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.
Biodegradable Laminates and Composites Containing Starch and Poly(hydroxyester-ethers)
Poly(hydroxyester-ethers) (PHEE) were added to a variety of thermoplastic starch composites in order to improve the mechanical and water-resistant properties of these systems. Thin film coatings of PHEE's were found to adhere well to starch sheets and foams and provided resistance to cold water over short periods of time (hours-days). Adhesion was decreased by high water or glycerol contents in the starch and was increased by addition of partially hydrolysed polyvinyl alcohol. Extruded starch foam peanuts containing 5-20% PHEE were found to have a thin surface layer consisting mainly of PHEE. This probably explains, at least in part, why the starch/PHEE foams have a higher expansion ratio, greater water resistance and reduced friability compared to foams made from starch alone.
Biodegradable Plastic Materials in Blends for Cost-Effective Low Temperature Applications
An on-going Pittsburg State University project focuses on the development of biodegradable polymer blends that can be used for low temperature durable and cost-effective bioresorbable castration clips for the farm industry. Clip materials must be non-food contaminants while being functional at the below zero degree polybutylene succinate and polybutylene/adipate copolymer were formulated into injection moldable blends that can withstand down to -20°C (negative 20 degrees Centigrade)."" weather of the North American farm belt winter months. Using the glass transition temperature (Tg) and solubility parameter (?) criteria pre-selected biodegradable materials polycaprolactone
Biodegradable Polymer Blends for Medical Applications
Biodegradable polymers are used in medical applications, among many reasons, because of their history of biocompatibility. In this report an attempt has been made to establish the structure created by reactive processing of poly (caprolactone) and Easter 14766 with dicumyl peroxide (DCP). Results showed that PCL quantitatively formed tetra-functional branches while the Easter 14766 formed a combination of tri and tetra-functional branch points. The Easter 14766 was also shown to be more reactive than the PCL, with half as much DCP being required to achieve equivalent amounts of branching. Both Easter 14766 and PCL displayed typical branching behavior with increase in melt elasticity and zero shear viscosity. Easter 14766 showed a little improvement in mechanical properties. However, studies showed PCL to be insensitive to branching.
Biologically Derived Conducting Plastics
A new biological strategy has been developed to synthesize water-soluble conducting polyaniline. In this approach, anilines are polymerized by the enzyme horse-radish peroxidase (HRP) catalysis in aqueous buffer solution at pH 4.3 in the presence of a template. Strong acid polyelectrolytes such as polystyrene sulfonate (SPS) and the aqueous micelles formed by strong acid surfactants such as dodecylbenzenesulfonic acid (SDBS) are favor-able templates to form nano-scale reactors for the growth of conducting polyaniline. The properties of this enzymatically synthesized polyaniline are consistent with the polyaniline that is traditionally prepared via either chemical or electrochemical procedures. This biological approach offers unsurpassed ease of synthesis, processability, stability (electrical and chemical), and environmental compatibility.
Blends of Metallocene Polyethylenes for Recycling of Xerographic Toners
This paper presents experimental results on the blends of metallocene polyethylenes (mPE) for recycling of xerographic toners by reactive extrusion. The experiments were carried out in a reactive twin screw extruder. The evaluation of the mechanical properties and morphology for different blend consist of black xerographic toners with mPE with and without compatibilization by reactive processing. It is rather surprised that the impact strength property is synergistic behavior. The impact strength and the modulus of elasticity of the blends using compatibilizer can be significantly improved. Morphology studies employed scanning electron microscopy (SEM) show that not only the domain size of the phase of black toner can be reduced but also the interfacial adhesion can be enhanced by proper compatibilizeation. Phase morphology and domain size indicate that efficient dispersion was obtained for the compatibilized system whereas the phase of black toner was agglomerated in the interfaces without compatibilization.
Chemo-Rheology and Structure Development of a Solventless System for Manufacturing Electronic Pre-Pregs
Current processes used to manufacture electronic pre-pregs and laminates use solvent based systems. Solvents are environmentally unfriendly and add no value to the final product. We are developing a new solventless process, based on the concept of continuous Resin Transfer Molding or Injection Pultrusion. The first step in designing the process is to select a suitable chemical system. The viscosity of the system should be such that it allows proper impregnation at a temperature at which not much reaction takes place. To predict the required pulling force, the friction at the wall as the material solidifies needs to be truly understood. A potential resin system has been identified and its chemo-rheology and structure formation will be discussed.
