SPE Library

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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Conference Proceedings
EOS Polymer Laser Sintering: Enabling Applications Through New Materials
Cary Baur, February 2020
EOS specializes in laser sintering technology, which uses thermoplastic powder, along precise thermal control and laser power, to produce three-dimensional parts from a digital file. Our technology is widely used across many industries, from flame retardant polyamides for ductwork in commercial aircraft to PEKK - carbon filled materials for high temperature, chemically resistant, and high mechanical strength applications such as brackets and valves for oil and gas, automotive, and aerospace. Our focus is on providing machines that can utilize many materials to meet our customers' needs and a wide selection of custom materials targeted at their specific application criteria. This presentation provides an overview of how our technology works, what types of materials we use, and how we approach material development to enable new, advanced applications with our customers. 
HP Multi Jet Fusion Additive Manufacturing - the Technology and Fit into Production Manufacturing (Paper)
Barbara Arnold-Feret, February 2020
Additive manufacturing and polyolefins seem to have been a match made in heaven. However, the very characteristics of polyolefins that made it an ideal material for molding and other plastics processing can made it more of a challenge in the additive manufacturing side. Where some of the additive manufacturing equipment currently on the market utilizes polyolefins as a functional building material, the polyolefin material can create a cross road in performance. These issues can affect accuracy, strength, and speed of platform issues in use. An outline of how HP deals with the processing of plastics using Multi Jet Fusion (MJF) and with explainations, details and breakdowns to de-mythicize the MJF process is presented. Understanding the process helps understand where polyolefins fit into the HP MJF printing material universe. To explain the details of the Multi Jet Fusion (MJF) process, familiarity with the mechanism of how the fusion of the plastic is done and the basics of the interface need exploration. This paper is an overview of the MJF process, why the process serves as a unique method of manufacturing and summarizes the HP materials roadmap as of January 2020.
HP Multi Jet Fusion Additive Manufacturing - the Technology and Fit into Production Manufacturing (Presentation)
Barbara Arnold-Feret, February 2020
Additive manufacturing and polyolefins seem to have been a match made in heaven. However, the very characteristics of polyolefins that made it an ideal material for molding and other plastics processing can made it more of a challenge in the additive manufacturing side. Where some of the additive manufacturing equipment currently on the market utilizes polyolefins as a functional building material, the polyolefin material can create a cross road in performance. These issues can affect accuracy, strength, and speed of platform issues in use. An outline of how HP deals with the processing of plastics using Multi Jet Fusion (MJF) and with explainations, details and breakdowns to de-mythicize the MJF process is presented. Understanding the process helps understand where polyolefins fit into the HP MJF printing material universe. To explain the details of the Multi Jet Fusion (MJF) process, familiarity with the mechanism of how the fusion of the plastic is done and the basics of the interface need exploration. This paper is an overview of the MJF process, why the process serves as a unique method of manufacturing and summarizes the HP materials roadmap as of January 2020.
Determination of Interfacial Strength in Semi-rigid Laminates
Glendimar Molero, February 2020
A testing methodology to evaluate the adhesive strength of epoxy coatings and multi-layered polymeric laminates was developed by implementing a linearly increasing normal load scratch test. Finite element methods (FEM) modeling was also carried out to quantitatively investigate the corresponding stress profile that causes delamination to occur during scratching. By including the exact material constitutive behavior, surface characteristics, and geometry of each laminate layer in the numerical framework, the delamination strength of the laminates can be quantitatively determined using numerical modeling. The determination of the delamination strength between the weakest layer is possible by normalizing geometric factors and material properties in the FEM model. This procedure can be employed to improve laminate performance through changes in formulation and processing conditions.
