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Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.
Conventional cross-linked polyurethane (PU) or PU networks are unable to be reprocessed in the melt state into reshaped, high-value recycled products. This is because of the irreversible nature of the cross-links in PU, a common feature of thermosets which prevents the cross-linked network or thermoset from ever returning to a melt state. We have recently discovered several chemical platforms for making cross-linked polymers melt-reprocessable by instilling a reversible nature to the cross-links as a function of temperature. Here, we describe our approach for making reprocessable polyhydroxyurethane (PHU) networks that exhibit full property recovery associated with cross-link density after multiple melt-state reprocessing steps. PHUs are a class of non-isocyanate-based polyurethanes (NIPUs) that can be synthesized via reaction of amines with cyclic carbonates; the PHUs contain urethane linkages with adjacent primary or secondary hydroxyl groups. In the presence of appropriate catalyst, we have synthesized PHU networks with robust properties at room temperature and many tens of degrees above room temperature. These networks containing appropriate catalyst can be effectively reprocessed at least three times at 140 degrees C leading to full recovery within error of rubbery-state plateau modulus and room-temperature tensile strength and strain at break.
This study describes the preparation and characterization of electrospun films made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) produced by mixed bacterial cultures derived from a cheese whey (CW) industrial by-product. A mild thermal post-processing step carried out on the electrospun fibers mat, at a temperature below the biopolymer’s melting point, yielded a film with high transparency, enhanced crystallinity, and potentially sufficient mechanical and water barrier properties for sustainable packaging applications.
I would propose creating a summary of efforts to utilize PET in extrusion blow molding. The main processes for making PET bottles involve creating an expensive injection mold in combination with expensive blow mold tooling. This approach works for large volume production of 100million containers or more, but many potential packages for lower volume users are not well served. Resin suppliers have created grades of PET with increased melt strength that have begun to address this market need. These materials are imposing problems for recycling of PET which needs to be addressed. I think a summary paper of the activity that has taken place will be of interest to ANTEC attendees. I have not written the paper but will if the organizers wish a presentation.
Foaming technology is a useful way to optimize material consumption in plastic processing, increasing the material cost/benefit ratio and improving some properties such as the impact resistance, the insulation properties, and the dimension stability, among others. For compostable biopolymers, the foaming technology should not affect the biodegradation properties of the material.This work is oriented to analyze the effect of foaming parameters on the density and material hardness in a foamed poly lactide acid (PLA) part. In the foaming process, the PLA pellets are exposed at room temperature to a highly pressurized gas in order to saturate the pellets, then the material is processed in an injection molding machine. The effect of saturation and desorption time before the injection molding process is studied.A PLA from Nature Works is used. The most recommendable process window for the foaming of the material is proposed.
During the regeneration of tissues and organs, growth factors (GFs) play a vital role by affecting cell behavior. However, because of low half-life time and quick degradation of GFs, their stimulations on cells are relatively short and discontinuous. In our study, a releasing scaffold platform, consisting of polycaprolactone (PCL) nanofibers and vascular endothelial growth factor (VEGF)-encapsulated gelatin particles, has been developed to extend the influence of GFs on mesenchymal stem cells (MSCs) and endothelial cells (ECs). The results showed that this kind of scaffold could direct the differentiation of MSCs to ECs and maintain the stability of its tubular structure for an extended period of time, thus suggesting its potential application in vascular tissue engineering.
Over the last few decades, the move towards more sustainable development and environmental protection has offered many opportunities to develop both biodegradable and biobased composite materials with excellent performance. This new class of materials promises to enable the circular economy concept and sustainable development for our future. In this work, the properties comparison between renewable bioresourced fillers and synthetic conventional fillers were presented and discussed. This works reveals that biocarbon-filled poly(butylene terephthalate) (PBT) hold very high potential to replace existing mineral filler-filled PBT composites in automotive applications. With high biobased content, lower density and cost, it is obvious that the biocarbon filler can be used as a substitute for conventional fillers to develop more eco-friendly products.
