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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Recycling

Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.

Trends & Challenges for Start-Up & Emerging Companies in the Clean-Technology Marketplace

Eric Koester, March 2008

The years 2006 and 2007 saw popular culture embrace issues such as global warming, alternative energy production, biofuels, hybrid transportation, and carbon credits. Clean Technology became the fastest growing investment sector and produced some of the most-watched initial public offerings of the recent past. While this new 'fame' has led to an increase in new companies and initiatives, investment dollars, state and federal legislation, and media coverage, it has also led to concerns that the marketplace is a bubble without strong fundamentals to drive the marketplace. Certain investment funds have set up new funds designed to purchase failed and distressed cleantechnology companies. What is the current status of the clean-technology marketplace? What fundamentals exist for the companies that are succeeding and those that fail? Where are the investment dollars and how can companies take advantage of the current marketplace? While some may question aspects of the clean technology revolution, it is without question that a fundamental shift in our consciousness and our culture are occurring -- that has led to unique opportunities and challenges for tomorrow's leaders in clean-technology markets.

Using Recycled Polyethylene: Avoiding the Pitfalls

Frits van der Klooster & Chris Ernst, March 2008

Advanced Blending Technologies has developed a software program that creates low cost optimized blends from wide-/off-spec and/or recycled Polyethylene streams of material, by providing blend formulations based on up to seven selectable material properties. The resulting blends are prioritized by least cost and eliminate the need for costly “Trial and Error” experimenting with blends. Combined with rapid testing of incoming material streams, the OptiMISER® system has successfully been used to convert 100% virgin material processors to 100% recycled usage, at substantial bottom line savings. The OptiMISER system provides the materials engineering needed to maintain production efficiency and insure product quality. Using recycled or wide-/off-spec PE usually results in decreased manufacturing efficiencies, increased scrap and worse; decreased end product quality. This paper discusses a systematic approach which allows the use of up to 100% recycled and/or wide-/off-spec materials while maintaining or even increasing manufacturing efficiencies, reducing process scrap, insuring a consistent end quality product, and significantly reducing overall finished product costs.

The Litterability of Plastic Bags: Key Design Criteria

K.Verghese, RMIT University Centre for Design , M.Jollands & M.Allan , RMIT University School of Civil, Environmental and Chemical Engineering, March 2008

Single use plastic bags are used by the billion in supermarkets, fast food outlets and retail stores because of their excellent fitness for use, resource efficiency and cheap price. They come in many varied shapes, sizes and materials. Because of their light-weight nature they are only a tiny fraction of the tonnage of plastic used in the packaging industry, yet they make a major contribution to litter, thanks to their large surface area and lack of biodegradability. In 2006 the Australian Government Department of Environment and Heritage initiated and funded, courtesy of the Natural Heritage Trust, a study to investigate the effect of bag design on litterability. This paper draws on report materials from the study that are the intellectual property of the Commonwealth. The paper presents a review of previous studies on plastic bags, a review of international plastic bag regulations, as well as the results of an assessment of the environmental impact of bag design using a streamlined life cycle assessment and the litterability of bag design using equipment including wind tunnels. The paper concludes with recommendations for bag design to maintain resource efficiency while reducing litterability.

The Use of Peroxide Masterbatches in the Processing of Regrind and Post Consumer Waste

Marty Paisner, March 2008

To be both green and profitable, many plastic manufacturing processes need to reprocess scrap into useful, saleable products. By its very nature the regrind derived from scrap is usually heterogeneous particularly by way of its melt properties. The proper use of peroxide masterbatches can transform regrind, and also post consumer waste, into a useful raw material stream where not only the melt properties are homogenous, but other desirable properties are developed, resulting in high quality products. This paper shows the chemistry behind peroxide‐induced modifications of polypropylene and polyethylene, the increased melt flow rate by using peroxides in reaction extrusion, the advantages of using the peroxide additive in concentrate form, and a method for increasing the properties of commingled polypropylene and polyethylene.

