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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Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.
Reforming useful plastics products into solid-shape energy fuels
Diversion of waste streams, such as plastics, woods, and papers, from municipal landfill and extraction of useful products is an area of increasing interest across the country, especially in densely populated areas. One promising technology for recycling rubbish is to burn the high energy content components in standard coal boilers. This research seeks to reform wastes into block shapes that are compatible with typical coal combustion processes. In order to comply with the standards of coal-fired power plants, the feedstock must be mechanically robust, moisture resistant, and retain high fuel value. Two different type of waste stream, one based on household waste with high papers content, and the other based on construction waste with a significant wood fraction, were processed using a compression molding technique. The resulting mechanical properties, moisture absorption, and generation of energy from burning were investigated. The effects of solid waste particle size, compression pressure and temperature were studied to identify the optimal processing conditions. The feed-stream was augmented with recyclable plastics such as polystyrene and poly (ethylene terephthalate) to enhance the binding attraction for easy transport with improved mechanical properties, and the hardness of the composites was probed for the stability of solid fuels. Water uptake tests were also carried out for prepared samples to examine the durability of samples under humid conditions. Lastly, burning tests were performed to calculate the calorific value of the different samples resulting from the increased plastic contents. This research will contribute to alleviate the environmental problems related to landfill space, while producing an alternative fuel.
Silicone Elastomers - Clear as Glass Transparent Liquid Silicone Rubbers For Lighting Applications
For many years PC and PMMA were materials of choice for optical applications beside glass. These poly- meric materials have advantages such as weight reduction, increased freedom in design complexity, and better manufacturing economics due to lower energy consumption and less post processing when com- pared to glass. One has to also consider the tradeoffs when making a decision to use thermoplastics due to their less superior thermal, UV and chemical resistance against glass.A new alternative is now available with the "glass-clear" LSR7OOO silicone elastomer family from Mo- mentive Performance Materials. This new material combines the physical property benefits of silicones, ease & high productivity process advantage of liquid silicone rubbers (LSR) and an optical transparency of 95%. Since silicone polymers have an inorganic backbone, it offers better thermal and UV resistance when compared against thermoplastics.LED Lighting demands a combination of extreme material properties. For this application typically re- quires materials to withstand the harsh blue light radiation in combination with a maximum lamp temper- ature of up to 150?C for 100,000 hrs, which is the lifetime of a typical LED System. Due to its inorganic backbone, LSR7OOO offers superior performance in this extreme environment compared to other trans- parent organic plastics. LSR7OOO provides an outstanding thermal, UV, and blue light stability which makes this material an ideal candidate for the production of lenses for high power LEDs in the automotive and consumer lighting markets.Liquid Silicone Rubber Processing also brings various advantages. Due to its elastomeric properties, molded in stress and birefringence on finished parts are minimized. Material waste is reduced to a mini- mum through cold runner technology. Due to its low viscosity and processing conditions, LSRs are able to replicate parts with intricate details.This paper gives an overview of the special material properties of the ultra-transparent LSR7OOO and compares physical data to commercial optical thermoplastics. Application examples highlight present and future use of this innovative material. For many years PC and PMMA were materials of choice for optical applications beside glass. These poly- meric materials have advantages such as weight reduction, increased freedom in design complexity, and better manufacturing economics due to lower energy consumption and less post processing when com- pared to glass. One has to also consider the tradeoffs when making a decision to use thermoplastics due to their less superior thermal, UV and chemical resistance against glass. A new alternative is now available with the glass-clear" LSR7OOO silicone elastomer family from Mo- mentive Performance Materials. This paper gives an overview of the special material properties of the ultra-transparent LSR7OOO and compares physical data to commercial optical thermoplastics. Application examples highlight present and future use of this innovative material molded in stress and birefringence on finished parts are minimized. Material waste is reduced to a mini- mum through cold runner technology. Due to its low viscosity and processing conditions
Sourcing Bioplastics from Plant-Based Wastes: Examples of Progress
Biobased plastic materials have captured much attention recently, but the raw materials for their building-blocks are typically food crops – not an ideal or sustainable approach. However, obscure biochemical processes are being used to transform organic wastes into useful compounds for polymers and plastics. This paper reviews some recent developments in researchers’ efforts toward exploiting wastes as raw materials, especially plantbased food and industrial wastes. The paper will also discuss the practical issues and commercial limitations of “upcycling” these waste materials into biobased plastics.
