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.

The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?

Not an SPE member? Join today!

Use % to separate multiple keywords.

Search SPE Library

Recycling

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

Polymerization of Lactide to Polylactic Acid and Co-polymers of Polylactic Acid using High Viscosity Kneader Reactors

Boyd T. Safrit, George E. Schlager, Ziang Li, May 2013

Polymerization of lactide to polylactic acid (PLA) can be performed using conventional reactor technology such as stirred tank reactors, but the conversion and/or final molecular weight may have to be controlled to a lower level. At higher conversion and/or molecular weight, the reaction mass will become very viscous, which limits the ability of conventional reactor technology to provide adequate mixing, minimize mass transfer effects on reaction kinetics, remove exothermic heat of reaction and ensure proper heat transfer in order to eliminate hotspots/thermal degradation. Kneader reactor technology has been used over 60 years in many high viscosity applications such as reactions and polymerization, devolatilization, and drying. This technology can handle the higher conversion and molecular weight polymerizations of lactide and other copolymers of lactide, while also providing the heat transfer required for proper temperature control. Using model kinetics and rheology data, a study was performed that shows the capability of kneader reactor technology for lactide polymerizations as well as other copolymers. Kneader reactor technology can also be used to remove the unconverted monomers from the polymer and expected results from the continuous operation of a polymerizer and finisher will be shown.

Polyphenol-Titania Complex as a Possible Flame Retardant Additive for Polyolefins

Weeradech Kiratitanavit, Zhiyu Xia, Sethumadhavan Ravichandran, Ruchi Bakshi, Jayant Kumar, Ramaswamy Nagarajan, May 2013

Flame Retardants (FR) are often compounded into plastics to ensure fire safety. However, some types of halogenated FR additives are environmentally persistent and toxic to humans. Here we report the development of an alternative FR additive based on polyphenol-titania complex that exhibits a combination of radical scavenging and char forming properties. The thermal stability and heat release capacity of blends of this complex with polypropylene are compared to those containing conventional halogenated FR.

Post Consumer Recycled Based NORYL™ Engineering Thermoplastics Product Portfolio for Electronic and Electrical Applications

Kirti Sharma, Michael Todt, Norihiro Takamura, May 2013

The Noryl™ resin compositions discussed in this paper are prepared using polyphenylene ether and post-consumer recycled (PCR) polystyrene (PS). The use of PCR in these environmentally progressive Noryl™ resin products may reduce plastic waste diverted to landfill, thereby lowering carbon footprint and energy conservation when compared to virgin Noryl™ resins. A comparison of properties of Noryl™ resins comprising PCR PS versus virgin Noryl™ resins will be presented in this paper. Life cycle assessment work is in progress and will also be presented during conference.

Preparation and Biodegradability Study of Polymer Blends of Poly(Lactic Acid) and Poly(R)-3Hydroxybutylate-co-(R)- 3-Hydroxyvalerate)

Sommai Pivsa-Art, Natee Srisawat, Narongchai O-Charoen, Sorapong Pavasupree, Weraporn Pivsa-Art, Hideki Yamane, Hitomi Ohara, May 2013

Polymer blends of poly(lactic acid) (PLA) and poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] (PHBV) for biodegrdadable textile application purpose were prepared to improve the flexibility of PLA. using twing screw extruder at 180-190°C. The ratios of PLA:PHBV were varied with 100:0, 90:10, 80:20, 70:30, 60:40, 50:50 and 0:100 by weight. Polyethylene glycol (PEG) having molecular weight of 6000 and 4000 were added to the polymer blends as compatibilizer at 2, 4, 6, 8 and 10 phr. It was found that addition of PEG having molecular weight 4000 g/mol showed better mixing and flexibility. PEG molecular weight 4000 g/mole resulted in higher tensile strength and Young’s Modulus than PEG 6000 g/mole). The biodegradability of PLA/PHBV was analyzed. The crystallization parts in the polymer blends retarded the biodegradation.

Preparation and Characterization of Poly(Lactic Acid)/Poly(Vinyl Alcohol) Blend

Peng Yu, Bin-yi Chen, Tai-rong Kuang, Xiang-fang Peng, May 2013

In this study, polymer blends based on poly(lactic acid) (PLA) and organic particles polyvinyl alcohol (PVOH) were prepared by melt mixing using a triple screw extruder. Phase morphology, thermal properties, dynamic mechanical properties and mechanical properties of the blends were investigated. Differential scanning calorimetry reveals that the addition of PVOH remarkably decrease the cold crystallization temperature and increase the degree of crystallinity of PLA/PVOH blends. Dynamic mechanical properties show that a general decrease of E? is observed with the addition of PVOH content, yet the loss tangent peaks broaden and slightly shift to higher temperature. From mechanical tests, it is found that tensile strength and the elongation at break decreased markedly with the addition of PVOH content, yet notched impact strength slightly increase.