Tie Layer Adhesion Chemistry for Multilayer Packaging
Mou Paul, February 2020
Multilayer packaging is an integral part of today’s life ranging in applications from food packaging to medical, consumer and industrial applications. By virtue of a multilayer structure, a combination of functionalities can be achieved which is not possible with a single layer structure. Orientation of multilayer films is important for various commercial packaging forms, especially when they are related to shrink such as barrier shrink bags, retail skin packaging, shrink films etc. Orientation enhances barrier properties and improves mechanical properties and can support packaging weight reduction. This is of a significant interest in light of sustainable packaging as oriented films can help to reach the goal of packaging waste reduction. In a multilayer film, a compatibilizer or a tie resin is often needed to adhere together the dissimilar polymers such as apolar polyethylene or polypropylene with polar substrates such as polyamides, ethylene vinyl alcohol (EVOH), polyesters, glass, paper, metal, coatings. Maleic anhydride grafted polymers, ethylene- acid copolymers, ionomers, ethylene-ester copolymers are some common examples of tie resins. The adhesive property of a tie resin is very critical for delivering the total functionality of a multilayer package. It becomes even more challenging when the packaging fabrication involves orientation and shrink as stretching and orientation can significantly reduce interlayer adhesion. A thorough review of the factors that influence adhesion at highly oriented structures can facilitate fundamental understanding and product strategy development. This paper will focus on a review of tie resins and how it impacts adhesion in multilayer packaging, particularly on oriented films. A major thrust will be given to understand the influence of molecular architecture of the tie resins and the interaction of tie layers with other layers on the adhesion properties. Effect of processing on tie layers will also be discussed. The paper will concentrate on journal and patent literature including brief summary of impactful data and will aim to establish fundamental understanding on adhesion in highly oriented structures.
Glass Filled Polypropylene with Improved Heat and Chemical Stability
Jing Liu, February 2020
In response to the high demand on lightweighting in the automotive industry, various reinforced polypropylene solutions have been explored and developed. Properties of filled polypropylene which have been greatly improved include stiffness, impact strength, higher fluidity and heat and chemical resistance. Thanks to these improvements, a broader range of performance requirements formerly exclusive to engineering plastics can now be achieved by polypropylene solutions alone. In this paper, we will discuss the development of PolyOne’s short-glass-fiber reinforced polypropylene which provides enhanced stiffness and impact properties, along with excellent heat and chemical stability.
Fundamentals of Twin-screw Compounding - Effective Mixing, the Key to Product Quality
Justyn Pyz, February 2020
The process for compounding thermoplastic formulations, both highly filled fiber or mineral products as well as color and additive MB, is comprised of several unit operations. These typically include: feedstock introduction, polymer or polymer/pigment melt-mixing, distributive/dispersive mixing of pigments/minerals/additives, removal of volatiles, and pressurization for die discharge. However, at the end of the day, if the fiber, mineral or pigment is not properly mixed into the polymer matrix, the product is not saleable. While the above list denotes a specific unit operation associated with mixing, mixing occurs along the entire length of the screw configuration in the co-rotating fully intermeshing twin screw extruder. It can range from dispersive mixing (i.e. wide disc kneading block combinations as part of, for example, titanium dioxide incorporation) to distributive mixing (that occurs during melt conveying as a result of rotation of screw bushings). Mixing in the screw bushings results from material reorientation in the apex region and circulatory flow induced by drag forces in the screw channel. The magnitude of the resultant mixing at any point along the screw depends upon the extruder barrel and screw configuration, characteristics of the materials being processed, and operating conditions. The required type and intensity of mixing depends on 1) the process task (talc filled vs. carbon black based MB), and 2) the relative physical and rheological properties of the materials being mixed. Independent of material parameters, mechanical energy input will vary according to basic extruder geometry characteristics (2 lobe vs. 3-lobe, outer diameter/inner diameter ratio [Do/Di]), element configuration, as well as operating conditions such as RPM, throughput rate, degree of fill, and barrel temperature profile. Material parameters such as viscosity, viscosity differential, elasticity, interfacial surface tension, thermal stability, as well as imposed discharge constraints, such as material temperature, particle size, and particle size distribution will dictate as well as limit the type and intensity of mixing necessary (or allowed) to accomplish the unit operation. This presentation provides a further discussion of the issues noted above as well as associated examples especially considering Polyolefins.
