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
EFFECT OF PROCESSING PARAMETERS ON PULSE COOLING EFFICIENCY IN INJECTION MOLDING
Pulse cooling provides a convenient way for varying mold temperature within limited range. Even so, it can reduce cycle time or improve part qualities. Due to its narrow operation window, choosing proper parameters is rather important. In this study, influences of flow temperature (FT), stop temperature (ST) and temperature sensor locations for coolant switch on the cooling efficiency are investigated. The results show that mold temperature varies from 66.5ƒøC to 71.5ƒøC when ST increases from 700C to 760C. When sensor location changes from 4 mm to 8mm beneath mold surface, mold surface temperature will increase from 670C to 68.50C.
STRUCTURAL STUDIES ON POLYPROPYLENE NANOCOMPOSITES DURING COMPLETE UNIAXIAL FILM PROCESSING CYCLE
The mechanistic changes that take place during heating-stretching-holding-cooling of typical film processing of polypropylene nanocomposite were investigated using a hybrid real-time spectral birefringence technique. The results on as-cast films indicated the nanoplatelet poles were highly oriented perpendicular to the plane of the film resulting in a uniplanar axial symmetry. During the heating, real-time measurements revealed that the presence of clay particles reduced the rate of PP/PPgMA melting. Throughout the deformation, the nanoclay enhanced the molecular orientation/strain-induced crystallization as compared to the PP. The nanocomposite films were found to exhibit a more affine deformation and increased the toughness of the system.
PLA PROPERTY IMPROVEMENT: IMPROVING THE PRACTICAL HEAT RESISTANCE
OF POLYLACTIC ACID (PLA)
Polylactic Acid (PLA) is a renewable polymer with
many unique features including compostability. However
PLA suffers from several performance deficiencies which
limit its market potential. A key deficiency is its ability to
withstand elevated use temperatures above 55C.
PolyOne’s objective was to explore a range of approaches
to identify a practical path to improved heat performance
while seeking to maximize renewable content and
processability. This paper addresses the industry need for
a high renewable content polymer with practical heat
resistance without relying on any additional thermal
treatments such as annealing. Various PLA-based
compounds were prepared and screened using DMA in an
effort to correlate results to the heat distortion temperature
(HDT) exhibited by injection molded PLA. It was
concluded that polymer blends offered the greatest
commercial viability of all the approaches considered
under normal injection molding conditions. Multi-phase
compatible polymer blends were found to have the most
significant impact on blend properties. All components of
the preferred blend composition are commercially
available today. Heat performance can be tailored based
upon performance requirements and bio-content
objectives. The PLA content of the blends studied varied
from 72% to 35% while the corresponding HDT (under
0.455 MPa load) ranges from 57 ºC to 101 ºC. Potential
increased bio-derived contents are also considered.
PLA PROPERTY IMPROVEMENT: IMPROVING THE PRACTICAL HEAT RESISTANCE OF POLYLACTIC ACID (PLA)
Polylactic Acid (PLA) is a renewable polymer with many unique features including compostability. However, PLA suffers from several performance deficiencies which limit its market potential. A key deficiency is its ability to withstand elevated use temperatures above 55 ?§C. PolyOneƒ??s objective was to explore a range of approaches to identify a practical path to improved heat performance while seeking to maximize renewable content and processability. This paper addresses the industry need for a high renewable content polymer with practical heat resistance without relying on any additional thermal treatments such as annealing. Various PLA-based compounds were prepared and screened using DMA in an effort to correlate results to the heat distortion temperature (HDT) exhibited by injection molded PLA. It was concluded that polymer blends offered the greatest commercial viability of all the approaches considered under normal injection molding conditions. Multi-phase compatible polymer blends were found to have the most significant impact on blend properties. All components of the preferred blend composition are commercially available today. Heat performance can be tailored based upon performance requirements and bio-content objectives. The PLA content of the blends studied varied from 72% to 35%, while the corresponding HDT (under 0.455 MPa load) ranges from 57 ?§C to 101 ?§C. Potential increased bio-derived contents are also considered.
STUDIES ON THE USE OF POLYBUTENE AS A MATRIX
FOR WOOD-PLASTIC COMPOSITES
Currently commercialized wood plastic composites (WPCs) are brittle and are produced using commodity plastics such as HDPE PP PVC etc. This study examined the feasibility of using a ductile plastic such as polybutene-1 (PB-1) as a matrix for manufacturing WPCs with improved toughness. The tensile flexural and impact properties of injection molded samples with varying proportions of wood flour were characterized. The results of the mechanical properties of the composites were compared to those of HDPE and PP-based WPCs. The tensile and flexural properties were lower than those of HDPE and PP. In contrast the impact strength of PB-1 was superior to those of HDPE and PP and thus confirmed it suitability for use as a matrix in composites intended for use where they may be subjected to high impacts.
