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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
Not an SPE member? Join today!
| = Members Only |
|
Categories
|
Conference Proceedings
EFFECT OF LAYER SEQUENCING ON THE INTERFACIAL STABILITY
OF COEXTRUDED MULTILAYERED FILMS INCORPORATING BALLISTIC RESISTANT MATERIALS
Flow simulations and coextrusion experiments were employed to characterize layer sequencing effects on the interfacial stability of coextruded five-layered films incorporating ballistic-resistant materials. A simple model of coextrusion was able to rank the relative coextrusion stability of multilayered structures qualitatively in terms of viscosity matching and viscoelastic considerations. However thermal analyses and coextrusion experiments revealed that the overriding factor determining coextrusion performance was the thermal stability and degradation characteristics of the materials utilized to produce the multilayered films. Therefore any predictive analysis of coextrusion should also consider appropriate degradation mechanisms and their affect upon melt rheology.
EFFECT OF LAYER SEQUENCING ON THE INTERFACIAL STABILITY OF COEXTRUDED MULTILAYERED FILMS INCORPORATING BALLISTIC RESISTANT MATERIALS
Flow simulations and coextrusion experiments were employed to characterize layer sequencing effects on the interfacial stability of coextruded five-layered films incorporating ballistic-resistant materials. A simple model of coextrusion was able to rank the relative coextrusion stability of multilayered structures qualitatively in terms of viscosity matching and viscoelastic considerations. However, thermal analyses and coextrusion experiments revealed that the overriding factor determining coextrusion performance was the thermal stability and degradation characteristics of the materials utilized to produce the multilayered films. Therefore, any predictive analysis of coextrusion should also consider appropriate degradation mechanisms and their affect upon melt rheology.
POLYMER GEL ELECTROLYTE OF PMMA AND IONIC LIQUID FOR APPLICATION IN ELECTROCHEMICAL DEVICES
Polymer gel electrolyte is one of the most useful solid electrolytes for replacing conventional liquid electrolytes. To overcome the drawbacks from conventional electrolytes solvent, ion gels by in situ polymerization of methylmethacrylate (MMA) in hexafluorophosphate (BMIPF6) were developed with crosslinking agent. Ion gels were prepared with respect to weight ratio of MMA/BMIPF6. The transparent, self-standing and flexible ion gels with high ambient ionic conductivity and good thermal stability were obtained. The ion transfer behavior and its temperature dependency were investigated. The structure of crosslinked network of ion gels were observed by optical microscope and confirmed with swelling ratio test.
SUBSTITUTION OF POLYLACTICACID (PLA) IN PLACE OF POLYVINYLCHLORIDE (PVC) IN TRANSPARENT SIGNAGE FOR RETAIL USE
This project aims to investigate the material properties of Polylactic acid (PLA) and to compare them with Polyvinyl chloride (PVC) which is currently used in retail signage. There problems inherent in changing a process from an established material to a biodegradable polymer. The mechanical properties of PLA are under scrutiny to determine if it can be a reasonable substitute for PVC a non biodegradable plastic that must be land-filled or recycled at considerable cost after its post-consumer use. Many environmentalists suggest that biodegradable plastics can be substituted to fill the same roles as conventional polymers. PLA is a biodegradable polymer that is available in grades that are transparent and are manufacturable in most common thermoplastic processing methods including extrusion. PLAƒ??s substitution for PVC in this application can help to eliminate landfill and reduce overall pollution.
RESIN LIFE CYCLE ESTIMATION
TO HELP GUIDE SUSTAINABILITY CHOICES
Life cycle analysis (LCA) is an accepted
methodology to determine the environmental impact of a
certain material or package at different stages in its
product life. In some cases however LCAs can be
complex and expensive to carry out. DuPont is looking at
ways to internally estimate the LCA of its products by
using a modular approach: building estimates of
nonrenewable energy and green house gas emissions by
summing proprietary information on our ingredients and
unit operations. The output of this tool will be used to
target our internal improvement efforts and potentially
help our value chain partners make better multilayer
flexible packaging design choices.
RESIN LIFE CYCLE ESTIMATION TO HELP GUIDE SUSTAINABILITY CHOICES
Life cycle analysis (LCA) is an accepted methodology to determine the environmental impact of a certain material or package at different stages in its product life. In some cases, however, LCAs can be complex and expensive to carry out. DuPont is looking at ways to internally estimate the LCA of its products by using a modular approach: building estimates of nonrenewable energy and green house gas emissions by summing proprietary information on our ingredients and unit operations. The output of this tool will be used to target our internal improvement efforts and potentially help our value chain partners make better multilayer flexible packaging design choices.
