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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Polymer Modifiers and Additives
Characterization and Processing of Thermally Conducting Thermoplastic Elastomers For A Microclimate
A commercially available grade of thermally conducting TPE was characterized and processed into tubing for use in a microclimate cooling system. This paper details the material characterization, extrusion of the resin into tubing, and the evaluation of tubing properties. A series of extrusion trials was conducted to establish a relationship between processing parameters. It shows there is a weak relationship between draw ratio and tensile properties. At last, future work is proposed to further improve the thermal conductivity of this material.
Characterization of Polycarbonate – Using Thermogravemetric-Rheology Analysis
The objective of this work is to study the rheological characteristic of the formulations and the processing of plastic production. In this work, introduced two polycarbonate resins were melt blended using two different twin-screw extruders, targeted to investigate the PC blends on the characterization behavior of the grade. Formulation and processing parameters showed an excellent effect on controlling the viscosity. The research aims to identify the underlying science by conducting a systematic study of two stages. First, the polycarbonate 30/70% (Grade-3) was chosen from historical data mining extracted in our project as was showing a high number of adjustment; the material was melt-blended using (Coperion) a Co-rotating twin-screw extruder (SB). The two polycarbonate resins (PC1/PC2) were PC1 content (30wt%-pph) of MFI (25gm/10mins) and PC2 content (70 wt.%-pph) of MFI (6.5gm/10mins). The grades also included four different color pigments and three additives. The second stage, the same material was included the same composition were blended in steps of eleven in a Thermo Haake Mini Lab II twin-screw micro compounder (ML). The steps (%PC1/%PC2) were (100%/0%), (90%/10%), (80%, 20%)… (0%/100%). This resulted in eleven batches. The rheological behavior of the compositions with pigment (WP), without pigments and additive (WOP) at 280 0C have been characterized through experimental measurements. The viscosity measurements of Variation PC blends of (30-70%) and at (0%, 30%, and 100%) were characterized at certain processing of (SB) and (ML). Thermogravimetric analysis (TGA) was performed under the effect of heating rate, Glass transition temperature (Tg) for PCs blends was measured and related it is affected by the minute variation blends, viscosities, and the various interactions indicated a significant effect on color changes.
Comparison of Longevity of PE- and PP-based TPO Waterproofing Membranes
This study compared the longevity performance of polypropylene (PP) and polyethylene (PE) based thermoplastic polyolefin (TPO) waterproofing membranes. It was demonstrated that PE-TPO outperformed PP-TPO for both heat aging and standard UV aging in terms of tensile property retention, weight retention and resistance of surface cracking. Better longevity for PE-TPO is attributed to the lack of tertiary carbon which is intrinsic to PP and prone to chain scission.
Development of Shape Memory Thermoplastic Polyurethane (TPU)/Polylactic Acid (PLA) Polymer Blend
Shape memory polymers represent a family of stimuli-responsive materials that can be used in many applications. Polylactic acid (PLA) is a type of shape memory polymers that is biocompatible and biodegradable. By blending PLA with thermoplastic polyurethane (TPU), its shape memory effect would be improved. This study aims to optimize the shape memory effect of TPU/PLA polymer material systems and investigate the influence of material compositions and processing conditions on their shape memory effects. Blends were fabricated with different compositions and/or different thermal history. Experimental results revealed that the addition of TPU increased the recovery but decreased the fixity at the same time. Overall, the 65/35 TPU/PLA blend has the best shape memory performance. The duration of stretching at the transition temperature in the process of the test of the shape memory properties influenced the crystallization of samples. The sample could show a bad shape memory effect if the stretching time is too long.
Engineering Impact Modification of Polypropylene for Low-temp/High-strain rate Loading Conditions
This communication presents a systematic investigation of polypropylene (PP) formulations modified using SEBS (Styrene-ethylene/butylene-styrene) and POE (Polyolefinic elastomer) block copolymers for impact modification. Impact performance of PP formulations containing POE, SEBS+POE and SEBS is compared under extreme conditions (high strain rate at -15°C and -30°C) and during quasi-static fracture tests at 25°C. Present work also discusses the effect of talc reinforcement on the fracture toughness of these formulations. The focus of the present work is to investigate the failure mechanisms of these formulations and understand how it correlates with the size, shape and other morphological features of the phase-separated SEBS and/or POE domains. The results show that the formation of crazes is the major energy absorbing mechanism at subzero temperatures. The 1 um domain sizes for SEBS modified PP leads to the stabilized craze formation and the highest fracture energy absorption amongst all the formulations investigated. It is shown that the effective stiffness of the dispersed phase and optimum particle size controls the damage density and energy absorption for polypropylene under extreme conditions.
Erucamide Slip Analysis in Polyethylene by GC using a Nitrogen Chemiluminescence Detector
Additives are commonly used in polyethylene applications to provide processing and long-term stability as well as to enhance or modify polymer performance for specific physical properties. Slip agents are one type of modifier used to alter the coefficient of friction in polyethylene films. Fatty amide based slip agents function by migrating to the surface of the film to provide a lubricating layer which enables the film surfaces to slide more easily across one another and when in contact with blown film extrusion and conversion equipment to facilitate processing. A combination of direct (e.g. XRF) and indirect (e.g. HPLC) analytical methodologies are used to measure the additive types and levels used for polyethylene applications. For slip agent analysis, the fatty amide is typically separated from the polymer matrix using an extraction technique (e.g. Soxhlet, Microwave, ASE) or by use of total polymer dissolution followed by polymer precipitation. The extract is then filtered and analyzed by a chromatographic technique, typically, HPLC-UV, GC-FID, or GC-MS. In some instances, polymer matrix signals from oligomers or other additives can interfere with the analysis. Furthermore, the slip agents from various suppliers are a mixture of fatty amides so analysis of the erucamide peak requires inherent knowledge of the specific amide distribution for the supplied slip agent. In this paper, a new and novel use of a gas chromatograph with a nitrogen chemiluminescence detector will be presented which illustrates a universal calibration of erucamide slip agents that compensates for the various amide distribution profiles from three different suppliers. This approach can also be extended to other slip agents such as behenamide and oleamide.
