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.
Effect of Photo-Oxidative Degradation on Environment Stress Cracking Behavior of Polycarbonate
The combined effect of two major causes of polymer failure, photo-oxidative degradation and environment stress cracking (ESC), have been investigated in this paper. Polycarbonate (PC) injection molded specimens were aged for 168 hours at 50 °C in an ultraviolet (UV) weatherable chamber. Then the stress relaxation and tensile tests were carried out in the ethanol environment to examine ESC behavior of PC. The results show that the tensile yield stress and stress relaxation resistance of PC improve slightly due to photo-oxidative degradation, while the ethanol will accelerate the failure of undegraded PC. When the previous degraded specimens were tested under the presence of ethanol, the stress relaxation rate increases significantly and the surface cracks appear to be more intensive in comparison with other ones. This indicates that there is a synergistic effect between photooxidative degradation and environmental stress cracking for PC injection molded parts.
Electrospun Protein and Polysaccharide Nanostructures to Improve Barrier Properties of Multilayer Systems Based on Polyhydroxyalcanoates and Biopolyesters
This work studies de effect of incorporating high barrier se lf-adhesive nanostructured interlayers of zein, pullulan and whey protein isolate between of polyhydroxyalkanoate (PHA) materials. Oxygen and water vapour barrier properties were greatly influenced by the morphology, thickness and inherent barrier of the electrospun interlayer materials. Thus, zein (in agreement with previous works) and pullulan formed fibrillar structures which significantly contributed to improve barrier properties of the multilayer systems. On the other hand, electrospun WPI formed bead microstructures and did not improve oxygen and water barrier properties of these multilayer systems. While the oxygen barrier properties was significantly improved by the presence of a zein nanostructured interlayer, the water vapour permeability of this multilayer system was seem to vary among materials since the zein interlayer was only efficient as a barrier element in the PHA materials as compared to polylactic acid (PLA).
Evaluating the Effects of Using Post Consumer Polyamide 6 (PCR-PA6) Resin for Automotive Component Application
Plastics consumption into various products has substantially grown over the years. Increasing resin prices and escalating environmental legislatives towards landfills are encouraging recycling of plastics. Recyclability of thermoplastic materials facilitates innovative application established on their residual contents. The plastic scrap thus is classified into predominant categories as postindustrial resin (PIR) and postconsumer resin (PCR). Postconsumer resin (PCR) is recovered from recycled products such as disposable packaging containers, bottles, and commodities in landfills. Discarded carpets are becoming a compelling source of PCR- Nylon resins. This paper evaluates the use of PCR-PA6 resin for automotive component application. The lifetime performance of these formulations was estimated through prolonged heat aging and testing at various intervals.
Evaluation of Natural Fiber Reinforced Recycled Polypropylene Composites
This paper examines the tensile strength and Izod impact behavior of natural fibers and wood particles in recycled polypropylene composites for injection molding. The initial round of testing compares the performance of the straight recycled polypropylene resin versus non-compatibilized natural fiber or particle composites, and then the different composite performance was indicated through the addition of a compatibilizer. The mechanical properties of natural fiber or wood particle and recycled PP composites without a compatibilizer were firstly compared with those of only recycled PP. Then, some natural fiber or wood particle and recycled PP composites using various compatibilizers were investigated. It was found that the elongation at break and the Izod impact strength of some natural fiber or wood particle and recycled PP composites using specific compatibilizer were indicated for high flexibility and adhesive formation as compared with some natural fiber or wood particle and recycled PP composites without a compatibilizer. The difference between natural fibers and wood particle was also discussed.
