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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Kazumi Tada , Daisuke Fukuzawa , Ayako Watanabe , Hiroshi Ito, May 2010
3-dimensional FEM simulation was performed to clarify the mechanism on surface replication in micro-injection molding and thermal nano-imprinting.Especially the filling behavior into micro- and nanosurface features was discussed in comparison with the experimental results. The simulation results and the experimental results of injection molding show possibility of the generation of air traps in the filling stage and it is considered that those air traps have a strong relation with replication shape and replication rate. The simulation results of thermal imprinting clarified penetration behavior of polymer melt into nano-surface feature and show that the aspect ratio of the cavity and imprinting pressure influenced flow behavior in thermal imprinting.
Stretch hood films used to protect and unitize pallet
loads are becoming more sophisticated structures that
combine the unique properties of several advanced
polymers. The combined properties of reactor TPO resins
and ethylene copolymers will continue to expand the
envelope of application and performance possibilities for
film engineers delivering enhanced strength and pallet
security heat resistance extensibility elastic recovery
and material use reduction. This paper will discuss the
relationships between film formulation and degree of
orientation on the elastic and physical properties of a
three-layer stretch hood film structure.
Stretch hood films used to protect and unitize pallet loads are becoming more sophisticated structures that combine the unique properties of several advanced polymers. The combined properties of reactor TPO resins and ethylene copolymers will continue to expand the envelope of application and performance possibilities for film engineers, delivering enhanced strength and pallet security, heat resistance, extensibility, elastic recovery, and material use reduction. This paper will discuss the relationships between film formulation and degree of orientation on the elastic and physical properties of a three-layer stretch hood film structure.
Walter Michaeli , Laura Flórez , Dominik Obeloer , Markus Brinkmann, May 2010
Foaming an injection molded thermoplastic part can reduce its weight warpage and the associated processing costs but it also results in a loss of mechanical performance. This loss can however be mitigated through specific modifications of the foam structure while at the same time the material consumption is minimized. This paper analyzes the changes that are induced by foaming in the mechanical performance of thermoplastic materials and demonstrates the gain in mechanical strength that can be achieved by inducing modifications of the foam structure for example in the skin thickness the mean cell size and the foam density.
Walter Michaeli , Laura Flórez , Dominik Obeloer , Markus Brinkmann, May 2010
Foaming an injection molded thermoplastic part can reduce its weight, warpage and the associated processing costs, but it also results in a loss of mechanical performance. This loss can, however, be mitigated through specific modifications of the foam structure, while at the same time the material consumption is minimized. This paper analyzes the changes that are induced by foaming in the mechanical performance of thermoplastic materials and demonstrates the gain in mechanical strength that can be achieved by inducing modifications of the foam structure, for example in the skin thickness, the mean cell size and the foam density.
High-frequency induction heating is an efficient way to rapidly heat mold surface by utilizing a high-frequency skin effect. Because the procedure allows for the rapid heating and cooling of mold surfaces, it has been recently applied to the injection molding in various purposes. The present work introduces various industrial applications of high-frequency induction heating to high-quality injection molding including: (i) moldability improvement in thin-wall injection molding, (ii) improvement of replication ratio of micro-features, and (iii) remove of weldlines for a mobile phone cover which contains multiple holes.
Isotactic polypropylene (PP) has been reactivelyblended with an ethylene-octene copolymer (EOC) in atwin screw extruder. Free radical polymerization ofstyrene and a multifunctional acrylate during meltextrusion has resulted in an enhancement of mechanicalproperties and discovery of unique features in bothamorphous and crystalline phases. DSC indicates thatsmall lamellar crystals are present in the reacted blends which melt and recrystallize in a much different mannercompared to ungrafted PP. XRD reinforces DSC resultsin that the size and perfection of the alpha crystallinephase are reduced by grafting. SEM shows a uniquecross-hatch structure as indicated by XRD. Polarizedlight microscopy gives evidence that grafting andbranching within the reacted blend causes a gelation-likerecrystallization.
Recent earth environmental concern requires easy
recycle material system and the use of biodegradable
polymer and natural fiber is noticed in composite materials.
