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

Opportunities and Development of Bio-Based Materials for SMC (Sheet Molding Compound)

Dwight Rust, September 2008

Current and future changes in the automotive industry present an increased opportunity for thermosets. Bio-based materials in SMC present an opportunity to help automotive manufacturers in the US to meet the 2020 Freedom Car weight and 14.9 km/L (35 mpg) CAFÉ requirements as currently mandated by the federal government. Developments in the industrial bio-technology sector are also leading to knowledge to provide opportunities to use bio-based materials to provide solutions using SMC to lower costs and weight. The National Composite Center is leading collaborative efforts in the development of biobased resins fillers and reinforcements. The result of these collaborations in both biobased materials and the interface of nano technology are presented. The opportunities exist for the development of biobased materials to produce a lighter weight SMC.

Characterisation of the Direct-SMC (D-SMC) Process

Tobias Potyra, September 2008

It is a well established fact that Conventional Sheet Molding Compound (SMC) manufacturer/ SMC parts manufacturer uses steps such as resin mixing blending sheet manufacture rolling or festooning maturation & transportation before actual molding. Often times the sheet manufacturing and the molding operations are in two different locations. While it offers some flexibility in isolating sheet manufacturing from molding it also leads to challenges in planning logistics storage and maintaining quality through out the process steps. These factors are some motivation for the industry to develop a process that combines “In-line compounding” with molding operations. The potential for cost savings is large but raw material properties at each step needs calibration and control.

Advanced Composite Class A Closures - Production Ready or Production Proven?

Martin Starkey, September 2008

Over the last 7 years Gurit has continued to develop advanced composite materials to address the needs of the niche automotive market with a proven track record as a innovative Tier 2 supplier. In 2006 the decision was taken to strengthen this position with the investment and move to a Tier 1 role. Through close collaboration with Aston Martin Gurit successfully introduced its Class A composite body system CBS 96 onto their premium vehicle DBS establishing our first 20000 sq. ft. advanced composite manufacturing facility. This presentation aims to establish the production route for these OEM quality components and the evolution of the manufacturing processes over these critical 18 months. The presentation will detail how cycle times have evolved through on line and off-line processes the analysis of Quality trends including 'Right First Time' and reject causes and finally to draw trends from the analysis and establish the future opportunities for Gurit's range of innovative advanced composites in this market.

Theoretical Simulation of Cure-Induced Deformations of Composite Car Body Panels

Medhi Kiasat, Hamid Mostofi, September 2008

This paper is dedicated to a realistic prediction of the deformations of advanced composite car body panels during curing. In the present work a cure-dependent viscoelastic model is used for the resin to establish the cure-dependent orthotropic viscoelastic properties of a unidirectional glass/polyester ply via micromechanical fiber/matrix models. Also the anisotropic curing shrinkage of the unidirectional ply is obtained from unit cell calculations by inserting the measured curing shrinkage of the resin. These evaluated properties are used in the finite element model of the laminate which is verified by an experimental study of the deformations of square cross-ply laminates. As an application of this effort different parts of a car body like the roof and the trunk are modeled considering various symmetric and asymmetric stacking sequences for them. Both open-mold and closed-mold curing conditions are simulated. It is concluded that the curing stresses have a viscoelastic nature which may not be modeled by using the available elastic models. The curing stresses induce significant deformations in the composite panels which cannot be avoided even if symmetric laminates are cured in closed molds. The initial curvatures and bends of the panel in the mold affect its final deformed shape.

Damage Repair of Low Velocity Impacted Woven Thermoplastic Composites

Uday Sharma, September 2008

In this study the low velocity impact behavior of three layer thermoplastic laminates consisting of woven glass fiber and polypropylene has been investigated. Panels with dimensions of 100 x 100 mm were subjected to impact energies between 4 and 16 Joules using an instrumented dropping weight impact tower. Results suggested that the woven thermoplastic composites exhibit good energy absorbing properties with approximately 73% of the impact energy being absorbed after a 16 Joule impact. The impact damaged plates were cut into 100 x20 mm coupons and tested under four point bending (4PB). The result showed a reduction in flexural strength of approximately 27% after a 16 Joule impact. Following this a simple compression molding damage repair process was applied to the low velocity impact damaged laminates. Repaired samples were tested under 4PB and results showed a significant recovery of flexural strength to approximately 98 % of the undamaged strength. These results suggest that a simple one step process could be used to successfully repair impact damaged thermoplastic composites.