Compatibilizers to Improve Regrind Utilization and Recycling of Multilayer Barrier Rigid Packaging
Hyunwoo Kim, February 2020
Blow molded or thermoformed multilayer containers of polyolefin with barrier polymers like ethylene vinyl alcohol (EVOH) or polyamide (PA) are being offered as a sustainable packaging solution for oxygen or chemical barrier. It is common that the trim scrap materials are recycled back to the packaging article as a regrind layer. Recycling of the trim scrap materials from the multilayer articles of these incompatible polymers is not straightforward. Without proper compatibilization, recycling of the multilayer packaging structures can result in undesirable results such as large un-melts and gels, poor processability, and deterioration of the properties of the finished products. One solution to this recycling challenge is to utilize functionalized polyolefin materials to compatibilize the immiscible polymers in the recycled stream. Compatibilizers like polyethylene resins functionalized with polar functional groups can effectively promote the mixing of polyolefin resins with polar EVOH or PA polymers. In this work, we evaluated functionalized polyethylene products as a compatibilizer for the polyolefin/barrier regrind from the multilayer articles to address the utilization challenge of post industrial recycled materials.
Recycling and Sustainability: Plastic Industry Challenges and How to Face Them
Jungdu Kim, February 2020
In the last 50 years, plastic materials have become one of the most important material used in the most diverse range of end-use applications. They have their benefits as well as challenges. In the recent years, plastic has been under scrutiny for its impact on environment. To understand the plastic challenge, it is important to look at a larger picture. Many aspects must be taken into consideration when selecting material: technical properties, economical aspects and environmental impact. Understanding all criteria is key to select the most sustainable material. SONGWON will explain how it can enable the industry to overcome some of the recycling challenges. It will show the importance of sustainability and the concrete actions it is taking to continuously become more sustainable.
Material Options for TPO Waterproofing Membranes
Yushan Hu, February 2020
Fast developments in thermoplastic polyolefin (TPO) waterproofing membranes demand polyolefin systems that can help manufacturers develop custom-tailored formulations to fit specific designs, production processes, and end-use requirements. Though polypropylene (PP) based material formulations are industry norm for TPO membranes that provide a heat resistant and low cost solution, there are still unmet needs for the roofing applications. Recent advances in polyolefin catalysis allowed the polyethylene (PE) architecture that combines good thermal resistance and high flexibility at the same time. These PE based materials opens up new material options for waterproofing membranes with superior longevity, improved flexibility and broad welding characteristics.
Characterization of the Field Failure of Polyethylene Pipe Using Slow Crack Growth Tests (Paper)
Byoung-Ho Choi, February 2020
Due to its excellent mechanical, physical, and chemical properties, polyethylene is being widely used as a substitute for conventional metal pipes. Especially, in the case of polyethylene pipes, it is very important to secure long-term lifetime, therefore, various standard test methods to evaluate long-term lifetime with various fracture mechanisms have been proposed in ISO or ASTM. Among various failure mechanisms of pipe-grade polyethylene materials, slow crack growth (SCG) may be frequently occurred in actual filed conditions, so various standard test specimens such as PENT, FNCT, CRB have been developed to evaluate SCG characteristics. However, the existing SCG tests are reported to be difficult to evaluate SCG properties of the recently developed pipe polyethylene material in time due to technical issues, and to overcome these issues, a new test specimen, Stiffness-Constant K (SCK) specimen, has been recently proposed. In this study, CRB and SCK specimens were used to evaluate the integrity of polyethylene pipes that were damaged during portable water transportation. The CRB test was used for the evaluation of crack initiation characteristics of the pipe, and the SCK specimen was used for evaluating SCG characteristics of the pipe. The SCG characteristics of the damaged polyethylene piping materials were compared with the regular polyethylene materials to analyze the root causes of the failure of the polyethylene piping materials in use.
