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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Ken Miyata, Yuuki Ichikawa, Motohiro Noguchi, Akihiro Nishioka, , Tomonori Koda, Go Murasawa, May 2010
Film cast condition in T-die extruding processing affects molecular structure development. Relationship between the molecular structure development and the external form, width and thickness in T-die extruding of high-density polyethylene (HDPE) was studied. The film width and thickness distribution changed proportional to cast conditions, chilled roll speed, chilled roll surface temperature, mass throughput rate. On the other hand, molecular orientation, crystalline orientation and other factors did not develop proportionally to the cast conditions. The cast conditions are important factors to affect molecular structure. Molecular structure is also an important for heat seal properties. Heat seal strength changed depending on cast conditions. In low chilled roll speed heat seal strength was low. The failure mode was peeling. In high chilled roll speed heat seal strength was high. The failure mode was changed to tearing. To discuss major factor to decide heat seal properties, the effects of molecular orientation and film thickness were studied. The film thickness was not major factor to decide heat seal properties in this study. Both peeling and tearing were observed for film thickness from 10 to 30 ?¬m. However film thickness is also important factor to affect the heat conductive rate directly. Crystallinity was important factor to affect heat seal properties. Molecular orientation was also a major factor to decide heat seal properties in this study. The failure mode of peel test was changed drastically at 0.025 birefringence. Molecular orientation was an important factor to decide heat seal properties as well as crystallinity.
George C. Jacob , Marv L. Dettloff , Ha Q. Pham , Nikhil E. Verghese , Rajesh H. Turakhia , Carol O’Connell , Gary Hunter, May 2010
In order to take full advantage of the properties of epoxy thermosets it is sometimes necessary to improve their toughness. Usually this is done by adding toughening agents. Typical toughening agents such as thermoplastics or elastomers can do a good job of improving toughness but often this improvement comes at the expense of desirable mechanical properties such as modulus, thermal properties such as the glass transition temperature (Tg) and/or ease of processibility of the uncured formulation (undesirable changes in viscosity). This paper focuses on the use of an amphiphilic block copolymer that gives a better balance of improved toughness without tradeoffs to other key performance properties and processibility.
The enhanced mixing of gas and polymer phases is important in all stages of the foam extrusion process. Much of the mixing in extrusion foam process is distributive, and prefers mixers which can divide and recombine melts at high rates and low energy. The twin-screw extruder provides the flexibility in screw elements design for better mixing. The effect of five different screw configurations on foaming characteristics of polystyrene (PS) with supercritical carbon dioxide (CO2) in a twin-screw extruder was investigated. It was found that with proper design of screw elements, it is possible to make foams with optimal foam density and cell morphology using twin-screw extruder system.
Ken Miyata, Taku Ozama, Akihiro Nishioka, Tomonori Koda, Go Murasawa, May 2010
The effect of molecular weight on heat seal properties for high-density polyethylene (HDPE) film was studied. HDPE compounded with 3 to 20 wt % higher molecular weight components was cast into film. Heat seal tests were carried out for the cast HDPE film. The heat bar temperature was controlled at 125 and 128 ?§C. The seal pressure was kept at 0.2 MPa constantly. The heat seal time for applying heat and pressure was varied from 0.5 to 2.0 sec. The molecular structure developed during the heat seal process was evaluated by differential scanning calorimetry (DSC) and wide-angle x-ray diffraction (WAXD) and relationships were drawn againstheat seal strength measured by T-peel test. Generally, by compounding higher molecular weight components, heat seal strength was decreased. However dosage of 3 to 10 wt % higher molecular weight components could shorten seal time to obtain sufficient heat seal strength at 128 ?§C heat seal temperature.
The quality of an injection molded part is strongly
influenced by the filling balance of the mould cavity.
This paper presents a method and the relevant software
application to determine the best gate location for an
injection molded part. The proposed optimization
method automatically and iteratively calculates the gate
position that maximizes the melt flows balance during
the filling phase. The software is based on the Moldflow
Plastics Insight®/Microsoft Visual Basic® interface and
uses a non-linear optimization algorithm based on the
Gauss-Newton and Conjugated Gradient techniques. The
effectiveness of the developed method is demonstrated
through some significant case studies.
