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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Recent Advances in Additives - Paper: This article presents some characteristics of the composites based on rice husk filler and polyolefin (Polyethylene and polypropylene). The influences of rice husk content and compatibilizers on mechanical properties of the composites were investigated. An increase in rice husk content led to increased modulus and decreased tensile, bending and impact strengths of the composites in the case without modification. However, the presence of the compatibilizers based on maleic anhydride grafted polyolefin caused an increase in tensile, bending and impact strengths of the composites. Furthermore, some additives such as processing stabilizer, UV stabilizer and fungal resistance agents were also added in order to improve some properties of rice husk/polyolefin composites during processing and using. The experimental results indicated that the addition of the additives improved significantly some properties of the composites.
Recent Advances in Additives - Presentation: This article presents some characteristics of the composites based on rice husk filler and polyolefin (Polyethylene and polypropylene). The influences of rice husk content and compatibilizers on mechanical properties of the composites were investigated. An increase in rice husk content led to increased modulus and decreased tensile, bending and impact strengths of the composites in the case without modification. However, the presence of the compatibilizers based on maleic anhydride grafted polyolefin caused an increase in tensile, bending and impact strengths of the composites. Furthermore, some additives such as processing stabilizer, UV stabilizer and fungal resistance agents were also added in order to improve some properties of rice husk/polyolefin composites during processing and using. The experimental results indicated that the addition of the additives improved significantly some properties of the composites.
Recent Advances in Characterization: During the process of manufacturing (injection molding, blow molding etc.) or later handling of polypropylene impact copolymers, white marks may appear when the material is subjected to stress. A significant effect of the so-called stress w hitening or blushing is an aesthetic issue because the white marks can be easily identified. The stress whitening phenomenon is attributed to voids created within the deforming polymer.
In this work, several ICP's with varying rubber composition and phase viscosity ratios were examined using digital imaging and microscopy techniques in order to establish the relation between the composition, the resulting morphology and to relate this to stress whitening resistance.
It was shown that stress whitening could be solely attributed to rubber cavitation. The smaller the rubber particle size, the better the resistance to stress whitening. The required morphology also implies that these materials will suffer from a lower impact performance compared to conventional impact copolymers.
Advances in Compounding and Extrusion - Paper: The co-rotating fully intermeshing twin-screw extruder has evolved significantly in the 60 years since it was commercialized in 1957. While this equipment might be considered a "mature" technology, it has not experienced a decline in new developments as might be expected, but a rather significant number of advancements have been introduced during the intervening years. Even today the technology continues to evolve. For example in the last 20 years several significant developments have been introduced. These include a) the implementation of high torque (power) designs, b) the use of increased screw rpm in conjunction with high torque for improved operating flexibility and productivity, and c) a breakthrough technology for feeding difficult to handle low bulk density materials. However, one area of twin-screw technology that has not evolved as much is screw elements geometry. Conveying elements and kne ading blocks have remained essentially the same since the original Erdmenger design patents were filed in the late 1940's and early 1950's. In spite of their longevity in the market, there are still unknown qualitative as well as quantitative operational characteristics. This paper will focus on kneading blocks, specifically looking at some significant aspects related to performance. These include pressure generation as a function of 1) absolute pressure, 2) disc profile (2-lobe vs 3-lobe) , 3) disc width, 4) disc stagger angle, and 5) material viscosity.
Advances in Compounding and Extrusion - Presentation: The co-rotating fully intermeshing twin-screw extruder has evolved significantly in the 60 years since it was commercialized in 1957. While this equipment might be considered a "mature" technology, it has not experienced a decline in new developments as might be expected, but a rather significant number of advancements have been introduced during the intervening years. Even today the technology continues to evolve. For example in the last 20 years several significant developments have been introduced. These include a) the implementation of high torque (power) designs, b) the use of increased screw rpm in conjunction with high torque for improved operating flexibility and productivity, and c) a breakthrough technology for feeding difficult to handle low bulk density materials. However, one area of twin-screw technology that has not evolved as much is screw elements geometry. Conveying elements and kne ading blocks have remained essentially the same since the original Erdmenger design patents were filed in the late 1940's and early 1950's. In spite of their longevity in the market, there are still unknown qualitative as well as quantitative operational characteristics. This paper will focus on kneading blocks, specifically looking at some significant aspects related to performance. These include pressure generation as a function of 1) absolute pressure, 2) disc profile (2-lobe vs 3-lobe) , 3) disc width, 4) disc stagger angle, and 5) material viscosity.
