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.

Analysis of Silicone Polymers at Trace Levels by Pyrolysis Gas Chromatography/Mass Spectroscopy

Myer Ezrin, Gary Lavigne, May 2002

Silicone polymer release liner surfaces on paper, for self stick stamps and labels, become contaminants in paper recycling. Low print adhesion is one major problem limiting the inclusion of silicone release liners in recycling feed stock. A very sensitive method of analysis of silicone polymer during and after recycling employs pyrolysis GC/MS. The analysis provides a measure of siloxanes, ignoring inorganic silicon compounds such as silicates. The method also distinguishes between linear and branched polysiloxanes by different pyrolysis products. High sensitivity, to ppb, may be possible using single ion monitoring or selected ion data collection of mass spectra.

CAPE-VIT - A Different View of Education in Plastics Design

H. Elmecker, A.M. Brito, A.S. Pouzada, May 2002

Education for the growing needs of the plastics industry is recognized as needing a different approach that will enable a quicker integration of the graduates in the working world. Under the auspices of the EU programme Leonardo da Vinci a group of universities and institutions developed a course programme and structure for preparing engineers with skills for plastics design and processing with a sound awareness of the environmental issues. Specific characteristics of the course are the project driven methodology and the integration of training periods in the industry as from the first year of the four-year long course.

Investigation of Applicability of Two Biodegradable Polymers for Mechanical Applications

Rolf Koster, May 2002

Three types of specimens of a polyester-amide and a poly-hydroxybutyrate have been tensile and tensile-impact tested. These specimens represent different geometric characteristics; one specimen has a cold weld line. The influence of injection molding settings on tensile behavior was in agreement with tensile-impact results. Embrittlement was found for all specimen types and both materials after 20 months of storage. The beneficial effect of annealing on toughness was shown for poly-hydroxybutyrate specimens without weld line.

Characterization of Molecular Weight Degradation of Polyamides by Gel Permeation Chromatography

Anthony R. Cooper, Gibson B. Pinkerton, May 2002

Polyamides are susceptible to attack by environmental pollutants. The surface layer is degraded and the development of a critical thickness of this layer results in a catastrophic loss of mechanical properties. In this work nylon was exposed to nitrogen oxides and the fracture strength was measured. After a period of no change the fracture strength decreased dramatically. Exposed samples were microtomed and the molecular weight distribution of nylon was determined, as a function of depth from the surface, by Gel Permeation Chromatography (GPC). A critical depth for degradation was established beyond which the specimen exhibited unacceptably low fracture strength.

Composite Films of Polypropylene from Post-Consumer Plastics Waste to Substitute Cellulose Paper

Ruth M. Campomanes Santana, Sati Manrich, May 2002

The aim of this work is to obtain composite films of polypropylene (PP) to substitute paper. The plastic component is PP from mineral water bottle (PPb) collected from municipal plastic waste (MPW) and the filler component is CaCO3. Composite films with weight ratio of PPb and CaCO3 (70:30) were prepared. These films were surface treated by corone discharge. Preliminary results have shown a good printability with pencil and pen ink on these films without treating and an improved printability with ink jet after surface treatment. These films were then compared to cellulose paper by physico-chemical characterizations.

Control of State Parameters in Blow Moulding

R. DiRaddo, P. Girard, I. Laroche, May 2002

The blow moulding industry has achieved a good understanding of the process, which has been in large scale operation since the 1960's. Consequently, control of machine settings such as heater band temperatures, die gap position, die and mould temperatures is quite advanced. However, to date, little work has been done to address the control of state parameters describing material behaviour during processing, such as parison weight and temperature distribution. Control of state parameters is essential as material property changes, environmental factors and machine operating drifts can significantly change the dynamic operating point of the machine.

Polymers in Tissue Engineering: Basic Principles, Main Challenges and Characterization Requirements

R.L. Reis, May 2002

This keynote lecture discusses the use of biodegradable polymers as tissue engineering scaffolds. The basic principles of tissue engineering are addressed, going from scaffolds processing to some brief information on biological studies. These topics are introduced in a way that an audience composed by plastic engineers can easily became aware of the importance of the field and understands its complexity, as well as the role of biodegradable polymers on its success.