Characterization of the Field Failure of Polyethylene Pipe Using Slow Crack Growth Tests (Presentation)
Byoung-Ho Choi, February 2020
Due to its excellent mechanical, physical, and chemical properties, polyethylene is being widely used as a substitute for conventional metal pipes. Especially, in the case of polyethylene pipes, it is very important to secure long-term lifetime, therefore, various standard test methods to evaluate long-term lifetime with various fracture mechanisms have been proposed in ISO or ASTM. Among various failure mechanisms of pipe-grade polyethylene materials, slow crack growth (SCG) may be frequently occurred in actual filed conditions, so various standard test specimens such as PENT, FNCT, CRB have been developed to evaluate SCG characteristics. However, the existing SCG tests are reported to be difficult to evaluate SCG properties of the recently developed pipe polyethylene material in time due to technical issues, and to overcome these issues, a new test specimen, Stiffness-Constant K (SCK) specimen, has been recently proposed. In this study, CRB and SCK specimens were used to evaluate the integrity of polyethylene pipes that were damaged during portable water transportation. The CRB test was used for the evaluation of crack initiation characteristics of the pipe, and the SCK specimen was used for evaluating SCG characteristics of the pipe. The SCG characteristics of the damaged polyethylene piping materials were compared with the regular polyethylene materials to analyze the root causes of the failure of the polyethylene piping materials in use.
Quantification of LMWO in Polyolefin Products for Food Packaging and Hygiene Application
Shuhui Kang, February 2020
Quantification of Low Molecular Weight Oligomers in Polyolefin Products for Food Packaging and Hygiene Application Trace amounts of low molecular weight aliphatic polyolefin oligomer or LMWO (less than a few percent) exist in many polyolefin products such as polyethylene (PE), polypropylene (PP) and propylene-ethylene copolymers. These low molecular weight (MW) chemicals either are volatile or readily migrate out of the bulk polymer. Many governments such as US, China and EU require strict compliance with the legal maximum amount of LMWO content present in these products. In the past, quantification of LMWO content mainly relied on gas chromatography (GC). However the upper limit of LMWO MW that can be measured by GC is less than 1000 Dalton while LMWO with MW around 2000 Dalton is also a regulatory concern. In addition, due to the semi-crystalline nature of these polymers, the GC measurement of LMWO is significantly influenced by sample preparation method, and thus carries great uncertainty. High Temperature Gel Permeation Chromatography (GPC) with band-filter based infrared detector, a new GPC technique emerging in the market in recent years, provides an excellent opportunity to characterize polyolefins of both low and high MW due to high sensitivity and excellent linearity of detector response. In this paper, we demonstrate that the LMWO in propylene-ethylene copolymer (Vistamaxx™ polymer) and PE homopolymer can be accurately quantified through a methodology developed with GPC-IR by a comprehensive analysis on the effects of all kinds of noise factors and a new way of column calibration. Excellent results have been achieved. Quantification of fractions with MW less than 500 by GPC-IR are compared with GC and are generally consistent. The method of using GPC-IR for the quantification of LMWO in lieu of GC has not been reported else where. Due to the broader MW range detectable by GPC-IR over GC, it can be expected that this new method will become very useful for polyolefin society as regulations become more and more stringent. As a complementary tool for GC, this method could also be developed into a standard protocol widely available to the industry for quantification of LMWO in polyolefin materials.
Characterization of Solids Flow Behavior in Degassers and Purge Columns
Jayant Khambekar, February 2020
In polyolefins industry, reliable flow of powder/resin through degassers and purge columns is of high importance. It is directly connected to purging performance. If flow problems occur in degassers and/or purge columns, volatile organic compounds (VOCs) in the product can exceed specifications. Cross-contamination between grades can also occur during grade changeover. The system may experience limitations on the maximum discharge rate that can be achieved. In extreme cases, the system may need to be shutdown if resin bridges/arches over the outlet of the purge column, highlighting importance of reliable flow through a purge column. Scientific techniques are available to characterize the flow behavior of a resin/fluff/powder in degassers and purge columns. This paper will focus on the characterization methods to determine solids flow behavior in processing vessels. These methods are based on proven direct-shear techniques which consider the friction and cohesiveness of solids as a function of consolidation pressure on the solids. Such characterization is conducted at several different consolidation pressures, to cover the expected range in the degasser. This testing is not qualitative rather it is quantitative. It provides a basis to determine important geometric features of degassers and purge columns to achieve reliable flow without arching, buildup, or discharge-rate limitation. This paper will describe details of the characterization methods, and its use for designing and/or modifying a degasser/purge column.