STUDIES ON THE USE OF POLYBUTENE AS A MATRIX FOR WOOD-PLASTIC COMPOSITES
Currently commercialized wood plastic composites (WPCs) are brittle and are produced using commodity plastics such as HDPE, PP, PVC, etc. This study examined the feasibility of using a ductile plastic such as polybutene-1 (PB-1) as a matrix for manufacturing WPCs with improved toughness. The tensile, flexural, and impact properties of injection molded samples with varying proportions of wood flour were characterized. The results of the mechanical properties of the composites were compared to those of HDPE and PP-based WPCs. The tensile and flexural properties were lower than those of HDPE and PP. In contrast the impact strength of PB-1 was superior to those of HDPE and PP and thus confirmed it suitability for use as a matrix in composites intended for use where they may be subjected to high impacts.
CONTINUOUS EXTRUSION PRODUCTION OF MICROCELLULAR RIGID PVC
This study investigated the effect of PVC formulation on the cell morphology of rigid PVC foamed with supercritical CO2 in a continuous extrusion process. Cell morphology was controlled by blending two acrylic based processing aids (all-acrylic foam modifier K-400 and acrylic-based impact modifier KM-334) using a mixture design. The experimental results indicated that fusion is not the only criterion to control the density or expansion achieved in microcellular rigid PVC foams. The melt must have a viscosity low enough to allow bubble formation and growth as well as melt elasticity/strength high enough to prevent cell coalescence.
THE OPTICAL IMPACT OF LOW-INDEX INORGANIC FILLERS ON THE PERFORMANCE OF PLASTIC ARTICLES PIGMENTED WITH TITANIUM DIOXIDE
The primary uses of titanium dioxide pigments in polymer applications are to impart opacity to and provide protection from degradation by ultraviolet light for pigmented plastic articles. With regard to the former, misconceptions exist regarding the possibility of replacing titanium dioxide with inorganic materials of lower refractive index without impacting opacity. We provide in this paper both the theoretical background and experimental evidence from film data that illustrate the impact on opacity performance of low-index fillers.
CHARACTERIZATION OF POLY (CAPROLACTONE)/CASSAVA STARCH BLENDS
Three types of poly (caprolactone) / cassava starch blends were prepared by melt mixing. Type I were uncompatibilized blends, Type II were compatibilized with oxidized poly (caprolactone) and in Type III thermoplastic cassava starch had been used as dispersed phase. The samples were characterized by tensile tests, scanning electron microscopy, wide angle x-ray scattering, infra-red spectroscopy and differential scanning calorimetry. The mechanical properties of the poly(caprolactone) rich blends were lower than those of neat poly(caprolactone). There were no large differences in mechanical behavior among the three systems evaluated. Nevertheless the mechanical performance was comparable to LDPE behavior, therefore these type of blends could substitute LDPE in several applications with a more ecologcal performance due to their complete biodegradation in less than a year.
RECENT ADDITIVE DEVELOPMENT FOR ROTATIONAL MOLDING
Proper additive selection is essential in rotational molding due to the severe processing conditions and oxygen rich environment. In addition light stability is often an essential element for outdoor applications. In this paper we will review different classes of stabilizers their functions and effects on rotational molding process and product properties. New stabilizers with cycle time reduction and improved color characteristics will be highlighted with supportive field trial data. In addition to address the durability of rotomolded parts the performance of different light stabilizers will also be reviewed and compared.
POLYMER MODIFICATION WITH SPECIALTY HYDROCARBON FLUIDS
Specialty hydrocarbon fluids are used to enhance
polyolefin formulations for improved performance. These
specialty hydrocarbon fluids have uniquely defined
structures and narrow molecular weight distributions that
provide exceptional compatibility with olefin-based
polymers elastomers plastomers and other rubber
products. As a result the dispersion of specialty
hydrocarbon fluids in the polymer can be readily achieved
in the extruder by a simple melt blending process.