Structure-Property Relationships in a New Family of Bio-Based, Compostable Blown Films
This paper is concerned with the influence of processing conditions on microstructure development and performance of a new family of biobased and compostable blown film products based on Mirel? PHB copolymers (product referred to as B5009). The unique combination of performance attributes of B5009 blown films including biobased carbon content and compostability, along with an excellent balance of tear propagation resistance, puncture toughness and tensile strength will be highlighted. The potential applications of the subject film, that has similar to superior mechanical properties compared to LLDPE, will be reviewed. The synergistic advantages that can be garnered with multi-layer film structures (through coextrusion with other polymers) will also be discussed.
Study of Morphology on Microcellular Injection Molded Scaffolds for Tissue Engineering
In this research, injection molding was combined with a novel material combination, supercritical fluid processing, and particulate leaching techniques to produce highly porous and interconnected structures that have the potential to act as scaffolds for tissue engineering applications. The foamed structures, molded with Poly(?-caprolactone) (PCL) and Poly(ethylene oxide) (PEO) with salt as the particulate, were processed without the aid of organic solvents, which can be detrimental to tissue growth. The pore size in the scaffolds is controlled by salt particulates and interconnectivity is achieved by the cocontinuous blending morphology of biodegradable PCL matrix with water-soluble PEO. Nitrogen (N2) at the supercritical state is used to serve as a plasticizer, thereby imparting moldability of blends even with an ultra high salt particulate content, and allows the use of low processing temperatures. Interconnected pores of ~200 ?m in diameter and porosities of ~72% are reported and discussed.
Sustainable In-Machine Mold Cleaning and Part Deburring & Deflashing Using Dry Ice - Changing the Game Rules with CO2
For plastic processors there is a great demand to increase the productivity of their equipment and the quality of their parts, while maintaining healthy margins. This can be a balancing act between using the most effective technology while working within a shrinking budget. This paper discusses the advantages of dry ice blasting as a replacement for solvent and/or mechanical cleaning for the removal of contaminants from tooling as well as its use to deburr and deflash plastic parts. While the principles discussed herein are applicable to multiple plastics processes (BM, Ext., etc.), the focus of this paper will be on injection molding and the various steel and aluminum mold substrates commonly used. The reader will achieve a benchmark understanding of the role and relevance of dry ice in mold cleaning, part deburring & deflashing and its impact on product quality, production cost, production efficiencies, worker safety and health and environmental responsibility. Research from several industry case studies will be discussed. The results confirm that dry ice cleaning can remove contaminant layers from various common mold metals and is a good alternative to other commonly used manual, abrasive methods as well as successfully deburr and deflash plastic parts.
Sustainable Materials for Horticultural Application
Bioplastic materials were compounded utilizing soy, poly-lactic acid (PLA) and poly-hydroxyalkanoate (PHA) biopolymers along with ethanol industry co-products and biomass additives to manufacture horticultural plant containers. Various formulations and processing conditions were studied to improve mechanical properties of the plastics. These materials were developed and compounded at Iowa State University and subsequently injection molded into 4.5 inch greenhouse pots at R&D/Leverage, Lee's Summit, Missouri. The bioplastic pots were evaluated for their performance by studying plant growth of vegetable and ornament crops grown in them under greenhouse and field conditions. The pots were also characterized for degradation and water retention. Commercial polypropylene pots, 4.5” green color, were used as the control treatment for the study. Comprehensive growth studies along with degradation results identified numerous bioplastic types that performed as well as or better than commercial polypropylene plant containers. Among the different material types, SPA-PLA, a blend of soy and PLA resins, was observed to produce the best results in terms of plant growth compared to polypropylene plastic pots during plant production. This is attributed to the slow release of fertilizing compounds during the degradation of soy protein. Certain bioplastic pot types were observed to retain soil moisture content over a longer time period than pots made from other environmentally friendly materials, such as paper or peat moss. Such properties are considered beneficial during the plant production cycle when using horticultural pots because they require less watering.