PROCESS CONTROL AND PRODUCT EVALUATION IN MICRO MOLDING USING A SCREWLESS/TWO-PLUNGER INJECTION UNIT
A newly developed injection molding machine equipped with a screwless/two-plunger injection unit has been employed to mould miniaturized dog-bone shaped specimens on polyoxymethylene and its process capability and robustness have been analyzed. The influence of process parameters on ?¬-injection molding was investigated using the Design of Experiments technique. Injection pressure and piston stroke speed as well as part weight and dimensions were considered as quality factors over a wide range of process parameters. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses, considering both average values and standard deviations.
NANOMECHANICAL MEASUREMENTS IN ULTRATHIN POLYMER FILMS
Using a nano-bubble inflation technique developed in our lab we have measured the absolute creep compliance of polymer films down to a thickness of 9nm [1-3]. Materials studied were a poly (vinyl acetate) (PVAc), a polystyrene (PS) and a polycarbonate (PC). All three materials showed dramatic stiffening of the rubbery plateau compliance as the thickness was reduced below approximately 100nm, with the stiffness increasing by some three orders of magnitude for the thinnest films. In the region where the stiffness is thickness dependent, the stiffness of all three materials varies as approximately the inverse of the square of the thickness. Interestingly, while the change in stiffness was common to all materials, the reduction in the glass transition temperature which is commonly observed in thin free standing films was very different. The PS showed a decrease of approximately 50K at a thickness of 11nm which is comparable to literature data. The PVAc showed no change in Tg down to 23nm while the PC showed a large decrease of ~90K at 9nm.
CREATING POLYMER-CARBON NANOTUBES NANOCOMPOSITES BY CRYOMILLING
The efficiency of using a cryogenic milling device for mixing a polymer with highly agglomerated multi-walled carbon nanotubes, to create polymer nanotubes nanocomposite, was evaluated. PEO/CNT and PE/CNT nanocomposites studied contained 1% and 2% of MWCNTs, and were blended in a cryogenic milling apparatus using two sizes of milling balls, and different milling times. The nanocomposites were characterized using SEM and DSC. Intimate contact between polymeric matrices and the CNTs was observed through SEM analysis. The thermal analysis results showed small variations in the transition temperatures of the nanocomposite when compared with the unfilled polymers.
EFFECT OF HEAT SEALING PRESSURE ON PROPERTIES OF HEAT-SEALED
ORIENTED POLYPROPYLENE/CAST POLYPROPYLENE (OPP/CPP) FILM
Oriented Polypropylene/Cast Polypropylene (OPP/CPP)
film is made by laminating OPP and CPP which is widely
used as general packaging material. OPP functions as a
moisture resistant layer while CPP provides better heatsealability.
In earlier investigations effects of heat-sealing
temperature on properties of heat-sealed OPP/CPP film
were investigated. The optimum heat-sealing temperature
was found to be 140°C. In this study different seal
pressures were used at 140°C. It was revealed that the peel
strength is dependant on the seal pressure whereby the
maximum peel strength was achieved at 0.03 MPa. The
mechanical properties on the heat sealed part were
examined by means of tensile test with circular notch peel
test and scanning electron microscopy.
EFFECT OF HEAT SEALING PRESSURE ON PROPERTIES OF HEAT-SEALED ORIENTED POLYPROPYLENE/CAST POLYPROPYLENE (OPP/CPP) FILM
Oriented Polypropylene/Cast Polypropylene (OPP/CPP) film is made by laminating OPP and CPP, which is widely used as general packaging material. OPP functions as a moisture resistant layer while CPP provides better heatsealability.In earlier investigations, effects of heat-sealing temperature on properties of heat-sealed OPP/CPP film were investigated. The optimum heat-sealing temperature was found to be 140?øC. In this study, different seal pressures were used at 140?øC. It was revealed that the peel strength is dependant on the seal pressure, whereby the maximum peel strength was achieved at 0.03 MPa. The mechanical properties on the heat sealed part were examined by means of tensile test with circular notch, peel test and scanning electron microscopy.