Benefits for using these fluids have been demonstrated in
both non-crosslinked and cross-linked polyolefin
formulations and in highly filled systems. Benefits
include improved processability flexibility elasticity
durability and most importantly longer retention of
polymer properties in applications with broad service
temperature requirements. The plasticization effect
provided by these fluids helps reduce the viscosity of
modified polymer. They also improve the processability
in terms of better flowability higher output and lower
head pressure and extruder torque. These fluids are free of
aromatics and chlorine. They do not interfere with the
common vis-breaking grafting or cross-linking agents
used in blend formulations. In comparison to traditional
process oils they exhibit improved long-term permanence
due to their low volatility and high thermal and oxidative
stability. Applications requiring increased flexibility
durability and lower permanent set can benefit from the
extremely low glass transition temperature of hydrocarbon
fluids. This paper reviews the utility of specialty
hydrocarbon fluids in several polyolefin-based polymer
formulations for wire and cable pipe and tubing and
automotive applications.
POLYMER MODIFICATION WITH SPECIALTY HYDROCARBON FLUIDS
Specialty hydrocarbon fluids are used to enhance polyolefin formulations for improved performance. These specialty hydrocarbon fluids have uniquely defined structures and narrow molecular weight distributions that provide exceptional compatibility with olefin-based polymers, elastomers, plastomers, and other rubber products. As a result, the dispersion of specialty hydrocarbon fluids in the polymer can be readily achieved in the extruder by a simple melt blending process.Benefits for using these fluids have been demonstrated in both non-crosslinked and cross-linked polyolefin formulations and in highly filled systems. Benefits include improved processability, flexibility, elasticity, durability and, most importantly, longer retention of polymer properties in applications with broad service temperature requirements. The plasticization effect provided by these fluids helps reduce the viscosity of modified polymer. They also improve the processability in terms of better flowability, higher output, and lower head pressure and extruder torque. These fluids are free of aromatics and chlorine. They do not interfere with the common vis-breaking, grafting or cross-linking agents used in blend formulations. In comparison to traditional process oils, they exhibit improved long-term permanence due to their low volatility and high thermal and oxidative stability. Applications requiring increased flexibility, durability and lower permanent set can benefit from the extremely low glass transition temperature of hydrocarbon fluids. This paper reviews the utility of specialty hydrocarbon fluids in several polyolefin-based polymer formulations for wire and cable, pipe and tubing, and automotive applications.
NOVEL ECO-FR" STYRENIC POLYMERS"
Flame retardants (FRs) additives are commonly usedin polymeric materials, with non-halogenated flameretardants being preferred for environmental, health andsafety reasons. However, developing non-halogenated FRsis a challenge for styrenic polymers such as acrylonitrilebutadiene-styrene (ABS) since they burn very easily anddo not produce any char. Here, we have developed ahalogen-free flame retardant system for ABS using woodor cellulose as a charring material and ammoniumpolyphosphate (APP) as a catalyst. The use of theseadditives permits compounding and molding of ABS atlow temperatures. The resulting materials can achieve a V-0 or V-1 rating on UL-94 type tests.
POSS/PP NANOCOMPOSITES: CHARACTERIZATION AND PROPERTIES
It is known that molecules of polyhedral oligomeric silsesquioxane (POSS) can self-assemble into nanoparticles by bottom-up self assembly process. This was used in this work to obtain nanocomposites of polypropylene (PP) and POSS. A compatible sorbitol type nucleating agent aided dispersion POSS in PP melt and provided templates for self-assembly into 50-200 nm particles during fiber spinning process. A typical polypropylene formulation containing 0.3 wt% nucleating agent and 5-10 wt% POSS was spun into fibers with close to 70% reduction in diameter and showed 40-45% increase in modulus and 70-75% increase in yield strength compared to unfilled PP. An optimum concentration of POSS was identified.
DEVELOPMENT OF NOVEL ONE-STEP HYBRID PROCESSING
The plastics processing industry typically must pre-compound using extrusion prior to part fabrication by injection molding (IM). The aim of this work is to implement a novel method that combines compounding and part fabrication into one processing step, thereby eliminating a costly, heat-intensive extra step. Poly(trimethylene terephthalate) (PTT) is blended with 10, 15, 20, and 30 % fiberglass (FG) by three methods, including standard IM, pre-compounding followed by standard IM, and a novel, one-step IM process using an innovative mixing screw design. The effect of processing method on the mechanical, impact, and thermal properties of a FGPTT composite is presented.
