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.
Flow Charactristics of Rubber-Toughened Glass-Fiber Reinforced Nylon 66
This research deals with studying the effect of incorporating thermoplastic rubbers on the flow properties of virgin and Post-Industrial glass-fiber-reinforced nylon 66. Rubbers used in this study were Styrene-Ethylene- Butylene-Styrene and Ethylene-Propylene grafted with maleic anhydride. Flow properties of the composites were examined by the melt flow index and rotational viscometry. The melt flow index (MFI) data showed a drastic reduction in MFI when both rubbers were added to recycled and virgin glass-fiber-reinforced nylon 66. The highest reduction in MFI, which implies an increase in viscosity and molecular weight of the composites, was observed at higher rubber content. The measurements of the dynamic viscosity vs. shear rate showed an increase in viscosity with increasing rubber content at both glass fiber contents. The zero shear viscosity of the composites was found to generally deviate positively from the log additive rule.
Conventional electropolishing (EP) of Cu involves anodic oxidation and dissolution in a stirred electrolyte solution. Rate and planarization efficiency are governed by diffusion across the stagnant boundary layer. We developed a membrane-mediated electropolishing process (MMEP) in which the substrate is covered by de-ionized water and separated from electrolyte and cathode by a charge-selective membrane. Ion transport occurs by electro-migration of cations across a thin layer of water which is established at the substrate/membrane interface by lubrication mechanics. MMEP provides high removal rates and much higher planarization efficiencies than EP. In addition it consumes no reagents, generates no waste and leaves the substrate uncontaminated.
Recycling and Reuse of Vinyl Wallpaper
Vinyl wallpaper has two principal materials of natural and synthetic origin used in its manufacture: Thermoplastic polymer (PVC) Polyvinyl chloride combined with cellulose fibre. The present paper will follow an interdisciplinary approach aimed at producing strategies for the recovery and reuse of these materials, thereby minimising the level of wallpaper waste entering landfill. Consideration will be given to preparation, characterisation and properties of the compounded and moulded recyclate. A range of techniques used to characterise these materials will be discussed, including image analysis, thermo gravimetric analysis, compressive strength, impact and recovery measurements.
Reducing Resin Waste by Optimizing Polymer Process and Machine Design
Polymer processing and converting operations, whether they relate to extrusion coating, blown film extrusion, producing sheets for thermoforming or manufacturing finished articles by injection molding, generally involve some amount of resin waste. A total conversion of the resin into an article of desired quality is an exception rather than a rule.As material costs constitute the bulk of the total costs associated with any product, the aim should be to keep the resin waste as low as possible. With the quality of the product depending largely on the machine and processing parameters, one of the easiest and most effective methods of reducing polymer waste is to optimize the design of the converting machinery at the design stage before they are built as well as optimization of processing conditions.With the illustration of several examples representative of blown film extrusion, flat film extrusion, extrusion coating, blow molding and pelletization process, this paper demonstrates how by applying this strategy resin waste could be reduced.
Residence Time and Deformation Characteristics of the Real Screw Extruder
We consider distributive mixing in the single-screw extrusion process. Several mixing measures in the extrusion process were proposed in the literature to quantify the mixing performance. In our previous research, we proposed the “Deformation Characteristics” (DC) as a new deformation measure of the screw extrusion process using the Cauchy-Green deformation tensor.In this work, the fourth-order Runge-Kutta method has been employed for numerical integrations to obtain the residence time and the deformation characteristics, using the three-dimensional velocity fields obtained by the finite element analysis with the periodic boundary conditions along the down-channel direction in the real screw geometry.
Sacrificial Mold Embossing for High Density, High Aspect Ratio Micro/Nano Structures
An unconventional embossing method is evaluated in which de-embossing is avoided to prevent the deformation or damage of the polymer microstructure on the substrate due to one or more of the following issues involved in hot embossing process: higher feature density, higher aspect ratio, bad surface quality and under-cuts. In this study, a PDMS mold is used to transfer a SU-8 structure to a water-soluble polymeric stamp under low pressure and low temperature, which is used as the rigid tool in the following hot embossing and can be reused by being dissolved in water, an environmentally benign solvent. This method has potential uses in the replication of high aspect ratio microstructure on polymeric materials that cannot be easily achieved using other methods.