To apply the natural fiber for the structural parts the use as
reinforcement of Sheet Molding Compound (SMC) is
desirable because it is expected that SMC can be used in
various fields in terms of high productivity and
dimensional stability. Considering that fiber reinforced
composite is used for structural part the use of long-span
must be possible. Therefore the evaluation of the
durability such as degradation is very important subject.
In this study SMC (Sheet Molding Compound) that
reinforcement was jute cloth were prepared. The jute cloth
reinforced SMC was immersed in hot water to promote the
degradation. And after immersion an increase ratio of
water and bending properties were compared with that of
jute cloth reinforced SMC without immersion. As a result
the fracture mechanism changed from the combination
of crack propagation in matrix area and delamination
in the interface around the fiber bundle to only crack
propagation in matrix area by water immersion.
Recent earth environmental concern requires easy recycle material system, and the use of biodegradable polymer and natural fiber is noticed in composite materials. To apply the natural fiber for the structural parts, the use as reinforcement of Sheet Molding Compound (SMC) is desirable because it is expected that SMC can be used in various fields in terms of high productivity and dimensional stability. Considering that fiber reinforced composite is used for structural part, the use of long-span must be possible. Therefore, the evaluation of the durability such as degradation is very important subject. In this study, SMC (Sheet Molding Compound) that reinforcement was jute cloth were prepared. The jute cloth reinforced SMC was immersed in hot water to promote the degradation. And after immersion, an increase ratio of water and bending properties were compared with that of jute cloth reinforced SMC without immersion. As a result,the fracture mechanism changed from the combination of crack propagation in matrix area and delamination in the interface around the fiber bundle to only crack propagation in matrix area by water immersion.
Wilailak Chanklin , Shuzhao Li , Huining Xiao, May 2010
The hydrophobic modification of cellulose fiber (CF) and cellulose microfibril (CMF) was conducted by grafting 1'Octadecanol using TDI as a coupling agent. The optimum reaction conditions obtained for grafting were: molar ratio of cellulosic materials:1'Octadecanol:TDI 1:1:1 (molar ratios of OH groups in fibers and reactive groups in reagents), temperature of reaction 120?øC and reaction time 3 h. The grafting was confirmed by FT-IR; and TGA measurement indicated that the amounts of grafting were 16.9wt% and 13.9wt% for CF and CMF,, respectively. Moreover, the surface morphology and hydrohphobicity of the grafted fibers were investigated by SEM and static contact angle measurement.
M.A. Rodriguez-Perez , P. Garcia de Acilu Laa , J. Arevalo-Guiterrez , C. Saiz-Arroyo , E.Solorzano , J.A. de Saja, May 2010
Low density polyethylene/nano-silica nanocomposites has
been foamed using an improved compression molding
process. Different amounts of nanosilica (from 1 to 9 % by
weight) were used. A high level of particle dispersion was
achieved both in the solid precursor and in the foams. It
was found a significant increment of the mechanical
properties both in solids and foams; being the increase in
properties more significant in the foams. A reduction in
cell size has been observed with the addition of nanosilica.
Cell sizes in the microcellular range were obtained.
M.A. Rodriguez-Perez , P. Garcia de Acilu Laa , J. Arevalo-Guiterrez , C. Saiz-Arroyo , E.Solorzano , J.A de Saja, May 2010
Low density polyethylene/nano-silica nanocomposites has been foamed using an improved compression molding process. Different amounts of nanosilica (from 1 to 9 % by weight) were used. A high level of particle dispersion was achieved both in the solid precursor and in the foams. It was found a significant increment of the mechanical properties both in solids and foams; being the increase in properties more significant in the foams. A reduction in cell size has been observed with the addition of nanosilica.Cell sizes in the microcellular range were obtained.
