John Coulter, Burak Bekisli, Tyler Skiba, John Beaumont, May 2011
The melt rotation technology has been proposed to reduce the distribution variations of filler particles due to shear-induced migration in injection molded parts. The technique had been successfully employed to address the filling imbalances due to shear gradients formed during the polymer flow through runners. An experimental analysis has been carried out this time for a filled polymer. Glass-filled polypropylene has been injection molded using a multi-cavity mold system both with and without melt rotation implementations and parts have been analyzed by microscopic imaging. The preliminary results suggest that application of melt rotation results in more balanced filler concentration levels.
Wenli Zhu, Mohammadreza Nofar, Wentao Zhai, Chul B. Park, Jed Randall, May 2011
This paper investigates the effect of chain extender on the crystallinity behavior of Polylactide with/without the presence of dissolved CO2 by a high-pressure differential scanning calorimeter (HPDSC). It is shown that without CO2, the crystallinity increases by decreasing the branched structure due to better chain regularity. With the presence of low-pressure (15bar) CO2, the crystallinity of PLAs significantly increased due to CO2ƒ??s great plasticization effect. However, with the increase of pressure (from 15bar to 45bar), crystallinity dramatically decreases, even though more CO2 is dissolved. However, as the pressure increases from 45bar to 60bar, the crystallinity of all PLAs dramatically increases.
Francois De Buyl, Vincent Rerat, Damien Dehaunynck, Scott Miller, May 2011
Modification of polypropylene resins with ñ,ý-unsaturated carboxylic functional-silanes by melt extrusion processing in presence of free radical initiator was demonstrated while preventing significantly undesired ý-scission phenomenon in comparison to prior work on vinyl- and methacryloxy-silanes. Modified PP was then used for enabling crosslinking into injected parts, showing enhanced high temperature resistance for both neat PP resin or glass-fibers-PP composites. Another improvement was water uptake in wood-fibers PP composites, which resulted in significant improvement of impact and tensile properties and stability under heat and water aging. Relevance of this work will be discussed in applications such as Automotive, Appliance, and Building.
Burak Bekisli, John Rodgers, Qi Li, John Coulter, May 2011
The wide variety of biomedical applications employing biodegradable polymers requires a similarly wide range of biodegradation properties. In this study, a dynamic melt manipulation technique in injection molding has been investigated as a low cost, high volume manufacturing alternative to respond these requirements. The technique utilizes an additional oscillatory motion during injection molding to induce molecular alignment of polymer molecules in the final product. Preliminary experimental results have indicated that biodegradation process is dependent on these orientation levels and therefore polymeric medical devices with different degradation characteristics can be obtained simply by changing the manufacturing parameters.
Present work study the effect of high-pressure crystallization on morphology and thermal behavior of two different homopolymers of isotactic poly(1-butene). Both materials were non-isothermally crystallized under pressure in range from 20 to 200 MPa using a pvT 100 apparatus and thus prepared samples were investigated using wide-angle X-Ray scattering, differential scanning calorimetry and polarized light microscopy. Results showed significant effect of pressure on formation of metastable phases Iƒ?? and II with respect to material properties on thermal behavior and morphology in isotactic poly(1-butene).
Zhenhua Chen, Kristin Kynard, Changchun Zeng, Chuck Zhang, Ben Wang, May 2011
This work focuses on poly (methyl methacrylate) (PMMA) multi-walled carbon nanotubes (MWCNTs) nanocomposite foams prepared by using carbon dioxide as the foaming agent. CNTs nanocomposites were synthesized using anti-solvent process, and the foam morphology was tuned by the process design and incorporation of nanoparticles in the polymer matrix. The synergism between CNT and attractive retrograde phenomenon of PMMA in CO2 atmosphere was explored to generate foams. Thus nanocomposites were saturated with CO2 at 0 oC and 580psi followed by foaming at temperature in 70 oC. The cell morphology of nanocomposite are analyzed and compared with that of pure PMMA foam.