The Effect of Addition of PCL on the Mechanical Properties and Thermal Transitions of PLA
Biodegradation of polymers is becoming an increasingly important consideration for packaging and biomedical applications. The availability of biodegradable materials would allow the invention and continuation of many polymer applications without any hazardous effects on the environment. Material scientists are focusing more intently on making environmentally-friendly polymers by developing biodegradable polymeric materials. Polylactic acid (PLA) and polycaprolactone (PCL) are two systems of application of this interest.Polylactic acid (PLA) is a frequently investigated, readily biodegradable polymer made from renewable agricultural products. It’s mechanical properties, and biocompatibility allow PLA to be used in a wide range of applications, such as biomedical implants and food packaging. However, despite it’s good tensile strength and high melting point, PLA is too brittle to be used in many of these applications. Polycaprolactone (PCL), on the other hand, is a very flexible and biodegradable polymer. In general the degradation of a polymer depends on various factors such as molecular weight, amorphous phase content, moisture level, temperature and pH. The main disadvantage of PCL is that the overall tensile strength of PCL is low. In addition, the low melting point of approximately 60 °C limits its use in many applications. We investigated the benefits of blending these systems and optimized one blend composition. Nanocomposites of this blended system are studied in detail.
Thermal Analysis and Nano-Mechanical Properties of Natural Fiber or Cornstarch-Reinforced Biodegradable Biocomposite
Thermal analysis and nano-mechanical properties of natural fiber or corn starch-reinforced biodegradable composite were conducted by using a differential scanning calorimeter (DSC) and nano-indenter, respectively. Thermal flow properties of composites were also investigated by using capillary rheometer. The effect of coupling agent and filler on isothermal and non-isothermal crystallization was investigated by Avrami equation and its modified equations. Analysis of kinetic data according to nucleation theories was also performed. Nano-mechanical properties of the reinforcing materials used in this study were also investigated by continuous nanoindentation technique.
Weldability of Bio-Renewable Ultrasonic Exfoliated Nanocomposites
In this work the weldability of bio-renewable nanocomposites was studied. Soybean proteins were denatured in a glycerin solvent and plasticized with a screw extruder. The glycerin contained clay platelets that were exfoliated with high power ultarsonics (2.2 kW @ 20 kHz). Various levels of exposure to the ultrasonic energy were used to exfoliate the clay platelets resulting in nanocomposites with various levels of exfoliation. It was also seen that these materials were not effectively welded with hot plate welding; however, success was found with vibration welding where significant material pullout was seen at the faying surfaces after tensile testing.
Control of Moisture & Volatile Organic Compounds by Sorbent-Loaded Composites
The integrity performance and service time of certain automotive subsystems is adversely affected by moisture ingress into contained environments. Corrosion of air conditioning (AC) system components caused by moisture initially present in the refrigerant and moisture permeated through the seals during the AC unit service life is one example. Another one is water vapor condensation in optical components used for night and rear vision systems as well as optical proximity sensors often causing their malfunction in changing environmental temperature and humidity conditions. Desiccating multiforms attached to a condenser coil have long been used in automotive AC units to absorb the residual moisture and the moisture permeating from outside. The new direction in AC moisture control is the use of sorbent-loaded polymer composites in AC structural parts that eliminate the need for individual desiccating multiforms their assembly operation as well as the associated noise from the assembly. Desiccating composite enclosures and seal materials are simultaneously targeted for improving performance of optical components. Volatile organic compound (VOC) emissions from fuel tanks and lines into atmosphere can also be reduced by using VOC absorbing composite materials as reactive barriers to permeation in fuel tank and supply line design. The performance of sorbent-loaded composites is evaluated from the standpoint of two distinct design targets: removal the target vapor from the contained environment and reducing the rate of ingress from the external environment. The concepts of the layer reactivity the adsorptive capacity and the sorption rate are applied to the homogeneously reactive media and the sorbent-loaded polymer composites. The corresponding differences in performance and design requirements are discussed.
