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

SCREW DESIGN CONSIDERATIONS FOR BIOBASED POLYMERS

Edward Steward, May 2008

The family of biobased polymers is ever growing in number and in popularity and the extruder/screw manufacturing businesses need to keep abreast of the machinery requirements of these polymers to insure that efficient processing is understood. This paper will look at the extrusion parameters and logic that are important to determining the most efficient screw designs and extrusion operating conditions for processing biopolymers. Vented and non-vented operation will be discussed. PLA data will be used as the basis for the conclusions.

THE USE OF ANTISTATIC AGENTS IN INTERNAL LAYERS OF MULTILAYER FILM STRUCTURES

David J. Walsh , Andrew Smillie , Christina Troeltzsch, May 2008

When Entira™ antistatic agents are used in the internal layer of a multilayer film structure the measured surface resistivity will be higher than when it is used in a surface layer. However the static decay times of the film are unchanged and the film retains its antistatic properties as evidenced by for example its resistance to dust pick up. This is an attractive solution in applications which are hyper-sensitive to risk of contamination since the contact layer can be a pure polyolefin.

THE USE OF ANTISTATIC AGENTS IN INTERNAL LAYERS OF MULTILAYER FILM STRUCTURES

David J. Walsh , Andrew Smillie , Christina Troeltzsch, May 2008

When Entira antistatic agents are used in the internal layer of a multilayer film structure, the measured surface resistivity will be higher than when it is used in a surface layer. However the static decay times of the film are unchanged, and the film retains its antistatic properties as evidenced by, for example, its resistance to dust pick up. This is an attractive solution in applications which are hyper-sensitive to risk of contamination since the contact layer can be a pure polyolefin.

POLYOXYMETHYLENE (POM) FOR ROTATIONAL MOLDING APPLICATIONS

Michael J. Gehrig, May 2008

Polyoxymethylene (POM) commonlyreferred to as acetal or polyacetal wascommercially introduced to the rotationalmolding markets in 2006. This presentation willprovide an introduction to POM that includesfeatures and properties processing guidelines andmarket applications.

THE EFFECTS OF PLGA COMPOSITION ON MORPHOLOGY AND MECHANICAL PROPERTIES OF BIOSCAFFOLDS

Linus Leung , Christine Chan , Soo Baek , Hani Naguib, May 2008

In this study bioscaffolds using poly (DL-lactide-co-glycolide) acid (PLGA) were studied. The gas foaming/ salt leaching technique in a batch setup was employed. The effects of material composition on the morphology and mechanical properties using this process were investigated. Characterization of scaffolds fabricated with PLGA 85/15 and 50/50 showed that lower relative density was achieved with an increasing poly(DL-lactide) acid content. Furthermore the effect of PLGA composition on modulus of the scaffolds was minor.

A COMPARISON OF BLOWN AND CAST HDPE FILM USING EXPANDABLE MICROSPHERE TECHNOLOGY

Sarah Schirmer , Christopher Thellen , Jo Ann Ratto, May 2008

High-density polyethylene (HDPE) blown and cast films were extruded with 0.5% 0.75% and 1.0% microspheres by weight comparing two different grades of microspheres using two different temperature profiles. All films were analyzed for oxygen and water vapor barrier as well as tensile properties. The blown film samples demonstrated significantly lower oxygen and water vapor permeation rates than the cast films as well as a higher Young’s modulus; however the cast films showed a higher toughness.

NOVEL SINGLE SCREW ELONGATIONAL COMPOUNDER FOR THERMALLY SENSITVE MATERIALS

Keith Luker, May 2008

At Antec 2007 a new single screw compounder(SSE) was introduced. The mixing elements along thescrew had axial flutes with elongational mixing (AFEM).In some process conditions such a mixer can also haveupstream axial flow with additional elongational anddistributive mixing. The Recirculator [1] hereafterAFEM demonstrated effective compounding ofimmiscible blends to 1 micron and particulate mixing tothe 500 nanometer scale. [2]

ACETAL ALLOYS FOR ROTATIONAL MOLDING APPLICATIONS

Michael J. Gehrig, May 2008

In 2007 two new acetal thermoplastic alloyshave been developed for rotational moldingapplications. These alloys provide the molderwith exceptional market opportunities as theyoffer the combined properties of the host andadditive resins. These materials are processorfriendly and moderately priced. This presentationwill provide an introduction to the new alloys processing guidelines and market opportunities.

ACETAL ALLOYS FOR ROTATIONAL MOLDING APPLICATIONS

Michael J. Gehrig, May 2008

In 2007, two new acetal thermoplastic alloys have been developed for rotational molding applications. These alloys provide the molder with exceptional market opportunities as they offer the combined properties of the host and additive resins. These materials are processor friendly and moderately priced. This presentation will provide an introduction to the new alloys, processing guidelines, and market opportunities.

