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

MEASURING THE INFLUENCE OF UV STABILIZERS (HALS) ON MELT FRACTURE IN POLYETHYLENE PACKAGING FILMS BY OPTICAL PROFILOMETRY

T. Tikuisis, J. Bayley, D. Wunderlich, M. Adams, May 2010

Modern flexible packaging requires excellent aesthetic properties for film and print appearance (e.g. high gloss). These, and other optical properties, are directly influenced by film surface roughness, of which melt fracture is a leading cause. Such film surface irregularities can also negatively impact printing quality by causing distortion. In this paper, film surface roughness effects influenced by UV stabilizers are investigated. The use of optical profilometry to quantify differences in melt fracture performance will also be discussed.

NANOPARTICLE INDUCED RADIAL STRUCTURAL GRADIENT IN MELT-SPUN POLYPROPYLENE/PPGMA FIBERS

Jane Hitomi Fujiyama-Novak, Miko Cakmak, May 2010

The role of nanoparticles on the evolution of structural hierarchy in clay and polymer for fibers was elucidated. The stream of polypropylene nanocomposite that exited the die without application of a take up presented orientation gradient in the radial direction with the broad surfaces of the clay parallel to the surface of the fibers. The polymer exhibited high preferential orientation levels in the edge of the fiber. With take up, the clay particles enhanced the orientation of amorphous and crystalline phases. Measurements of the clay orientation revealed that the nanoplatelets contributed positively to the birefringence of the fibers.

NANOCOMPOSITE POLYPROPYLENE FILM FOR FOOD PACKAGING APPLICATIONS

Sarah Schirmer , JoAnn Ratto , Danielle Froio , Christopher Thellen , Jeanne Lucciarini, May 2010

Polypropylene (PP) was compounded with 7.5% montmorillonite layered silicate (MLS) and 2.5% compatibilizer; then extruded to produce both blown and cast nanocomposite films. The nanocomposite films were characterized and morphology specifically from x-ray diffraction (XRD) and transmission electron microscopy (TEM) showed limited interaction between the PP and MLS. There was however significant improvement in thermal barrier and mechanical properties over the neat PP films both before and after exposure to a high temperature sterilization process.

RELATIONSHIP BETWEEN SHEAR STRAIN AND MICROSTRUCTURE OF POLYPROPYLENE NANOCOMPOSITE BASED ON RHEOLOGICAL ANALYSIS

Guo Jiang , Han-Xiong Huang, May 2010

Polypropylene/clay nanocomposite was compounded by a twin-screw extruder. Rheological property development of samples collected from four different positions along the extruder and microstructure of the endobtained samples was investigated. Flow field parameters including shear rate and residence time profiles were simulated. Then the shear strain was calculated. The relationship between the shear strain and microstructure of nanocomposite was analyzed based on rheological analysis. Results showed that dispersion of clay in polymer matrix can be reflected by the shear strain generated by the flow along the extruder.

EFFECT OF PROCESSING PARAMETERS ON PULSE COOLING EFFICIENCY IN INJECTION MOLDING

Ashish Batra, Lisa Madenjian, Wenbin Liang, Gary Marchand, , Dan Moldovan, Jacob Jones, May 2010

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 66.5ƒ?øC to 71.5ƒ?øC 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

Jane Hitomi Fujiyama-Novak, Miko Cakmak, May 2010

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)

Shixiong Zhu , Roger Avakian, May 2010

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)

Shixiong Zhu , Roger Avakian, May 2010

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

K. A. Afrifah , R. A. Hickok , L. M. Matuana, May 2010

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

K. A. Afrifah , R. A. Hickok , L. M. Matuana, May 2010

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

Carlos A. Diaz , Laurent M. Matuana, May 2010

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

Sandra P. Davis, Philipp M. Niedenzu, Austin H. Reid, Jr., May 2010

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

Jiong Yu, Eric Wallis, May 2010

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

Jiong Yu , Eric Wallis, May 2010

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

Charlie Y. Lin , Bruce A. Harrington , David B. Dunaway, May 2010

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

Charlie Y. Lin , Bruce A. Harrington , David B. Dunaway, May 2010

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"

Tze-Wei Liu , Satish K. Gaggar , Sushant Agarwal , Adam Al-Mulla , Rakesh K. Gupta, May 2010

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

Byoung-Jo Lee , Sayantan Roy , Sadhan C. Jana, May 2010

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

Jennifer K. Lynch, Thomas J. Nosker, Kendall Mills, Keith Luker, May 2010

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.

IMPACT MODIFIED HIGH MODULUS PC/ABS BLENDS: AUTOMOTIVE AND NON-IMPACT MODIFIED HIGH MODULUS PC/ABS BLENDS: AUTOMOTIVE AND NONAUTOMOTIVE

Amit S. Kulkarni , Parminder Agarwal , Jim DeRudder , Karin van de Wetering , Ying Li , Jenny Zhang, May 2010

The latest applications in automotive and computer & business equipment markets require a high modulus resin coupled with superior impact behavior. It is a challenge to deliver these new features in products, coupled with other desirable properties such as low thermal expansion and optimal melt-flow that enables filling of complex parts. This manuscript details the development of new PC/ABS blends based on novel filler technology to deliver these market needs.