Injection Molded Polylactide (PLA) Composites for Automotive Applications
Polylactide (PLA) is a biodegradable compostable thermoplastic polymer produced from corn an annually renewable resource. In moving towards developing a sustainable vehicle use of materials such as PLA could greatly contribute to the goal of a more environmentally friendly vehicle. To date several non-automotive applications of PLA have been commercialized. These include PLA fiber/textile applications for clothing carpeting and linens; as well as blow molded articles for food packaging. Thus far for automotive use a single niche application of compression molded PLA has been developed. Here we seek to optimize the injection molding process conditions and composition of PLA composites for automotive interior applications. The effects of adding various reinforcements to the PLA resin for property improvements were assessed. Crystallinity modulus and strength properties were evaluated by differential scanning calorimetry (DSC) tensile and flexuarl testing.
Use of Agricultural Materials In Flexible Polyurethanes for Automotive Applications
The use of renewable materials in commercial products has gained attention over the past several years. Biomaterials can offer significant advantages over conventional materials such as: sustainability reduction of petroleum dependence lighter weight of components and potential lower cost. In our studies we demonstrate the use of soy-derived materials in two primary thermoset applications: sheet molding compounds (SMC) and polyurethane foam. SMC composites were produced using soy resin in place of a portion of the vinyl ester resin to evaluate mechanical performance process capabilities and component performance. In addition composite reinforcements of continuous hemp fiber non-woven hemp mats fiberglass and hybrids (fiberglass/continuous hemp twine mixtures) were examined. Results indicate that the soy resin composites demonstrate equivalent properties to those of the vinyl ester resin composites and are equally able to be molded in to complex geometries. While substitution of glass reinforcement with natural fibers was found to reduce the mechanical performance of the composites hybrid composites of glass and hemp fibers provided promising results. Hydroxylized soy oil has also been used as a polyol in flexible polyurethane foam formulations. Foam formulations have been optimized for mechanical and processing performance. One of the key technical challenges of soy foams are their inherent odor. Two odor reduction methods will be discussed including a novel low odor method to functionalize soybean oil.
Wood & Flax Fibre Polyolefin Composites
In this work natural fiber and wood composites based on neat and recycled polypropylene (PP) were fabricated by melt processing. Different formulations including various reinforcement content different types of coupling agents different types of reactive additives and an impact modifier were developed. The reinforcements were in the form of natural fibers like banana flax rice husk and palm fibers and of wood sawdust. For the long fiber composite systems processing was done by compression molding of piles of long fiber mat and extruded polypropylene film. For the short fiber composite the samples were prepared by extrusion followed by injection molding. The tensile flexural and impact performance were characterized and all composites show superior mechanical properties when compared with the pristine matrix. Mechanical performance of the wood composites was also evaluated before and after conditioning in water for 1 and 7 days. Results indicate that the composites resist to humidity very well. The results also demonstrate the effect of formulations on the performance of the recycled composites.
A Study of Foaming Agent in Bio-Based Polymer Foams
In this study, the effect of variety foaming agents in bio-based polymer such as chemical blowing type of AC and BIH, and physical type of microsphere, has been investigated. The basic matrix of bio-based polymer was compounding PLA with native starch and calcium carbonate in twin screw extruder prior to introducing variety foaming agents at low temperature by dynamic rheometer to avoid the degradation of foaming agents.The topology of cross-section of their foams structure by SEM revealed that physical type of microspheres attained much better density but lower porosity than the others.
