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.
Use of recycled carbon fibers in thermoplastic articles
Carbon fibers are widely used in the aerospace and sporting goods industry to reinforce thermoset matrix composites. Carbon fibers are also finding use within the automotive industry in thermosets and thermoplastics, due to the high specific modulus and strength. With use, comes manufacturing waste and disposal issues. Typically, carbon fiber containing composites are considered unrecyclable. Recently, carbon fiber has been reclaimed from the composite manufacturing process. This has been largely driven by the need to increase the supply of carbon fibers in the marketplace, but also the desire to reduce costs of materials made with carbon fiber. Costs of carbon fiber can range to $40/lb. Costs of engineering thermoplastics can rival and exceed the cost of carbon fiber. Thus, displacement of either of these two materials with a cheaper, physically equivalent material will make carbon fiber reinforced materials more economically tenable in the market. The disposal of manufacturing wastage from composite manufacture drives up cost of production of these engineered lightweight materials. With properly designed processes, recycled carbon fiber may be able to be produced for a fraction of the cost of virgin fiber. The economic recovery of these fibers will allow for the economic use of carbon fiber in more products than is currently feasible. Recycled fibers compounded with engineering resins were used to fabricate thermoplastic parts. This report will detail the processes used to obtain the recycled carbon fibers, the properties of the materials, products manufactured and details of economic and engineering factors in the recycling of composite materials.
Recycling Mixed Domestic Post Consumer Film
Mixed Domestic Plastics will become an important source of plastic recyclate feedstock over the coming years, three streams are typically found – bottles, rigids and flexibles (films). Bottles and trays are readily sortable and recyclable back into similar articles. Film poses significant recycling problems. Recycling Mixed Domestic Post consumer film poses many challenges, this paper outlines the principal issues, both technical and commercial and provides solutions to move the process forward. Mixed Domestic film recycling poses five principal technical hurdles – 1. Handling of commingled film waste including residual paper, cans etc 2. Separation of olefinic & non-olefinic streams 3. Devolatilisation of highly printed film 4. Compatibilisation of mixed olefinic (PE/PP) stream 5. Management of residuals in recyclate Described is the front end of the process to handle commingled waste, separation techniques for the two streams, level/type of devolatilisation required to negate ink/print effects, compatibilisation methods to homogenenise PE/PP and information on final applications, including commercial examples.
Plastic Ocean Debris and Biodegradation in the Marine Environment
Marine debris or ocean litter is a worldwide problem. In fact, 60 to 80% of the ocean litter is plastic based. 80% of the ocean debris is from land based sources. Plastic pellets from plastic manufacturers can flow into storm drains and end up in the oceans. The plastics can harm the environment in three ways: (1) plastic marine debris can cause injury and death to marine life by ingestion or entanglement; (2) plastic marine debris can release toxic chemicals in the marine environment that fish and other marine species consume and then are absorbed by humans when the animals are eaten; and (3) plastic marine debris can absorb toxins from industrial, urban, and agricultural runoff that are in the marine environment in higher concentrations than the surrounding water, and then enter our food chain through aquatic species who eat the plastic. UV light and oxygen can cause degradation of plastics in the marine environment. Biodegradation can occur for some biobased plastics. ASTM standards provide methods to test for biodegradation of biodegradable plastics. PHA and bagasse biodegradable plastics have shown biodegradation in the marine environment.
Microcellular processing of biobased, biodegradable polymer blends
Using microcellular injection molding to prepare renewable polymer composites could lead to components with lower cost, improved material properties, and an extended range of applications.
Using low-cost waste for polyhydroxybutyrate bioplastics
Biopolymer-based composites reinforced with a byproduct of coconut-fiber processing were made successfully using compression molding.
A STUDY OF ELECTROSPUN POLYCAPROLACTONE (PCL) FIBERS FOR POSSIBLE BIO-ABSORBABLE MESH REPLACEMENT IN VAGINAL SURGERY
The importance of electrospun fibers as tissue scaffolds has been an area of significant growth. In this work, we will utilize electrospinning in conjunction with a biodegradable polymer, Polycaprolactone (PCL) to make thin fibers. These PCL fibers can be made into a mesh for tissue scaffolds. Electrospinning utilizes electrostatic force to draw fibers from solution.
A NOVEL 3-D BLOW MOLDING METHOD AND ITS PART THICKNESS CONTROL STRATEGY
In this study, a novel air traction 3-D blow molding machine was presented. Distinct from conventional blow molding machine, this 3-D blow molding machine utilized compressed air to draw the extruded parison through the closed mold. The results showed that the new 3-D molding machine was low flash waste and high molding quality. To further improve the performance of the 3-D blow molded product, a control strategy based on fuzzy iterative learning control algorithm was designed and implemented to control the wall thickness of blow molded part. The results showed that after five times iterations, the average axial thickness of 3-D bend pipe converged to the object area of thickness.
