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.
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.
Wood Fiber Composites from Recycled Polyolefin
Wood composites based on recycled polypropylene (PP) were fabricated by melt processing. Different formulations involving two different types of coupling agents two different types of reactive additives and an impact modifier (IM) were used. The reinforcements were in the form of wood sawdust. The mechanical performance of the resulting composites was evaluated before and after conditioning in water for 1 and 7 days. The composites show superior mechanical properties when compared with the pristine matrix and resist humidity very well. The results also demonstrate the effect of formulations on the performance of the recycled composites.
Wood Fiber Reinforced Poly(lactic acid) Composites
Natural fiber-reinforced composites are increasingly being used in applications in the automotive furniture or building industry. The processing and physical properties of these composite materials are the very important parameters in respect to the design layout and product guaranty. This paper presents the results of the study of processing and physical properties of environmentally friendly wood fiber reinforced poly(lactic acid) (PLA) composites that were produced by a micro-compounding molding system. Wood fiber-reinforced polypropylene (PP) composites were also processed and compared to PLA/wood fiber composites. The mechanical thermal-mechanical and morphological properties of these composites have been studied. PLA/wood fiber composites have mechanical properties of sufficient magnitude to compare with conventional thermoplastic composites. The tensile and flexural properties of the PLA/wood fiber composites were significantly higher when compared with the virgin resin. The addition of 20 wt % of wood fibers in PLA/wood fiber composite improved the flexural strength of PLA by 19 % the flexural modulus by 115 % and the tensile strength and tensile modulus by 5 wt % and 77 % respectively. The flexural modulus (8.9 GPa) of the PLA/wood fiber composite (30 wt % fiber content) was comparable to that of traditional (i.e. polypropylene/wood fiber) composites (3.4 GPa). Incorporation of the wood fibers in PLA resulted in a considerable increase of the storage modulus (stiffness) and a decrease in the tan delta values. The addition of the maleated polypropylene coupling agent (MAPP) improved the flexural and Izod impact properties of the wood fiber reinforced composites. The morphology as indicated by scanning electron microscopy (SEM) showed good dispersion of wood fiber in the PLA matrix. Microstructure studies also indicated a significant interfacial bonding between the matrix and the wood fibers. The specific performance evidenced by the wood fiber reinforced PL
A New Class of High-Performance Compostable Plastic Bags and Can Liners
Heritage Bag Company has developed compostable bags and liners, which are produced from composites utilizing polymer and mineral materials technology of Heritage Plastics, Inc. This product line is based on proprietary blends of different biodegradable polymers which have been modified using mineral reinforcement technology to produce a readily extrudable polymer composite. This modification yields polymer processing, end-use products such as film and bags with characteristics very similar those obtained with higher-alpha olefin LLDPE resins, yet meet the requirements of ASTM D 6400-99.
Application of Recycled Industrial Polyolefins in Pail Design Using FEM
This paper presents the application of recycled industrial HDPE and PP and their blends with virgin resins in pail design using finite element analysis. Results predict that these blends can be used in pails for the packaging of non food grade materials such as paints, oil and grease.
Abbreviated Terms for Plastics - Implications and Challenges
Abbreviated terms are routinely employed in the plastics industry in generic marking of molding products to assist in identification of the plastics for separation in recycling besides in trade and technical literatures. Existing ISO, ASTM and other standards provide clear guidelines for abbreviated terms for polymer families. In practice, however, a wide range of inconsistent abbreviated terms are quite common in the industry. This has significant implications for the general consumers as well as those involved with plastics recycling. The challenge is to arrive at uniform globally acceptable single set of abbreviated terms in order to addressing this issue.
Compatibilization of Polypropylene/Polysulfone Membranes
Polypropylene (PP) and polysulfone (PSU) have not been previously blended due to viscosity and processing temperature variations. These blends made using an environmentally-friendly process showed structureproperty improvements with the addition of functional polyolefins.
Applications of Thermoformability Analyzer
Thermoforming consistent parts depend on knowing and controlling several material and process variables, the most important being the quality of the sheet feed stock. The extruded sheet of the same material could vary in terms of polymeric contamination, thickness, thermal stresses, and amount of regrind, volatiles, color, gloss and grain. Mold material and mold temperature could also vary. Many times, effects of such variations manifest during actual thermoforming in form of tearing, wall thinning, shape distortion, fading, pinholes, and grain distortion. We illustrate use of novel equipment for rapid detection of such variables and their effects on thermoformability, sparring need for expensive plant time and material waste.