Israd Jafaar, Courtney LeBlon, Mohamed Ammar, John Coulter, Sabrina Jedlicka, May 2011
Novel materials possessing physical, mechanical, and chemical properties similar to those found in vivo provide a potential platform in building artificial microenvironments for therapeutic applications and well-defined biointerfaces for examining differentiation potential in stem cell biology. Poly(glycerol-sebacate) (PGS), a novel biocompatible and biodegradable elastomer is one such material. It provides an invaluable platform for in vitro culture studies to direct the differentiation of human mesenchymal stem cells (hMSCs) into specific lineages and functional cell types. This paper presents work in PGS material characterization, synthesis, microscale manufacturing, and investigations related to its use as a susbtrate for in vitro hMSC culture.
Matthew Mackey, Mason Wolak, James Shirk, Lionel Flandin, Anne Hiltner, Eric Baer, May 2011
There is a need in electronic systems for capacitors with high energy density. Our approach to improve polymer film capacitors is to combine, through microlayer coextrusion, two polymers with complimentary properties: one with a high dielectric constant (polyvinylidene fluoride based polymers - PVDF) and one with a high breakdown strength (polycarbonate). Multilayered films with many alternating layers of polymers were produced and exhibited improved breakdown characteristics due to the development of a treeing type failure mechanism. In addition, a reduction of polarization hysteresis was observed due to layer confinement effects on the solid state structure of PVDF.
A study has been made of prediction of crazing stress and birefringence in oriented glassy polymers. The ROLIEPOLY (RP) polymer rheological model proposed by Likhtman and Graham (2003) was employed, together with the Kramer theory of crazing (1983). Predictions were tested by comparison with results of a new experimental study of crazing and birefringence in monodisperse grades of polystyrene, following model melt-stretching histories. The RP model produced accurate predictions of birefringence, provided orientation occurred on a time-scale slower than the entanglement Rouse relaxation time. Crazing stress was predicted successfully with the model under the same conditions.
Abbass Mokhtarzadeh, Avi Benatar, Chung Wu, May 2011
Hot plate, vibration, IR, and combined IR heating with vibration welding of ASA were studied. For hot plate welding it was found that higher hot plate temperature and longer heating times improved the weld strength with the strongest welds approaching the bulk strength. For IR welding there was an optimum heating time, but even for that time the weld strength was significantly lower than for other processes. Vibration welding of ASA resulted in weld strengths that were about 72% of the bulk strength. Combined IR heating with vibration welding resulted in just a slight improvement over vibration welding alone.
CC Chau, S Incorvia, S Solovyou, T Powers, May 2011
The effect of nucleation and quenching on the crystallization kinetics of PLA and its blend compositions were studied. Contrary to polypropylene, the nucleation effect of talc decreased rapidly as the cooling rate increased. The effect was enhanced as the talc content increased from 0.1 to 8%. The nucleation behavior is analyzed in light of a modified Kissinger method. The lack of nucleation upon quenching was shown in a modified Kissinger plot which showed its correlation with Avrami analysis. Methods to control or enhance crystallization of PLA and some PLA blends are discussed.
A novel simultaneous milling and coating method which utilizes a fluid energy mill (FEM) is applied for the first time to prepare nanoparticle-coated CaCO3 additives for polymer composite materials. Simply milled (without coating) CaCO3 particles and as-received CaCO3 particles were used as references for comparison. The effects of the grinding pressure and the content of the coating on the particle size and flowability of CaCO3 were studied. The composite made of PP and this specially prepared CaCO3 have larger elongation at break, elastic modulus and impact strength, compared to the simply milled calcium carbonate.