The gaining importance of sustainability in recent years has also led to a closer look on lightweight materials such as fiber reinforced plastics. However, these materials usually pose a challenge in application. Purposeful virtual engineering and prediction is part of it. A new approach allows the reliable prediction of discontinuous fiber reinforced plastics based on integrative simulations while taking local fiber orientation and local fiber length into account. The results obtained with this method already show an improvement in prediction of simple part geometries. Further gain in quality is expected by complex parts where fiber orientation distribution and fiber length distribution spread more widely.
Attached growth bioreactor process provides surface area to support the growth and attachment of bacteria, and thereby a means to biologically remove organics from wastewater. In this work, an open-cellular polyvinylidene fluoride (PVDF) foams consisted of macroporous structures were designed and fabricated to promote the efficiency of existing biofilm carriers for wastewater treatment. A manufacturing approach that integrated compression molding and particulate leaching was employed to fabricate the PVDF foams. Different contents of salt were used as leaching agent to fabricate PVDF foams with macroporous structures of different total protected surface areas. Experimental studies were conducted to elucidate the structure-to-performance relationships of these macroporous PVDF carriers in terms of bacteria-to-carrier interaction and organic removal efficiency.
Recycled and Waste Materials in Selected Automotive ApplicationsKarnik Tarverdi, Peter S Allan & Paul J Marsh,Wolfson Centre for Materials Processing, Brunel University London,Institute of Materials and Manufacturing, United KingdomAbstractThe objective of this project was to investigate the potential use of recycled and waste materials in automotive components. Few components were selected for the investigation. All of them had the potential to be manufactured from waste and recycled materials. The trial materials which included recycled polypropylene and an industrial particulate solid waste stream, were processed into prototype components that were evaluated and compared with the respective production counterparts.The overall results indicated a clear potential for the use of the project materials in their respective applications.
Polyolefin production requires ~8% of global oil and natural gas production for monomer supply and the energy required for polymerization; often these polyolefins are used in short term applications such as packaging. While researchers work toward long term solutions involving sustainable polymers, the short term focus on how to better recycle polyolefins currently in the production/consumption cycle must be addressed. Given their chemical similarity and similar density, recycled polyolefins are difficult to separate from recycle streams often resulting in mixed stream recycle feeds. Previously we presented the role of residual oligomer after Ziegler-Natta polymerization of polyethylene (PE) and isotactic polypropylene (iPP) in preventing cross interfacial crystallization of immiscible PE-iPP bilayers which resulted in weak interfacial adhesion. We also presented strategies for promoting cross interfacial crystallization via processing (rapid interfacial quenching) and materials selection (thickened interfaces) in PE-iPP bilayers. Here we investigate the role of interfacial adhesive strength between three PE-iPP blends in the absence of applied shear during processing. With poor interfacial adhesion between PE/iPP, brittle failure of each blend was observed, as expected with immiscible polymer pairs. When interfacial adhesion strength exceeded that of the strength of component homopolymer, exciting synergism was observed between PE/iPP blends. Processing in the presence of applied shear flows (injection molding and film extrusion) will also be discussed. This finding highlights the importance of considering interfacial strength when designing mixed polyolefin recycle streams.
