SPE Library
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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Conference Proceedings
LASER WELDING OF TRANSPARENT PLASTICS BY MEANS OF THE INTERMEDIATE FILM METHOD
Laser transmission welding is an innovative joining process for plastics. Since one joining part has to be laser absorbing the polymer has to be pigmented with an absorbent material. By this however the material is colored to a certain extent. Reducing the absorbing material to the joining area enables the welding of transparent polymer parts without any pigmentation. The possibilites of this method to expand the laser welding spectrum are presented in this paper.
COUPLED FEA SIMULATION OF THE DEMOULDING PROCEDURE OF
INJECTION MOULDED PARTS
A reasonable design of the injection mould has to
guarantee that the moulded part can be demoulded without
damaging either the ejection system in the mould or the
part. In the conventional mould design this damaging
occurs at the very end of the development process of the
injection mould when it is already assembled.
A simulation procedure is presented which enables the
mould maker to mechanically layout the demoulding
system. It combines a process simulation with a structural
analysis and hence maximises the advantage of using CAE.
A PLASTICS EDUCATION OUTREACH PROGRAM FOR
MIDDLE SCHOOL AGED GIRLS
This paper describes a plastics education program for middle school girls. The goals of the program were to expose the girls to science and engineering and to educate them about plastics. The program included an overview of plastics and hands-on experimental investigations. Experiments included making a polymer environmental issues and the structure and properties of polymers. In addition to giving detailed descriptions of the program this paper includes recommendations for further improvements of the program.
IMPROVED MICRO-CELLULAR MOLDING OF LONG GLASS FIBER (LGF) REINFORCED THERMOPLASTICS
Molding equipment modified for micro-cellular injection molding to address concerns of potential damage to reinforcing glass fibers in molded parts has recently become available. Test data indicates use of this equipment results in a significant improvement in glass fiber length retention and mechanical properties relative to traditional micro-cellular molding when processing LGF reinforced polypropylene and nylon.
EFFECT OF ENVIRONMENTAL STRESS CRACKING AGENTS ON FATIGUE AND CREEP OF A MDPE PIPE
The effect of concentration of Igepal CO 630 on slow crack propagation in MDPE pipe was investigated. The kinetics and mechanism of crack propagation in fatigue at R=0.1 and creep at 50 ?øC were compared to those in air. The fatigue and creep behavior followed the same stepwise crack growth mechanism as in air at all the concentrations used. As the concentration increased to 0.01 vol. % the creep lifetime decreased significantly whereas the lifetime in fatigue gradually increased. At higher concentrations the lifetime was similar in creep and fatigue.
POLYMER FOAMS FLEXURAL MODULUS OPTIMAZATION: EFFECT OF DENSITY PROFILE
Several parameters are known to influence the flexural modulus of structural foams. In this paper the effect of density profile in terms of skin thickness transition zone smoothness and core density are discussed in order to predict and optimize the flexural modulus based on the constraints of fixed amount of material and beam thickness. The results obtained under the imposed constraints clearly shows that the I-beam model is not optimum and a smooth transition is needed to maximize flexural stiffness while reducing abrupt changes in the local materialƒ??s properties.
INTELLIGENT PROCESS CONTROL FOR INJECTION MOLDING
An intelligent system combining a simplified simulation model and fuzzy inference has been developed for determining the process parameters of injection molding.First preliminary optimization based on a simplified simulation model was employed for the initial setting. Then a fuzzy inference model based on expert knowledge was used for correcting defects. By communicating with the machine controller the intelligent system was integrated with the injection molding machine to optimize process parameters real time. An experimental study was carried out for verification.
THE EFFECTS OF MATERIAL SELECTION ON RF SYSTEMS INCLUDING RFID
As the electronics industry tends to convergence of voice and data communications wireless networks become ubiquitous and radio frequency identification gains popularity the effects of material selection on RF performance become increasingly important; this paper discusses how electric fields are affected by polymers and polymer composites.
EFFECTS OF THE FOAM MORPHOLOGY IN THE MECHANICAL PROPERTIES
OF INJECTION MOLDED THERMOPLASTIC FOAMS
The foaming reduces both material and energy consumption in the injection molding while minimizing warpage and shrinkage in the molded part. However until now the design potential of injection molded foams has remained rather unexploited because the relation between foam morphology and resulting mechanical properties is not fully understood. This paper studies the effect of morphological parameters such as cell diameter density distribution and skin thickness on the mechanical properties of injection molded foams.
INJECTION MOLDING CREATES LARGE HOLLOW CHANNELS- THE NEW INNOVATIVE GITBLOWTECHNIQUE
The new GITBlow specialty injection molding process can be used to produce thick-walled molded parts with adjacent thin-walled zones and extremely large hollow sections inside the thickpart areas. In this way it is possible to achieve parts that were previously made by joining together different parts to create assemblies. This paper presents the technology involved highlights the possibilities and fields of application and sums up the test results obtained so far.
