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.
SPE Bioplastic and Renewable Technologies Division April 2016 Newsletter
Read the latest issue of the SPE Bioplastic and Renewable Technologies Division newsletter.
Carbide slag as a filler in poly(vinyl chloride)/wood composites
Using an industrial waste as an inorganic filler in plastic/wood composites improves the fire and mechanical properties of the material, as well as reducing its financial and environmental cost.
Biodegradation properties of poly(butylene succinate) and chitosan nanocomposites
Soil burial tests, conducted under natural conditions, were used to investigate the biodegradability of bio-nanocomposites containing silica, silicate, and graphene reinforcements.
A Study on the Mechanical Properties of Recycling PC/ABS Blends Produced by Vent-Type Injection Molding
The mechanical properties of recycling PC/ABS blends produced by three kinds of molding conditions were discussed, including such parameters such as the cylinder temperature and the type of injection molding processes. Mechanical properties and the degradation rate with the increase of recycling times were investigated. The comparison of different cylinder temperature produced by vent-type injection molding was conducted, also the research between cent-type injection molding and non-vent-type injection molding, based on the detailed SEM observation on the fracture surfaces after Izod impact test. It can be found that, with the increase of recycling times, the material produced by vent-type injection molding machine demonstrated higher mechanical properties and lower degradation rate in mechanical properties than non-vent-type injection molding machine.
Advances in Adhesive Technology for Bonding Liquid Silicone Rubbers to Plastics and Metals
LORD Corporation offers new adhesive solutions that effectively bond platinum-cured liquid silicone rubber (LSR) to various substrates directly in an injection or compression molding process. This technology does not require plasma treatment or other complicated and costly surface preparation steps. In this study, three new adhesive systems were tested to bond LSR to various substrates, including polycarbonate, thermoplastic elastomer, polyamide, and stainless steel. Parts were molded and peel tested. This process and product technology offers a number of benefits compared to existing technology, including enhanced design freedom, more robust processing, less surface preparation requirements, and environmental friendliness.
An Effective Way of Processing Immiscible PP/PS Blends into High Strength Fiber
A new method for processing high strength fiber from immiscible PP/PS blends was developed. In contrast to conventional melt spinning with high jet stretch, the new method adopts a low jet stretch ratio and a subsequent hot drawing step above the Tg of PS for making a blend fiber with a highly oriented PP phase. Initial results demonstrated that 70/30 PP/PS blend fibers processed by zero jet stretch and 8X hot drawing at 100°C can achieve a tensile strength above 300 MPa, 6 times higher than that of corresponding blend fibers produced by conventional high jet stretch. This process also provides a new route for recycling immiscible polymer waste mixtures and may have a high potential for industrial applications. By making immiscible polymer blends recyclable, this method can lead to improved design flexibility for system integration and achieving multi-functional products.
Analysis on Mechanical Properties of Poly-lactic Acid Composites with Organic-Montmorillonite by Injection Molding
Biodegradable material enacts as an important role on reducing impacts in environment problem. This paper investigated the mechanical properties of Poly-lactic Acid (PLA) and PLA/nanocomposites by variant parameters of injection molding process. Effects on tensile strength between molecular orientation and density have been tested and discussed. The micron clay composites, organic-montmorillonite (OMMT) is used for filler materials in this study, and coupling agent, such as silane has been adopted to enhance polymer branches to catch OMMT and then improved both materials bonding. Effects on mechanical properties by different mixing ratio of pure PLA, PLA/M (PLA with OMMT) and PLA/S/M (PLA with silane and OMMT) clay composites have been prepared and the most significant factor for mechanical properties in tensile and impact strength with injection molding parameters have been obtained. The thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC) have also been used to measure the thermal properties of such PLA and PLA clay composites. Results show that the tensile properties of PLA/S/M are superior to that of PLA/M and the PLA/S/M4 of 4wt% OMMT has the largest tensile strength as 84.85MPa as increases approximately 8.0% higher than that of pure PLA specimen. However, the impact strength of PLA/M is superior to that of PLA/S/M. The PLA/M4 has the best impact strength as 0.625J/cm2 as increasing 54.3% higher than that of pure PLA specimen. Results of this study can be applied to future applications of in-vivo medical assistive device or fixed scaffold products by injection molding processes.
Application of Air Gap to Enhance Acoustic Performance of Biobased PLA Foams
There is an increasing need for lightweight, biodegradable and efficient sound absorbers in various industries. Polylactic acid (PLA) open cell foams have been previously identified as an effective sound absorber. This study investigates the integration of air gap to enhance acoustic performance of PLA foams. PLA foams of two different cell sizes were characterized and tested for the frequency range of 800-6300 Hz. It was identified that increasing the gap caused an increase in maximum absorption and a shift in peak frequency to lower values. The data recorded will allow for determination of parameters such as pore size and air gap for acoustic solutions in the industry.