Mechanical Spectral Hole Burning (MSHB) is a novel rheological technique to probe dynamic heterogeneity for polymeric materials, which exhibit relatively weak dielectric responses. In the present work, mechanical spectral hole burning (MSHB) was applied to a block copolymer and a series of polystyrene solutions in order to investigate its capability of detecting the heterogeneity and the possible relationship between the length scale of heterogeneity and hole properties. The results illustrate the power of MSHB to probe the dynamic heterogeneity of polymeric systems as evidenced by the presence or absence of mechanical holes in the vicinity of the order-disorder transition of a block copolymer. The results also suggest the hole properties are not governed by the length scale of the heterogeneity, rather they are dominated by the dynamics, i.e., whether the MSHB is performed in close to Rouse regime, rubbery plateau regime, transition regime from plateau to terminal region or the terminal flow regime.
W. Michaeli, Sebastian Hessner, Fritz Klaiber, May 2010
Thermoplastic urethanes (TPU) offer broad property range, processing flexibility, and biocompatibility for medical applications. Alcohol based disinfectants have a long history of effective and safe use. Expanding on earlier rheology molecular weight data indicating minimal reduction, we conducted a long term compatibility study covering all known urethane types in a hemo-dialysis setting with a simulated clinical exposure protocol for 90 days. After 90 days exposure, minor changes in physical properties on the catheter body and components were detected, often similar to the saline control. Most importantly, resultant properties far exceeded ISO requirements for catheters.
W. Michaeli , Sebastian Hessner , Fritz Klaiber, May 2010
The manufacturing of optical components by
injection moulding and injection-compression moulding
is a serious challenge for mould and machine technology
as well as for process control. Polymer lenses were
manufactured with a modularly designed injectioncompression
mould base thus different injectioncompression
moulding technologies could be examined.
To evaluate the quality of optical parts the accuracy of the
moulded geometry as well as the resulting optical
performance has been analysed. At present a geometrical
moulding accuracy in the lower micron range has been
achieved. Overall injection-compression moulded lenses
showed a better optical performance than injection
moulded lenses.
The manufacturing of optical components by injection moulding and injection-compression moulding is a serious challenge for mould and machine technology as well as for process control. Polymer lenses were manufactured with a modularly designed injection-compression mould base, thus different injection-compression moulding technologies could be examined. To evaluate the quality of optical parts the accuracy of the moulded geometry as well as the resulting optical performance has been analysed. At present a geometrical moulding accuracy in the lower micron range has been achieved. Overall injection-compression moulded lenses showed a better optical performance than injection moulded lenses.
Plastic products are occasionally designed in such a
way that due to required injection locations and polymer
flow traits the product will inherit certain quality defects.
Two specific defects that if generated could often
constitute a non-conforming product are weak weld lines
and burn marks. Initial process alterations can be utilized
in order to minimize or eliminate defects; however more
costly mold or product alterations are often necessary.
This paper presents a case study of how plastic flow
simulation and the latest in melt management technologies
can be utilized in order to create products that re-define
the industries approach to handling these specific product
defects.
Plastic products are occasionally designed in such a way that, due to required injection locations and polymer flow traits, the product will inherit certain quality defects. Two specific defects that if generated could often constitute a non-conforming product are weak weld lines and burn marks. Initial process alterations can be utilized in order to minimize or eliminate defects; however more costly mold or product alterations are often necessary. This paper presents a case study of how plastic flow simulation and the latest in melt management technologies can be utilized in order to create products that re-define the industries approach to handling these specific product defects.
One of the problems encountered in the extrusion of
complex profiles is the unbalanced flow of polymer melt
as it leaves the die. In this study a systematic method to
obtain balanced flow is proposed by using a CFD tool.
First the results of a production test that is performed for
a profile and the results of the CFD simulation compared
and it is seen that the velocity distribution at the die exit
is similar indicating an unbalanced flow. For the profile
to be produced a new die geometry which provides
balanced flow at the die exit is proposed by use of
numerical simulations. A balanced exit flow is achieved
by using flow separators.
One of the problems encountered in the extrusion of complex profiles is the unbalanced flow of polymer melt as it leaves the die. In this study, a systematic method to obtain balanced flow is proposed by using a CFD tool. First, the results of a production test that is performed for a profile and the results of the CFD simulation compared and it is seen that the velocity distribution at the die exit is similar, indicating an unbalanced flow. For the profile to be produced, a new die geometry which provides balanced flow at the die exit is proposed by use of numerical simulations. A balanced exit flow is achieved by using flow separators.
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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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