Within SABIC we are further expanding our market facing approach in Petrochemicals business with new segments, and focus approach, in order to further intensify customer intimacy and to provide more focused solutions. Personal hygiene is one of the identified ‘segment’, which will enable SABIC to accelerate the pace of innovation, to respond to the personal hygiene industry challenges, and to follow the market trends by working in ever-closer collaboration with the customers. Increase in child population, growing female workforce, and rising per capita income are the key factors driving the demand for personal hygiene products across the globe. SABIC is focusing on delivering sustainable solutions that help to our customers to achieve their ambitions. SABIC® is already offering few commercial PP-fiber grades (MFR 10-35) for lightweight non-woven fabrics for personal hygiene applications. SABIC® PP grades in hygienic applications are1) utilized in existing extrusion equipment without significant modifications2) achieving excellent fiber thickness uniformity3) produced with phthalate free technology/catalysts, and such SABIC® PP fiber portfolio for hygienic non-woven products are available globally.SABIC technology team is further working on new developments to fulfill customer demands for advanced solutions in hygiene fabrics, and flexible packaging. Some of the developments and solutions offerings are to be elaborated during the conference, alike: soft-touch, melt-blown, breathable film solutions etc…SABIC is persistently pursuing innovative technologies to bring about broad-based improvements in the products offerings, while maintaining the momentum to meet changing market requirements.
The lack of commercially relevant compatibilizers from renewable sources is limiting the usage of biopolymer blends and composites in today’s market. This work studies potential new compatibilizers that can be used in applications involving blends of sustainable polycarbonates and polyesters. Poly(propylene carbonate) (PPC) and poly(butylene succinate) (PBS) were functionalized separately using maleic anhydride (MAH) and an initiator to trigger free radical grafting. Different amounts of MAH were used during the melt compounding to study the effect of the MAH amount on the extent of the reaction. The resulting compounds were examined by means of titration, proton NMR and parallel plate rheometry. Formulations using both PPC and PBS successfully reacted with MAH, as evidenced by the appearance of new chemical shifts in their proton NMR spectra associated with midchain grafting and end groups reactions. The PPC compounds showed an increase of the grafting efficiency with addition of more MAH. The PBS formulations had maximum grafting efficiency value at 2% MAH. Rheometry showed that incorporation of 2% of MAH and DCP produced an increase in the viscosity of both PPC and PBS in comparison to their neat counterparts. Evaluating all these results together, it can be concluded that the PPC with 2% MAH and DCP is the most reactive compound and the one that could perform more efficiently as a compatibilizer. In addition, melt compounding presents an economic method to produce biocompatibilizers of high reactivity and high molecular weight.
With increasing interest towards biobased and/or biodegradable polymers that generate high performance composites, instead of petroleum based products, creates new opportunities and research challenges. Poly (butylene succinate) (PBS) is supposed to be one of the most promising biodegradable polyesters because of its good mechanical strength and high heat deflection temperature. However, the low impact strength of poly (butylene succinate) (PBS) has limited its application in some fields. Therefore, poly (butylene adipate-co-terephthalate) (PBAT) and poly (butylene succinate) (PBS) were melt-compounded to fabricate a novel PBS/PBAT blend to improve the impact strength of PBS. The effect of PBAT on the properties of the final binary blends, including mechanical properties, thermal properties and rheology properties, is studied in this research. Rheological properties revealed a strong shear-thinning tendency of the blend resulting from the high compatibility between PBAT and PBS. The partially compatibilized PBS/PBAT blends show high tensile strength (~50 MPa), high impact strength (~200 J/m) and a moderate tensile modulus (~500 MPa). A PBS/PBAT system can be a good candidate to fabricate high impact biodegradable products.
The effects of adding metal stearates to a powder injection molding (PIM) feedstock prepared with a wax based binder system and silicon powder was investigated. The rheological properties and molding properties of the feedstocks were characterized. Predictive viscosity models were developed for each feedstock. The zero-shear viscosity was constant with the introduction of metal stearates while, the yield stress was seen to decrease. The molded green parts were produced with a traditional injection molding process. The surface quality of the molded green parts did not seem to change. The quality through the thickness changed as vacuum voids started to form with the introduction of the metal stearates.
