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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Juan D. Sierra , María Noriega , Silvio Ospina , Elkin Cardona, May 2010
This research work is focused on the effect of citrate plasticizers on thermal and viscoelastic properties of Polylactic acid (PLA). As expected the glass transition temperature decreases with addition of citrates demonstrating the effectiveness of citrates as a PLA plasticizer. It was observed that the decrease in glass transition temperature with the increase of citrate content behaves in exponential way. Viscoelasticity of PLA is considerably affected by the presence of citrate plasticizer. The zero shear-rate viscosity and pseudoplasticity index decrease could be correlated with the plasticizer content by using an exponential function.
S. Sanchez , R. Ibarra , F. Solis , L. Cordoba, May 2010
ABS/montmorillonite nanocomposites were obtained via conventional melt mixing by single screw capillary extrusion. Nanocomposites from 0.5 to 9 % Volumetric Fraction (VF) of nanoclay were formulated. Melt rheology shows a decrease in the Newtonian range as modified clay increases. The opposite is true for the viscosity at zero shear. Shear thinning behavior is observed as clay content is increased. From XRD, it is inferred an increase of nanoclay d-spacing independent from the clay content in samples from the capillary rheometer. TEM shows both intercalated and exfoliated clay structures obtained from capillary extrusion. The processing conditions in conventional equipment for plastics transformation, i.e. extrusion, may lead to obtain intercalated and exfoliated nanocomposites, without the need for complex tooling configuration.
Michael Heinzer , Myoungbae Lee , Rachel VanHouten , Ozma Lane , James E. McGrath , Donald G. Baird, May 2010
Poly(arylene ether sulfone) block copolymers are studied as candidates for membrane materials in polymer electrolyte membrane fuel cells. Highly fluorinated versions are of particular interest as increase hydrophobicity of the fluorinated blocks will induce greater phase separation resulting in improved proton conductivity. This work studies the effect of processing temperature on membrane properties and compares results for highly-fluorinated poly(arylene ether sulfones) to results for the sparingly fluorinated copolymer. Proton conductivities are below the expected values, which is likely due to high processing temperatures having detrimental effects on ion clusters in copolymer chain coupled with a lack of ample time for phase separation. Studies of the phase separation kinetics and final film morphologies can help better understand the drying process.
Shailesh Vidhate , Jaycee Chung , Nandika D’Souza, May 2010
In this work conductive nano composite has been
prepared by incorporating multiwall carbon nanotubes
(MWCNT) in polyvinylidene fluoride (PVDF) by melt
blending method. The creep behavior of PVDF
composite is studied by compression test. To study the
time and stress dependent piezoresistive behavior of the
prepared composite mechanical testing was
synchronized with electrical resistance measurement.
Comparison of mechanical creep with the creepdependent
resistance implied that there is a conducting
percolation attributed to the physical contacts between
MWCNT and a mechanical network formed by the
molecular chains of the polymer matrix and the
interaction between the filler and the matrix.
Shailesh Vidhate , Jaycee Chung , Nandika D’Souza, May 2010
In this work conductive nano composite has been prepared by incorporating multiwall carbon nanotubes (MWCNT) in polyvinylidene fluoride (PVDF) by melt blending method. The creep behavior of PVDF composite is studied by compression test. To study the time and stress dependent piezoresistive behavior of the prepared composite, mechanical testing was synchronized with electrical resistance measurement. Comparison of mechanical creep with the creepdependent resistance implied that there is a conducting percolation attributed to the physical contacts between MWCNT and a mechanical network formed by the molecular chains of the polymer matrix and the interaction between the filler and the matrix.
Research on biodegradable materials has been
stimulated due to environmental and economic concerns.
The blends of polycaprolactone and a starch based
material were prepared by compounding with a twin-screw
Brabender. DSC TGA and DMTA were used to
characterize the blends and indicated some degree of
interaction between the neat polymers. With respect to the
neat PCL DSC results of the blends revealed peak shift
and depression in either the melting or melt crystallization
point and the glass transition temperatures obtained from
the maxima loss tangent peaks of DMTA were also shifted.