Supercritical carbon dioxide has advantages of high solubility to the polymer and recovering easily by depressurizing, and it is expected to be use as a plasticizing agent. In this work, we studied on the effect of scCO2 on rheological properties of plastomer layered silicate nanocomposites. A rotational viscometer has been adapted to measure the viscosity of polymer under high temperature and pressure conditions. The rheological properties of Plastomer nanocomposites was performed at experimental conditions of various temperature and pressure. We observed that viscosity of polymer was dramatically reduced by CO2 addition.
The comparison of stress distributions has been investigated in thermoformed and injection molded parts of a similar design. Injection molding is traditionally preferred for automotive applications because of its ability to create parts with minimal internal stress. However in recent years because of potential cost reductions thermoformed parts are often being substituted. Matrox Inspector has been used to evaluate internal stress created by both processes. Results show a difference in the comparative stress distributions of similar parts that is dependent on location.
Unsaturated polyester (UP) and vinyl ester (VE) resins are two of the most widely used thermoset resins in fiber reinforced composites due to their low cost and good processability. Adding nanoparticles like carbon nanofibers (CNFs) as a third phase into conventional composites results in hybrid nanocomposites with improved mechanical properties and multi-functionalities, and at the same time makes the curing reaction even more complex. In this paper, the effects of CNFs on the reaction kinetics of the two free radical polymerization systems are studied. VE/CNF kinetics is presented in more detail including interesting interactions between CNFs and curing ingredients in the system. Preliminary reaction kinetics data of UP/CNF is also presented.
Jian-Kang Wang , Xiang-Yang Liu , Han-Xiong Huang, May 2010
Microcellular injection molding attracts more and more interests in industry because of its advantages, such as weight reduction, energy saving, cycle time reduction, etc.. In order to investigate the filling process of microcellular injection molding, a visual mold was developed in this work. The filling processes of polystyrene/carbon dioxide was observed and recorded using a digital camera, while the mold cavity pressure was measured by a sensor. The final bubble morphology was observed using scanning electron microscope. The experiment results showed that melt temperature and mold cavity pressure were two most prominent factors influencing bubble morphology.
Saeedeh Mazinani , Abdellah Ajji , Charles Dubois, May 2010
The structure and properties of polyethylene terephthalate (PET)/multi-wall carbon nanotube (MWCNT) fibers were investigated in this work. PET/MWCNT nanocomposite was obtained through melt mixing and CNT masterbatch dilution into desirable concentration. PET/CNT nanocomposite was then shaped to microfibers at different CNT concentrations and drawing conditions. The dispersion and distribution of CNT were optimized and the effect of processing condition on the morphology of nanocomposite was investigated by various microscopy techniques. Through the dispersion optimization, conductive fibers were obtained at 2% concentration of MWCNT. The study of crystalline structure of the fibers shows the role of CNT addition on enhancement of crystallinity in rod-like fibers; while in drawn fibers, it causes decrease in both the crystallinity and orientation during melt-spinning. Fiber production enhances the electrical conductivity along fiber axis. In addition, the increase in crystallinity by adding CNT shifts the mechanical properties to quite brittle behavior.
A fluorescence/multilayer technique was used to
determine the distribution of glass transition temperatures
(Tgs) in nanoconfined poly(methyl methacrylate) films.
Poly(methyl methacrylate) exhibits an attraction to silica
shown by an increase in Tg near the substrate.
Perturbations in dynamics associated with Tg near a free
surface lead to a Tg decrease. Both effects are shown to
penetrate some tens of nanometers into a nanoconfined
film. Effects of nanoconfinement on the transition between
free-surface bulk and substrate Tg are explored with
potential application to nanocomposite behavior.
A fluorescence/multilayer technique was used to determine the distribution of glass transition temperatures (Tgs) in nanoconfined poly(methyl methacrylate) films. Poly(methyl methacrylate) exhibits an attraction to silica, shown by an increase in Tg near the substrate. Perturbations in dynamics associated with Tg near a free surface lead to a Tg decrease. Both effects are shown to penetrate some tens of nanometers into a nanoconfined film. Effects of nanoconfinement on the transition between free-surface, bulk, and substrate Tg are explored, with potential application to nanocomposite behavior.
P.R.W. Hanna , E. Maziers , M.P. Kearns , M. McCourt , G.M. McNally, May 2010
The temperature at which densification ends for a range of blends comprising a metallocene catalysed medium density polyethylene (PE) in two different physical forms (powder and micropellets) were investigated using a novel data acquisition system (TP Picture??) developed by TotalPetrochemicals [1]. The various blends were subsequentlyrotomoulded and test specimens prepared for mechanical analysis to establish the relationship between densification rate and bubble size / distribution on the part properties.The micropellets exhibited more rapid bubble removal times than powder.