Development and Use of Eco-Plastics in Mexico and Latin America
In Mexico and other countries of Latin America, the per capita consumption of plastics has more than doubled during the last decade. This results in the increased generation of plastic residues which leads to the growing plastics waste disposal problem. This paper presents a concept of Eco-plastics" which is an integrated approach to solving plastic waste generation challenges in Latin America. A feasibility study is recommended as a first step towards the implementation of this concept."
Dispersed Nanoclay in GFRP as a Barrier Against Environmental Attack
E-glass fiber-reinforced vinyl ester plastics with up to 5 wt% montmorillonite dispersed in the matrix were immersed in distilled water for nine weeks. At one week intervals, samples were removed and sectioned, both perpendicular and parallel to the fiber direction. Scanning electron microscopy revealed progressive degradation of the matrix and the glass reinforcement. However, the rate of moisture attack decreased with increasing amount of dispersed clay; this was confirmed by strength, stiffness and ductility measurements.
Eco-Design of Plastics Products
An unintended consequence of the growing consumption of plastics is the increase in amount of plastics products discarded daily by consumers worldwide contributing to growing share of plastics in municipal waste streams. With the product life cycle of most products getting shorter each day, product designers have a responsibility to minimize the negative impacts of their designs on the environment. This paper describes best practices for incorporating environmental impact considerations during various stages of plastics product development, and provides specific guidelines to assist designers for eco-design of plastics products.
Effect of Environmental Stress Cracking Agents on, Fatigue and Creep of a MDPE Pipe
The effect of environmental liquids on slow crack propagation in MDPE pipe is investigated. At 50°C, the differences in kinetics and mechanism of crack propagation in fatigue and creep are described relative to that in air. The relationship between fatigue and creep was strongly affected by the presence of environmental liquids.
Effect of Molecular Weight on the Interfacial Properties of GF/PP Injection Molded Composites
For the fabrication of GF/PP injection molded composite, 3 types of PP with different molecular weights were used in order to simulate the recycling process of PP. Effects of weight-average molecular weight on interfacial adhesion between GF and PP were investigated. Moreover, effects of fiber length was also examined through high-back and low-back pressure at the injection molding condition.
Bio-Based Polyurethane Nanocomposites
Polyols derived from soybean oil are new polyurethane raw materials derived from the renewable resources, and with isocyanates they produce polyurethanes that can compete in many aspects with ones derived from the petrochemical polyols. Combined with polyisocyanurates, they produce materials of good thermal, oxidative and weather stability.The main objective of this research is to synthesize mechanically reinforced polyurethanes, and study the influence of the concentration of nanoparticles on the properties of the new material. Two different soybean oil based polyols, SOY169 and SOY201 were selected to synthesize the polyurethane nanocomposites using a diisocyanate (pure MDI) as a curing agent. The clay used at different concentrations (0%, 1%, 3%, and 5%) in the synthesis of the nanocomposite polyurethanes was organo modified Montmorillonite clay, Cloisite®10A. Methanol was chosen as solvent media in preparing the samples.Several methods were used to analyze the samples like, mechanical tests – Tensile strength, Flexural modulus, and Notched Izod Impact strength; Thermal analysis – Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), and Thermogravimetric Analysis (TGA); Structural analysis – Atomic force microscopy (AFM), Fourier Transform Infrared spectra (FTIR).
Failures of Plastic Products Due to Not Adequately Replacing of Metals by Plastics
Replacing metals by plastics often results in unreliable products. The main failure causes will be presented. As a practical example mechanical and thermal failures of a waste water tank designed for metal and replaced by HDPE will be discussed in detail. The solution to a problem to design snap-fit assemblies on buckling ribs is outlined.
Bio-Fiber Composites from Recycled Polyropylene
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 contents, 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 humidity very well. The results also demonstrate the effect of formulations on the performance of the recycled composites.
Fracture Behaviour of Injection Moulding Post-Consumer Wood/Plastic Composite Foams
This study investigates fibre reinforced microcellular foams produced via injection moulding using recycled polymers. The objective is to determine the effect of wood, blowing agent and coupling agent contents on impact and tensile properties. Birch wood fibres were blended with a post-consumer HDPE/PP matrix to produce the composites. Azodicarbonamide was used as a blowing agent while maleic anhydride polypropylene copolymer was used as a compatibilizer. Optimal results were obtained with 20 wt.% wood contents.
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