Tensile Property Changes in Commercial Biopolymer Products Based on Environmental Conditons
The current trend towards sustainability has created new interest in biodegradable plastics. While many investigations have examined the behavior of biodegradable plastics, the changes in properties that may occur during use have not been fully developed. The mechanical properties of seven types of biodegradable plastics were analyzed. In addition, the properties of polystyrene (PS) used in similar applications were examined. The effects of UV exposure, humidity and accelerated aging on the mechanical properties were studied. In general, the strength of several biopolymers was less than that of PS. Polylactic acid and wheatstraw had a higher strength than PS. The properties of biodegradable plastics deteriorated significantly upon exposure to UV radiation and humidity. Accelerated aging data indicates that after 6 months under ambient conditions, the biodegradable plastics also have a reduction in strength and modulus. Additional improvements may be necessary to resist environmental effects so that biopolymers can be effective replacements for traditional plastics.
The Effect of High-Recycle-Content on CSD PET Bottle's Thermal Stability
It is not uncommon to see a 25-30% post-consumer recycled (PCR) content in a carbonated soft drink (CSD) PET bottle on the market. With the growing availability of PCR resin, food and beverage brand owners are pushing for higher recycling content in their packaging. Recent studies have been published showing that high-recycling-content in PET packaging will adversely affect the performance of pressurized bottles when compared to virgin material or low-recycling-content counterparts. However, little has been done to quantify the degradation of the specific material properties that govern pressurized bottle performance. This paper focuses on quantifying changes in the short- and long-term material properties that govern a bottle’s ability to retain its original shape when subjected to sustained carbonation pressurization. This performance attribute is typically characterized as ‘thermal stability,’ which is the ability of the package to retain its shape and molded-in feature definition over time, after pressurization. Two commercially available packages, one molded of 100% recycled PET and another molded of typical PET (30% recycled PET content), are used to extract the test samples. The study indicates that the effect of the high-recycle-content on the CSD PET bottle cannot be over-looked. The results of the tensile tests show that the 100% recycled PET is stiffer and tougher in the axial direction (up to 26%), but softer and weaker in the hoop direction (up to 14%), compared with its typical PET counterpart. Based on the creep test results, the 100% recycled PET also creeps 50% faster. This will have a noticeable effect on the bottle’s thermal stability, which is only 1-2% (height and diameter growth or contraction under carbonation pressure) for most commercial packages on the market. The effect will become more pronounced for non-cylindrical designs or designs with non-cylindrical features. Failure to adequately retain the bottle’s shape (thermal stability) will a
The Potential for Solid Biomass Wastes as Fillers in Polymer Compounds
Two solid waste streams that originated either directly from biomass or from the processing of biomass material have been evaluated for their potential as fillers in thermoplastic compounds. In this initial investigation the two materials were taken directly form the source and compounded with the thermoplastic without any conditioning. Injection molded samples were characterized, mechanically tested and compared to compounds made from a commercial masterbatch. The results indicated that both of the waste materials could be used to make compounds with consistent, and, for some applications, improved properties compared to current commercial compounds.
The Response of Highly Loaded Polylactic Acid Masterbatches Containing Pigmentary Titanium Dioxide
The use of bio-based polymers continues to gain commercial acceptability. With this growth, the need to impart opacity, whiteness, UV protection and printability to commercial articles is becoming more critical. Titanium dioxide (TiO2) is typically the pigment of choice to meet these criteria. While TiO2 is traditionally delivered as a highly loaded masterbatch, it is well known that many bio-based polymers are sensitive to masterbatch processing conditions. Understanding whether bio-based polymers are tolerant of the processing conditions used in high solids loading without significant performance degradation is the subject of this paper. Using polylactide (PLA) as a model system, the compounding performance of highly loaded TiO2-PLA masterbatches is discussed.
The Role fo PVC Resins in Sustainable Design
The concept of sustainability is often stated in a number of ways but four core principles appear throughout: Protect the environment, promote human health, conserve resources, and assure social and economic well-being to the global population. PVC resin has intrinsic properties that allow finished products to meet all four of these objectives. PVC resin and products compare favorably to other materials in life cycle assessments when reviewing key impacts of resource and energy conservation, and greenhouse gas emissions. Sustainability assessments at the business level are excellent tools to promote these principles and track performance. This paper was prepared for the Society of Plastics Engineers Annual Technical Conference (SPE ANTEC) Vinyl Session, April 22, 2013 in Cincinnati, Ohio.
