Polypropylene Compounds Research Articles

Comparing End-of-Life Vehicle (ELV) and Packaging-Based Recyclates as Components in Polypropylene-Based Compounds for Automotive Applications.

Increasing recycled plastic content in cars to 25% by 2030 is one of the key measures for decarbonizing the automotive industry defined by the European Commission. This should include the recovery of plastics from end-of-life vehicles (ELVs), but such materials are hardly used in compounds today. To close the knowledge gap, two ELV recyclate grades largely based on bumper recycling were analyzed in comparison to a packaging-based post-consumer recyclate (PCR). The composition data were used to design polypropylene (PP) compounds for automotive applications with virgin base material and mineral reinforcement, which were characterized in relation to a commercial virgin-based compound. A compound with a 40 wt.-% ELV-based bumper recyclate can exceed one with just a 25 wt.-% packaging-based recyclate in terms of stiffness/impact balance. While the virgin reference can nearly be matched regarding mechanics, the flowability is not reached by any of the PCR compounds, making further development work necessary.

Recovery of an Antioxidant Derived from a Phenolic Diphosphite from Wastewater during the Production of a Polypropylene Compound: A Step towards Sustainable Management.

Organic phosphoester (OPE) antioxidants are currently required due to their contribution to enhancing the quality of polymers, including polypropylene (PP). In this research, an integral methodology is presented for the efficient extraction of bis(2,4-dicumylphenyl) pentaerythritol diphosphite from industrial wastewater. Upon employing the solid-phase extraction (SPE) technique, the recovered compound is subjected to a comprehensive analysis of the recovered compound using high-performance liquid chromatography (HPLC), mass spectrometry (MS), thermal analysis (TGA), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Subsequently, purified Bis(2,4-dicumylphenyl) pentaerythritol diphosphite was evaluated as a thermo-oxidative stabilizer after incorporation into PP resins. The relative standard deviation (RSD), Error (Er), linearity (R2), and percentage (%) recovery were less than 2.6, 2.5, more significant than 0.9995, and greater than 96%, respectively, for the inter-day and intra-day tests of the chromatographic method and the SPE. Except for chloroform, which was necessary due to the solubility properties of the investigated analyte, the use of environmentally friendly solvents, such as methanol and acetonitrile, was considered during the development of this research. The OPE extracted from industrial wastewater was characterized by FTIR, UV-Vis, DSC, TGA, and MS, allowing the elucidation of the structure of Bis(2,4-dicumylphenyl) pentaerythritol diphosphite (BDPD). The recovered OPE was mixed with PP resins, allowing it to improve its thermal properties and minimize its thermo-oxidative degradation. Organophosphorus flame retardant (OPE)' concentration in wastewater is alarming, ranging from 1179.0 to 4709.6 mg L-1. These exceed toxicity thresholds for aquatic organisms, emphasizing global environmental risks. Using a validated solid-phase extraction (SPE) technique with over 94% recovery, the study addresses concerns by removing organic contaminants and supporting circular economy principles. The high economic and environmental significance of recovering BDPD underscores the need for urgent global attention and intervention.

Precision control and parameter optimization in screw extrusion 3D printing of polypropylene materials

Fused Deposition Modeling (FDM), a widely-utilized additive manufacturing (AM) technology, has found significant favor among automotive manufacturers. Polypropylene (PP) compound is extensively employed in the production of automotive parts due to its superior mechanical properties and formability. However, aiming at the problem of poor dimensional accuracy of pure PP parts, the quality of products can be enhanced by optimizing the combination of processing parameters. In this paper, the dimensional accuracy of 3D-printed components made from pure PP material is investigated. Key influencing factors such as infill percentage, infill pattern, layer thickness, and extrusion temperature are considered. To gain a deeper understanding, fluid simulation is conducted, and mathematical models are established to correlate processing parameters with dimensional accuracy. Furthermore, the Taguchi's experiments are designed and the experimental data are subjected to rigorous Signal-to-Noise ratio and ANOVA analyses. Within the experimental range, the lower extrusion temperature, infill percentage and layer thickness yield the best dimensional accuracy. Considering the influence factors of X, Y and Z directions, the optimal processing parameters for PP prints using screw extrusion 3D printers are determined as follows: an extrusion temperature of 210 °C, an infill percentage of 40 %, a layer thickness of 0.3 mm, and a concentric circle infill pattern. This study provides reference value for the subsequent improvement of the dimensional accuracy of the printed parts.