Advances in Compounding and Extrusion - Paper: Single-reciprocating screw compounding (kneader) technology was developed and introduced more than 70 years ago. Surprisingly this technology is not largely considered when companies evaluate their compounding needs. With an ever-increasing demand for higher shear sensitive materials and additives, higher load filling, and better distributive and dispersive mixing requirements, this paper revisits this technology that is becoming more and more relevant in today's marketplace. The paper also discusses many of the noteworthy advancements that have been made with this equipment over the years.
Advances in Compounding and Extrusion - Presentation: Single-reciprocating screw compounding (kneader) technology was developed and introduced more than 70 years ago. Surprisingly this technology is not largely considered when companies evaluate their compounding needs. With an ever-increasing demand for higher shear sensitive materials and additives, higher load filling, and better distributive and dispersive mixing requirements, this paper revisits this technology that is becoming more and more relevant in today's marketplace. The paper also discusses many of the noteworthy advancements that have been made with this equipment over the years.
Advances in Compounding and Extrusion - Paper: Toughening of homopolymer polypropylene (PPH) in the post reactor step by incorporating external elastomers has become an attractive area of research. In this investigative work, PPH was post-reactor blended with different types of Polyolefin elastomers (POE) that were selected based on the co-monomer type and density. The performance behavior of PPH/POE blends with and without a nucleating agent was compared to in situ (in the reactor) modified PPH with Ethylene Propylene Rubber (EPR). The addition of POE in PPH, increased toughness at room temperature and the stiffness of the blends decreased. The addition of a nucleating agent was noted to improve the toughness and stiffness compared to their non-nucleated counterparts, while the tensile strength remained unchang ed. At -20°C, the impact strength results showed no significant improvement in PPH/POE blends with and without addition of the nucleating agent. The melting temperature and the crystallinity of PPH matrix decreased and the crystallization temperature rema ined unchanged. On the other hand, the nucleating agent has kept the melting temperature unchanged and increased the crystallinity and crystallization temperature of the blends. The morphology analysis have shown clearly the phase separation of the blends components thus demonstrating the immiscibility of the blend system. The addition of the nucleating agent was seen to decrease the domain size of POE phase thus leading to the improvement in the toughness properties of the blends. ICP materials have shown better mechanical properties and more uniform rubber dispersion than the blends system.
Advances in Compounding and Extrusion - Presentation: Toughening of homopolymer polypropylene (PPH) in the post reactor step by incorporating external elastomers has become an attractive area of research. In this investigative work, PPH was post-reactor blended with different types of Polyolefin elastomers (POE) that were selected based on the co-monomer type and density. The performance behavior of PPH/POE blends with and without a nucleating agent was compared to in situ (in the reactor) modified PPH with Ethylene Propylene Rubber (EPR). The addition of POE in PPH, increased toughness at room temperature and the stiffness of the blends decreased. The addition of a nucleating agent was noted to improve the toughness and stiffness compared to their non-nucleated counterparts, while the tensile strength remained unchang ed. At -20°C, the impact strength results showed no significant improvement in PPH/POE blends with and without addition of the nucleating agent. The melting temperature and the crystallinity of PPH matrix decreased and the crystallization temperature rema ined unchanged. On the other hand, the nucleating agent has kept the melting temperature unchanged and increased the crystallinity and crystallization temperature of the blends. The morphology analysis have shown clearly the phase separation of the blends components thus demonstrating the immiscibility of the blend system. The addition of the nucleating agent was seen to decrease the domain size of POE phase thus leading to the improvement in the toughness properties of the blends. ICP materials have shown better mechanical properties and more uniform rubber dispersion than the blends system.