RHEOLOGY PROCESSING AND ELECTRICAL PROPERTIES OF CARBON NANOTUBE/POLY(ETHER ETHER KETONE) NANOCOMPOSITES
The inhomogeneous dispersion of carbonnanotubes (CNTs) acts as the main hindrance forexploiting the exceptional properties associated with CNTin polymer/CNT composites. However only fewsystematic studies clearly relate the structural featureswith the property profile of nanocomposites based ondifferent nanotube grades. The aim of this study thereforewas to process nanotube-based polymeric composites andto correlate their degree of dispersion with the resultingrheological (both shear and elongation) as well aselectrical behavior. A range of multi-wall carbonnanotubes (MWNT) and single-wall carbon nanotubes(SWNT) reinforced high temperature semi-crystallinepoly (ether ether ketone) (PEEK) were prepared by meltcompounding process. The composites with high degreeof nanotube dispersion shows nearly five orders ofmagnitude increase in storage modulus and an abruptincrease of ten orders magnitude in electrical conductivityby adding only 2 wt% of nanotubes. Additionally boththe melt strength and the elongational viscosity cansignificantly increase by incorporating nanotubes.However this increment effect strongly depends on thedegree of dispersion of nanotubes in the polymer matrix.As highlighted by the experimental results both thedispersion and interfacial interaction between the matrixand nanotubes are the key factors for improving theproperties of such nanocomposites.
PROCESS ANALYTICAL TECHNOLOGY FOR IMPROVED PROCESS UNDERSTANDING AND CONTROL OF A HOT MELT EXTRUSION PROCESS
The development and application of an in-line near infrared spectroscopic measurement system is discussed. Key results included a rapid, in-line method to measure the composition of a multi-component process stream at the exit of the extruder, and identification of a process model that is used to understand the disturbance rejection capabilities of the process. The composition monitoring yielded further process understanding; specifically system residence time distribution mapping and process disturbance identification. Lastly, the potential for prediction of process disturbance rejection capabilities is discussed.
EFFECT OF HYGROTHERMAL TREATMENT ON RHEOLOGICAL AND
MECHANICAL PROPERTIES OF RECYCLED POLY(ETHYLENE
TEREPHTHALATE)/ RECYCLED POLYPROPYLENE BLENDS
Poly(ethylene terephthalate) (PET) is one of the most
important fibers for industrial production due to its high
performance low cost and recyclability. The amount of
waste that arise from post-consumer PET especially in the
beverage industry have made recycling of poly(ethylene
terephthalate) (PET) a beneficial effort in reducing
environmental pollution. Studies of blends and composites
using recycled PET have been carried out with several
polymeric materials like polyethylene and polystyrene. In
this work recycled poly(ethylene terephthalate)/ recycled
polypropylene (RPET/RPP) blends was subjected to
injection molding and then subjected to hydrothermal
treatment in water bath at below transition glass
temperature to determine the amount of moisture
absorption. As polypropylene tends to degrade at a faster
rate than poly(ethylene terephthalate) the results show
that defect of polypropylene effect the tensile strength and
modulus of the RPET/RPP blends.
EFFECT OF HYGROTHERMAL TREATMENT ON RHEOLOGICAL AND MECHANICAL PROPERTIES OF RECYCLED POLY(ETHYLENE TEREPHTHALATE)/ RECYCLED POLYPROPYLENE BLENDS
Poly(ethylene terephthalate) (PET) is one of the most important fibers for industrial production due to its high performance,low cost, and recyclability. The amount of waste that arise from post-consumer PET especially in the beverage industry have made recycling of poly(ethylene terephthalate) (PET) a beneficial effort in reducing environmental pollution. Studies of blends and composites using recycled PET have been carried out with several polymeric materials, like polyethylene and polystyrene. In this work, recycled poly(ethylene terephthalate)/ recycled polypropylene (RPET/RPP) blends was subjected to injection molding and then subjected to hydrothermal treatment in water bath at below transition glass temperature to determine the amount of moisture absorption. As polypropylene tends to degrade at a faster rate than poly(ethylene terephthalate), the results show that defect of polypropylene effect the tensile strength and modulus of the RPET/RPP blends.