Enhancing properties and manufacturability of post-consumer recycled polypropylene via gas counter-pressure injection molding

In contemporary times, the most effective strategy to mitigate the environmental effects of plastics and their manufacturing is through recycling. Nonetheless, the production of high-quality items from recycled materials remains a challenge. This study addresses these challenges, specifically in the context of the injection molding process for recycled polypropylene. The key issues identified include poor surface finish of the molded items, mold contamination with oily residues, and strong odors during processing. The proposed solution involves the innovative use of gas counter pressure in conjunction with injection molding. The study explores various nitrogen pressure levels to assess their impact. Findings indicate that an optimal pressure level significantly improves the surface quality of the products and reduces the accumulation of dirt in the mold cavities. Additionally, the research investigates the potential impact of this method on the mechanical performance of the molded items. Results confirm that the appropriate use of gas pressure does not deteriorate these properties. While gas counter pressure does not mitigate odor emissions, it represents a promising step forward in developing a high-quality recycled polypropylene compound. This approach could pave the way for more advanced recycling techniques, enhancing the quality of products made from recycled plastics.

Predicting Ductile–Brittle transition temperatures for polyolefins using convolutional neural networks and instrumented notched Charpy experiments

For polyolefins, a transition from ductile- to brittle fracture behavior can be observed at decreasing temperatures, which is typically characterized by the Ductile–Brittle Transition Temperature (DBTT). For each material, the DBTT needs to be determined by performing multiple impact tests across wide temperature ranges. In this study, we utilize Convolutional Neural Networks (CNN) to predict the DBTT from single Instrumented Notched Charpy (INC) experiments instead. Our dataset consists of over 6732 INCs encompassing 132 Polyethylene (PE) and Polypropylene (PP) compounds. For each of these compounds, we examine 51 impact tests at temperatures ranging from -40 °C to 60 °C. We train models on combinations of instrumentation signals and fracture surface images. We test the trained networks on 1683 INCs, where we achieve a R2-score of 0.96 and an average error below 5 °C of predictions compared to experimentally determined DBTTs. The presented methodology provides a flexible way of predicting DBTTs in case of non-instrumented testing or if thermal specimen conditioning is not possible. This allows for fast screening of new materials.

Polyolefin ductile-brittle transition temperature predictions by machine learning

Polymers show a transition from ductile-to brittle fracture behavior at decreasing temperatures. Consequently, the material toughness has to be determined across wide temperature ranges in order to determine the Ductile-Brittle Transition Temperature This usually necessitates multiple impact experiments. We present a machine-learning methodology for the prediction of DBTTs from single Instrumented Puncture Tests Our dataset consists of 7,587 IPTs that comprise 181 Polyethylene and Polypropylene compounds. Based on a combination of feature engineering and Principal Component Analysis, relevant information of instrumentation signals is extracted. The transformed data is explored by unsupervised machine learning algorithms and is used as input for Random Forest Regressors to predict DBTTs. The proposed methodology allows for fast screening of new materials. Additionally, it offers estimations of DBTTs without thermal specimen conditioning. Considering only IPTs tested at room temperature, predictions on the test set hold an average error of 5.3°C when compared to the experimentally determined DBTTs.

Revolutionizing transportation composite structures: Lightweight, sustainable, and multi-scale hybrid design through waste tire-driven graphene, hemp fiber, and bio-based overmoulding

The pursuit of lightweight, environmentally friendly composite structures in transportation is crucial for minimizing ecological footprints and promoting energy-efficient manufacturing techniques. This study presents a novel approach by replacing traditional long glass fiber reinforced homopolymer polypropylene (homoPP) compounds with short hemp fiber reinforced homoPP, incorporating graphene nanoplatelets (GNP) derived from recovered carbon black via waste tire pyrolysis, resulting in a remarkable 15% weight reduction. With new compound formulation by adjusting the amounts of compatibilizer and GNP, injection moulding process was integrated with overmoulding process by using bio-based UD prepregs to enhance the adhesion of injected part and interfacial interaction by decreasing the stress concentrations in the structure. This novel hybrid composite design having 40 wt% hemp fiber, 1.0 wt% GNP and 2.7 wt% compatibilizer provided to improve flexural modulus and strength by 169% and 67.9%, respectively, compared to neat homoPP. The overmolding process employed bio-based natural fibers reinforced UD tapes as inserts, leading to an impressive enhancement of 211% in tensile modulus and 93.6% in strength, further surpassing the performance of neat homoPP. This work not only achieves the conversion of conventional composite structures into recyclable, sustainable thermoplastic composites but also introduces multi-scale reinforcements with customizable functionality, demonstrating a significant step forward in the development of environmentally conscious materials and manufacturing methods by adopting Life-Cycle Assessment (LCA) methodology regarding the sustainability of the newly developed composites.