TGA studies showed decreased thermal stability of the
PCL rich phase blends with increasing wt.% starch based
material. Tensile test concluded improved modulus in the
blends in comparison with the neat PCL. (Ref.9)
Jun Tae Kang, Seong Hun Kim, Seung Goo Lee, May 2010
Bamboo fiber may withhold great potential as an alternative to wood, and bamboo can be a raw material to fabricate a composite material and its applicability is being widely investigated. Cellulose fibers can be aligned to the length of the bamboo providing maximum tensile and flexural strengths and rigidity. Increased research in the recent years has considerably contributed to the use of bamboo fibers as a reinforcing material for broader applications. However, it is difficult to obtain polymer/bamboo fiber composite having its excellent mechanical properties, because the bamboo fibers covered with lignin show lack of interfacial adhesion. Therefore, it is necessary to enhance the interfacial adhesion by extracting lignin without microstructure disruption and adding silane coupling agents.
In this research the influence of silane coupling agent, composites with pristine bamboo fiber, delignified bamboo fiber, and delignified and silane treated bamboo fiber were newly prepared and investigated, respectively.
The electrical and mechanical properties of Polycarbonate and Polybutylene Terephthalate carbon nanotubes (CNT) nanocomposites were studied with respect to injection molding processing parameters, by means of design of experiments (DOE). Results demonstrated that the injection molding parameters had a significant effect on the properties of polymer/CNT nanocomposites. While the melt temperature had the most significant effect on the resulting volume resistivity, combination of parameters affected the mechanical properties of each polymer/CNT nanocomposite.
Nowadays various technologies are capable of producing hybrid plastics/metal-composites. However they all have disadvantages due to several manufacturing steps and limitations in the achievable complexity of the part geometry. An innovative approach to produce plastics/metal-composites is to combine the injection molding of plastics and the die casting of metals to a new hybrid multi-component process within a single mould and on a single machine. Combining the plastics injection molding and the die casting of low-melting metal alloys plastics parts with integrated electrically conductive tracks can be produced. A selection of promising results concerning this new process is presented.
Nowadays, various technologies are capable of producing hybrid plastics/metal-composites. However, they all have disadvantages due to several manufacturing steps and limitations in the achievable complexity of the part geometry. An innovative approach to produce plastics/metal-composites is to combine the injection molding of plastics and the die casting of metals to a new hybrid multi-component process within a single mould and on a single machine. Combining the plastics injection molding and the die casting of low-melting metal alloys, plastics parts with integrated electrically conductive tracks can be produced. A selection of promising results concerning this new process is presented.
Applications in the automotive, medical and
electronics industries continue to drive
improvements in polymer performance. Specifically,
greater UV resistance, greater chemical resistance,
higher service temperature, and processing stability
are becoming more essential for consumer product
components. Styrene-ethylenebutylene-styrene
(SEBS) copolymer rubbers, SEBS/polypropylene
blends, TPEs and polypropylenes are emerging as
high performance materials integral to handles,
grips, elastic components, oil gels for
telecommunications, medical parts, automotive
gaskets and hoses. TPEs in particular are being
employed to replace plasticized low durometer PVC
due to safety concerns as a component material for
medical devices. The bond strengths of these
polymers with specially formulated adhesives with
and without atmospheric plasma surface
modification were investigated. The results of bond
strength improvement tests are presented.
Layered silicates used as nano filler are suitable for
improving the mechanical properties of polymers. As an
alternative to melt compounding an in-situ polymerisation
process for the production of PA6-nanocompounds is
investigated. During the in-situ process the layered
silicates are dispersed in the monomer caprolactam
leading to an intercalation process. The following anionic
activated polymerisation process itself takes place in corotating
twin screw extruder.
The production of a polyamide compound containing
0 2 and 4 wt.-% nano-scaled silicates was successful. The
in-situ produced compounds were injection moulded and
their mechanical properties were analysed.
Layered silicates used as nano filler are suitable for improving the mechanical properties of polymers. As an alternative to melt compounding, an in-situ polymerisation process for the production of PA6-nanocompounds is investigated. During the in-situ process, the layered silicates are dispersed in the monomer caprolactam, leading to an intercalation process. The following anionic activated polymerisation process itself takes place in corotating twin screw extruder. The production of a polyamide compound containing 0, 2 and 4 wt.-% nano-scaled silicates was successful. The in-situ produced compounds were injection moulded and their mechanical properties were analysed.