Advancements in Laser Marking and Engraving Using Integrated, Through-The-Lens Vision
Laser marking and engraving for the automotive industry poses many challenges to the plastic mold manufacturer. In the past, laser-marking systems have not been intuitive in confirming part identification or part positioning. Inaccurate placement of the mark due to a part misalignment or the engraving of incorrect marking information due to a lack of part identification results in waste parts and reduces product profitability in a highly competitive market.This paper describes the procedure for laser marking using a through-the-lens vision process, Integrated Mark Positioning (IMP), and data compiled comparing marking with and without IMP. Results show that a mark placement accuracy of 0.03 mm with a part placement variation of 4 mm or larger can be achieved. System configuration, operation and benefits of integrated vision are also covered.
Comparison of N2 and CO2 in Extrusion Foaming of Wood-Fiber Composites
Producing cellular wood-fiber/plastic composite (WPC) with physical blowing agents (PBA) offers unique advantages over chemical blowing agents (CBA). This paper compares the foaming behaviors of two environmentally benign PBAs, namely N2 and CO2, to help understand PBA-based foaming mechanisms in WPC. This understanding will help in making proper choices about PBAs and foam processing parameters.
Improvement of the Mechanical Properties of Soy Protein Isolate Based Plastics
Biodegradable plastics based on soy protein were prepared with glycerol as a plasticizer and compounded with different additives such as: polycaprolactone and zinc stearate as well as heat treated at various temperatures after the injection molding process in order to characterize base material strength and the effect of water absorption. The results indicated that the polycaprolactone and, respectively a medium to high heat treatment enhanced the tensile strength and decreased the water absorption significantly.
Injection-Molding Degradation of Biodegradable Polylactide
The effects of degradation on the mechanical and aesthetic properties of injection-molded biodegradable polylactide (PLA) parts were studied. Standard tensile test specimens were molded from NatureWorks 3051D injection-molding grade PLA. Barrel residence time, machine nozzle temperature, and shear rate were varied during the injection-molding process. The resulting specimens were analyzed in a tensile testing machine. Tensile strength, tensile modulus and visual inspection were used to characterize the extent of degradation that occurred during each process.
Chemical Recycling of Pet with Solid State Shear Pulverization Technology
Post-consumer PET (polyethylene terephthalate) bottles have been recycled into film and sheet products ever since the Containers and Packing Recycling Law came into effect in 1997. There has been a growing need, however, for a chemical recycling process. In this process post-consumer PET bottles are recycled into monomers that can be used as feed stocks for the recycled production of PET bottles for beverages. This paper reveals a chemical recycling process using an alkali solution in order to depolymerize PET material in to its monomers (terephthalic acid and ethylene glycol) within a short time. Unlike ther researchers, we did not use the flakes of PET, but used powdered PET produced based on solid state shear pulverization (SSSP) technology to achieve maximum yield (98%) and purity (95%) of the monomers in a short reaction time. The powdered PET has unique physical properties that affect experiment conditions temperature and pressure. The resulting terephthalate salt was treated with sulfuric or hydrochloric acid to yield highly pure terephthalic acid. Results show that the best percentage conversion of PET flakes is 1.5mol/l NaOH for 2 hours in 200 °C and for PET powder 1 .5 mol/l NaOH for 1.5 hours in 150 °C.
Clear Barrier at Atmospheric Pressure – the Second Phase
The barrier properties of transparent layers deposited on flexible plastic substrates are of interest to many in the packaging industry. Numerous methods have been used to manufacture transparent barrier coatings with varying degrees of success to address evolving environmental laws requiring the reduction or elimination of volatile organic compounds (VOCs), which are the byproduct of curing liquid topcoats. There is also a consumer preference to visually inspect packaged products through packaging prior to purchase. This paper will present new evidence since the 2006 SPE FlexPack Conference of the potential for clear barrier at atmospheric pressure through the use of plasma processing as integral steps in a composite, or several stage, process for deposition and polymerization of functional barrier coatings. XPS analysis of polymerized film showed presence of silicon, carbon and oxygen in ratios different from the monomer, and in fact approaching a Si:O atomic ratio of 1:2 confirming cross linking effects, and the plasma polymerized organo-silicon films displayed good functional barrier properties without the environmental concerns of VOCs.
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