Experimental Analysis of the Material Degradation of PET on a Co-Rotating Twin-Screw Extruder
Plastics, starting from inexpensive mass-produced articles to technical high-end applications, are being used in ever more areas of life. The main drivers are their flexible product properties and the resultant broad application possibilities. To be able to offer plastic products inexpensively and conserve the environment at the same time, more and more attention is being paid to plastics recycling. Polyethylene terephthalate – in short PET – is of particular significance here because of its frequent application in the film and packaging industry and its special material properties. The recycling of PET, however, can only be carried out a limited number of times because it’s processing necessarily results in both thermal and mechanical stresses on the material. This is the basis for the reactions at molecular level, which result in a shortening of the molecule chains (material degradation) and exert a negative effect on the product properties. The aim of this study is to identify the factors that influence the material degradation of PET in twin-screw extrusion. To do this, various screw configurations and different speed and throughput conditions are examined in a series of experiments. Furthermore, material specimens are removed along the length of the screw in order to evaluate the influence of individual screw sections. By determining the intrinsic viscosity of the specimens, it is possible to measure the mean molecular weight and thus the material damage. Based on the test results, guidelines are drawn up for the compounding of PET so as to ensure as little damage as possible to the material.
Experimental Investigations of the Mechanical Recycling of Offcuts from the Production of Continuous Fiber-Reinforced Thermoplastic Sheets by Injection Molding
This paper examines the recycling of sorted plastic offcuts produced during the manufacture of continuous carbon-fiber-reinforced polyamide 66 sheets. The idea is to process the offcuts so that they can be conveyed to a value adding application. For this study, the offcut is shredded into recyclate and processed by injection molding to produce specimens. The processing properties of the recyclate and the mechanical properties of the specimens are at the focus of the investigations. Good processability of the recyclate is achieved in the tests by using a stuffing device in the hopper of the injection molding machine. With optimum injection molding parameters, an outstanding tensile strength of 293 MPa is obtained in the tests.
Tunable Synergistic Property Enhancements in Green Polypropylene Composites with Waste Paper and Cardboard via Solid-State Shear Pulverization: Size Reduction and Dispersion
Synergistic green composites of polypropylene (PP) with cardboard and waste paper are produced via solid-state shear pulverization (SSSP) without any compatibilizers or surface modification. The property enhancements are comparable to those from more expensive forms of cellulose. Additionally, optimization of SSSP processing, commercial viability and melt processability of the composites are evaluated.
Fabrication and Improved Performance Evaluation of Poly-(3-Hydroxybutyrate-co-3-Hydroxyvalerate) with High Molecular Weight Natural Rubber for Novel Composites
PHBV (Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)) is a bio-derived semi-crystalline polymer of interest to the packaging industry looking for alternatives to the petroleum based materials currently used. The brittle nature of PHBV material requires blending with other polymers such as Poly (?-caprolactone) (PCL), Poly (L-lactic acid) (PLA), and natural rubber. Natural rubbers (NR), cis-1,4-polyisoprene, are classified as elastomers due to their high elasticity and yield strength. Therefore, the objective of this study was to characterize the thermal and mechanical properties of PHBV blended with natural rubber in two different concentrations.
What Consumers & Customers Want in Sustainability
Today everyone is concerned about Sustainability - protecting today's environment for future generation. Sustainability has become major initiative by all companies. Consumers want sustainable/ Green packaging but most of them do not want to pay more for Green Packaging. Consumers & Customers want 'Cost-effective Sustainable' Packaging”. It's responsibility of everyone in supply chain to work together to meet demands of their consumers and customers.
Functional and Design Opportunities Using Physical Vapor Deposition and UV Curable Coatings
Interest in alternatives to electroplated chrome is expanding dramatically. Color and appearance affects are limited with traditional chrome electroplating and successful “paint-on-chrome” applications are expensive and highly proprietary. Collectively the automotive, home appliance and cosmetic market are actively searching for alternatives with the appearance and durability of electroplating, but without the environmental side effects, appearance and functional design limitations, and costs associated with this decades old process. “Chrome look” processes and coatings for decorative and automotive lighting PVD applications have been used in the UV curable coating industry for over twenty years. As development of UV curable coatings for PVD has progressed, so has the understanding of the process and its unique capabilities and applications. This paper will address the advantages of PVD as a chrome alternative to include functional / design capabilities that are either cost prohibitive, or impossible to achieve with electroplated applications, as well as describe some of the tradeoffs associated when using coatings systems as an alternative for chrome electroplating.