Functional Alkane Solvent Systems
An oligomeric hydrocarbon, Poly(α-olefins) (PAOs), were previously reported as a potential greener solvent to replace conventional alkanes solvent due to its lower toxicity, flammability and volatility. However, its poor solubility toward most organic substrate may limit its applications as solvent. This work demonstrated three strategies to introduce polarity in PAOs and recycle polar additives simultaneously: polymerization of polar monomers onto a PAO anchor, host-and-guest interaction and end-group modification of a PAO anchor, vinyl-terminated polyisobutylene (PIB). In the first method, RAFT polymerization gave a better control of polar polymers onto PIB in order to maintain hydrocarbon solubility over other two polymerizations (hydroboration/O2 initiation, ATRP polymerization). Secondly, the polar polymer, poly(isopropylacrylamide) (PNIPAM) could be successfully brought into and recover back out an alkane phase by treating with chemicals via a hydrogen bond network. The reversible solubilization of PNIPAM were used in recyclable Rhodium catalyzed hydrogenation. Lastly, a hydrophilic moiety (Hexamethylphosphoramide, HMPA) was successfully incorporated onto PIB. The hydrocarbon soluble Lewis base catalyst can be used in allylation of benzaldehyde in PAOs. Other ongoing studies are exploring this molecular recognition based solubilization with other solubilizing agents, other precipitation agents and exploring the use of this chemically responsive solubility both as a tool to prepare new solvent systems and new sorts of recyclable catalysts.
How Poor Selection of Materials, Design, Tooling and Design Errors Affect the Aesthetics of Plastic Parts and What Designers Need to Know About the Science of Color and Appearance - Part 1
Most engineers and designers come from the metal world. Therefore, many of them make assumptions on the predicted performance of plastic properties based on their metals background. Unlike metals, the knowledge of color and appearance is extremely important in the case of plastics. Most plastic parts have dual functions— physical performance and aesthetics. Aesthetics are important since very few of the parts need to be painted or otherwise decorated if designed and manufactured with due diligence. On the other hand, even if we are designing the most aesthetically critical metal components such as exterior automotive parts, we mostly choose the metals and alloys based on the physical properties, weight, and cost. The aesthetics are left to the paint specialist, who will in most cases find a paint system (primer, paint, and application method) that will meet the cost, durability, and cosmetic requirements. In other words, aesthetics and physical properties are quite independent of each other. A vast majority of metal parts meet their aesthetic and environmental requirements just by getting brushed, plated, chromate conversion coated or anodized. Plastic parts not only need to meet the short-term color and appearance requirements, but also need to be resistant to long term color shift and fading. This paper is in two parts. Part 1 - Appearance and Color Factors - Material - Design - Tooling and Processing Part 2 –The fundamentals of Color and Appearance, Specifications, Measurement and Tolerances
Influence of Additive Type On the Properties of Polyolefin Blends
The aim of this work was to compare the effects of compatibilisation with different additives on the properties of polyolefin blends, made from different PP and PE grades, to mimic the mixed polyolefins found in post-consumer waste and investigate ways to improve the properties of these mixtures. We found, that it is possible to compatibilize such polyolefin blends via the addition of ethylene-octen- or olefinic-block copolymers, where the type of copolymer shows an influence on the properties achievable. Also the blends show differently improved impact behavior, depending on the polyolefin which builds the major phase of the blend. These results show that it is possible to recycle such mixed polyolefin streams towards a suitable material with reasonable properties.
Ship Less Air –Flexible Chip Bag Filling Simulation for Sustainability
The snack flexible packages on the market today, such as potato chips, pita chips, taco chips, tortilla chips, etc., are typically sold by weight, that is, the packages need to fulfill the label claims by weight. However, the size of the packages is determined by the overall volume of the products. The determination of the overall volume of a given product weight is not trivial. The volume is a function of chip broken rate, chip size distribution profile, bag width, bag film gage and material, production line speed (bag/minute), VFFS machine type, etc. Traditionally, the size of the bag is determined by trial & error process through iterative lab testing and production trials. This approach typically results in unnecessary large bags due to the concerns of sealing contamination induced leakage issues in the case of the bag being too small. This leads to significant sustainability issues in shipping and distribution since the shipping trucks are often cubed out by volume (not by weight) for chip/snack packages. The energy is wasted by shipping more air (thus, less chip/snack packages) during distribution. In this work, authors propose a novel approach of bag size determination by using a virtual simulation of the VFFS chip filling process, where the potential influential attributes, such as chip broken rate, chip size distribution profile, bag width, bag film gage and material, production line speed (bag/minute), and VFFS machine type, can be modeled and their impact on the bag size can be quantified. A progressive 3-case simulation is performed and presented in this paper. The results are directionally correct based on the authors’ observation and past experience. Currently, authors are looking for industry partners (brand owners, co-packers and machine manufacturers) to collect production data and validate the analysis model. The intent of this paper is to bring the awareness of applicability of the simulation technology regarding to the bag size determination and chip/snack filling process, and ultimately help the industry in adopting the technology to make the chip bag filling process more sustainable, i.e., to ship less air.
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