Sustainability Metrics and Characterization - Paper: Polyethylene has been adopted for a variety of industrial, agricultural, and packaging applications with an estimated market of $164 billion and a projected global demand growth of 4% through 2018. The pressure for landfill diversion strategies have increased with cons umer awareness of traditional end-of-life practices. Regulatory bodies have instituted minimum post-consumer recycled ( PCR ) content laws to increase the long-term sustainability efforts of polymer use in commodity goods (e.g., SB 270 in California); thus, the ability to empirically quantify the post-consumer recycled content is vital for compliance. A stepwise multivariable regression approach was employed to develop a n equation capable of empirically determining the post-consumer recycled content from a va riety of certification markers. The empirical equation determined the post-consumer content of unknown film samples within ~10 wt% of the true value.
Sustainability Metrics and Characterization - Presentation: Polyethylene has been adopted for a variety of industrial, agricultural, and packaging applications with an estimated market of $164 billion and a projected global demand growth of 4% through 2018. The pressure for landfill diversion strategies have increased with cons umer awareness of traditional end-of-life practices. Regulatory bodies have instituted minimum post-consumer recycled ( PCR ) content laws to increase the long-term sustainability efforts of polymer use in commodity goods (e.g., SB 270 in California); thus, the ability to empirically quantify the post-consumer recycled content is vital for compliance. A stepwise multivariable regression approach was employed to develop a n equation capable of empirically determining the post-consumer recycled content from a va riety of certification markers. The empirical equation determined the post-consumer content of unknown film samples within ~10 wt% of the true value.
Sustainability Metrics and Characterization - Paper: Commercially available virgin and post - consumer recycled (PCR) polyethylene was characterized fo r catalyst (Ti, Pb, Al, Cr, Fe) during sheet extrusion of varying levels of PCR content (0, 30, 40, 90, 95 and 100%). An energy dispersive x-ray fluorescence (XRF) detection system was installed in the extrusion line directly after the die. The X-ray spectra and raw counts were obtain ed every 45 seconds and reported with sample time and sheet location within the roll. Data were uploaded every 45 seconds to a secured custom web-based software platform. Process samples were compared to bench top analysis using Inductively Coupled Plasm a Optical Emission Spectroscopy (ICP-OES). Our results indicate the potential use of XRF for in-process catalyst and regulated monitoring for polymer performance, safety and traceability in recycled plastics before and during conversion. More research is needed for validation of in-process monitoring systems for conversion processes and feedstock sources.
Sustainability Metrics and Characterization - Presentation: Commercially available virgin and post - consumer recycled (PCR) polyethylene was characterized fo r catalyst (Ti, Pb, Al, Cr, Fe) during sheet extrusion of varying levels of PCR content (0, 30, 40, 90, 95 and 100%). An energy dispersive x-ray fluorescence (XRF) detection system was installed in the extrusion line directly after the die. The X-ray spectra and raw counts were obtain ed every 45 seconds and reported with sample time and sheet location within the roll. Data were uploaded every 45 seconds to a secured custom web-based software platform. Process samples were compared to bench top analysis using Inductively Coupled Plasm a Optical Emission Spectroscopy (ICP-OES). Our results indicate the potential use of XRF for in-process catalyst and regulated monitoring for polymer performance, safety and traceability in recycled plastics before and during conversion. More research is needed for validation of in-process monitoring systems for conversion processes and feedstock sources.
Sustainability Metrics and Characterization - Paper: Commercially recycled linear low-density polyethylene (LLDPE) pellets containing pigments were blended individually by weight then extruded with varying levels of recycled content. Either calcium carbonate only (white) or a mixture of white and carbon black pigment were blended with recycled polymer at virgin/recycled ratios of 0, 20, 40, 60, 80, and 100% wt/wt. Each blend was evaluated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. Linear relationships were investigated for statistical significance of PCR content and pigment on extruded sheet properties. Extractions in n-hexane were carried out in accordance with Code of Federal Regulations (CFR) Title 21, B, Part 177.1520 to determine compliance for uses with direct food contact. Results of thermal and spectrophotometric analysis did show potential for PCR marker identification. All extractives were below allowable threshold of 5% per CFR suggesting the potential use of recycled polyethylene for direct food contact applications. More research is needed to evaluate the use of various feedstock sources of recycled polyethylene for direct food contact application.