THE EFFECTS OF RADIUSED CORNERS ON MELT FLOW IMBALANCES
A special case of mold filling shear induced imbalances in a geometrically balanced runner system is studied in a four-flow mold. The case compares and contrasts the detectable differences theoretically attributed to corner effects seen in the two outermost flow channels. Aninety degree corner and a full radius corner are investigated through use of interchangeable mold inserts which create both conditions.
NANOCOMPOSITES ENTREPRENEURIAL EDUCATION
A pilot nanocomposites entrepreneurial education course was implemented at Pittsburg State University as part of a proposed nanotechnology entrepreneurship emphasis. This effort is designed to inculcate in our students the role of polymeric materials innovation in product development and commercialization. Course performance was evaluated via studentsƒ?? satisfaction indices as per the CUES (Consortium for Upgrading Educational Standards) Assessment Model. CUES-AM data yield a true satisfaction index of 0.92 indicating very good course performance.
DETERMINATION OF THE PVT PROPERTY OF ASYMMETRIC PS/CO2 DROP AT HIGH TEMPERATURE AND PRESSURE
Due to the high viscosity it is not easy to form
an axisymmetric shape out of a PS/CO2 drop. In
this study the asymmetric PS/CO2 sessile drops
are observed to determine the swelling of a PS
melt with dissolved CO2. A rotational device in a
high-pressure and high-temperature cell with a
visualization window was built. The degree of
asymmetry is mathematically defined and an
algorithm is developed to integrate the
asymmetric profile for determining the PVT (i.e.
volume swelling) of the PS/CO2 solution.
DETERMINATION OF THE PVT PROPERTY OF ASYMMETRIC PS/CO2 DROP AT HIGH TEMPERATURE AND PRESSURE
Due to the high viscosity, it is not easy to form an axisymmetric shape out of a PS/CO2 drop. In this study, the asymmetric PS/CO2 sessile drops are observed to determine the swelling of a PS melt with dissolved CO2. A rotational device in a high-pressure and high-temperature cell with a visualization window was built. The degree of asymmetry is mathematically defined, and an algorithm is developed to integrate the asymmetric profile for determining the PVT (i.e.volume swelling) of the PS/CO2 solution.
PHOTO-INDUCED FOAMING OF UV CURING MONOMER / POLYMER BLEND WITH CO2
Cross-linking of a UV-curing monomer was utilized
to make bubbles in a polystyrene matrix. The UV-curing
monomer was instantly polymerized and cross-linked by
exposure to UV light. Excess heat was produced during
the polymerization which was utilized to induce bubble
nucleation in the CO2-saturated polymer. The
polymerization of UV curing monomer formed a highly
cross-linked structure which suppressed the bubble growth.
The resulting foam contained 20 micron cells at 1 x 108
/cm3.
PHOTO-INDUCED FOAMING OF UV CURING MONOMER / POLYMER BLEND WITH CO2
Cross-linking of a UV-curing monomer was utilized to make bubbles in a polystyrene matrix. The UV-curing monomer was instantly polymerized and cross-linked by exposure to UV light. Excess heat was produced during the polymerization, which was utilized to induce bubble nucleation in the CO2-saturated polymer. The polymerization of UV curing monomer formed a highly cross-linked structure which suppressed the bubble growth. The resulting foam contained 20 micron cells at 1 x 108 /cm3.
ADHESION PROMOTION USING FLAME PLASMA
SURFACE TREATMENT
The converting industry uses a significant amount of polyolefins from
polyethylene coated paper board to metalized paper & film as well as polyolefin
thin films.
ON-LINE OPTICAL MONITORING OF NANOCOMPOSITE COMPOUNDING
On-line monitoring of compounding of PA6 with
nanoclay is examined to investigate the level of exfoliation
and degradation under a variety of conditions in real-time.
On-line rheological and optical reflectance measurements
are compared with off-line analyses of compounded
samples to investigate the relationship between these
readings and exfoliation/intercalation and/or degradation
of the nanocomposite. The effect of the processing (twinscrew/
single-screw temperature and screw speed) on the
resulting melt quality and the ability to assess this quality
in real-time is discussed.
ON-LINE OPTICAL MONITORING OF NANOCOMPOSITE COMPOUNDING
On-line monitoring of compounding of PA6 with nanoclay is examined to investigate the level of exfoliation and degradation under a variety of conditions in real-time. On-line rheological and optical reflectance measurements are compared with off-line analyses of compounded samples to investigate the relationship between these readings and exfoliation/intercalation and/or degradation of the nanocomposite. The effect of the processing (twinscrew/ single-screw, temperature and screw speed) on the resulting melt quality and the ability to assess this quality in real-time is discussed.
DEVELOPMENT OF MELT-MODULATION TECHNOLOGY FOR
ENHANCED INJECTION MOLDING
An improved mechanical apparatus and control
method to enable enhanced melt modulation during
injection molding has been developed and evaluated. As
part of this new actuators were designed with the
objective of decreasing both the size and cost relative to
previously explored melt modulation systems. In addition
different control techniques were applied in order to
enhance the system performance. The results show that
significant improvements were realized but potential
remaining challenges are also presented in the paper.
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