The ambition of developing innovative and technically high-quality products is one of the main reasons for the growing use of fiber-reinforced plastics (FRP) in industry. In particular, the opportunity to combine lightweight construction with a high degree of design freedom and functional integration leads to the preferred use of composite materials in the automotive and aerospace industries.During the operation time the composite parts are exposed to continuously changes of environmental influences which lead to aging of the polymers. This includes frequent temperature changes, dampness, saline media and mechanical loads for instance. The aging effects, caused by the interaction with the surrounding media, result in various changes of the material properties. Strength losses, embrittlement, degradation of the molecular weight or optical changes are some examples which can occur during the aging process and may induce a prematurely failure of the composite parts.In order to predict the life time of those components, the effects of the aging process and the influences on several material properties have to be known. Hence, in the following the environmental aging of a woven fabric reinforced, a short glass fiber-reinforced and an unreinforced polyamide 6 will be investigated and the influences on the material properties will be characterized.
The valorization of side-steam products from bio-refinery is of crucial interest to develop further the viability of a bioeconomical system. The corn oil is one of the important co-products from the bioethanol industry with a production of more than 2.7 billion pounds in 2015 in USA. [1] In this investigation we propose to create new materials with higher added value by developing new monomers and polymers through transamidation and successive polyesterification. The resulted sustainable materials can be used as toughening agent for both thermoplastic and thermoset polymers.
In recent decades, poly(butylene succinate) (PBS) has been attracting attention as a promising and important polymer in the bio-based and biodegradable polymer family due to high thermal resistance and good mechanical properties. However, compared with other biodegradable polyesters (e.g., poly (lactic acid)), the high cost of PBS limits the widespread applications, especially for the packaging industry. In this paper, PBS-based copolyesters were prepared successfully by a two-stage melt synthesis, and degradability of the polyesters was investigated. It was found that the degradability of PBS could be tuned over a wide range by adjusting the degradation catalyst and lowering crystallinity by forming random copolymers. Based on our previous work on the tunable properties of PBS-based polyesters, the degradation results indicated that the enzymatic degradation mainly depends on the morphology and thermal properties, while the ratio of ester groups in polymer is the crucial factor for base-catalyzed hydrolysis.
Environmentally friendly thermal insulation and energy saving materials are in high demand for buildings, packaging, and other applications. Here, we report ultra-low density composite foam materials that are mainly composed of cellulose, an abundant degradable and recyclable green material. Nanocrystalline cellulose (NCC) was mixed with 0-20 wt.% polyvinyl alcohol (PVA) in an aqueous solution, followed by ice crystallization and freeze drying processes to fabricate the NCC/PVA cellular structures. Ultralight foams with densities as low as 0.026 g.cm-3 (porosities as large as 98.22%) were successfully prepared and their compression and thermal conductivity behaviors were characterized. The results revealed that the compressive stiffness and strength of NCC foams can be significantly enhanced (about an order of magnitude) by the introduction of 20 wt.% PVA as an elasticity enhancer. The thermal conductivity of NCC/PVA foams remained approximately unchanged with an increase in the PVA content and varied only between 0.037 and 0.041 W/mK, a range that is common for commercially available insulation materials. A relatively low thermal conductivity with enhanced mechanical properties of these NCC-based foams offers a potential bio-based material composition for insulation applications.
In this study, trypsin hydrolyzed gliadin (THGd) from wheat was used as a curative and reinforcing filler in synthetic isoprene rubber (IR). Curing kinetics of the THGd compounds demonstrated that THGd was most effective when utilized as an activator in place of zinc oxide and stearic acid (ZnO/STE). The THGd vulcanizates exhibited comparable or higher moduli to the control, but lower crosslink densities and slower curing kinetics. THGd was able to facilitate crosslinking, as shown by swelling experiments, but further study is needed to match/exceed the kinetic properties of the control. Interestingly, THGd was very effective as a reinforcing filler and reinforcement increased as a function of molding time. Thus, rubber processing was favorable to the self-assembly of hydrolyzed protein into a reinforcing phase.
Outline: Motivation, Introduction, Changing of Properties, Processing and Testing Equipment, Results, The Dilution Effect, Transferability of Results, Summary
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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
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