PVC/Wood Flour Composites Compatibilized with Chlorinated Polyethylene

Virginia O. Guffey, Amiel B. Sabbagh, May 2002

Chlorinated polyethylene (CPE) has been demonstrated to be an effective compatibilizer for dissimilar materials in various mixed-polymer or recycled-polymer systems. In this paper the use of chlorinated polyethylene to compatibilize polymer/natural fiber composites is discussed. Examples of applications in PVC/wood flour composites are given.

Detailed Energy Measurements in Injection Moulding

A.J. Dawson, H.S. Rajamani, R. Collis, L. Owen, D. Owen, P.D. Coates, May 2002

Growing concern for ecological issues, including international standards agreements such as ISO14001, demonstrate a clear requirement to conserve energy for both environmental and cost issues. Energy measurements on injection moulding machines both in the laboratory and in industry demonstrate the potential of process energy measurements in the development of a systematic management approach to the environmental concerns of an organization. The data gathered can also provide useful information to both the processor regarding the performance of the machine in question, and the power companies regarding the specification of supply equipment.Detailed energy measurements during the injection moulding cycle provide data regarding the energy consumption of specific machine components and/or phases of the injection moulding cycle, providing valuable data for machinery manufacturers and processors.

Development of a Heat/Pressure Formable Wood Fiber Thermoplastic Composite from Recycled Paperboard

Tom Mase, Lawrence T. Drzal, Bob Jurek, May 2002

In this paper, an engineered material made from paperboard and powdered polypropylene is examined. A wet, paper process was chosen for converting paperboard waste into an engineered, cost effective composite material. Using a fourdrinier, a 30 inch wide continuous sheet of paper/plastic stock was produced for subsequent thermal molding. Tensile modulus and strength of 6,000 and 50 MPa, respectively, were obtained for a material having just less than 30 percent polypropylene. Additionally, moisture content and water absorption was examined. Testing and failure analysis indicate that increasing the percent of polypropylene will improve the mechanical properties.

Development of Inorganic Composites for Production of Structural Elements

Ioan I. Negulescu, Roger K. Seals, Simioan Petrovan, May 2002

The overall goal of the paper is to develop recycled plastic lumber products with improved mechanical properties using inorganic filler consisting of Louisiana residuals, such as phosphogypsum, in conjunction with recycled plastic resins. Blends have been established and samples have been prepared by mixing polyethylene derived from detergent bottles with inorganic fillers in the inner chamber of a Haake rheometer. Reactive mixtures have been made in the same way using maleic anhydride in addition to polyolefin and inorganic filler. The actual composition of blends has been calculated from thermogravimetric data. Tensile properties have been determined for each composition using both an INSTRON machine and a dynamo-mechanical spectrometer.

The Effect of Aqueous Media on Creep of Recycled Plastics

Jeffrey Exley, Brad Williams, May 2002

There continues to be a need for additional uses of recycled plastics. A significant portion of recycling applications require outdoor exposure including use in aqueous applications. This paper covers the effects of water on the properties of recycled plastics under tensile loads. The paper also covers long term creep effects.

Effect of Multiple Processing Cycles on Post-Consumer Plastics Recycled via Solid-State Shear Pulverization

Klementina Khait, Erin G. Riddick, John M. Torkelson, May 2002

It is well known that reprocessability of plastics is essential during both manufacturing and consequent recycling. Post-consumer materials, and in particular a five component blend of high- and low-density polyethylene, polypropylene, polystyrene, and polyvinyl chloride representing American film waste, have been successfully reprocessed multiple times by solid-state shear pulverization on a laboratory scale pulverizer. A processing cycle included pulverization, injection molding and conventional grinding. Physical properties such as notched Izod impact strength, elongation at break and flexural properties remained unchanged after four cycles. No change in color or surface appearance of the injection molded test specimens was observed.

Experimental Study of Prepreg Bonded Single-Lap Composite Joint

Su-Seng Pang, Guoqiang Li, May 2002

Neat resin bonded single-lap composite joint has been extensively used in composite structures. Lower strength and longer fabrication time have been identified as technical barriers in practice. In order to increase the joint strength and reduce the fabrication time, two types of prepreg composites were used to bond composite single-lap joints. Test specimens were prepared per ASTM D 3165-95 standard. Accelerated conditioning was conducted to investigate the environmental resistance of specimens. The shear strength of various specimens was obtained using tension tests. Compared to control specimens, prepreg bonded samples exhibit higher tensile strength, higher environmental resistance, and shorter fabrication time.

