SPE Library

Torque, time, and temperature were simply applied to monitor the dynamic esterification of degradable starch-based polymers reacted by different types of acids and catalyst. The formation of C=O double bond and C-O single bond at the region of around 1710cm-1 and 1250cm-1 respectively denotes some successful consequence. SEM was furthermore applied to check the compatibility between modified starch and polymer while TGA for the check of starch before and after modification.

A prior advanced materials selection process via the digital logic approach (DLA) yielded five materials as suitable choices for the housing of the Signal Detector Control Head Unit (SDCHU), with ABS (acrylonitrile-butadiene-styrene) terpolymer and aluminum 1100 as the top two choices. In an effort to study the long term perspective, durability and environmental impact of the SDCHU, a life cycle value analysis (LCVA) was performed on the SDCHU with ABS as the housing material and then with aluminum 1100 as the housing material. The LCVA results indicate that ABS is the choice material in seven of the eight impact categories studied such as costs, energy usage, conventional pollutants, green house gases released, fuels used, ores used, hazardous waste generated and water used. Normalized environmental impact data show that the 5.6% increase in hazardous waste is offset by the 8 - 52% reduction in the other seven categories due to ABS use in the SDCHU housing.

This study focuses on the ability of U-PVC to be processed a number of times. Three different types of U-PVC were investigated: virgin lead stabilised and virgin calcium/zinc stabilised material and reground, 20 year old, post-consumer windows. Each material was extruded four times and samples taken at each stage for rheological and mechanical analysis.

Foamed products based on renewable raw material have a high application potential e.g. for packaging because of their biodegradeability. This may permit renewable raw materials to substitute polymers like polystyrene in some applications.A common way to process renewable raw material like starch is to produce starch based resins with twin screw extruders. These resins can be used on conventional polymer processing machines, but the step of compounding the starch on twin screw extruders causes costs which make these resins economically unattractive.Due to a new extrusion technology these costs can be reduced by a direct processing of starchy material like maize. A characteristic of this extruder is a very short (2 L/D), conic, multiple flighted screw in a barrel with spiral grooves. The energy for the plasticizing process is yielded just by the transfer of mechanical energy of the rotating screw into friction in a shear gap between screw and barrel.In order to understand the process different geometries of screw and barrel have been used in the experiments, additionally the process parameters have been varied. The results lead to an optimised configuration of the extruder and to a better understanding of the influence of process parameters on the product properties.

This paper presents an investigation on the strategies to increase the post consumer HDPE recycling of extrusion blow molded oil containers in Australia and proposes a novel oil drain rack designed to drain out the residual oil effectively from the used oil containers, based on the requirements of the clients.

The manufacturing of Plastic Fuel Systems is an ever changing and technology driven field. The field is influenced by governmental emission standards that are becoming tougher to meet with plastic fuel tanks. Several new technologies have been developed to accommodate the environmental legislative changes.

The Stress Corrosion Cracking (also called Environmental Stress Cracking) process in Polybutylene (PB) tubing consists of three stages: 1) Crack initiation, 2) Slow crack growth, and 3) Dynamic crack propagation. The first two stages primarily determine the useful lifetime of PB tubing, since the third stage occurs in a relatively short time interval. In this paper, an examination of PB field failures, observation of crack initiation mechanisms, and evidences of chemical degradation as a primary cause of failure are presented. To evaluate crack initiation time in mechno-chemical conditions, a modification of ASTM standard environmental stress cracking technique is employed to accelerate the crack initiation process in PB and a simple extrapolation technique is proposed to estimate the time of crack initiation in service conditions.

Filled thermoplastic polyetherimide and polystyrene samples were prepared and their morphological and melt processing properties were studied with respect to the processing conditions and filler loadings. The results should provide insights that are needed to solve complex issues encountered in the industry dealing with the recycling and processing of this important class of thermoplastic materials.

Coatings or paints are generally pigmented polymeric dispersions or powders that are usually applied as a secondary process step to form a layer on the substrate. Eliminating coatings can drastically reduce the cost of the part as well as provide environmental advantages. In recent years there have been major advances in alternatives to coatings for automotive plastic parts. These advances are categorized into two main areas, material development and process development. From a materials perspective, new colorants and modifiers have been developed as additives to plastic resins that provide the aesthetic and physical and chemical properties required. From a process perspective, advances in process technology in areas of extrusion, co extrusion, injection molding, laminating films, and thermoforming of multiplayer sheets have been developed. This paper will examine these different alternatives to coatings for automotive plastic applications.

Over 2 million tons of post-consumer carpet is landfilled each year. This waste carpet is a potential resource for composites. Since waste carpets can be rapidly identified and sorted by face fiber, this paper focuses on the processing and properties of nylon 6 post-consumer carpet. The carpet is cleaned, shredded and extrusion pelletized. This feedstock is compounded with glass fibers and compatibilizers. Based on the properties achieved and the projected costs, applications are identified.

A continuous process for decrosslinking high resiliency polyurethane foam in an extruder with ultrasonic devices was developed. Rheological, structural and NMR relaxation and diffusion characterizations of decrosslinked foam were performed. The decrosslinked foam was blended with the virgin polyurethane rubber (PUR) and cured and the blend properties were investigated.