Tianhua Ding, Rama Konduri, Rodney Fonseca, Chris Van der Weele, Shun Wan, May 2011
New family of ENH flame retardant PBT (polybutylene terephthalate) and PBT/PC(polycarbonate) thermoplastic resins developed is aimed at helping electrical/electronics (E/E) manufacturers and suppliers comply with regulations restricting use and disposal of hazardous substances. The non-chlorinated, non-brominated FR PBT and PBT/PC products deliver similar mechanical, physical, thermal and flame retardant performance compared with their brominated FR based counterparts. Some of those resin properties will be discussed in this publication.
Clinton Kietzmann, Lu Chen, Harold Feng, Franco Costa, Ronan Le Goff, May 2011
In recent years, injection molding technologies have been developed which use variable mold heating and cooling to increase part quality without significantly increasing cycle time. These processes are not suited for simulation with a conventional steady-state (cycle-average) mold thermal analysis. This paper presents the development of a new 3D finite element based transient mold cooling simulation capability which includes coupling the mold thermal solution with the mold filling and packing simulation. The predicted transient mold temperatures are validated against measured mold temperatures for two instrumented injection molding trials.
The specific interfacial morphology and strength of paired polymers will be discussed. The focus is on two different types of interfaces during injection molding processes: (I) hot interface represents two melt streams meeting (weldline) and (II) cold interface is defined as the overmolding of a second melt to a chilled, hardened preform. A cold interface occurs during a multi-shots injection molding process. Regarding the strength amorphous and semicrystalline polymers were used, for the visual inspection of interfacial morphology by light microscopy semicrystalline POM was investigated. In conclusion, new aspects about a correlation between interfacial morphology and bonding strength are addressed.
This paper provides insights into a newly launched portfolio of environmentally progressive products. These molding compositions are based on a polybutylene terephthalate (PBT) that is made by chemical regeneration of post consumer recycle polyethylene terephthalate (PCR PET) and converted into PBT. These products can then be used in a variety of automotive and consumer applications. These new products' manufacturing processes require less energy and non-renewable fossil fuels as compared to the manufacturing processes of conventional fossil fuel based materials. We will present the comparison of properties results of molding compositions using this new technology and traditional PBT will be presented.
Partha Majumdar, Hanzhen Bao, Ranjana Sharma, Elizabeth Crowley, James Bahr, Bret Chisholm, May 2011
A novel method to synthesize polycarbonate-polydimethylsiloxane block copolymers with controlled block molecular weight and an alternating block architecture was investigated. The method investigated consisted of the synthesis of polycarbonate oligomers/polymers possessing allyl-functional endgroups and the subsequent coupling of the oligomers/polymers with hydride-terminated polydimethylsiloxane oligomers/polymers using hydrosilylation. GPC and NMR were used to demonstrate successful block copolymer formation. Characterization using AFM showed nanoscale phase separation. The optical clarity of a PC-PSiO block copolymer produced with this method was significantly better than that of a commercially available PC-PSiO block copolymer, indicating smaller PDMS domains resulting from the more uniform block copolymer structure.
Nemat Hossieny, Mohammadreza, Chul B. Park, May 2011
Expanded polypropylene (EPP) bead foam products are prepared using the steam-chest molding method. It was shown that 3.9 bar is the most promising steam pressure to get better mechanical properties. The density and tensile property profile across the molded sample were measured. It was observed that the high pressure and temperature steam softens the beads on the surface causing them to squeeze and compact together. This leads to increase in the density and tensile property at the outer surface of the molded part as compared to the central part.
Joel Pozos, Nicolas Juarez, Pedro Sanchez, May 2011
The temperature of an oven named OPT are evaluated. Two types of moulds, an aluminium ball-like and stainless steel cube-like, were used. Finite element software was used to find a combination of hot air flow velocity and the oven internal surface geometry. The temperatures obtained in the OPT were compared with temperatures obtained in Benchmark oven. For validation purposes the OPT was compared with simulations. The agreement between the OPT and the ROT time-temperature curve behaviour is remarkable. The OPT gas consumptions are compared with in an oven named here the Kearns found in the literature.
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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.
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