Computer Predictions of the Behavior of Fiber-Reinforced Composites During Molding

Alejandro Londoño-Hurtado, September 2008

Mechanistic Computer simulations of flexible fiber suspensions are developed to study the molding of fiber reinforced composites. Fibers are modeled as chains or rigid beads connected by springs. Parameters such as fiber concentration fiber length and stiffness can be modified to match specific processing conditions. Simulation results include final fiber orientations and fiber distributions within a molded part. Specific applications for this type of simulations are compression molding of Sheet Molding Compound where defects such as Fiber-Jamming and Fiber-Matrix separations are difficult to predict and still not well understood.

Techniques and Results for Fiber Length Distribution Determination as a Function of Thickness in Long Fiber Reinforced Injection Molded Thermoplastics

Vlastimil Kunc, September 2008

A novel measurement technique was developed to obtain unbiased fiber length distribution (FLD) measurements at specified locations in the thickness of the sample. This technique relies on elastic energy stored in long fiber thermoplastics (LFT) which is released during partially constrained burn-off. This release results in an increase of thickness dimension of the sample and partial disentanglement allowing sample selection and subsequent filament separation. Quantitative FLD results and the measurement technique are discussed in detail. The FLD in long fiber reinforced injection molded thermoplastics is shown to vary as a function of thickness.

Polymer Clay Nanocomposites of Linear Low Density Polyethylene (LLDPE) and Polyoxymethylene (POM)

M. Shahlari, P. L. Roberts and S. Lee, May 2008

Polymer-clay nanocomposites involving a blend of two otherwise incompatible thermoplastic polymers were prepared and investigated for the effects of adding organically modified clay. Linear low density polyethylene (LLDPE) and polyoxymethylene (POM) at several composition ratios (70/30, 50/50, 30/70) were melt mixed with 5% Cloisite 15A and 5% Cloisite 30B, respectively. Their blends were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The LLDPE/POM (70/30) blend nanocomposites incorporating Cloisite 15A showed co-continuous morphology according to the SEM images, while those with Cloisite 30B showed some limited levels of compatibility. Further, Cloisite 15A improved the melting temperature of LLDPE and POM while Cloisite 30B had no significant effect on the LLDPE melting temperature but increased the melting temperature of POM. As for the LLDPE/POM (30/70) blends, Cloisite 15A made the two originally incompatible phases indistinguishable, while the blends containing Cloisite 30B showed a significant decrease in the domain sizes. However, the blend samples without organoclay incorporation did not exhibit any compatibility and the dispersed phase was totally segregated. TGA results showed that addition of clay decreased POM degradation temperature but there was no significant changes detected in PE’s. The clay’s compatibility with one or both polymers is shown to make a significant difference in the blend morphology and compatibilization mechanisms of the polymer-clay nanocomposites, which are phenomenologically explained in this paper.

THE ACCURACY OF STANDARD DRAG FLOW AND PRESSURE GRADIENT CALCULATIONS FOR SINGLE-SCREW EXTRUDERS

Mark A. Spalding , Greg A. Campbell, May 2008

Simulation and design of single-screw extruder screws using the standard pseudo-Newtonian Tadmor method is known to deviate from measured performance yet many screw designers have used the method successfully for many years. The research provided here shows the conditions when the method can be used for design work and when it deviates to an unacceptable level.

MULTILAYER RHEOLOGY EFFECTS IN COEXTRUDED STRUCTURE DESIGN

Joseph Dooley , Chunxia Costeux , Robert Wrisley , Andrew Schlader, May 2008

Multilayer coextrusion is a process in which two or more polymers are extruded and joined together in a feedblock or die to form a single structure with multiple layers. This paper will discuss techniques for measuring experimental rheology data for monolayer and multilayer structures. These data will then be used to show the effects of multilayer rheology in the design of coextruded structures.

THE EFFECTS OF RUNNING DIFFERENT BARREL TEMPERATURE PROFILES FOR VARIOUS RESINS

Walter S. Smith , Luke A. Miller , Jason Willis , Timothy W. Womer, May 2008

Differences in solids conveying screw pressure profile generation output motor energy required will vary between resins barrel temperature profiles and resin preheat temperatures on a single stage low compression barrier screw design.