Crushed Recycled Glass as a Stiffening Agent for HDPE Compared to Traditional Plastic Lumber Fillers
bstract The objective of this study was to determine the flexural, impact, and tensile properties of a compound of crushed recycled glass, HDPE, and coupling agent using a two-level, three-factor designed experiment. This study determined that glass content, sieve size, and coupling agent all have a significant effect on the mechanical properties. The use of recycled crushed glass was found to increase the flexural modulus, but not as efficiently as calcium carbonate, wood flour, and fiberglass. Additionally, crushed glass improved the impact strength but decreased the tensile strength. It was found that smaller glass particle size performed better and the use of coupling agent decreased all mechanical properties.
New Compatibilizers for Styrenic/Olefinic Blends
Styrenic block copolymers (SBC's) are increasingly being used as compatibilizers (interfacial agents) in polystyrene and polyolefin blends with either virgin and/ or recycled resins. Many technical articles and patents on blends of styrenic and olefinic polymers indicate that styrenic block copolymers and more specifically styrene-butadiene- styrene copolymers function as compatibilizers. This paper reports the effectiveness of new block copolymers to compatibilize styrenics and polyolefins. In addition, a comparison of physical properties of blends using new block copolymers is made to those currently used in the industry.
Opportunities for Reinforced Plastics in Automotive Applications
This paper presents the motivation for using fiber-reinforced plastics in automotive applications and the advantages and limitations concomitant therewith. Applications of fiber-reinforced plastic components in current and future vehicles have been selected for discussion to provide examples of how these materials can be used to support the drive toward the continuous improvements in performance, energy-efficiency, manufacturing cost, and environmental conservation.
Development of Novel Applications of Crosslinked Elastomer Scrap in Thermoplastics
Materials ranging from impact-modified thermoplastics to thermoplastic elastomers (TPE) can be obtained from blends of recycled ethylene-propylene-diene rubber (EPDM) containing carbon black with poly(propylene) (PP) by varying the ratio of components in the blend. This study focused on developing TPE materials from PP and recycled ground rubber. The effect of rubber particle size, melt flow index (MFI) for the PP, and weight percent of the constituent fractions on the physical properties of the resultant blends was quantified. A design of experiments based on the processing conditions and variables was performed to determine the optimum processing conditions. Compatibilization techniques were used to improve the quality of the scrap rubber/plastic blends in response to the structural requirements of several potential applications. The cost factors for scale-up to manufacturing operations were also considered. It was found that the MFI of PP is a major factor controlling the mechanical properties of the blends. Through proper selection of the components and compatibilization techniques, blends were found to be tailorable to specific applications.
Profile Extrusion of Highly Filled Recycled HDPE
Recycled high density polyethylene (HDPE) filled with up to 70 wt% rice hulls was compounded and tested for dynamic shear properties on a parallel plate rheometer. A 60 wt% formulation was extruded through two profile dies. Extrudate tearing occurred at all throughputs. The magnitude of the tearing increased with increasing throughput and decreasing land temperature. Observations, 2-dimensional finite element and fully 3- dimensional finite volume simulation suggest the tears are most severe where the wall shear stress is relatively lower.
Recycling PVB Automotive Windshield Interlayer
PVB (polyvinyl butyral) windshield interlayer retains physical properties very well, owing to being effectively packaged in glass prior to recycling. However, the cost of removing all of the contaminant has precluded PVB's acceptance in many applications where it might, otherwise, have been usefully recycled. We have found that finely pulverizing the scrap, with its attendant residues, allows melt-process manufacture of products meeting automotive requirements for vibration damping, tensile strength, tear resistance, and flexibility, over a wide range of temperatures.
Sorption Properties of PAN/Chitosan Composite Fiber
Composite fiber of PAN and chitosan was obtained by hydration-melt spinning process. The fiber showed a fibrillar structure which can be converted easily into pulp-like structure by beating. PAN/chitosan pulp showed much higher amount of acid dye uptake than chitosan powder or activated carbon which is used for the color removal from the waste water of dyeing industry. This better sorption for the composite fiber is considered to result from the relatively large surface area due to its pulp-like shape.