Applications & Markets for Renewable Resource Based Sheet Molding Compound

Rob Seats, September 2007

Unsaturated polyester resins based on renewable resource raw materials (soy and corn) have been commercially available since the late 1990s. These resins have successfully been formulated into sheet molding compound and are compression molded into parts used by the John Deere Corporation to manufacture farm machinery. This paper will discuss the economics and environmental effects of using renewable resource based composites describe the current applications where the technology is being used and consider the future of bio based technology in the composites industry.

Development & Thermo-Physical Properties of Bio-Based Polymer / Clay Nanocomposites

Mahmoodul Haq, September 2007

Bio-based resin systems obtained as blends of functionalized vegetable oils and petroleum based resins have been found to increase toughness of petroleum based resins and improve their environmental friendliness. Nevertheless this improvement in toughness generally compromises the stiffness of the resin system. Nano-scale layered silicate (nano-clay) polymer nanocomposites exhibit enhanced mechanical and physical properties at relatively low weight fractions of inclusions. The reported study shows that proper stiffness – toughness balance along with enhancement in many other physical properties can be obtained by incorporating nano-scale layered silicates in bio-blended polymers. Polymer nanocomposites with varying clay contents and varying bio-blend (epoxidized soya bean oil) in unsaturated polyester resins were manufactured. Tensile properties and moisture absorption properties were studied. Fracture surface morphologies and characterization of nanocomposites were performed using electron microscopy. The resulting bio-blended polymer nanocomposites exhibit promising results for use in structural applications.

Renewable Bio-Composites for Automotive Applications

Angela Harris, September 2007

PowerPoint Presentation at ACCE 2007.

Effect of Additives on the Structure and Properties of Wheat Straw-Polypropylene Composites

Leonardo Simon, September 2007

Natural fibers from agricultural activities have been emerged as alternative fillers in the thermoplastic industry. Crops such as wheat straw are renewable and low cost materials that combined with thermoplastics such as polypropylene provide engineering products with unique characteristics. Due to the wide range of thermoplastics and potential agricultural fillers the influence of additives in the systems is one of the points yet to be determined for different combinations of matrix and filler. In this study composites containing 30 wt-% of wheat straw (WS) fibers and polypropylene (PP) were prepared in a batch mixer. The individual effects of two coupling agents and a lubricant in the composites were investigated. Scanning electron microscopy (SEM) was used to examine the morphology of wheat straw particles and composites. The water absorption behavior and mechanical properties were assessed for those composites prepared. Results showed a strong interaction between filler and matrix in compositions containing coupling agent; differences were observed in the performance of the two coupling agents tested. Furthermore the lubricant used contributed to the water absorption of the composites.

Evaluating Extrusion Compression Molding for Imparting Better Surface Finish in Long Fiber Thermoplastics Using In-Mold Film Technology

Pritam Das, September 2007

Automotive applications of compression molded products with a thermoplastic matrix have been growing rapidly within the last few years as demonstrated by increased use in applications including front-ends bumper beams dashboards and under body shields. Long fiber thermoplastics (LFTs) have received much attention due to their processability by conventional technologies. However applications of LFT materials have been limited in external body parts that require a good surface finish. Painting LFT parts is rare and requires considerable equipment investment. Further painting is often associated with environmental concerns such as Volatile Organic Compounds (VOCs) and high energy consumption. This paper innovates the process of extrusion compression molding for long fiber thermoplastic parts by placing a film (with a thermoplastic olefin backing) in-mold that melt bonds to the LFT material. This results in a compression molded LFT part that has the nice surface finish required for exterior applications. In order to evaluate the process variables potentially contributing to the surface quality are identified and analyzed. A Design of Experiments is carried out to investigate thoroughly yet economically the effect of four process variables. Gloss chip resistance and adhesion of film to substrate are tested according to ASTM standards. These test results are used to evaluate the effect of the processing variables considered and to establish optimum operating parameters.