Separating Effective High Density Polyethylene Segments From Olefin Block Copolymers
Yongfu Li, February 2020
Block copolymers (BCP) synthesis often results in a complex polymer mixture containing the desired BCP as well as one or both parent blocks. Interactive liquid chromatography separation of parent blocks from BCP is typically challenging, because the parent blocks are structurally the same as the blocks contained within the BCP. In this presentation, we first present the fundamental studies of liquid chromatography with preloaded adsorption promoting solvent barriers to overcome this challenge for the separation of a model BCP. The approach was then leveraged to the separation of olefin block copolymers (OBC). The OBC contains a “hard-soft’ block OBC with a high density polyethylene (HDPE) block and a relatively low density polyethylene (VLDPE) block targeted as thermoplastic elastomers. One of the major challenges is to fractionate HDPE segments from the other components (block copolymers and VLDPE segments). In this work we have overcome this challenge by using liquid chromatography with preloaded adsorption promoting barriers. A solvent plug (barrier) is introduced in front of the sample which specifically promotes the adsorption of HDPE segments on the stationary phase (porous graphitic carbon). Under selected thermodynamic conditions, VLDPE segments and block copolymer chains crossed the barrier while HDPE segments followed the barrier solvent and thus enabled separation. The barrier solvent composition was optimized and the chemical composition of fractionated polymer chains was investigated as a function of barrier solvent strength using an online Fourier-transform infrared (FTIR) detector. Our study revealed that both the HDPE segments as well as asymmetric block copolymer chains (HDPE block length >> VLDPE block length) are retained in the separation and the barrier strength can be tailored to retain a particular composition. At the optimum barrier solvent composition, this method can be applied to separate effective HDPE segments from the other components.
Thermodynamic Interactions in Blends of Poly(ethylene-co-ethyl ethylene) and 1,4-Polyisoprene
Xuejian Chen, February 2020
Isoprene rubber, while extensively used in the tire and footwear industries, has limited applications due to its poor resistance to heat, UV and ozone, and low glass transition temperature. Such limitations can be improved by adding elastomeric polyolefins (composed of saturated hydrocarbons) to the polydiene rubber. Random copolymers of polyethylene and poly(ethyl ethylene) (PE-co-PEE) exhibit tunable glass transition temperatures. The addition of PE-co-PEE to 1,4-polyisoprene (PI) might potentially improve rubber performance. In order to provide quantitative guidance for such blends of olefin and diene elastomers in product design, the thermodynamic interactions between PI and PE-co-PEE were quantified via small angle light scattering (SALS) and small angle neutron scattering (SANS). PI was partially saturated with hydrogen to various extents (20-80%), which produced copolymers of PI and poly(ethylene-alt-propylene) (PI-co-PEP), to lower the critical point in the blends with PE-co-PEE. In this way, the cloud points (by SALS) could be observed in an accessible temperature range and SANS data could be collected within the homogeneous state. Temperature dependencies of the apparent interaction parameter (χ) were well described by the random copolymer theory (RCT) and χ of the homopolymer pairs (PI/PEE, PI/PE, PEP/PEE) were extracted. The χ parameter between PE-co-PEE and PI-co-PEP decreased dramatically as the PEP content (i.e. olefin content) in PI-co-PEP was increased.
Universal Calibration for Polyolefins, Resolution versus Reproducibility, Optimizing the Balance
David Gillespie, February 2020
High demands for polyolefins sample throughput necessitate optimization of chromatography systems for speed, often at the cost of resolution. Universal Calibration techniques in high-temperature SEC are especially sensitive to column resolution due to the increased slope of the product, IVxM, which is steeper than a traditional calibration against backbone molecular weight. Moreover, optimization methods must be included to preserve data relative to band-broadening effects between higher speed and higher resolution systems. Herein, we examine the use of analytical SEC columns as we balance shear rate effects and resolution versus run time for a Universal calibration system including both LDPE and HDPE samples. A methodology of comparing resolution enhancements and dilution effects versus number and type of GPC columns will be presented.


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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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