THE DIFFERENT USES OF THE MELT FLOW INDEX EQUIPMENT

Rabeh H. Elleithy, May 2008

The Melt Flow Index (MFI) of a polymer could be measured using MFI equipment and following ASTM D1238. Although MFI is a single point it is the most known test that uses MFI equipment. However MFI equipment could yield more information about the polymer. Principally by changing the heating temperature the dwell time and the load a whole set of information could be obtained from the MFI equipment. This paper sheds some light on some of the possible information that could be gained from MFI equipment by changing temperature time and load.

THE DIFFERENT USES OF THE MELT FLOW INDEX EQUIPMENT

Rabeh H. Elleithy, May 2008

The Melt Flow Index (MFI) of a polymer could be measured using MFI equipment and following ASTM D1238. Although, MFI is a single point, it is the most known test that uses MFI equipment. However, MFI equipment could yield more information about the polymer. Principally, by changing the heating temperature, the dwell time, and the load a whole set of information could be obtained from the MFI equipment. This paper sheds some light on some of the possible information that could be gained from MFI equipment by changing temperature, time, and load.

THE FUTURE OF THE PLASTICS INDUSTRY: DECLINE OR GROWTH?

Roger F. Jones, May 2008

In 2006-2007 General Electric decided to divest its plastics operations as insufficiently profitable. Since GE has been a pioneer in the plastics industry for close to a century one has to ask ƒ??just what does the future hold for the rest of us?ƒ? Will plastics continue to growth faster than the overall economy or is this now all in the past? This paper will examine the question from both a national and a global view.

WATER AND ION TRANSPORT THROUGH SULFONATED STYRENIC PENTABLOCK COPOLYMER MEMBRANES FOR REVERSE OSMOSIS APPLICATIONS

Geoffrey M. Geise , B. D. Freeman , D. R. Paul, May 2008

Membrane-based desalination technologies such as reverse osmosis are becoming more widely used as global water shortage increases. There is a need to develop improved membrane materials for use in reverse osmosis. One such membrane a sulfonated pentablock copolymer is evaluated here for its water and salt transport properties. The effects of block molecular weight sulfonation fraction and solution-casting technique have been studied in terms of pure water and sodium chloride permeability.

WATER AND ION TRANSPORT THROUGH SULFONATED STYRENIC PENTABLOCK COPOLYMER MEMBRANES FOR REVERSE OSMOSIS APPLICATIONS

Geoffrey M. Geise , B. D. Freeman , D. R. Paul, May 2008

Membrane-based desalination technologies such as reverse osmosis are becoming more widely used as global water shortage increases. There is a need to develop improved membrane materials for use in reverse osmosis. One such membrane, a sulfonated pentablock copolymer is evaluated here for its water and salt transport properties. The effects of block molecular weight, sulfonation fraction, and solution-casting technique have been studied in terms of pure water and sodium chloride permeability.

IMPROVED WEATHERING PERFORMANCE IN FLAME RESISTANT PC/ABS BLENDS VIA ADDITION OF TAILORED SILICONE COPOLYMERS

Srinivas Siripurapu , Todd Loehr, May 2008

Flame resistant (FR) PC/ABS blends are commonly used as material of choice for portable computer housings and entertainment consoles. Increased demand for aesthetics and design freedom has resulted in need for improved weathering performance on exposure to indirect ultraviolet (UV) radiation. New flame retardant polycarbonate blends using tailored silicone copolymers fill the gap with providing flame resistance at thin gages without compromising on this weathering requirement.

IMPROVED WEATHERING PERFORMANCE IN FLAME RESISTANT PC/ABS BLENDS VIA ADDITION OF TAILORED SILICONE COPOLYMERS

Srinivas Siripurapu , Todd Loehr, May 2008

DESIGN OF BIORESORBABLE SCAFFOLDS FOR TISSUE GROWTH

Vincent M. DiTaranto , Aldo Crugnola , Matthew Mandeville, May 2008

Scaffolds were designed for the purpose of growing rat osteosarcoma cells using the compression molding method. The material used in the scaffold was a mixture of polycaprolactone hydroxyapatite and glycerin. The porosity of the scaffold was obtained by using salt and subsequent leaching with distilled water. Salt retention after soaking was addressed by using ultrasonic leaching.Three major factors in the design of a scaffold: porosity interconnectivity of the pores and distribution of the materials were achieved.

LASER WELDING OF TRANSPARENT PLASTICS BY MEANS OF THE INTERMEDIATE FILM METHOD

Walter Michaeli , Wolf-Martin Hoffmann , Edmund Haberstroh, May 2008

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.