Energy Absorption in Foam Filled Glass Fiber Reinforced Plastic Sections with Light Metal Reinforcement
The automobile industry is seeing an increased need for the application of plastics and their derivatives in various forms such as fiber reinforced plastics, in the design and manufacture of various automotive structural components, to reduce weight, cost and improve fuel efficiency. A lot of effort is being directed at the development of structural plastics, to meet specific automotive requirements such as stiffness, safety management, strength, durability, environmental standards and recyclability. This paper presents the effect of foam filling on the energy absorption during impact, of typical automotive body sections made up of fiber reinforced thermoplastic material with or without metallic reinforcements. In particular the study compares energy absorption characteristics during impact of typical automotive sections made of fiber reinforced thermoplastic materials without foam filling, with foam filling, with foam and some light metallic reinforcements. An attempt is also made to present results on such energy absorption at varying temperature conditions such as low temperature, ambient and elevated temperatures. In all cases it is found that the inclusion of foam and some lightweight material reinforcement enhances not only the structural integrity of fiber reinforced plastic sections but also improves significantly the energy absorption of such material systems under impact.
The Advantages of Direct In-Line Compounding Systems
Composite Products, Inc. has commercialized in-line compounding technology to produce thermoplastic composites. Turnkey systems continuously compound thermoplastic resin with reinforcements i.e. ½ inch chopped glass, carbon or natural fibers to produce finished composites with outstanding toughness. Coloring, recycling of plant regrinds and use of recyclates are accomplished in-line with the molding process. The patented technology provides molders the ability to contain costs and simplify complex scheduling logistics to meet Just-In-Time shipping schedules.
Evaluation of a Wood Fiber-Based Compound by Torque Rheometry
The trend toward increased usage of renewable resources has led to the growing popularity of wood-filled materials. These emerging materials require extensive testing - beginning with formulation and ending with the final manufactured product. In the early stages of development, it is possible to acquire data comparing differences between recipes utilizing a Mixer/Measuring Head. The given blend can be compounded with a customized twin screw extruder and torque rheometer. Finally, a single screw extruder can quantify the rheology of the compound using a capillary die. The objective of this work is to investigate the behavior of a polyolefin based wood-filled compound using a torque rheometer.
Evaluation of Thermoplastic Polyurethane Based Thermoplastic Vulcanizates for Interior Automotive Applications
Although thermoplastic polyolefins (TPOs) have been considered as costwise and environmentally attractive materials, they face the difficulty in being used as potential automotive applications because of poor scratch resistance and oil resistance. The new thermoplastic vulcanizates (TPVs) composed of thermoplastic polyurethane (TPU) / polypropylene (PP) /polystyrene-block-poly(ethylene-co-propylene)- block-polystyrene copolymer (SEPS) systems have been found out to have outstanding oil resistance and scratch resistance. Now they can be used for various kinds of automotive applications such as injection molded, blow molded, extruded, calendered and further, slush molded automotive parts, particularly for automotive interior skins without any coat. The essential issue is conceivably just prolonged weathering resistance and durability. In this paper, this new TPVs are evaluated from the standpoints of weathering stability, long term heat aging and fogging as well as the mechanical and physical properties.
Evolution of Structural Hierarchy in Uniaxially Deformed Branched Poly Lactic Acid Films as Followed by Spectral Birefringence Technique and Others
Over the past two decades, the lactic acid homo and copolymers have been extensively investigated for a variety of medical and pharmaceutical applications; including wound closure1, dental repairs2, fracture fixation (bone plates, screws, pins, and splits)3, ligament reconstruction, vascular grafts4, nerve repairs5 and drug delivery6,7. They are also extensively used in controlled drug release area6-8. With the recent developments in the technologies for purification of the raw materials, the large scale usage of these lactic acid based polymers became quite feasible. This, in turn, is opening the door for application particularly in the biodegradable packaging.
Towards Design Guidelines for Injection Molded Biodegradable Plastics Products
Specimens of two semicrystalline biodegradable thermoplastics, polyester-amide and polyhydroxybutyrate, injection molded at various settings, have been tensile tested. Upper limits to wall thicknesses with respect to surface appearance were found less severe than for traditional plastics. Molding settings appeared important for mechanical behavior. A higher degree of crystallization was obtained for polyhydroxybutyrate when the cooling rate was decreased. The lowest possible mold fill pressures appeared preferable, increasing ductility for both materials.
Wasteless Distribution Medium: A New Development for the Resin Infusion Process
The typical resin infusion processes like SCRIMP (Seemann Composite Resin Infusion Molding Process) require the use of a distribution medium or system to increase the impregnation speed in large parts. Normally, a substantial amount of surplus resin remains in the distribution medium and has to be disposed with the medium or remains on the part as resin rich domains. A new patented type of resin infusion process is presented, which does not produce any surplus resin waste.
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