Injection molded bars have been made from blends containing recycled photodegraded polymers, then subjected to further ultraviolet (UV) exposure. Crystallinity measurements have been made at different depths from the exposed surface using X-ray diffraction and differential scanning calorimetry. Complementary information in the form of molecular mass distributions has been obtained using gel permeation chromatography, and the crystallinity results are interpreted in terms of molecular scission and photo-initiated molecular defects.

In recent years, pressure from economic and environmental requirements has been experienced in the field of polymer production. This trend towards single stage operational units, in processes such as low shear devolatilization of elastomer solutions, radical polymerization and polycondensation reactions, phase changing processes and the conversion from batch to continuous operation continues and has lead to the development of large volume, twin shaft horizontal processors (LVPs).These processors have been designed for applications requiring medium to long residence times (20-120 minutes).As an example of this new family of processors, the multi-purpose Reasol®, a new counter-rotating twin shaft processor, is introduced. Trials with model polymers have been performed in a 60L unit at the developer's test center. Its performance is described here by power consumption, RTD (residence time distribution) and self-cleaning and devolatilization efficiency.Trials show that product transport through the new LVP is characterized by a narrow RTD with a high degree of self-cleaning. Typically, the RTD exhibits a Peclet number in the region of 25-35. It is also shown that, unlike typical twin-screw extruders, the shape of the RTD curve is largely unaffected by the rotor speed or mass rate. Furthermore, rotor speed has a relatively small effect on mean residence time thus allowing the freedom to optimize rotor speed with respect to other processing objectives such as heat transfer, surface renewal or shear rate.The indications are that the characteristics of the RTD, power consumption and devolatilization are analogous to more traditional equipment such as twin screw extruders in spite of the larger free volume and residence time and the lower shear.The new LVP is commercially available up to sizes of 12,500 litres net processing volumes.

In this work, an extrusion process has been developed for the devulcanization of rubber crumb from recycled tires employing supercritical CO2. For that purpose supercritical CO2 has been injected in a twin screw extruder to swell the rubber crumb and to facilitate the otherwise impossible rubber extrusion process. As a consequence, waste rubber can be processed under mechanical shear and extensional forces at various operating conditions that may lead to different degrees of devulcanization.

Biocomposites such as particleboard and medium density fiberboard are currently made with formaldehyde-containing adhesives. Since the government is continuously developing and implementing very stringent regulations to eliminate formaldehyde emissions into the environment, alternative approaches must be developed to replace these adhesives. This study examined the concept of using a reactive extrusion process as a means of developing a new, formaldehyde-free binding system for wood composite products. The surfaces of wood particles were modified by grafting maleated polyethylene through a continuous reactive extrusion process. Chemical changes resulting from this treatment were followed by studying the FTIR and XPS spectra. The modified wood particles were compression-molded into panels, which were tested for bending properties. Both FTIR and XPS data revealed that the chemical reactions have taken place between the hydroxyl groups of wood particles and maleated polyethylene. The modulus of rupture (MOR) results showed that the composite panels compared favorably with current standard requirements for particleboard.

This work presents the effects of incorporating post-consumer and post-industrial recycled HDPE to their virgin counterparts and to LDPE in different contents to produce tubular film for packaging. Tensile, surface and optical properties for each blend were measured.A reduction in the HDPEs blends physical properties and an increment in those of the LDPE/recycled HDPE blends were obtained as the recycled HDPE component was increased.

Failures of plastic components are being seen more often in industrial, household and commercial settings. Many of these failures involve the transport of water and cause significant damage when they occur. These failures can be caused by improper material specification, bad design, over loading or incorrect molding conditions. Issues such as chemical resistance, environmental deterioration, geometric sensitivity, temperature dependence and aging are at times overlooked.

Eco-friendly green" composite materials are fabricated from inexpensive chopped natural fiber and poly(3-hydroxybutyrate) (PHB) through extrusion followed by injection molding processing. The incorporation of natural fiber in to the composite structure improved the modulus and impact strength of virgin bioplastic. Maleated PHB is synthesized by us and is also used as a compatibilizer in PHB based biocomposites."

Polymer blends such as result from recycling of postconsumer plastics often have poor mechanical properties. Microcellular foams have been shown to have the potential to improve properties, and permit higher value uses of mixed polymer streams. In this study, the effects of microcellular batch processing conditions (foaming time and temperature) and HDPE/PP blend compositions on the cell morphology (the average cell size and cell-population density) and impact strength were studied. Optical microscopy was used to investigate the miscibility and crystalline morphology of the HDPE/PP blends. Neat HDPE and PP did not foam well at any processing conditions. Blending facilitated the formation of microcellular structures in polyolefins due to the poorly bonded interfaces of immiscible HDPE/PP blends, which favored cell nucleation. The experimental results indicated that well-developed microcellular structures are produced in HDPE/PP blends at ratios of 50:50 and 30:70. Improvement in impact strength was associated with well-developed microcellular morphology.

Recycled poly(ethylene terephthalate) (R-PET) was chain extended with pyromellitic dianhydride (PMDA) in an industrial scale twin-screw reactive extrusion system. Reactive extruded recycled poly(ethylene terephthalate) (RER-PET) samples at different PMDA concentrations were characterised in terms of rheological properties; thermal transitions and crystallinity. The results confirm the increase in molecular weight with an increase of PMDA concentration, and the formation of branching at concentrations above 0.25 wt.% PMDA. Structural changes due to PMDA addition affect the Tm, Tc and the crystallinity; however, no significant change was observed for the Tg.