PVC or a Power Plant

Shreekant M. Diwan, Abhijit G. Patil, Arunakumari Gs, May 2013

Conservation of energy and environment is the call of the day. Every human being is aware of the terrifying rate at which the natural resources are being depleted and very well knows the difficulties in replenishing them, leave alone replenishing them at the same rate. The demand supply gap in the electricity is resulting in load shedding not only in residential areas but also in the industrial sector. On the other hand, serious efforts are being made to augment forest cover by adding to the ‘artificial forest’ with the tree plantation drive across the country, yet the natural forest coverage in India is actually on the decline. Scarce natural resource like wood and energy dependent metals - being major components of construction sector, need of the hour is to select alternatives which are more environment friendly and energy efficient. PVC – well established in the Western Hemisphere and finding increasing acceptance in the developing countries as well - is one such wonderful alternative to many of the conventional materials in the building and construction sector. This has resulted in this material getting designated as “Construction Polymer” – very rightly so! Owing to its excellent inherent resin characteristics and adaptability to numerous compounding ingredients, PVC can be formulated in various ways to meet different end use requirements. Further, technological advancements in processing have also given means to make this commodity polymer meet the ‘engineering’ requirements. A polymer which consumes much lesser energy and creates much lesser environmental impact compared to many of the traditional construction materials and even some of the major polymers during its entire life cycle, PVC has established itself in significant end use applications in the construction sector. This paper makes an honest attempt to critically evaluate the advantages of PVC Pipes & windows in saving energy and environment in a typical house over the cradle to grave co

Recycling of PLA

Sebastian Schippers, Christian Hopmann, May 2013

Polylactide (PLA) is a bioplastic which has a high potential for packaging applications. Due to a high raw material prize and a limited availability the usage of PLA is limited apart from some niche products at the moment. Nevertheless, the number of applications is increasing. At the Institute of Plastic Processing (IKV) the recycling behavior of PLA is evaluated. Recycling helps to cut the raw material consumption and lowers material costs. Additionally, it improves the ecological balance. Following the industrial praxis different recycling strategies are analyzed. This paper gives a review about the multiple processing of PLA and the processing with melt degassing.

Recycling of Polylactide for Packaging Applications

Christian Hopmann, Sebastian Schippers, May 2013

Reforming useful plastics products into solid-shape energy fuels

JeongIn Gug, William Rhatigan, Margaret Sobkowicz, Jerry Brien, May 2013

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

Chris Tan, Chris Tan, Oliver Franssen, May 2013

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

Mike Tolinski, May 2013

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

Raj Krishnaswamy, May 2013

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

Zhixiang Cui, Haibin Zhao, Yiyan Peng, Michael Kaland, Li-Sheng Turng, Changyu Shen, May 2013

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.

Study on the Effect of Material Elasticity on Acoustic Performance and Rheological Properties of Bio-Based PLA and PHA Blend Foams

Shahrzad Ghaffari Mosanenzadeh, Hani Naguib, Chul Park, Noureddine Atalla, May 2013

In this study, open cell foams were fabricated from blends of bio-based polymers to be used as sound absorbers. Different blends of Polylactide (PLA) with two grades of Polyhydroxyalkanoates (PHA) where foamed and characterized based on acoustic and mechanical performance. Rheological properties of pure polymers as well as their blends were studied to investigate the effect of material elasticity on the acoustic absorption of the resulting foams.

Sustainable In-Machine Mold Cleaning and Part Deburring & Deflashing Using Dry Ice - Changing the Game Rules with CO2

Steve Wilson, May 2013

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

Gowrishankar Srinivasan, David Grewell, Michael R. Kessler, William Graves, Schrader James, May 2013

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

Kelly M. Buffum, Hannah K. Pacheco, Satya Shivkumar, May 2013

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

Jay Z. Yuan, Clinton A. Haynes, Patrick A. Harrell, May 2013

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

Peter Allan, Paul Marsh, Robert Withnall, May 2013

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

Joy Bloom, J. Donald Connolly, Peter Jernakoff, William T. Sedar, May 2013

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.