Polypropylene Degradation on Co-Rotating Twin-Screw Extruders.

Nowadays, usable plastic materials with defined properties are created by blending additives into the base polymer. This is the main task of compounding on co-rotating twin-screw extruders. The thermal and mechanical stress occurring in the process leads to a mostly irreversible damage to the material. Consequently, the properties of the polymer melt and the subsequent product are affected. The material degradation of polypropylene (PP) on a 28 mm twin-screw extruder has already been studied and modeled at Kunststofftechnik Paderborn. In this work, the transferability of the previous results to other machine sizes and polypropylene compounds were investigated experimentally. Therefore, pure polypropylene was processed with screw diameters of 25 mm and 45 mm. Furthermore, polypropylene compounds with titanium dioxide as well as carbon fibers were considered on a 28 mm extruder. In the course of the evaluation of the pure polypropylene, the melt flow rates of the samples were measured and the molar masses were calculated on this basis. The compounds were analyzed by gel permeation chromatography. As in the previous investigations, high rotational speeds, low throughputs and high melt temperatures lead to a higher material degradation. In addition, it is illustrated that the previously developed model for the calculation of material degradation is generally able to predict the degradation even for different machine sizes by adjusting the process coefficients. In summary, this article shows that compounders can use the recommendations for action and the calculation model for the material degradation of polypropylene, irrespective of the machine size, to design processes that are gentle on the material.

Validation Experiment on Internal Barrier Wall Made of Polypropylene Compound in Levee

In Korea, levees are the fundamental countermeasure for floods caused by torrential rain in summer. In levee construction, loam is recommended instead of bed sediments because of problems like soil piping. A levee constructed with bed sediment requires the installation of a water barrier or an impervious core whereas the difficulty in procuring and transporting loam to the construction site creates an economic issue. Therefore, the purpose of this study was to verify the effectiveness of installing a barrier wall made of a polypropylene compound inside a levee. The wall helps increase the stability of the levee using bed sediments and can make levee construction economically feasible. When the water barrier was installed, a relatively slow increase in the water level was observed, and the behavior of the infiltrating line was also suppressed. In addition, there was no degradation or destruction till the end of the experiment. From these results, it is expected that the installation of the composite polypropylene water barrier will improve the stability of the embankment without the need to add quality soil.

Influence of material modification and fillers on the dimensional stability and warpage of polypropylene in screw‐extrusion‐based large area additive manufacturing

AbstractIn this work, the influence of a modification and fillers on the dimensional stability and warpage of semi‐crystalline polypropylene compounds in screw‐based Large Area Additive Manufacturing is investigated by material characterization and experimental testing. Polypropylene is modified by blending an amorphous polyolefin‐copolymer as well as the addition of three different fillers talc, glass fibers, and hollow glass beads, resulting in eight investigated compounds. A material characterization using Differential Scanning Calorimetry, Thermogravimetric Analysis, thermal conductivity measurements, and pvT‐measurements is carried out. Experimental investigations regarding dimensional stability and warpage deformation during processing are performed. By increasing the crystallization temperature and thermal conductivity from 112.3°C and 0.208 W/(m°C) to 127°C and 0.232 W/(m°C) through the use of a modification and talc, a better dimensional stability during processing is reached. Furthermore, both the modification of the base material and the introduction of talc or glass fibers lead to a significant reduction in the decrease in specific volume during cooling, as determined by pvT‐measurements, thus reducing warpage. The experimentally determined warpage deformation could be reduced by 69% when using 10 wt. % talc‐filler and by 78% when using 10 wt. % glass fibers, compared to the unmodified and unfilled base polypropylene.