Sustainability Metrics and Characterization - Presentation: Commercially recycled linear low-density polyethylene (LLDPE) pellets containing pigments were blended individually by weight then extruded with varying levels of recycled content. Either calcium carbonate only (white) or a mixture of white and carbon black pigment were blended with recycled polymer at virgin/recycled ratios of 0, 20, 40, 60, 80, and 100% wt/wt. Each blend was evaluated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. Linear relationships were investigated for statistical significance of PCR content and pigment on extruded sheet properties. Extractions in n-hexane were carried out in accordance with Code of Federal Regulations (CFR) Title 21, B, Part 177.1520 to determine compliance for uses with direct food contact. Results of thermal and spectrophotometric analysis did show potential for PCR marker identification. All extractives were below allowable threshold of 5% per CFR suggesting the potential use of recycled polyethylene for direct food contact applications. More research is needed to evaluate the use of various feedstock sources of recycled polyethylene for direct food contact application.
Sustainability Metrics and Characterization - Paper: The purpose of this research is to model the deflection behavior of railroad ties fabricated from recycled polyolefin post-consumer/post-industrial waste composed of HDPE (High Density Poly Ethylene) and PP/FG (Poly Propylene/Fiber Glass). A technical challenge in predicting the final part performance is a limited understanding of the impact of microstructural variations due to processing variability on the final produced part's spatially varying material properties. The ties fabricated using extrusion molding techniques have a solid shell region on the outer surface and an inner foamed core. The foamed core region has cells of differing dimensions and the resulting effective material properties will vary as a function of the cell size and density. The shell and the foamed core regions are an alyzed using micromechanics models for the prediction of the stiffness. The stiffness of the foamed core is calculated using the Monte Carlo method to investigate the macroscopic sensitivity to microstructural variations. The elastic moduli obtained from micromechanics is used for the shell and foam regions in a Finite Element model, and the computational results are compared to those obtained from experimental four point bend test results with a difference between the model and experiment being less than 2% for the predicted effective stiffness.
Sustainability Metrics and Characterization - Presentation: The purpose of this research is to model the deflection behavior of railroad ties fabricated from recycled polyolefin post-consumer/post-industrial waste composed of HDPE (High Density Poly Ethylene) and PP/FG (Poly Propylene/Fiber Glass). A technical challenge in predicting the final part performance is a limited understanding of the impact of microstructural variations due to processing variability on the final produced part's spatially varying material properties. The ties fabricated using extrusion molding techniques have a solid shell region on the outer surface and an inner foamed core. The foamed core region has cells of differing dimensions and the resulting effective material properties will vary as a function of the cell size and density. The shell and the foamed core regions are an alyzed using micromechanics models for the prediction of the stiffness. The stiffness of the foamed core is calculated using the Monte Carlo method to investigate the macroscopic sensitivity to microstructural variations. The elastic moduli obtained from micromechanics is used for the shell and foam regions in a Finite Element model, and the computational results are compared to those obtained from experimental four point bend test results with a difference between the model and experiment being less than 2% for the predicted effective stiffness.
This presentation will cover what an antimicrobial additive is and how this class of additives differs from disinfectants. Furthermore, what types of chemistries are commonly encountered will be discussed. Lastly the current global regulations that cover the use of antimicrobials will be covered.
When processing PVC via the direct extrusion method, the polymer is fed continuously into a compounder without prior stabilization. Additives like stabilizers, plasticizers, lubricants, fillers and others are added simultaneously, but separately, thus stabilization and mixing takes place in the compounder. This approach requires a carefully balanced setup of the first section of the extruder, which differs considerably to conventional PVC dry-blend processing.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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