High Performance, Wear Resistant Thermoplastic Co-Polyester Elastomers (COPE)
New wear resistance (WR) thermoplastic co-polyester elastomers (COPE) deliver improved performance over a wide range of speed and load conditions in sliding or moving applications. These elastomers have excellent cold temperature impact strength and work well at a broad range of temperature and humidity conditions, primarily in injection molded articles. Various grades with wide range of hardness are suitable for applications requiring excellent tribological properties. These elastomers provide outstanding ductility combined with the excellent chemical and environmental resistance properties of polyesters. The unreinforced and higher flexibility COPE grades fill the property gap between standard thermoplastic polyester urethanes and vulcanized rubbers by providing excellent fatigue strength and hence an increased operational lifetime. These elastomers are easy to process, recyclable and retain their impact strength down to -30 °C.
Important Factors Impacting the Performance of Polyolefin Pipes
The use of polyolefins in pipe applications has global acceptance. As such, polyolefin based pipes are expected to maintain their properties over an extremely long service life where the polymer must withstand climatic, extractive and mechanical forces. The success of polyolefin pipes has been enabled by the development of suitable resins with a defined molecular architecture plus stabilization systems which have enabled the protection of the polymer during both melt processing and the end use application. Through the proper development of the stabilizer systems for this challenging application it is possible to protect the polymer and also extend the service life of the pipe under various environmental factors.
Improvement of Melt Strength and Crystallization Rate of Polylactic Acid and its Blends with Medium-Chain-Length Polyhydroxyalkanoate through Reactive Modification
Poly(lactic acid) (PLA) was reactively modified by using a multifunctional co-agent (triallyl trimesate) in the presence of dicumyl peroxide. The viscosity, elasticity and melt strength of PLA increased substantially following reactive compounding. Furthermore, the rate of crystallization of co-agent in modified PLA was significantly higher than that of the pristine PLA and a distinct crystallization peak appeared. Reactively modified blends of PLA with an elastomeric polyhydroxyoctanoate exhibited similar features, and significant improvements in blend morphology.
Investigation of Blending Methods and Phase Morphology of Poly (Lactic Acid)/ Polystyrene Blends
Biodegradable poly(lactic acid) (PLA) blend with other materials is widely demanded as an effective approach for preparation of porous materials. In the present wok, two phases blends of PLA and polystyrene (PS) were prepared by twin-screw extruder and Torque Rheometer. For the latter blending method, the effects of various conditions such as blends mass and the temperature of mixing chamber on phase morphology were explored. A bimodal distribution of porous structure was presented after extracting the PS phase from the samples prepared by two different blending methods. Different with Torque Rheometer, the blends of twinscrew extruder rarely appears reunion phenomenon; therefore, a better phase morphology can be expected. It further found that the phase morphology of blends was apparently optimized under proper post annealing conditions.
Investigation of Chemically Aged Elastomers Based on Analytical Methods
For over one hundred years, components made of elastomers have been commonly used in practice. However, the knowledge concerning the aging behavior of the material lags behind the existing demands of modern day industries. The property spectrum of elastomeric components extends across a broad range. Areas of application for such materials include aerospace, automotive, and mechanical engineering, plant construction, shipbuilding and civil engineering sectors. When considering the moldability, workability, flexibility and adhesion of elastomers, it is unsurprising that these materials are employed in so many industries. Yet, despite their application in numerous fields, only limited amounts of research has been carried out concerning these materials, and hardly exceeds basic examinations. Hence, intensive studies are necessary in this area. Previous research has already verified that the mechanical properties of elastomers change over time. These scientific findings make intensified research regarding the long-term behavior of elastomers indispensable. Chemical aging studies are highly significant, because the molecular structure and the networking of the material change during the aging process. Due to these changes, various material properties may also alter. In order to be able to make more accurate predictions concerning the life span and durability of elastomeric components, all environmental influences must be intensively researched experimentally. Basic research in the field of chemical aging is essential. In this paper, the aging behavior of natural rubber was tested using the media air, distilled water, and 3%- and 6% de-icing salt solutions.