A STUDY OF THE FACTORS INFLUENCING THE PERFORMANCE OF A DIRECT TO PLASTICS WATER BASED COATING FOR THERMOPLASTIC OLEFINS
There is an increasing trend towards the use of Thermoplastic Polyolefins (TPO) in the marketplace particularly in the automotive sector due to the desirable mechanical properties. In order to achieve adhesion of coatings to TPO, automotive manufacturers have traditionally used solvent based chemical adhesion promoters or other forms of surface pretreatment to overcome the lack of bonding sites on this low surface energy substrate. Each of these pretreatment methods has their own drawbacks and all add an extra step to the coating process. A water based direct to plastics (DTP) coating for TPO is therefore very desirable due to the lack of flammable, environmentally detrimental solvent as well as the elimination of the pretreatment step. The barriers to achieving adhesion to TPO with a water based coating include the inability to wet out water over such a low surface tension substrate and the lack of bonding sites on the substrate. Once the barriers to adhesion are overcome, the coating must still meet the performance requirements of the finished coating. This paper explores a water based DTP coating and the role that adhesion promoters, surface tension modifiers, and resin systems play in the adhesion and overall performance of the coating on TPO. The study indicates that the selection and concentration of each of these is very important in overcoming the barriers to applying a water based DTP coating to TPO and achieving the overall performance required. In addition, the curing schedule for the coating systems examined plays a critical role in achieving the desired results.
A STUDY ON MATERIAL DISTRIBUTION AND MECHANICAL PROPERTIES IN CO-INJECTION MOLDING
In the co-injection molding process, sometimesreferred to as sandwich molding, two different polymermelts are either simultaneously or sequentially injectedinto a mold to form a part with a skin/core structure. Coinjectionmolding offers the flexibility of using the bestproperties of each material to reduce material cost andpart weight. Particularly, it allows, the use of recycledmaterial in the core without an adverse effect on surfacequality. The properties of a co-injection molded productdepend on the individual properties of the skin and corelayers, and the skin/core volume ratio. This paper presentsa study of the effect of molding parameters on materialdistribution and mechanical properties of co-injectionmolded plates. Two virgin materials were triedpolypropylene (PP), and thermoplastic polyolefin (TPO)as well as grinded TPO from plastic bumpers.
BLENDING OF RECYCLE PE BLOWN FILM AND INJECTION MOULDING GRADES
The affects on the mechanical and rheological properties of blends of recycled blown film (BM) and injection moulded milk containers (IM) were studied. Tensile, flexural and thermal properties remained unchanged with resultant increasing MFI. Anomalous results appear to occur between the 80/20% w/w (BM/IM) and 60/40% w/w (BM/IM) blends as confirmed by GPC, MFI and density.
ADHESION OF BIODEGRADABLE PLASTICS WITH BONE: A COMPARATIVE STUDY USING COMMERCIALLY AVAILABLE SCREW / PLATE SYSTEM AND BIODEGRADABLE POLYMER MELT ADHESIVES
Biodegradable bone plates are commonly secured to bone surfaces using screws in craniomaxillofacial surgery. Using melt adhesives potentially replaces the need for existing screws and the associated complex techniques and equipment. Previously we have shown the advantages of using biodegradable melt adhesives over screw systems. A time-based study comparing the effect of using melt adhesives and screws to secure bone implants to bone in a live goat model was performed. This paper demonstrates and compares the impact of using screws, plates, and melt adhesives on the healing of bone and operative time.
ADHESION OF BIODEGRADBLE PLASTICS WITH BONE: A COMPARATIVE STUDY USING COMMERCIALLY AVAILABLE SCREW / PLATE SYSTEM AND BIODEGRADABLE POLYMER MELT ADHESIVES
Biodegradable bone plates are commonly secured to bone surfaces using screws in craniomaxillofacial surgery. Using melt adhesives potentially replaces the need for existing screws and the associated complex techniques and equipment. Previously we have shown the advantages of using biodegradable melt adhesives over screw systems . A time-based study comparing the effect of using melt adhesives and screws to secure bone implants to bone in a live goat model was performed. This paper demonstrates and compares the impact of using screws plates and melt adhesives on the healing of bone and operative time.