Bioepoxy Foaming Using Polymethylhydrosiloxane
The Corporate Average Fuel Economy (CAFE) standards mandate that cars and light trucks have a fuel economy of at least 54.5 MPG by 2025 in an effort to eliminate 6 billion tons of cumulative CO2 emissions. This directive has spurred the automotive industry to focus on a variety of options. Among these are lightweight structural polymeric foams, which offer tailor-made solutions for significant weight reduction while not compromising on safety. However, most structural foams are petroleumbased, thereby contributing to the depletion of nonrenewable petroleum resources. Biopolymers, such as those from non-food based sources, offer a more environmentally-responsible alternative.
In this study, the effect of polymethylhydrosiloxane (PMHS) as a foaming agent on the properties of pine oilbased epoxy was investigated. The resulting materials were then tested for their compression properties, density, and microstructure. Lightweighting of up to 77 % was obtained and the delayed addition of foaming agent was shown to be more effective at improving specific mechanical properties, relative to immediate addition of foaming agent.
PC/ABS Recovered from Shredded Waste Electrical and Electronic Equipment
Our industry leading separation technology enables us to recover a variety of plastics from complex mixed streams such as shredded waste electrical and electronic equipment (WEEE). Plastic flakes recovered using our process are compounded and sold as pellets suitable for use in injection molding applications. Polyolefin and styrenic plastics have been in our product portfolio for nearly a decade, but recently we have been expanding our range of plastic products. This paper looks at the challenges of recovering additional plastics and the properties of PC/ABS we have recovered from shredded WEEE.
Determination of the Compositions of Fully Biodegradable Ternary Blends with Near-Infrared Spectroscopy
Comparison between near-infrared (NIR) spectroscopy in diffuse reflectance and transmission modes for determination of the compositions in fully biodegradable poly-(lactic acid)/poly-(propylene carbonate)/poly-(butylene adipate-co-terephthalate) (PLA/PPC/PBAT) blends was made. Principal component analysis (PCA) was firstly performed to qualitatively examine the response of two modes to concentration change. Then partial least square (PLS) models were developed for quantitative evaluation based on root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP) and coefficient of determination (R2). The data showed that NIR spectroscopy in both modes succeeded in extracting information of concentration of complex fully biodegradable PLA/PPC/PBAT blends, whereas diffuse transmission mode presented better performance than diffuse reflectance mode.
Development of a New Styrenic Elastomer Using Renewable Monomer
Utilizing a new renewable monomer called B-farnesene, Kuraray has developed a new hydrogenated styrene farnesene copolymer (HSFC) with unique chemical structure and differentiated properties. B-farnesene is produced from the fermentation of sugar extracted from sugarcane and is based on an innovative microbial engineering technology from Amyris. When B-farnesene is polymerized using anionic polymerization method, polymerization proceeds with conjugated diene moiety and poly-B-farnesene possesses a highly condensed, long alkyl side chain. This unique chemical structure results in differentiated features that conventional hydrogenated styrenic block copolymers (HSBC) do not have. In comparison to HSBC, HSFC exhibits higher flow ability, good adhesion, lower hardness without plasticizer, good permanent and compression set, and improved damping properties over a wide temperature range. With this property set, HSFC lends itself to applications such as adhesives, gels, low hardness compounds, and nonwovens. It is expected that HSFC will continue to expand and produce new market value to meet developing customer needs.
Differential Scanning Calorimetry (DSC) Quantification of Polyamide 12 (Nylon 12) Degradation during the Selective Laser Sintering (SLS) Process
Selective laser sintering, a 3-dimensional printing technique, converts powdered thermoplastic resins, e.g. polyamide 12 (nylon 12), into end-use parts by using a laser to melt and fuse the particles. In this layer-by-layer additive manufacturing process, the powder is both the raw material and the mold. Therefore, unsintered powder can be recovered and recycled in subsequent builds to significantly decrease net costs. To improve blending protocols, the powder quality, i.e. the degree of degradation, was quantified using differential scanning calorimetry. Contrary to the work of others, the results suggested that the sensitivity of differential scanning calorimetry to small changes in molecular weight could reproducibly detect small changes in oven-aged (degraded) powder.
Dupont's Renewably Sourced High Performance Polymers
Renewably sourced, also commonly referred as biobased, materials are an integral part of DuPont’s commitment to sustainable growth. DuPont is a market leader in high performance renewably sourced polymers for engineering applications. These include products based on polyamide, polyester and thermoplastic elastomers and contain between 20 to 100 percent renewable carbon by weight. By tapping innovative technology and strategic partnerships, DuPont has created novel methods of manufacturing high-performance materials from renewable resources. This new generation of materials, derived from biomass instead of petroleum, reduces the environmental footprint without compromising performance. This paper will provide an overview of renewably sourced engineering polymers and examples of commercial products in various applications.