GREEN COMPOSITES” FROM A CONJUGATED SOYBEAN OIL RESIN USING
CORN STOVER AS A NATURAL FIBER REINFORCEMENT
Novel “green composites” have been prepared using a
conjugated soybean oil resin and corn stover as a natural
fiber. Approximately 68 million metric tons of corn
stover the residue remaining after harvest is available
annually in the United States. The effect of the amount of
the natural fiber the length of the fiber and the amount of
the crosslinker on the structure and thermal and
mechanical properties of the composites has been
determined using Soxhlet extraction analysis
thermogravimetric analysis dynamic mechanical analysis
and tensile testing. Increasing the amount of corn stover
and decreasing the length of the fiber results in significant
improvements in the mechanical properties of the
composites. The Young’s moduli and tensile strengths of
the composites range from 386 to 1324 MPa and 3.5 to
6.5 MPa respectively.
GREEN COMPOSITES" FROM A CONJUGATED SOYBEAN OIL RESIN USING CORN STOVER AS A NATURAL FIBER REINFORCEMENT"
Novel green composites" have been prepared using a conjugated soybean oil resin and corn stover as a natural fiber. Approximately 68 million metric tons of corn stover the residue remaining after harvest is available annually in the United States. The effect of the amount of the natural fiber the length of the fiber and the amount of the crosslinker on the structure and thermal and mechanical properties of the composites has been determined using Soxhlet extraction analysis thermogravimetric analysis dynamic mechanical analysis and tensile testing. Increasing the amount of corn stover and decreasing the length of the fiber results in significant improvements in the mechanical properties of the composites. The Youngƒ??s moduli and tensile strengths of the composites range from 386 to 1324 MPa and 3.5 to 6.5 MPa respectively."Novel green composites" have been prepared using a conjugated soybean oil resin and corn stover as a natural fiber. Approximately 68 million metric tons of corn stover the residue remaining after harvest is available annually in the United States. The effect of the amount of the natural fiber the length of the fiber and the amount of the crosslinker on the structure and thermal and mechanical properties of the composites has been determined using Soxhlet extraction analysis thermogravimetric analysis dynamic mechanical analysis and tensile testing. Increasing the amount of corn stover and decreasing the length of the fiber results in significant improvements in the mechanical properties of the composites. The Youngƒ??s moduli and tensile strengths of the composites range from 386 to 1324 MPa and 3.5 to 6.5 MPa respectively."
PHOTOINITIATORS FOR UV LED CURING OF ACRYLATE THIN FILMS
The use of Ultra Violet Light Emitting Diodes
(UV LEDs) for carrying out rapid photo-initiated
polymerizations (curing processes) has gained much
attention recently due to several advantages that UV
LED’s hold over traditional UV curing systems such as
lower unit cost with no bulb consumption through
replacement minimal maintenance and cooler curing
source temperatures. UV LED’s have been applied in the
fields of coating and dental science. In this study UV
LED curing of ultra-thin films of acrylates was studied
with photo Differential Scanning Calorimetry (DSC). By
monitoring the amount of heat released during curing the
photoinitiators were screened; the effect of LED
irradiation time on the conversion has also been studied.
PHOTOINITIATORS FOR UV LED CURING OF ACRYLATE THIN FILMS
The use of Ultra Violet Light Emitting Diodes (UV LEDs) for carrying out rapid photo-initiated polymerizations (curing processes) has gained much attention recently, due to several advantages that UV LEDƒ??s hold over traditional UV curing systems, such as lower unit cost with no bulb consumption through replacement, minimal maintenance and cooler curing source temperatures. UV LEDƒ??s have been applied in the fields of coating and dental science. In this study, UV LED curing of ultra-thin films of acrylates was studied with photo Differential Scanning Calorimetry (DSC). By monitoring the amount of heat released during curing, the photoinitiators were screened; the effect of LED irradiation time on the conversion has also been studied.
RHEOLOGICAL BEHAVIOR OF POLYACRYLONITRILE COPOLYMERS PLASTICIZED WITH WATER
The presence of water can dramatically lower the melting point of polyacrylonitrile (PAN) homo- or copolymers and make it possible to melt-spin high acrylonitrile (AN) content PAN fibers. However, the behavior of PAN-water melt has not been adequately investigated and the rheology data for PAN-water melt is not available in literature. We developed pressurized capillary rheometer and used it in PAN/Vinyl Acetate (VA)-H2O viscosity measurement successfully. The shear viscosity at 195?øC decreases as water content increases from 17 wt-% to 23 wt-%. The rheology of PAN-water melt can be useful in characterizing the melt and spinning PAN precursor fibers.
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