DEVELOPMENT OF ION CONDUCTIVE POLYMER GELS WITH ADDITION OF IONIC LIQUID

Jiao Guo , Kyonsuku Min, May 2008

A new ion gel system consisting ofpolymethylmethacrylate (PMMA) and ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate(BMIPF?ÿ6) was developed by in-situ free radical?ÿpolymerization in the presence of crosslinking agent. Iongels were prepared with respect to different weight ratioof MMA to IL. The ion gel films were transparent selfstandingand flexible and exhibit a high ambient ionicconductivity. Thermal analysis and the interactionbetween PMMA matrix and IL were also investigated.

THIN NANOCELLULAR PLASTIC SHEET WITH PATTERNED FOAMING

Junya Kojima , Tomoyuki Takada , Yoshiharu Nishikori , Hiroyasu Tachibana , Fumio Jinno, May 2008

A thin nanocellular plastic sheet with a designed foaming pattern which is difficult to prepare using the supercritical CO2 foaming method has been developed using a photochemical foaming technology. For this purpose a new acrylic polymer with t-butyl ester groups that produce the foaming gas by chemical reaction is introduced. With this technology foaming of the plastic can be controlled by ultraviolet irradiation and heating. A large-format nanocellular sheet can be manufactured in a continuous process.

THIN NANOCELLULAR PLASTIC SHEET WITH PATTERERNED FOAMING

Junya Kojima , Tomoyuki Takada , Yoshiharu Nishikori , Hiroyasu Tachibana , Fumio Jinno, May 2008

A thin nanocellular plastic sheet with a designed foaming pattern, which is difficult to prepare using the supercritical CO2 foaming method, has been developed using a photochemical foaming technology. For this purpose, a new acrylic polymer with t-butyl ester groups that produce the foaming gas by chemical reaction is introduced. With this technology, foaming of the plastic can be controlled by ultraviolet irradiation and heating. A large-format nanocellular sheet can be manufactured in a continuous process.

AN ASSESSMENT ON OPTICAL QUALITY OF MOLDED BACKLITE COMPARED TO THERMOFORMED BACKLITE

Chengtao Li, May 2008

Injection molding and thermoforming are common processes in both plastics and automotive industry. A preliminary study was made comparing the quality of large complex transparent and optical rear window parts (automotive backlite prototypes) produced from an injection-compression molding process and a vacuuming thermoforming process. Optical quality on the parts was evaluated in terms of optical clarity (only the haze is discussed in this paper) optical distortion birefringence and stress shape and dimension. It was demonstrated that overall the molded backlites had much better optical quality than the vacuum thermoformed backlites based on the same shape and dimensions. Process recommendation quality control and improvement for large complex optical application of plastic products such as automotive polycarbonate (PC) glazing are given during the discussion.

AN ASSESSMENT ON OPTICAL QUALITY OF MOLDED BACKLITE COMPARED

Chengtao Li, May 2008

Injection molding and thermoforming are commonprocesses in both plastics and automotive industry. Apreliminary study was made comparing the quality oflarge, complex, transparent, and optical rear window parts(automotive backlite prototypes) produced from aninjection-compression molding process and a vacuumingthermoforming process. Optical quality on the parts wasevaluated in terms of optical clarity (only the haze isdiscussed in this paper), optical distortion, birefringenceand stress, shape and dimension. It was demonstrated thatoverall the molded backlites had much better opticalquality than the vacuum thermoformed backlites based onthe same shape and dimensions. Process recommendation,quality control and improvement for large complex opticalapplication of plastic products, such as automotivepolycarbonate (PC) glazing, are given during thediscussion.

MELT FRACTURE OF LINEAR POLYETHYLENES: MOLECULAR STRUCTURE AND DIE GEOMETRY EFFECTS

Mahmoud Ansari , Savvas G. Hatzikiriakos, May 2008

The melt fracture polymer extrusion instabilities are studied primarily as functions of the geometrical details of die (cylindrical slit and annular) and molecular structure of polymers. Experimental observations concerning the flow curves the critical wall shear/extensional stresses for the onset of the instabilities and the effects of geometry and operating conditions are presented for two linear polyethylenes mainly highdensity polyethylenes (HDPEs). It is found that sharkskin and other melt fracture phenomena are sensitive to details of the molecular weight distribution (MWD). It is also found that critical conditions for the onset of various melt fracture phenomena depend significantly on the type of die used for their study. For example sharkskin melt fracture in slit and capillary extrusion was obtained at much smaller critical shear stress values compared to those found in annular extrusion. Such observations explain the lack of correlation between experimental results from the laboratory and the full scale process.