Silicon solar cells lose 0.45% of power for every 1oC increase in temperature. If solar modules could dissipate heat more efficiently, the operating cell temperature would be lowered, increasing the module power output. In this paper, we present findings in using encapsulants with improved thermal conductivity to increase the heat transfer from solar cells into the environment. The outdoor performance of solar modules built with the improved encapsulant shows that 1-2% power gain can be achieved compared with the standard encapsulant. Further, modules with the improved encapsulant are anticipated to have better long-term reliability as compared with the standard encapsulant.
Biotechnology, information and medical industries have a high growth potential. A key technology for those industries is the replication of micro- and nanostructures. Precise micro- and nanostructured parts with functional surfaces can be produced economically by injection moulding. The whole process chain (thermal mould condition, moulding, demoulding) must be analysed carefully. To enable the precise production of such structures a new technique for variothermal injection moulding was developed at the IKV. An innovative laser heating unit was designed and built. The laser unit was implemented into an injection mould. Using this technique selective parts of the cavity could be heated with high temperature gradients of up to 300K/s. Preliminary measurements were done to correlate the laser power and the temperature change on the mould surface. A pyrometer and a laser control unit were implemented to realise a precise temperature profile on the mould surface without a temperature overshoot.
The effect of the degree of substitution (DS) of carboxymethylated starch (CMS) as green corrosion inhibitor of carbon steel on 200 mgL-1 NaCl solution was investigated. Physical/chemical structure of CMS was studied by Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (13C-NMR). DS of this bio-polymer was determined by back-titration. Its inhibitive properties were evaluated using polarization curves and electrochemical impedance spectroscopy. CMS acts as corrosion inhibitor and the protection level is highly dependent on the degree of substitution. The formation of a chelate between carboxylate groups and ferrous cations allows the inhibition mechanism of CMS to be explained.
Melt blowing is an extrusion process that produces nonwoven webs with fine fibers that are approximately 1 to 10 microns in diameter and find applications in filtration, sound and liquid absorbency and thermal insulation. We have introduced multiple layers within each microfiber and shown that novel web properties can be obtained. The number of layers within each micro fiber was varied from 2 to 27, although layers as high as a thousand can be achieved. We have shown that synergistic mechanical properties can be obtained in a controlled manner. The processing-structure-property behavior of multilayer melt blown webs will be discussed.
Processing undried polycondensates as PET or PA using a melt degassing single screw extruder is a real alternative to the conventional energy- time- and cost-consuming pre-drying process. Due to the industrial demand of processing recycled and low priced materials the moisture content or/and the resin mixture can substantially vary from batch to batch. This leads to a deviant molecular weight degradation and an unsteady final product quality. The paper presents an approach to compensate these variations in the feedstock in a closed-loop control. It is based on the direct influence of the degassing pressure on the moisture evaporation of the melt. The product quality is estimated online in the extrusion process e.g. via melt viscosity and is controlled by the degassing pressure in the extruder.
Processing undried polycondensates as PET or PA using a melt degassing single screw extruder is a real alternative to the conventional energy-, time- and cost-consuming pre-drying process. Due to the industrial demand of processing recycled and low priced materials, the moisture content or/and the resin mixture can substantially vary from batch to batch. This leads to a deviant molecular weight degradation and an unsteady final product quality. The paper presents an approach to compensate these variations in the feedstock in a closed-loop control. It is based on the direct influence of the degassing pressure on the moisture evaporation of the melt. The product quality is estimated online in the extrusion process, e.g. via melt viscosity, and is controlled by the degassing pressure in the extruder.
Walter Michaeli , Ina Michaelis , Joachim Grosse , Matthias von Walter , Erich Wintermantel , Nina Laar, May 2010
The overactive bladder syndrome (OAB) is defined as a symptom complex which is characterized with frequent urination, urinary incontinence and a strong, sudden urge to urinate even when the bladder is not full. About 10% of the total population have OAB and it occurs in every age group. Apart from the medical, oral therapy, the so called intravesical instillation is used as well. In order to minimise the numerous side effects of the oral therapy like dry mouth, dizziness or depressions a biodegradable, active agent carrying implant for the intravesical therapy of the OAB was aspired. After a project period of two years a biodegradable, active agent carrying polymer implant could be developed.
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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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