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.
Polypropylene, as a commodity recyclable thermoplastic, is studied in this research to evaluate the potential environmental impact resulting from volatile organic compounds (VOCs) emitted during multiple reprocessing. Unstabilized commercial polypropylene (PP) grade was processed several times by injection molding. Samples were examined after each cycle for total VOCs emissions with a flame ionization detector (FID) and cumulative VOCs emissions were obtained after each processing step. Corresponding structural changes were investigated with Fourier Transform Infrared (FTIR) Spectroscopy and results were correlated with rheological data that showed decreasing viscosity particularly after the 7th processing cycle.
Waste management is gradually becoming a priority within an integrated approach to nature conservation. Croatia has taken a number of good steps during the recent years. The first life-cycle and economy analyses in Croatia were made for managing of glass waste in 1997, but no serious study of plastic waste was made until recently. Among all types of plastic waste, only PET-bottles are collected in Zagreb (within the OHO system - Croatian Recycling System), so it was logical to make the first life-cycle analysis of PET-bottle. The results have shown the evaluation of PET-bottles' impact on the environment and the critical points" of PET-recycling were pointed out."
Commingled recycled plastic lumber (RPL) decking was exposed to the environment for eleven years. The weathering effect is examined by performing mechanical property tests on the full size deck boards before and after the exposure. Flexural tests on the weathered deck boards were conducted with the exposed side and the unexposed side tested in tension. The flexural properties after weathering are compared to the original flexural properties. These data show the effect of weathering on recycled high-density polyethylene based RPL. A life cycle cost analysis (LCCA) is also presented to compare the cost of a wood deck versus an all RPL deck. The purchase, maintenance, and disposal costs are included.
Nanocomposites containing biodegradable polymers and clays were investigated to improve biodegradable properties. Polycaprolactone (PCL) (83,000 and 43,000 g/mol molecular weight) was mixed with additions of either 2 or 5% of synthetically modified montmorillonite clay. A twin screw extruder was used to produce the pellets. The pellets were then co-extruded with multilayering technology to produce 15-inch wide films from a 256 and 1024 layer die multiplier configuration. This study focuses on the biodegradation studies in compost, soil, and marine environment with results showing improved biodegradation rates in selective nanocomposites and environments.
Recycled polymers are currently being used in the design of commercial products for the maritime structure industry. Marine pilings, pier fenders, and pier support elements are just some of the products being designed with recycled polymers. Understanding the effect of submersion in salt and fresh water on the mechanical properties of the material used in these products is important. This study will examine the tensile creep behavior of recycled HDPE in ocean water, fresh water from Lake Erie, distilled water, and air. A specially designed apparatus for aqueous creep testing was utilized to obtain the data for this study.
The recycling of post industrial ABS and PMMA was investigated. A material compound consisting of 100% post industrial (PI) recycled ABS and multicolored acrylic (PMMA) scrap from a manufacturing plants was blended and extruded. Test samples were injection molded and the test results were correlated to virgin material. Additionally, the material was used in injection molding of rear lamp housings in black and gray colors. The test results and economics are promising.
The manufacturing waste generated during the production of vinyl floor tiles is typically sent to landfills, rather than recycled, because of a lack of reuse options for this material. This waste is typically PVC loaded with approximately 80% limestone. The goals of this research are to characterize this material to determine the feasibility of reprocessing it and to measure the mechanical properties of the processed material. This study will also attempt to suggest an injection molding or extrusion application for the mixture.
Space Structures that require light-weight materials with sufficiently high strength and environmental endurance have been in increasing demand since the early 1980's. However, the biaxial behavior of these structural materials under pressurized loading, is rarely found in the literature. An experimental investigation was conducted to develop a test method and hardware to characterize the biaxial behavior of a fabric-film laminate intended for use as a structural envelope for large balloons. The material tested is a composite laminate of three layers. The three layers are: polyester-based woven fabric, 6 microns film of polyester (Mylar type A) and 6 microns film of linear low density polyethylene (LLDPE). The laminate structure provides high strength to weight ratio. In this study, a test technique has been developed to measure the biaxial response of the material to known stress ratios. The information gained from the test can be manipulated to estimate Poisson's ratio and the development of a material structural model.
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.
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 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
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