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.
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.
BIODEGRADABLE POLYURETHANE/SOY PROTEIN SHAPE-MEMORY POLYMER BLENDS PREPARED VIA ENVIRONMENTALLY-FRIENDLY AQUEOUS DISPERSIONS
Biodegradable and biocompatible shape-memory polymer blends of soy protein (SP) and polyurethane (PU) based on poly(?æ-caprolactone) (PCL) has been synthesized using environmentally-friendly aqueous dispersion technique. High-pressure supercritical carbon dioxide (scCO2) foaming technique was applied to the blends to generate three-dimensional interconnected porous structures or scaffolds with special enhanced benefits for potential biomedical applications such as soft tissue engineering and/or drug release. Blending PU dispersion (PUD) with SP significantly increased the biocompatibility and biodegradability properties of the materials and improved their shape-memory capability. The PCL soft segment was found to be miscible with SP over the entire range of concentration as confirmed by DSC measurements, where a single Tg located between the Tg of the pure SP and PCL soft segment was observed for all blend concentrations. The shape-memory behavior of the blends was investigated for different concentrations under free-stress condition. The rate of strain recovery was found to be SP concentration dependent. The stress recovery of the blend reached a maximum value at wSP = 0.1 weight fraction. This finding was attributed to the maximum increase in the degree of crystallinity of PCLsoft segment at wSP = 0.1 as conformed by X-ray analysis.
BIODEGRADATION OF POLY(HYDROXY BUTANOIC ACID) COPOLYMER MULCH FILMS IN SOIL
Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene mulch films; these are not environmentally friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, and film retrieval and disposal costs. In this study, an in-house laboratory scale test method has been developed in which the rate of disintegration, as a result of biodegradation, of films based on polyhydroxybutanoic acid (PHB) copolymers were investigated in a soil environment using residual weight loss method. The influence of soil composition, moisture levels in the soil and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films will be discussed.
HOW NUCLEATED MMW HDPE RESINS INFLUENCE BARRIER FILM STRUCTURE DESIGN
This paper describes a film structure study involving nucleated medium molecular weight high density polyethylene (MMW HDPE) materials that enhance film properties. Using these new nucleated MMW HDPEs, several film structures have been designed to improve moisture barrier, oxygen barrier, toughness and cost, as well as reduce the environmental footprint by downgauging existing film structures. The films in this study use a variety of polyethylene materials commonly used in the film converting industry.
IMPROVEMENT OF INTRINSIC VISCOSITY OF RECYCLED PET BY RADIO FREQUENCY HEATING
The improvement of Intrinsic Viscosity of recycled poly(ethylene terephthalate)(R-PET) pellets by an industrial radio frequency(RF) heating is described. RPET pellets are made from post-consumer PET bottles, degraded by hydrolysis during distribution process. Hence, intrinsic viscosity(IV) or molecular weight of RPET exhibits significant lower compared to virgin PET, caused from cleavages of chains. This study indicates thermal recycling method of solid phase polymerization to improve the IV values, namely molecular weight of RPET pellets.
IMPROVEMENT OF INTRINSIC VISCOSITY OF RECYCLED PET BY RADIO FREQUENCY HEATING
The improvement of Intrinsic Viscosity of recycled poly(ethylene terephthalate)(R-PET) pellets by an industrial radio frequency(RF) heating is described. RPET pellets are made from post-consumer PET bottles, degraded by hydrolysis during distribution process. Hence, intrinsic viscosity(IV) or molecular weight of RPET exhibits significant lower compared to virgin PET, caused from cleavages of chains. This study evaluates the feasibility of RF Heat Treatment to improve the intrinsic viscosity of the material.
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