M. Ponting1, D.S.Langhe, A. Hiltner, E. Baer, D.R.Paul, May 2010
The effect of multi-walled carbon nanotubes (MWNTs) on the curing kinetics of wind blade epoxy resin system was investigated. Isothermal differential scanning calorimetry technique was used to study the reaction kinetics. A comparison was made between the effect of pristine nanotubes and surface functionalized nanotubes on the epoxy polymerization kinetics. It was found that the curing reaction could be accelerated and resin conversion at room temperature could be increased using appropriate surface functionalization. This could find useful application in reducing the composite manufacturing times for large parts like wind blades.
M. Ponting , D.S.Langhe , A. Hiltner , E. Baer , D.R.Paul, May 2010
The effect of layer thickness on the physical aging of nanolayered glassy polysulfone (PSF) against a rubbery random copolymer ethylene octene (EO) layer was investigated via forced assembly coextrusion. A post-extrusion thermal treatment above the Tg of polysulfone was developed to allow for a reset physical aging process. Physical aging of thermally reset polysulfone/ethylene-octene nanolayered films was performed and monitored through a thermal aging under elevated temperatures. The relationship of layer thickness to polysulfone physical aging was investigated through thermal analysis microscopy and positron annihilation spectroscopy.
Nylon6 nanocomposites (with2.0 wt% and 4.0 wt% nanoclay-montmorillonite) and two kinds of PC film with thickness of 0.125 mm and 0.175 mm combined varied ink formulas were used to investigate the effect of nanoclay quantity on ink washout of in mold decoration molding (square plate specimen with thickness of 2.0mm). It was found that Nylon6 nanocomposites with nanoclay quantity of 4.0wt% would increase 30% washout area than of 2.0wt% addition quantity. In addition, higher injection speed would increase shear stress leading to large ink washout area whereas higher melt temperature would decrease ink washout area.
This paper presents a numerical study of melt flow behaviour of ABS plastic through the melt flow tube of the liquefier head of the Fused Deposition Modelling (FDM) rapid prototyping process using the finite element analysis. Main flow parameters including temperature, velocity and pressure drop have been investigated. Liquefier head of FDM machine has been modelled parametrically and the effects of physical modifications including nozzle angle variation on the melt flow parameters have been investigated accordingly. Results provide promising information on flow behaviour of new ABS based composites for processing in the FDM system to fabricate new products.
Babu Padmanabhan, Chetan Chincholi Jayanth, May 2010
Exfoliated organoclay in the polystyrene-block-poly(2-vinyl pyridine) was used the as a model material for investigating the heterogeneous nucleation effect of nanoclay in polymer foams. Using strictly controlled foaming process, the experimental results indicate that exfoliated clay in polymer matrix is able to decrease the cell size and increase the cell density. The cell size can be reduced to about 1.4 ?¬m and the cell density increase to 8.4*1010 cells/cm3 when 20 wt.% of organoclay was added. On the contrary, aggregated nanoclay has no effect on the cell size and cell density.
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Forced and starve feeding are well known feeding
methods to input material into a co-rotating twin screw
extruder. Polymers in powder form and materials such as
talc and mica are a challenge to introduce into the extruder.
The geometry of the intake zone screw elements and the
side-feed zone screw elements decide the conveying ability
and the intake capacity of the extruder. The problem of
lower intake capacity is solved by the use of Single Flight
Shovel (SFV) Triple Flight Shovel (TFV) and Regular
Flight Shovel (RFV) classified as 'FV' type elements
(Patent Pending). The screw flights are designed to plough
through the material similar to the working of a
snowplough. Increase in intake capacity compared to
Erdmenger-type and Schubkanten-type screw elements is
discussed.
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Forced and starve feeding are well known feeding methods to input material into a co-rotating twin screw extruder. Polymers in powder form and materials such as talc and mica are a challenge to introduce into the extruder. The geometry of the intake zone screw elements and the side-feed zone screw elements decide the conveying ability and the intake capacity of the extruder. The problem of lower intake capacity is solved by the use of Single Flight Shovel (SFV), Triple Flight Shovel (TFV) and Regular Flight Shovel (RFV) classified as 'FV' type elements (Patent Pending). The screw flights are designed to plough through the material similar to the working of a snowplough. Increase in intake capacity compared to Erdmenger-type and Schubkanten-type screw elements is discussed.
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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