Flow Behavior of Core Material in Sandwich Injection Molding with Sequential and Simultaneous Injection

Daisuke Watanabe, Hiroyuki Hamada, Kiyotaka Tomari, May 2002

The sandwich injection molding technique can be used in wide ranges of engineering applications for recycle. In this study, flow behavior of core material in sandwich injection molding with sequential and simultaneous injection was investigated. Flow behavior of materials in sandwich injection moldings revealed to divided into four regions (Primary injection region, core advance region, core expansion region and break region). The flow length of core expansion region was increased with increasing of simultaneous injection time of skin and core material. And it is revealed that the core layer was formed as wide and thin structure with increasing of simultaneous injection time.

Investigation of Applicability of Two Biodegradable Polymers for Mechanical Applications

May 2002

Three types of specimens of a polyester-amide and a poly-hydroxybutyrate have been tensile and tensile-impact tested. Important geometrical parameters for these specimens are wall thickness and gate dimensions, as well as a weld line in one specimen type. Explanation of the combined influence of geometry and injection molding settings on tensile behavior was in agreement with tensile-impact results. This influence was maintained after 20 months of storage in closed boxes but minor embrittlement was found for all specimen types and both materials. The beneficial effect of annealing on strain at break for all poly-hydroxybutyrate specimens was also shown.

Key Elements in the Survival of Plastics Recycling Industries

Lee Hornberger, May 2002

The growth of the plastics recycling industry was spurred by increased resin prices and the landfill crisis of the 1980's. Many of the recycling companies that started in the 1980's and 1990's quickly learned that economic recycling of plastic waste was a difficult and challenging task. For many of these companies, the problems were overwhelming and they went out of business. Those that survived into the 21st century are a unique group of entrepreneurs. The bulk of the survivors are small companies with sales under $20 million.In this study, 36 plastic recycling companies in the U.S. and Europe were evaluated to determine the elements that aided their survival. Three elements that were present in the majority of these companies were: an ability to develop and maintain their own technology, financial or technical support from external sources, and strong leaders who were determined to make the business survive. These companies are the models for their industry. The stories of these companies could be of particular value to the emerging automotive and electronic post-consumer plastics recycling industry.

Micro Molding - A New Way""

Jim Catanzaro, Bob Kadykowski, May 2002

Small parts less than one quarter of a pellet require a complete rethink by molding engineers and mold designers. Total part cost justification becomes more challenging based upon the amount of material wasted and tooling costs. Micro machinery is helping to meet the requirements of accuracy through simplicity. There is no need for complicated multiple profile closed-loop servo controlled injection and metering functions.The two-stage plunger over plunger injection unit is capable of processing basic polyolefins to high temperature LCP materials. Shot pot injection provides accuracy of volumetric control by eliminating variation caused by slider or check ring shutoff inconsistency. The minimum number of components used in the design achieves simplicity.

Model-Based Control of Material Distribution in Thermoformed Parts

R. DiRaddo, P. Girard, S. Chang, May 2002

The thermoforming industry has achieved a good understanding of the process, which has been in large scale operation since the 1950's. Consequently, control of machine settings such as heater band temperatures, plug position, plug and mould temperatures is quite advanced. However, to date, little work has been done to address the control of state parameters describing material behaviour during processing, such as sheet temperature and material distribution in the part. Control of state parameters is essential as material property changes, environmental factors and machine operating drifts can significantly change the dynamic operating point of the machine.

Morphological Development and Mechanical Performance of Injection Molded Starch Based Composites

Rui A. Sousa, Rui L. Reis, António M. Cunha, Michael J. Bevis, May 2002

Conventional injection molding and Multiple live Feed Molding (MLFM) has been used to process starch based biodegradable composites aimed for load bearing bone replacement/fixation applications. Blends of starch with : (i) poly(ethylene vinyl alcohol) and (ii) cellulose acetate were studied. Both polymers were reinforced with bone-like ceramics (hydroxylapatite) in amounts up to 50 % wt.. The use of MLFM allowed for the inducement of molecular anisotropy into the moldings. However it was necessary to prevent material degradation associated to shear dissipation effects and to the longer residence times.