The Role of Surface Interactions in Renewable Poly(Butylene Succinate)-Silica Nanocomposites
Polymers from renewable resources are beginning to compete with conventional fossil fuel derived materials as fossil resources become increasingly expensive and difficult to extract. The same lightweight, high-strength properties of petroleum-based polymers and composites are required for renewable materials, and a better understanding of processing properties will improve their prospects in the market. One route to widening the thermophysical property window of biobased polyester poly(butylene succinate) (PBS) is the incorporation of reinforcing fillers. In this work, PBS is melt-mixed with high-surface-area fumed silica to create nanocomposites. The surface of the silica nanofiller is chemically modified to explore the effects of surface functionality on filler dispersion and required mixing energy. Rheological and thermal measurements show that structural properties of the filler have a larger influence than surface modification. Comparison of blending techniques provides guidance for improved nanocomposite preparation. The demonstrated mechanical property improvements over neat polymer enable a broader range of applications for these novel renewable materials.
The Roles of Multiple Factor Concurrency and Statistical Distribution in Plastic Part Failure
When a plastic part fails, a tough question is often asked, “Why are a limited number of parts failing?”. This is particularly true with seemingly random failures at significant, but low, failure rates. Two aspects are generally linked to such low failure rates, multiple factor concurrency and the statistical nature of plastic failures. Failure often only takes place when two or more factors take effect concurrently. Absent one of these factors, failure will not occur. Plastic resins and the associated forming processes produce parts with a statistical distribution of performance properties, such as strength and ductility. Likewise, environmental conditions, including stress and temperature, to which the resin is exposed through its life cycle is also a statistical distribution. Failure occurs when a portion of the distribution of stress on the parts exceeds a portion of the distribution of strength of the parts. This paper will review how the combination of multiple factor concurrency and the inherent statistical nature of plastic materials can result in seemingly random failures.
Thermal ageing performance of novel Ultrol® Nuclear 60 year Cables.
Wire and Cable manufacturers generally qualify products for class 1E application by envelope type testing to user specifications and environmental conditions recommended by IEEE standards 323- 1974 and 383-1974. Early cable qualification required only radiation in 1960s. 1960s and early 1970s added thermal aging to ICEA requirement. However the ageing requirement was very minimal (1 week @ 121°C). The long term ageing requirement was not as nearly stringent as present until IEEE 383- 1974 was added to standards. To determine the ability of samples to withstand normal operation, IEEE 383- 1974 introduced ageing samples to “End of Life” condition. Samples were heat aged to a timetemperature condition in excess of 40 years of service life. Federal law and regulation recently allowed electric companies to renew their nuclear plants’ operating licenses for 20 years beyond their original, 40-year license term, which in turn triggered IEEE standard 383-2003 to govern minimum requirements to meet 60 years. General Cable Corporation, GCC simply in this paper, recently completed qualification programs. The major milestones in the development included (a) product life improvement of our established products, Ultol® products, from 40 yrs to 60 yrs. (b) introduction of Ultrol® medium voltage power cable with 60 year life. Cable constructions tested were 600V instrumentation cables, 600V power cables, 600V control cables, 2000V power cables and 15kV Power cables. This paper presents Arrhenius thermal aging data collected for materials used in the qualification programs using IEEE 101-1987 as basis confirms that a 90°C conductor temperature has a life in excess of 60 years.
Thermal and Crystallization Behavior of Poly(Lactic Acid) and Poly(Trimethylene Terephthalate) Blend Fibers
Biodegradable poly(lactic acid) (PLA) and poly(trimethylene terephthalate) (PTT) blend fibers were prepared in this study. PLA and PTT were blended in a twin screw extruder with varied contents of PTT 0-50 wt%.The PLA/PTT blend fibers were prepared by melt spinning technique. Thermal properties and crystallization behavior of PLA/PTT blends were investigated. PLA fiber was glossy and transparent while PTT fiber was opaque. The spinning of PLA/PTT blends fiber was difficult due to the difference in melting characteristic of PLA and PTT. However, the PLA/PTT blend fiber was successfully spun at PTT content of 10 wt% with the barrel temperature of 250 °C and would be suitable for textile application.