MELT FRACTURE OF LINEAR POLYETHYLENES: MOLECULAR STRUCTURE AND DIE GEOMETRY EFFECTS

Mahmoud Ansari , Savvas G. Hatzikiriakos, May 2008

The melt fracture polymer extrusion instabilities are studied primarily as functions of the geometrical details of die (cylindrical, slit and annular) and molecular structure of polymers. Experimental observations concerning the flow curves, the critical wall shear/extensional stresses for the onset of the instabilities and the effects of geometry, and operating conditions are presented for two linear polyethylenes, mainly highdensity polyethylenes (HDPEs). It is found that sharkskin and other melt fracture phenomena are sensitive to details of the molecular weight distribution (MWD). It is also found that critical conditions for the onset of various melt fracture phenomena depend significantly on the type of die used for their study. For example, sharkskin melt fracture in slit and capillary extrusion was obtained at much smaller critical shear stress values compared to those found in annular extrusion. Such observations explain the lack of correlation between experimental results from the laboratory and the full scale process.

EXTRUSION-ASSISTED DIRECT-FOAMING ROTATIONAL MOLDING PROCESS

Kimberly Christian , Emad Abdalla , Gregory Eberle , Remon Pop-Iliev, May 2008

This paper focuses on the evolution and experimental validation of the novel patent-pending Extrusion-Assisted Rotational Foam Molding (EARFM) process intended for the fabrication of high quality integral-skin fine-celled foamed-core polyolefin moldings. The process innovatively conjoins the traditional rotational foam molding technology with extrusion melt compounding in a deliberate attempt to reduce the principal intrinsic disadvantages associated with rotational foam molding i.e. the energy intensive and very lengthy processing cycles. A lab-scale custom-made heavy-duty experimental setup along with three mold shape variations (cylindrical flat plate and container-like) have been designed and built. It was used for conducting a comparative experimental process validation by using all three mold designs for processing integral-skin foamed core polyethylene (PE) parts. The process control optimization included resin formulation optimization direct foaming concept implementation for process simplification and mold venting system re-design. The thereby modified process resulted in even shorter processing cycle times lower energy consumption and improved foam morphologies.

EXTRUSION-ASSISTED DIRECT-FOAMING ROTATIONAL MOLDING PROCESS

Kimberly Christian , Emad Abdalla , Gregory Eberle , Remon Pop-Iliev, May 2008

This paper focuses on the evolution and experimental validation of the novel patent-pending Extrusion-Assisted Rotational Foam Molding (EARFM) process intended for the fabrication of high quality integral-skin fine-celled foamed-core polyolefin moldings. The process innovatively conjoins the traditional rotational foam molding technology with extrusion melt compounding in a deliberate attempt to reduce the principal intrinsic disadvantages associated with rotational foam molding, i.e., the energy intensive and very lengthy processing cycles. A lab-scale custom-made heavy-duty experimental setup along with three mold shape variations (cylindrical, flat plate and container-like) have been designed and built. It was used for conducting a comparative experimental process validation by using all three mold designs for processing integral-skin foamed core polyethylene (PE) parts. The process control optimization included resin formulation optimization, direct foaming concept implementation for process simplification, and mold venting system re-design. The thereby modified process resulted in even shorter processing cycle times, lower energy consumption, and improved foam morphologies.

MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF RIGID POLYURETHANE FOAMS

Nora Catalina Restrepo-Zapata , E. Alexander Ossa H. , Felipe Cano Mejia, May 2008

Cellular materials are formed by solid cells in a gaseous core. They exhibit good strength to mass ratio and they are used as insulators and as a core in sandwich composite manufacture. This work describes an extensive study on the structure and physical-mechanical properties of rigid polyurethane (PU) foams. The effect of composition and processing conditions on the mechanical properties were studied. Morphology specific strength and density were evaluated to determine the optimal levels of processing for a required application. Foam morphology was characterized using stereoscopy and optical microscopy. A basic mechanical property as compression strength was measured in the plateau zone.

MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF RIGID POLYURETHANE FOAMS

Nora Catalina Restrepo-Zapata , E. Alexander Ossa H. , Felipe Cano Mejia, May 2008

Cellular materials are formed by solid cells in a gaseous core. They exhibit good strength to mass ratio and they are used as insulators and as a core in sandwich composite manufacture. This work describes an extensive study on the structure and physical-mechanical properties of rigid polyurethane (PU) foams. The effect of composition and processing conditions on the mechanical properties were studied. Morphology, specific strength and density were evaluated to determine the optimal levels of processing for a required application. Foam morphology was characterized using stereoscopy and optical microscopy. A basic mechanical property as compression strength was measured in the plateau zone.