Hybrid Bio-Based Composites from Nano-Reinforced Bio-Petro Polymer Blends & Natural Fibers

Rigoberto Burgueño, September 2007

Natural fiber composites or biocomposites have recently gained much attention due to their low cost environmental friendliness and their potential to compete with glass-fiber composites. However the use of all-natural resins is limited due to performance concern and hence the blending bio-resins in petroleum resins has gained importance due to their improved toughness and environmental friendliness. Nevertheless addition of bio-resins generally compromises stiffness barrier and thermal properties. The enhancement of polymer stiffness and barrier properties with small concentrations of layered silicates is well established. With this context the paper presents the development and thermo-physical characterization of a hybrid composite material with increased environmental friendliness that can retain stiffness without sacrificing toughness barrier and thermal properties. Hybrid biocomposites were made from bio-based resins (blends of unsaturated polyester and epoxidized soya bean oil) reinforced with organo-nanoclays and natural fibers (unprocessed industrial hemp). Results show that an optimum material design that maximizes the synergy of the constituents is possible and provide an initial benchmark in identifying such balance.

Investigation of Sheet Molding Compound Fabricated from Soy-Based & Petroleum-Based Resins

Libby Berger, September 2007

Plaques fabricated from sheet molding compound (SMC) with soy-based resins in both glass fiber-reinforced and carbon fiber-reinforced versions are compared with the equivalent SMC with petroleum-based resins. Since soy-based resins are less sensitive to the price of petroleum than petroleum-based resins these materials represent potential cost savings to the automotive industry if the price of petroleum continues to increase as well as providing opportunities to decrease overall carbon dioxide emissions. Soy beans are also a renewable resource. Material thermal properties including dynamic mechanical analysis (DMA) and coefficient of linear thermal expansion (CLTE) are evaluated as are mechanical properties including tensile and compressive characterizations. The effect of humidity aging was evaluated by moisture absorption as well as residual tensile and compressive properties. For as-received properties the glass-reinforced version of the soy-based material is found to be similar in performance to the petroleum-based material. However the carbon-reinforced soy resin material has lower mechanical properties than the petroleum-based SMC probably due to a lack of fiber-matrix adhesion. In humidity aging the petroleum based materials absorbed less moisture than the soy-based although the relative property loss caused by humidity aging was similar for the petroleum-based and the soy-based materials.

Nano-Fibrillated High-Modulus Ductile (HMD) Technology in Environmentally Sustainable Xenoy iQ* Resins

Vikram Gopal, September 2007

Recently General Electric Plastics launched a series of High Modulus Ductile (HMD) products as an expansion to the Xenoy product line. In these HMD products a highly fibrillated nano network is combined with state of the art mineral filler technology allowing for retention of impact and tensile properties whilst increasing the modulus of molded articles. We have been successfully able to incorporate this technology in the Xenoy* (PC/PBT and PC/PET) resin which has resulted in superior chemical resistance low CTE excellent tensile strength fatigue and low temperature ductility. We will present a case study where HMD technology was combined with our environmentally sustainable low carbon footprint Xenoy iQ* resin offering excellent part performance lighter weight and increased first pass yield during processing.

Recent Developments in UV Stable SMC Technology

Rob Seats, September 2007

The desire for weatherable sheet molding compound for use in a wide range of applications is growing due to the potential of eliminating paint or coatings on the molded article. The elimination of paint or protective coatings can result in significant cost savings and an improved environmental profile for the article. These savings can be realized if existing coating facilities are at capacity or if a green field investment is being considered. Weatherable sheet molding compound (SMC) technology has been previously available but has been designed for specific applications. Transfer of this technology into other application areas has resulted in some performance issues. This paper discusses new developments in weatherable sheet molding compound technology that allow its use in a wider range of application areas.

A Study of Foaming Agent in Bio-Based Polymer Foams

Yi-Fan Wu, Chien-Chung Fu, May 2007

In this study, the effect of variety foaming agents in bio-based polymer such as chemical blowing type of AC and BIH, and physical type of microsphere, has been investigated. The basic matrix of bio-based polymer was compounding PLA with native starch and calcium carbonate in twin screw extruder prior to introducing variety foaming agents at low temperature by dynamic rheometer to avoid the degradation of foaming agents.The topology of cross-section of their foams structure by SEM revealed that physical type of microspheres attained much better density but lower porosity than the others.