Limitations & Level of Accuracy of Tests for Rotomolding Powders
The rotomolding industry commonly uses two connected tests to assess the quality of plastic powders: Dry Flow and Bulk Density. Industry-specific test methods are available for both parameters. Repeated measurements were carried out on five different rotomolding powders, in order to assess the influence of the various equipment and environmental parameters that are thought to affect the test. This enabled estimates to be made of the limits for the accuracy and repeatability that are achievable practically. The results obtained from the Dry Flow test suffer from significantly higher variance than those obtained from the Bulk Density test.
Mechanical Properties of Biodegradable Poly(Butylene Succinate) Blended with Poly(Ethylene Terephthalate) Recycle
This research was carried out to improve mechanical properties of PBS by melt blending with recycled PET flakes from drinking bottles. Content of PET adding was 1, 2 and 5% by weight. Properties of polymer blends were evaluated by tensile test, impact test, SEM, DSC, and TGA. It is found that blending PET into PBS yielded stronger mechanical properties compared to neat PBS. However, melt blending between them required high temperature enough to melt PET flakes, so it caused thermal scission in PBS molecules as evidenced in TGA analysis. PBS/PET blends had higher tensile modulus but reduced flexibility with higher PET content. For DSC analysis, it is found that blending PBS with PET increased crystallinity of PBS matrix due to nucleating effect of PET dispersed spheres.
Microcellular Foaming Behavior of Poly(butylene succinate)/Nanosized Calcium Carbonate Composites
In this paper, the foaming behavior and thermal property of biodegradable poly(butylene succinate) (PBS)/nanosized calcium carbonate(nanoCaCO3) composites were investigated. This article focused on the study of the effect of nanoCaCO3 on foam morphology of PBS using supercritical CO2 as the foaming agent. The presence of nanoCaCO3 acted as nucleation site to facilitate the crystallization of PBS that results in the increase of PBS crystallization up to 63.63%. The effect of incorporation of the nanoCaCO3 particles on the thermal stability was quantified by the temperature at 5% and 10% weight loss. Along with the addition of nanoCaCO3, the temperatures at 5% and 10% weight loss of PBS/nanoCaCO3 composites are higher than pure PBS. The SEM results shows that with the addition of nanoCaCO3, the foam samples cell size decreased and cell density increased greatly.
Morphological Analysis of Natural Fibers and Fiber Orientation Measurements for the Evaluation of Simulation Tools for Injection Molding Materials – NFC-Simulation
Due to environmental and sustainability issues, the request for renewable resources increases. Natural fiber-reinforced injection molded materials are therefore an interesting prospect for the automotive industry. To achieve a broader market launch of this new material in the automotive industry, numerical simulation of this new material is essential. Besides rheological and mechanical properties, the fiber morphology and the fiber orientation are the most important properties for the simulation. To evaluate the simulation results experiments are necessary. The morphology of natural fibers (sisal, hemp and regenerated cellulose fibers) was determined by image analysis of the original fibers and the fibers after the procedures of compounding and injection molding. Therefore the fibers were extracted from the granules and the injection molded components. The size of the fibers was significantly reduced during the compounding process, whereas no further reduction could be observed during the injection molding process. Quantitatively, the same results could be found in simulation based on a mechanistic model. Fiber orientation measurements were done via TeraHertz Spectroscopy to evaluate the simulation of the injection molding process and to be able to predict the mechanical properties of the components.
Morphological and Rheological Properties of PBS/Silica Nanocomposite Manufactured Using a High-Speed Twin-Screw Compounder
The effects of silica chemistry and high-speed compounding on the morphology and rheology of poly(butylene succinate) (PBS)/fumed silica nanocomposites were investigated in this work. The filler content of the nanocomposites was determined by thermogravimetric analysis and matched estimated values well. Depending on the distribution and surface chemistry of fillers, distinct surface texture could be identified in the PBS/silica nanocomposites. Using high-speed mixing and compatibilizing surface functionalizations can result in enhanced polymer-particle interactions and influence the composite rheology dramatically. The relaxation hierarchy can be identified from the linear viscoelastic response of PBS compounded with mixture of modified and pure fumed silica particles.
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