Transforming vulcanized styrene–butadiene waste into valuable raw material: an opportunity for high-impact polypropylene production

Polypropylene (PP) compounds with styrene–butadiene rubber residue (SBRr) from the footwear industry were produced, adding styrene-(ethylene–butylene)-styrene (SEBS) as a compatibilizer, with 20% and 30% of styrene (St.). The PP/SBRr and PP/SBRr/SEBS compounds were processed in a co-rotating twin-screw extruder and injection molded. The addition of 30% SBRr did not compromise processability, as torque and melt flow index increased slightly compared to neat PP. Significant increases in impact strength were achieved for PP/SBRr/SEBS (10–20% St.) and PP/SBRr/SEBS (10–30% St.), with gains of 316% and 248% related to PP. The elastic modulus, tensile strength, elongation at break, and Shore D hardness indicated greater flexibility for the PP/SBRr/SEBS, especially in the copolymer with 20% St. When the PP/SBRr system was made compatible with SEBS (30% St.), the elastic modulus, tensile strength, and Shore D hardness increased in relation to the PP/SBRr/SEBS (20% St.). Such behavior suggested that the SEBS copolymer (30% St.) was more effective in increasing the resistance to elastic deformation of the PP/SBRr/SEBS compounds, compared to SEBS (20% St.). The heat deflection temperature (HDT) indicated that even adding high content of SBRr to PP, the HDT was not severely affected, possibly due to its crosslinked character. PP/SBRr compatibilization with SEBS (20% St.) inhibited the PP crystalline peaks, as verified through X-ray diffraction (XRD). Stable morphology was achieved upon 10% of SEBS addition to PP/SBRr, providing proper interfacial adhesion and fine particles, contributing to toughening PP. Acquired results are promising for rubber recycling, aiming to produce high-impact polypropylene for containers and furniture accessories applications.Graphic abstract

Sumika partners with Hexagon to digitize sustainable compounds for engineers

Hexagon's Manufacturing Intelligence division and Sumika Polymer Compounds Europe (SPC Europe), a manufacturer of thermoplastic compounds, have partnered to digitize the performance of new sustainable automotive-grade polypropylene (PP) compounds, enabling engineers to design components that are more recyclable and offer a lower carbon footprint for future vehicles. Sumika is exhibiting its sustainable PP compounds at the upcoming PlastIndia 2023 event in New Delhi (Pragati Maidan) from February 1-5 in Hall 3H – Booth F17A.

Business Roundup

BUSINESS Business Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2022, 100 (43), p 15December 5, 2022Cite this:C&EN 100, 43, 15AbstractElementis will sell its chrome chemical business to Yildirim Group in a deal valued at $170 million. The business, which had sales of $171 million last year, is the only chromium chemical producer in North America. Braskem CEO Roberto Simões is stepping down at the end of the year. He will be succeeded by Roberto Bischoff, who was with the Brazilian chemical maker from 1979 to 2019. Keliber says it is preparing to start construction on a $600 million facility in Finland that it expects to produce 15,000 metric tons per year of lithium hydroxide. The company also plans to open a lithium mine nearby. Honeywell and Egypt’s Environ Adapt for Recycling Industries have signed an agreement to develop a plastics recycling plant in Egypt. It would use Honeywell’s Upcycle pyrolysis technology. TotalEnergies will build a plant in Carling, France, that makes polypropylene compounds for the auto industry with upView: PDF | Full Text HTML

Influence of Fiber Content and Dosing Position on the the Mechanical Properties of Short-Carbon-Fiber Polypropylene Compounds.

The properties of short-fiber-reinforced composites depend on the fiber length of the reinforcing fibers. This fiber length is typically influenced by processing to different extents. In this work, we investigate the influence of processing, i.e., the influence of residence time achieved via different dosing points in compounding, and the fiber content on the fiber length and mechanical properties of short-carbon-fiber-reinforced polypropylene. We found that, with increasing fiber content, the fiber length decreases from 900 to 300 µm after compounding and from 500 to 250 µm after injection molding. Additionally, a decrease in residence time in the compounder leads to an increase in the fiber length of approx. 300 µm compared to the longer residence time. This is later reduced by the injection molding step, but the longer fibers are still longer in the final molded test specimen, thus resulting in a 5-10% increased tensile strength and elastic modulus as well as an some increase in impact strength. As the injection molding step showed considerable fiber length reduction (down to 250 µm), further investigations of injection molding should be undertaken to preserve fiber length better for the increased performance of these composites.