Advancements in Laser Marking and Engraving Using Integrated, Through-The-Lens Vision

Faycal Benayad-Cherif, May 2007

Laser marking and engraving for the automotive industry poses many challenges to the plastic mold manufacturer. In the past, laser-marking systems have not been intuitive in confirming part identification or part positioning. Inaccurate placement of the mark due to a part misalignment or the engraving of incorrect marking information due to a lack of part identification results in waste parts and reduces product profitability in a highly competitive market.This paper describes the procedure for laser marking using a through-the-lens vision process, Integrated Mark Positioning (IMP), and data compiled comparing marking with and without IMP. Results show that a mark placement accuracy of 0.03 mm with a part placement variation of 4 mm or larger can be achieved. System configuration, operation and benefits of integrated vision are also covered.

Comparison of N2 and CO2 in Extrusion Foaming of Wood-Fiber Composites

G. Guo, G.M. Rizvi, C.B. Park, May 2007

Producing cellular wood-fiber/plastic composite (WPC) with physical blowing agents (PBA) offers unique advantages over chemical blowing agents (CBA). This paper compares the foaming behaviors of two environmentally benign PBAs, namely N2 and CO2, to help understand PBA-based foaming mechanisms in WPC. This understanding will help in making proper choices about PBAs and foam processing parameters.

Improvement of the Mechanical Properties of Soy Protein Isolate Based Plastics

Maria Vlad, Gowrishankar Srinivasan, David Grewell, May 2007

Biodegradable plastics based on soy protein were prepared with glycerol as a plasticizer and compounded with different additives such as: polycaprolactone and zinc stearate as well as heat treated at various temperatures after the injection molding process in order to characterize base material strength and the effect of water absorption. The results indicated that the polycaprolactone and, respectively a medium to high heat treatment enhanced the tensile strength and decreased the water absorption significantly.

Injection-Molding Degradation of Biodegradable Polylactide

Richard Haibach, May 2007

The effects of degradation on the mechanical and aesthetic properties of injection-molded biodegradable polylactide (PLA) parts were studied. Standard tensile test specimens were molded from NatureWorks 3051D injection-molding grade PLA. Barrel residence time, machine nozzle temperature, and shear rate were varied during the injection-molding process. The resulting specimens were analyzed in a tensile testing machine. Tensile strength, tensile modulus and visual inspection were used to characterize the extent of degradation that occurred during each process.

Interaction of HALS and Colorants

Steve Goldstein, May 2007

A series of colorants including yellows, reds, blues and greens have been evaluated when processed with monomeric and oligomeric HALS in PP and HDPE. Comparisons have been done in masstone and tint looking at effects on color shift and strength.

Chemical Recycling of Pet with Solid State Shear Pulverization Technology

Behzad Shirkavand Hadavand, Hossein Hosseini, May 2007

Post-consumer PET (polyethylene terephthalate) bottles have been recycled into film and sheet products ever since the Containers and Packing Recycling Law came into effect in 1997. There has been a growing need, however, for a chemical recycling process. In this process post-consumer PET bottles are recycled into monomers that can be used as feed stocks for the recycled production of PET bottles for beverages. This paper reveals a chemical recycling process using an alkali solution in order to depolymerize PET material in to its monomers (terephthalic acid and ethylene glycol) within a short time. Unlike ther researchers, we did not use the flakes of PET, but used powdered PET produced based on solid state shear pulverization (SSSP) technology to achieve maximum yield (98%) and purity (95%) of the monomers in a short reaction time. The powdered PET has unique physical properties that affect experiment conditions temperature and pressure. The resulting terephthalate salt was treated with sulfuric or hydrochloric acid to yield highly pure terephthalic acid. Results show that the best percentage conversion of PET flakes is 1.5mol/l NaOH for 2 hours in 200 °C and for PET powder 1 .5 mol/l NaOH for 1.5 hours in 150 °C.