Effect of Anhydride Type on Structure and Thermal Properties of Poly(Propylene Carbonate) Composites Produced by Reactive Extrusion
Poly(propylene carbonate) (PPC) is an environmental friendly thermoplastic aliphatic polycarbonate. To broaden the application of this material, three types of anhydride (maleic anhydride (MA), phthalic anhydride (PA) and pyromellitic dianhydride (PMDA)) were melt blending to end-cap PPC by reactive extrusion. FTIR, Raman spectroscopy, TGA, and intrinsic viscosity test were used to characterize structure and properties of anhydride end-capped PPC. Results indicate that the reaction mechanism between PPC with MA was different from PPC with PA and PMDA. Intrinsic viscosity test demonstrates that molecular weight of PPC-PMDA was higher than that of pure PPC. In addition, TGA results show that the thermal degradation temperature of PPC could be improved by adding three types of anhydride, and the T-5% of PPC-PMDA was the highest and increased by 26.3 ºC.
Effect of different fiber tex feeding on mechanical properties of glass fiber reinforced RPET composite by DFFIM process
Two different linear densities of Glass fiber (GF) consisting 1200 and 2400 tex, which were reinforced recycled PET (RPET) composites fabricated by DFFIM process. The results indicated that processing ability of GF/RPET composites with 180-rpm injection screw speed on fiber loading content were in range of 16 wt.% to 55.7 wt.% It was found that the incorporation of glass fiber into RPET composites improved tensile properties, bending properties and impact properties. However the improving tendency on mechanical properties of GF/RPET composites was constant, when fiber loading content was over 40 wt.% for impact strength and 50 wt.% for tensile and bending strength, respectively. At high fiber loading content, 2400 tex of glass fiber exhibited in higher agglomeration of glass fiber especially in core layer when compared with 1200 tex of glass fiber. In addition the fiber length was decreased with the increasing of fiber loading content. The decreasing of fiber length, fiber distribution, effectiveness coefficient and poor fiber orientation resulted in the declination of mechanical properties.
Reduced Post Crystallization of Polyhydroxybutyrate (PHB)
Polyhydroxybutyrate (PHB) belongs to the family of polyhydroxyalkanoates (PHA) and is both, biobased and biodegradable. Due to its linear chain structure, PHB is highly crystalline and has a melting temperature close to its decomposition temperature. Pure PHB crystallizes very slowly, so that the use for some technical applications is not commercially viable. This paper describes the crystallization of pure and nucleated PHB by means of differential scanning calorimetry (DSC). The cooling curve and the metabolic rate as a function of temperature are elaborated.
Environmental Stress Cracking of Medical Thermoplastics: Assessing Lifetime of High Performance Amorphous Resins in Presence of Hospital Cleaners
There is a critical need to quantify and predict the likelihood of Environmental Stress Cracking (ESC) in medical devices, due to the expanding use of medical cleaners in hospitals to prevent infection as well as increased FDA documentation requirements. This paper performs constant flexural strain ESC experiments on two high performance resins, Noryl 20%gf and Ultem 20%gf, using three common hospital cleaners (bleach, quaternary amine with isopropanol, and hydrogen peroxide). ESC testing was performed using a 7-day soak followed by tensile testing to assess residual stress-strain performance.
From strain-at-break results for this 7-day soak method, ratings were obtained for each resin-cleaner combination. These results can be fed into mechanical models of components to quantify likely failure locations and safety factors.
Using time-to-crack datasets, an initial estimate of the n exponent for the ESC dependence on stress was obtained. Also, it was found that the use of Hansen Solubility Parameters could, with reasonably accuracy, predict trends in ESC damage.
Environmental Stress Cracking Study of Alternative Welding Processes in Apparatus, Tank and Pipeline Construction
The infrared (IR) and vibration (VIB) welding processes are joining technologies established in series fabrication. They are characterized by their economically viable and efficient process management. These joining technologies are suitable for utilization in apparatus, tank and pipeline construction. However, they cannot be applied to this field. One reason for this is the lack of knowledge and proof in relation to the Environmental Stress Cracking (ESC). Within the framework of a research project promoted by AiF (Allianz industrieller Forschung), the vibration and infrared welding processes were investigated. Their potential for long-term applications was studied. The results show that minimum tensile creep welding factors of 0.8 are achieved by using the infrared (short-wave radiation emitter) and vibration welding processes. It was possible to obtain values which correspond to those of heated tool butt welding. Furthermore, the knowledge base of the mechanism of failure behavior of welded joints between plastics undergoing ESC was extended.
Evaluating the Effect of Nanoclay and Recycled HDPE on Stress Cracking in HDPE Using J-Integral Approach
This study employed the J-integral approach to investigate the effect of recycled HDPE and nanoclay contents on the long-term stress cracking behavior of pristine HDPE. This behavior was conventionally approached by using stress intensity factor K, which defined the stress cracking behavior as two failure mechanisms: creep and slow crack growth (SCG). Unlike the conventional approach, the J-integral method identified the short-term failure prior to the creep failure. By integrating the short-term and SCG failure behavior, this study derived a correlation between Jc and SCG. The SCG behavior of recycle-blended materials without nanoclay was governed by Jc which decreased as the recycled contents increased. The decrease of Jc led to a reduction in SCG failure time. In contrast, the addition of nanoclay (up to 6-wt%) reduced Jc and stress relaxation of the material, subsequently extending the SCG failure times.
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