Thermal Stability of Castor Oil Derived Polyurethanes
Polyurethanes synthesized using both unmodified and epoxidized, ring opened castor oil as a polyol were prepared and their thermal properties tested using thermogravimetric analysis and differential scanning calorimetry. Chemical changes upon degradation were investigated using Fourier transform infrared spectroscopy. The kinetics of degradation were elucidated using the Flynn-Wall and Flynn procedures. Epoxidized castor oil produces a rigid polyurethane exhibiting glassy behavior at ambient temperatures. All methods to determine activation energy of degradation indicate that, in a nitrogen environment, polyurethanes from unmodified castor oil are more thermally stable than those from modified castor oil. The appearance of peaks corresponding to amines, amides, and esters in FITR analysis of degraded samples suggests that the initial degradation step of the polyurethanes studied is the breaking of the urethane bond.
Thermoplastic Polyurethane/Polylactic Acid Tissue Scaffold fabricated by Twin Screw Extrusion and Microcellular Injection Molding
Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. They possess rigid and flexible mechanical properties. The TPU/PLA blend tissue scaffolds at different ratios were fabricated via twin screw extrusion and microcellular injection molding techniques (a. k. a. MuCell) for the first time. Multiple test methods were used in this study. Fourier transform infrared spectroscopy (FTIR) verified the presence of the two components in the blends. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between TPU and PLA. Scanning electron microscopy (SEM) images affirmed that the PLA was dispersed as spheres or islands inside the TPU matrix, and that the phase morphology further influenced the surface roughness of cells. The blends exhibited a wide range of mechanical properties that cover most human tissue requirements. It was found from DMA and viscosity tests that 25% PLA significantly reinforces the blends at low temperatures or deformation frequencies.
ToolingEDGE - High Performance and Sustainable Production
The strong emergence of new" economical and industrial regions on the globe supported by lower hand labor costs puts European Engineering & Tooling face to new challenges that evidence the necessity to develop new and revolutionary ways of making things. It is in this context and to answer to the new global challenges it was created an industrial and scientific Cluster the Portuguese Engineering and Tooling Cluster (E&T). This cluster represents an industrial value chain with specialized skills and competences from Design and Engineering to Tooling and Plastic Products. The E&T cluster is responsible for setting up a national strategy for the development and sustainability of this important economic sector combining a strong investment in technological and organizational innovation that will support a constant and progressive evolution on technical and organizational efficiency. The E&T strategic plan within 10 years is to be recognized worldwide as one of the most advanced in technological point of view and having the capacity to offer added value in the design and production of molds special tools and precision machined parts produced by injection or in materials with specific features for new applications. The R&D project ToolingEDGE - High Performance and Sustainable Production is one example of research activities being held by E&T cluster. The project aims to deploy technological solutions to prepare the E&T sector for sustainable competitiveness and to enable the penetration in new and/or added value markets considered strategic for the E&T notably: the aeronautics medical devices electronics automotive and packaging industries."
Toughening of Polylactide with Pre-heat Treated Natural Rubber
Both polylactide (PLA) and natural rubber (NR) are biocompatible and biodegradable polymers. PLA possesses high strength and modulus but low toughness, while NR exhibits excellent elasticity and ductility. In view of their complementary properties, NR seems an ideal candidate to toughen PLA. To the best of our knowledge, PLA blends showed increased ductility only when more than 10 wt% rubber was added. This study demonstrates a significant improvement in the toughness of PLA by melt blending PLA with pre-heated NR. SEM studies showed that the rubber phase was uniformly dispersed in the PLA matrix. With as little as 1 wt% NR, the elongation at break and tensile toughness of PLA/NR blend were significantly improved over those of neat PLA (207% vs. 16% and 83 MJ/m3 vs. 9 MJ/m3, respectively) without loss in tensile modulus and stress. In addition, by blending in PLA with 20 wt% NR, samples obtained did not even break in the notched Charpy impact test. FTIR spectrum indicated that carbonyl groups were generated in NR chains after hot shearing and led to enhanced compatibility between PLA and NR, which accounted for the improved toughness
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