PROPERTY VERIFICATION OF THERMOPLASTIC ELASTOMER BOTTLES PRODUCED FROM CUSTOM DESIGNED EXTRUSION BLOW MOLDING MOLDS
Santoprene grade 201-87 is a commonthermoplastic vulcanizate (TPV) used in blow moldingbecause of its excellent melt strength which lends to lesssag in the parison and ultimately lower wall thicknessvariations and a higher achievable maximum blow up ratio(BUR). However 201-87 (TPV 1) also has a particularlyhigh durometer which becomes a disadvantage in dextralapplications.Santoprene grade 201-55 (TPV 2) is another TPVwith mechanical characteristics comparable to that of theTPV 1 but with a much lower durometer and maximumachievable blow up ratio. The objective of this study is theretention of mechanical characteristics of the two TPVgrades being subjected to increased additive amounts of apolymer modifier Vistamaxx 6102 (Additive 1).
A BIREFRINGENCE-FREE COMPRESSION MOLDING PROCESS FOR OPTICAL PLASTICS LENSES
This paper investigates the process of precision compression-molding of plastics lenses with near-zero residual birefringence in the molded lenses. First, plastics preforms are injection molded by a conventional injection molding machine by net-shape molding technology. The preforms are then re-heated by infrared heaters and compressed under hydrostatic pressure conditions for form-finishing and stress-relieving. Once the preforms are heated above glass transition temperature, the moldings would release the frozen-in residual-stresses and retain the form accuracy via low compression pressure employed for shrinkage compensation. The compression molding process exhibits advantages of low process costs, high production efficiency, and good dimensional accuracy with zero-birefringence. First, experiments incorporated with Taguchi method are conducted for parameter optimization in residual stresses and form accuracy. The preliminary results show that plastic lenses optimized for form accuracy could have p-v values smaller than 0.35 micron plus RMS surface roughness less than 60 nm. More importantly, the plastic lenses are molded with little birefringence throughout the process.
FLOW FRONT ANALYSIS OF TIR LENS OF LEDS
WITH INJECTION MOLDING
This research is to investigate the TIR (Total
Internal Reflection) lens as secondary optical
element mounted on a LED for landscape and indoor
illumination. The TIR lens is like a cone bell with
the ratio of gate thickness to cavity thickness is
about 1: 10. The simulation software Moldex 3D is
used to simulate the melt front behavior for 3D
filling. Experimental results show that injection
speed mold temperature and melt temperature
significantly affect the final quality of TIR lens.
Molding parameters are obtained in this research to
improve the optical performance and that can be
applied on LED market in the future.
FLOW FRONT ANALYSIS OF TIR LENS OF LEDS WITH INJECTION MOLDING
This research is to investigate the TIR (Total Internal Reflection) lens as secondary optical element mounted on a LED for landscape and indoor illumination. The TIR lens is like a cone bell with the ratio of gate thickness to cavity thickness is about 1: 10. The simulation software, Moldex 3D is used to simulate the melt front behavior for 3D filling. Experimental results show that injection speed, mold temperature and melt temperature significantly affect the final quality of TIR lens.Molding parameters are obtained in this research to improve the optical performance and that can be applied on LED market in the future.
PREPARATION OF HIGH MELT STRENGTH POLYPROPYLENE BY THE REACTIVE EXTRUSION PROCESS AND ITS FOAMING APPLICATION
The reactive extrusion of maleic anhydride grafted polypropylene (PP-g-MAH) with ethylenediamine (EDA) as coupling agent was carried out in a co-rotating twin-screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP-g-MAH was replaced by maleic anhydride grafted high-density polyethylene (HDPE-g-MAH) or linear low-density polyethylene (LLDPE-g-MAH) to obtain hybrid long chain branched (LCB) polymers. Compared with the linear PP, PE and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low-frequency complex viscosity, significantly enhanced melt strength and strain-hardening behaviors. LCB polymers also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than linear polymer and their blends. Supercritical carbon dioxide (scCO2) was introduced in the reactive extrusion process. With the presence of scCO2, the motor current of twin extruder was decreased and LCB polyolefins with lower MFR, higher complex viscosity and increased tensile strength and modulus were obtained. This indicates that the application of scCO2 can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, facilitate the reaction between functional groups, and increase the LCB density. The foaming behavior of both linear and LCB polyolefins were studied. The results show that cellular materials produced from the LCB polyolefins have higher weight reduction, smaller cell size and better mechanical properties than those produced from the linear polymers.
|
This item is only available to members
Click here to log in
If you are not currently a member,
you can click here to fill out a member
application.
We're sorry, but your current web site security status does not grant you access to the resource you are attempting to view.
.jpg)
.jpg)
.jpg)
.jpg)
