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.
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Recycling
Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.
Effects of Montmorillonite Layered Silicates on the Crystallization Properties of Polylactic Acid
Recently, polylactic Acid (PLA) has been increasingly considered for many applications due to its origin from renewable resources and its biodegradability. Separately, there has been interest in montmorillonite layered silicates (MLS), because of their remarkable ability to improve polymer properties. Strength and barrier properties are particular improvements to PLA that are considered critical. We examine the influence of MLS and processing on the crystallinity of PLA nanocomposites. Screw speed and feed rate of an extruder connected to a blown film die were systematically varied. The materials were supplied by the Naticak Army Research Laboratory and developed by Ratto and Thellen.Increasing screw speed during manufacturing decreases the residence time and is associated with the generation of smaller crystallites. Feed rate is another variable that is considered.Permeability and non isothermal Differential Scanning Calorimetry (DSC) at a single heating rate was reported recently. Here we report on the Avrami parameters of the PLA and corresponding nanocomposites.
The Development of Soft TPO for Automobile Interior Skin That Enhance Recyclability
This study investigates soft thermoplastic olefin (TPO) for automobile interior skin such as instrument and door trim panel skin in order to replace polyvinyl chloride(PVC) resin, enhance recyclability and solve environmental problem. In this study, we investigated TPO material requirement by each process and results indicated optimum material composition for each process.
Fabrication of Composite Pipe With Recycled Polycarbonate and Crushed FRP Products
Injection molding with recycled polycarbonate (PC) and crushed FRP products was fabricated and examined on tensile, flexural and Izod impact test. The specimen of composition filled with 5wt% of FRP and modifier had highest mechanical properties. The composite had approximate equivalent tensile strength and higher Izod notched impact value than that of standard rigid PVC. Composite pipe made of this composition was manufactured by using extrusion process. The composite pipe has extreme high flexibility because in 50% diameter reduction of lateral compression test no fracture ccurred. Consequently, the composite pipe can become substitute of PVC.
Unexpected and Unusual Failures of Polymeric Materials
Some failures are predictable, such as due to exposure to environmental conditions. In this paper the focus is on failures that there was no reason to expect. While they may become obvious, they are unpredictable. Some are unusual, involving a cause and effect on the plastic that are not obvious. Examples are cracking of nitrile rubber, contamination of GPC samples by a filter syringe, and PVC plasticizer used for many years being declared unsafe.
Use of UV Cured Coatings on Plastics
As plastics fill more roles, they must offer the same physical properties as the materials they replace. Radically reducing VOC emissions and hazardous waste is now mandatory in many areas. Specialized formulation of resins can meet these needs to some degree. Coating the molded parts addresses all these concerns. UV cured coatings meet the most stringent environmental standards, while duplicating the physical properties of glass, wood, light metal and high VOC printing and finishing inks.
WEEE and RoHS - Environmental Design Strategies
Tough new environmental laws are rapidly spreading around the world that directly impact product design. Failure to heed them will result in lost revenue and increase the cost of doing business. This paper explains what they are and details essential strategies for dealing with them.
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.
Membrane-Mediated Electropolishing
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.
Biobased Nanocomposites from Toughened Bacterial Bioplastic and Titanate Modified Layer Silicate: A Potential Replacement for Reinforced TPO
Biobased ‘green’ nanocomposites are the materials for the 21st century. Polyhydroxybutyrate (PHB) a bacterial bioplastic is recently highlighted because of its renewable resource based origin and its potential to replace/substitute petroleum derived non-biodegradable plastic like polypropylene (PP). The major drawback of PHB is its brittleness. This work investigates toughening mechanisms for PHB via incorporation of elastomeric components. Maleated polybutadiene with high grafting and low molecular weight was identified as the compatibilizer. The toughened PHB was characterized through their thermo-mechanical rheological and morphological analysis. The resulting toughened PHB showed ~440% improvement in impact strength over pure PHB with only 50% loss in modulus. The loss of modulus was recovered to permissible extent through incorporation of titanate modified montmorillonite clay. The hydrophilic clay was modified by titanate-based treatment to make it organophilic and compatible with the polymer matrix. The toughened PHB on reinforcement with 5 wt.% titanate based modified clay gave ~400% improvement in impact properties and 40% reduction in modulus over virgin PHB. The novel toughened bioplastic nanocomposites show potential as a green replacement/substitute of specific TPO for use in structural applications.