ADVANCED MATERIALS FROM NOVEL BIO-BASED RESINS
Cereplast Hybrid ResinsTM also known asBIOPOLYOLEFINSƒ?› are bio-based plastic resins replacing 50 percent or more of the petroleum content in traditional plastic products with renewable source materials such as starches from corn tapioca wheat and potatoes. The addition of CereplastHybrid Resins TM to the existing line of CompostableResins TM further establishes Cereplast as the leadingsolutions provider in environmental and sustainable plastics. The first product from the Cereplast HybridResins TM family is BiopropyleneTM a 50 percent biobasedresin that can replace traditional polypropylenein many applications. Cereplast Hybrid Resins TM canbe processed at the same cycle time as traditional plastics on conventional equipment but requires less energy in the production process by using significantly lower processing temperatures. Inaddition Cereplast Hybrid Resins TM meet therequirements for toxicity set by ASTM D 6400-04specifications making Cereplast Hybrid Resins TMsafe for all applications. This paper further discusses mechanical properties and potential applications ofBiopropyleneTM.
CHARACTERIZATION OF VIRGIN-RPET COMPOSITES
Thermoformed polyethylene terephthalate (PET) produce trays (clamshells) produced by a large retail supplier using virgin resin were compared to PET clamshells containing 30, 70, or 100% recycled-PET (RPET). Comparisons were made of functional groups, ultravioletvisible (UV-Vis) light absorption, and thermal properties. An increase in the crystallization temperature was observed as RPET increased when compared to virgin PET. This suggests that the crystallization temperature (Tc) may be used as a quantitative indicator for determining the amount of RPET in a plastic composite.
AN OVERVIEW OF ENVIRONMENTAL ALTERNATIVES AS VIEWED BY A PLASTICS INDUSTRY ECONOMIST
The plastics industry has been under heavy criticism from environmentalists for contributing to pollution and litter, exposing consumers to toxic matter, and using more than its fair share of energy resources. Are any of these accusations valid? If so, has our industry been responsive to these challenges in a meaningful way? Do the solutions offered by the environmentalists, to the problems they raise, have merit? This paper will attempt to address major environmental issues at they concern the plastics industry from an economic and scientific viewpoint and summarize what makes sense and what does not.
ASSESSING AND IMPROVING NANOMATERIALS HANDLING IN EXTRUSION
The compounding of polymer nanocomposites involves the handling, feeding and cleaning of high volumes of potentially low bulk density powders. The Nanorisk Framework document  guides practitioners in how to assess the effectiveness of operations and engineering controls designed to contain nanomaterials and minimize the risk of exposure or environmental release. This paper reviews a new approach for measuring and evaluating the effectiveness of engineering controls and operating procedures when feeding nanofiller powders into a compounding extruder. A method will be described that uses the extruder itself as an effective means to reduce dust generation from the feed system.
ASSESSING AND IMPROVING NANOMATERIALS HANDLING IN EXTRUSION
The compounding of polymer nanocomposites involves the handling, feeding and cleaning of high volumes of potentially low bulk density powders. The Nanorisk Framework document guides practitioners in how to assess the effectiveness of operations and engineering controls designed to contain nanomaterials and minimize the risk of exposure or environmental release. This paper reviews a new approach for measuring and evaluating the effectiveness of engineering controls and operating procedures when feeding nanofiller powders into a compounding extruder. A method will be described that uses the extruder itself as an effective means to reduce dust generation from the feed system.
BENIGN PROCESSING OF HIGH PERFORMANCE POLYMERIC FOAMS OF POLY(ARYLENE ETHER SULFONE)
An environmentally benign process to produce high performance polymeric foams from poly(arylene ether sulfone) was developed. The high performance polymeric foams were produced by utilizing carbon dioxide and water as the physical blowing agents because they are plasticizers for the polymer. By controlling the vitrification of the poly(arylene ether sulfone) through the diffusion of the plasticizers and foaming temperature the cell size and foam density could be readily varied. The foam density varied between 15 to 85% of the unfoamedpolymer and cell sizes ranged between 1 to 200 ?¬m. Theaffect of the cell size and density on tensile properties will be discussed.
ENVIRONMENTAL STRESS CRACKING OF CPVC PIPE BY MIXED GLYCOLS
CPVC pipe is often used for containment of water in fire sprinkler systems, usually with glycerol as the antifreeze, but too often with ethylene or propylene glycol. Environmental stress cracking has caused much distress and economic damage. This test program shows that a mixture of these two glycols can be more damaging to CPVC pipe than either of the glycols by itself. Earlystage cracks are also illustrated, as observed by Scanning Electron Microscope at 1000X magnification.
ENVIRONMENTALLY SUSTAINABLE THERMOPLASTIC FOAMS: POLYLACTIDE FOAMS VERSUS POLYSTYRENE FOAMS
Polystyrene (PS) foams have a number of desirable properties and thereby have been used for many applications. However, one of the most notable drawbacks of PS foams is its non-biodegradability. In recent years, polylactide (PLA) has been viewed as an environmentally sustainable substitute of PS. In this context, this paper aims to provide head-to-head comparisons between PLA and PS foaming processes, in terms of the cell formation mechanisms and foamability of the resultant foams.
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