Production of third generation bio-fuel through thermal cracking process by utilizing Covid-19 plastic wastes

During this pandemic, it has become customary to wear a face waste mask to guard against coronavirus illness (COVID-19). However, huge production of face waste masks, PPE kit and gloves pose environmental risks, since existing disposal methods such as incineration and reclamation which are emitting hazardous substances. In the present study covid-19 medical waste material like waste face waste masks; gloves and PPE kit (personal protective equipment) are considered as the feedstock for the thermal degradation process. Mainly nylon, polyethylene and polypropylene compounds are present in the Covid-19 medical waste compounds, further feedstock material is subjected to physical characterization process like proximate, ultimate and thermo gravimetric analysis (TGA), to determine the moisture, ash, volatile matter and decomposition temperature respectively. The waste waste mask has lower ash content of 9.7 %, whereas gloves and other PPEs has 11.8 and 11.2 % of ash respectively. Similarly volatile matter is also higher for waste waste mask than other feed stocks. Pyrolysis process is carried out between a temperature range of 100 °C to 700 °C and the products of the pyrolysis process are pyrolytic liquid, gas and residue. The maximum pyrolytic oil is produced from waste masks, gloves and other PPE kit at 300, 350 and 320 °C respectively. The calorific value of the pyrolytic oil from waste mask, gloves and other PPE kit possess 40.85,40.11,40.31 MJ/kg respectively, which indicates that all the pyrolytic oil has closer to the diesel fuel. Therefore pyroltic oil obtained from the Covid-19 medical waste can be used as an alternative fuel for CI engine.

Borealis Fibremod™ used to produce all-thermoplastic tailgate for VW Multivan

Borealis Fibremod™ is used to produce the reportedly first and largest-ever all-thermoplastic tailgate for the new Volkswagen Multivan. This tailgate is said to demonstrate how customer-centric innovation and collaboration can produce high-performance parts which can lower the overall carbon footprint of vehicles. The Fibremod™ portfolio of lighter-weight polypropylene (PP) compounds is giving Tier One suppliers and OEMs the freedom to design and manufacture more sustainable and lightweight solutions for leading automotive brands and their increasingly electric fleets.

A new look for car interiors

A range of polypropylene (PP) compounds could help improve the aesthetics of interior automotive parts.

Polypropylene Compounding Compositions for Fabrication of Plastic Honeycomb Foundation

A current situation on comb foundation suggested the use necessity of semipermanent plastic foundations. The compositions of polypropylene compound were selected for fabricating plastic honeycomb foundations with honeybee affinity and high nesting rate. To further increase the nest making, and effective method of wax coating on a molded foundation that exhibits good adhesion was proposed. The honeycomb foundation obtained from the compounding compositions was regenerable and durable. It was able to prevent environmental pollution due to the existing disposable wax foundation and contribute significantly to the practicality and economic improvement of the environment beekeeping industry.

Facile Preparation of a Trilayer Separator with a Shutdown Function Based on the Compounding of β-Crystal Polypropylene and Hydrogenated Petroleum Resin

Facile Preparation of a Trilayer Separator with a Shutdown Function Based on the Compounding of β-Crystal Polypropylene and Hydrogenated Petroleum Resin

Business Roundup

BUSINESS Business Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2022, 100 (20), p 13June 6, 2022Cite this:C&EN 100, 20, 13AbstractSolenis has purchased the Turkish specialty chemical maker Neu Kimya. Neu Kimya’s offerings include chemicals for oil, gas, and water treatment, primarily for markets in the Middle East and southeastern Europe. Chemours says demand for green hydrogen has it considering expanding capacity for ionomer products in Europe and the US. The ionomers are used in Chemours’s Nafion membranes, which go in electrolyzers that turn water to hydrogen and in fuel cells that convert H 2 to power. Sumitomo Chemical and Newlight Technologies plan to launch polypropylene compounds for auto and textile applications based on Newlight’s AirCarbon material. In the firm’s process, microorganisms convert methane into polyhydroxybutyrate. Johnson Matthey has acquired a 4.3% stake in Enapter, which develops anion-exchange membrane electrolyzers for producing green hydrogen, for $21 million. The German firm will use JM’s catalysts to make its electrolyzers. EuroAPI says it will develop lipid nanoparticles to support Sanofi’s efforts toView: PDF | Full Text HTML