Feasibility of Continuous-Fiber Reinforced Blanks for Automotive Applications
Recent developments in the rapid processing of continuous-fiber reinforced thermoplastics (CFRTP) offer a method for automakers and suppliers to manufacture high-performance structures that meet automotive cost performance and volume requirements. Benefits of thermoplastic composites include rapid processing high toughness ease of recycling long shelf life and multi-stage processing. CFRTP tailored blanks are flat net-shape preforms comprising aligned continuous reinforcing fibers in a thermoplastic matrix. These tailored blanks can vary in thickness fiber orientation material composition and shape based on part requirements. Main benefits include material efficiency low scrap and low weight. This paper investigates the feasibility of stamp forming CFRTP tailored blanks. Experimental results are presented showing effects of forming on consolidated tailored blanks and the potential for a high quality surface finish.
Hemp Fiber Reinforced Sheet Molding Compounds for Automotive Applications
Natural fibers have been steadily gaining interest for use as a mechanical reinforcement material in place of fiberglass for thermoplastic and thermoset composites. In addition to their lower cost and lower density natural fibers are a renewable material and are less energy intensive to produce (grow) than glass fibers. In the current study hemp fiber reinforced SMCs (sheet molding compounds) were prepared and compared to conventionally reinforced glass SMC for cost density and mechanical properties. Continuous hemp fiber (in the form of twine) non-woven hemp mats fiberglass and hybrids (fiberglass/continuous hemp twine mixture) were examined. Severl commercial resins were screened for copatibility to the various fiber formulations and the effect of added compression during the compounding process was studied. In addition to mechanical performance moisture uptake measurements were performed for the hemp glass fiber reinforced materials. Selected SMC composites were evaluated against typical desired properties for automotive applications. Results show that certain formulations are currently close to target values. Next steps for additional optimization of composite formulation fiber dispersion fiber compatibility and moisture resistance will be discussed.
Introduction of Corn By-Products to Composites for Use in In-Line Compounding
Composite Products Inc. has been developing their Advantage and Advantage Plus In-Line
Compounding Processes to use alternative rein forcements and filler materials for automotive
and non-automotive applications. While fiberglass remains the favorite when it comes to
reinforcing thermoplastic composites natural reinforcements are beginning to gain renewed
interest. Corn by-products when added to polypropylene can offer several advantages. Corn
by-products offer low cost weight savings environmental friendliness and relatively good
material properties.
Polyurethane Structural Composites: An Innovative Process using In-Mold Decorating Films for Exterior Vehicle Parts
The Woodbridge Group continues to progress with innovative composite technologies for high performance applications encompassing its extensive expertise in the PU fields as well as its growing experience in composites. This paper presents a novel fabrication technology of PU Composites applicable for
vehicles. The novel technology is based on an open mould pouring process that allows the usage of
relatively low cost tooling low tonnage presses as well as a high level of component integration and process automation for the production of performance products. The process eliminates the need of in-mold or post-painting of the finished part by integrating in the composite structure a high performance film as a decorative exterior layer that provides a high quality surface resistant to environmental factors. The new process allows the fabrication of relatively thin lightweight structural composite with flexural modulus in the range known in other technologies as Polyurethane Structural Reaction Injection Moulding (PU-SRIM) and Sheet Moulding Compound (SMC) with Coefficient of Linear Thermal Expansion (CLTE) compatible with the In-Mould Decorating (IMD) films. The specific gravity of the part dependent on composition is lower than for similar strength products manufactured via PU-SRIM or SMC. End-product performance easily matches or exceeds the requirements of general transportation or other similar applications.
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