Thermoplastic Compounds Research Articles

Evaluation of Microbial Degradation of Thermoplastic and Thermosetting Polymers by Environmental Isolates

In this study, a microbial–enzymatic strategy was pursued to address the challenge of degrading thermoplastic and thermosetting polymers. Environmental microorganisms were isolated, and their enzymatic activities were assessed using colorimetric assays to evaluate their potential for producing enzymes capable of degrading these polymers. Microorganisms demonstrating higher positivity in the enzymatic assays were selected for a 30-day biodegradation experiment, in which epoxy resins, polyethylene terephthalate, or polystyrene served as the sole carbon source. The effectiveness of biodegradation was assessed through the ATR-FTIR analysis of the chemical composition and the SEM examination of surface characteristics before and after degradation. The results indicated that thermoplastic compounds were more susceptible to microbial degradation, exhibiting greater changes in absorbance. In particular, PET treated with Stenotrophomonas sp. showed the most significant efficacy, achieving a 60.18% reduction in the area under the curve with a standard error of ± 3.42 when analyzed by FTIR spectroscopy. Significant alterations in surface morphology were noticed in thermoplastic compounds. In contrast, thermosetting compounds demonstrated lower reactivity, as evidenced by the absence of band shifts in FTIR spectra and minor changes in bond absorbance and surface morphology.

Degradation effects in FRNC jackets of optical fiber cables

AbstractIn large scale manufacturing, polymeric materials for cable jackets are subjected to high temperature and shear, what can induce degradation processes. In result, changes in structure of polymer materials can occur what is critical for their applications. Permanent market pressure on increase of productivity and product reliability as well as rigorous administrative regulations in telecommunication industry are the driving forces for development and introduction of new advanced Flame Retardant Non-corrosive jacketing materials. Despite many studies, their behavior is still neither well characterized nor understood in large-scale production. The object of studies was characterization of a relationship between processing conditions and effects of degradation of FRNC cable materials. The main goal was to find the processing factors limiting the production speed. Materials taken into consideration were two commercially available thermoplastic FRNC compounds dedicated to fiber optic cables, based on linear low-density polyethylene/ethylene–vinyl acetate composites with high loading of aluminum trihydroxide and magnesium dihydroxide fillers. Thermal degradation of cable materials was studied with use of thermogravimetry and rheometry. The series of jacket samples under different processing conditions were produced. Material processing behavior was characterized, and tensile and heat aging performance of cable jacket were tested. The results showed that the primary limiting factors for line speed increase were the melt pressure and jacket tensile performance, but neither the shrinkage nor extruder motor load. The result and general approach to the FRNC investigation can be successfully used in cable industry or in other industries involving the extrusion of FRNC materials.

Environmental Performance of a Polyamide-Based Thermoplastic Compound with Brominated Flame Retardants

Thermoplastic compounds are present in various industrial, domestic and consumer applications thanks to their strength, lightness, flexibility and processing properties. However, thermoplastics are often derived from polymers formed from non-renewable sources, such as petroleum. In addition, the production processes have a high consumption of energy. For this reason, assessing the environmental impacts caused by the production process is of primary importance. This research evaluates the environmental performance of a polyamide-based thermoplastic compound with brominated flame retardants. The objective is to understand which phase of the production process has the most significant impacts. The assessment of environmental impacts was carried out through the Life Cycle Assessment methodology using SimaPro v9.5, Ecoinvent v3.9 database and ReCiPe 2016 v1.07 impacts assessment method. The primary data were generated and collected in a factory in northern Italy, and the Functional Unit considered is 1 kg of final product. The results show that the upstream phase accounts for more than 90% of the environmental profile, especially in human non-carcinogenic toxicity, with more than 56% of the total impacts and fine particulate matter formation with 18% shares. At the climate change level, the product delivers a total impact of 6.17 kg CO2 eq per kg of the final product. This study indicates that most of the impacts are caused by the production of raw materials. For this reason, it is necessary to introduce more sustainable and environmentally friendly raw materials.

Effect of Utilizing Cheek Retractors on Patient Satisfaction and Trueness of Peripheral Borders in Maxillary Digital Scans for Totally Edentulous Patients: An In Vivo Study.

To evaluate the effect of cheek retractors on the accuracy of capturing peripheral borders in totally edentulous digital scans by comparing the conventional impression technique to digital scans made using two different cheek retractors. Sixteen edentulous maxillary impressions were made using three techniques: the conventional impression technique, using modeling thermoplastic compound and zinc oxide eugenol paste; the digital intraoral scanning technique using the DIO scan retractor (DIO); and using the Br.nemark lip retractor (BRAN). The control impressions of each patient were poured, scanned using a desktop scanner, then transferred into a three-dimensional analysis software. DIO and BRAN groups were scanned using an intraoral scanner, imported, and superimposed using best fit algorithm on the corresponding control. The root mean square for the whole surface and for particular interest regions were calculated to assess the degree of trueness. The patients' perceptions of the impression techniques were the secondary outcomes. Statistical analyses were performed using the one sample T-test and Wilcoxon test (α=.05). Significant discrepancies were found for BRAN and DIO compared to the control. No significant discrepancies were found when comparing RMS of BRAN and DIO at different regions. Scan retractors had a significant impact on patient satisfaction, with patients preferring DIO. Edentulous intraoral scans made using cheek retractors had similar deviations when compared to each other but diverged from the conventional impression in edentulous maxilla. Patient preferences for intraoral scans over conventional impressions were confirmed. The use of different retracting methods during intraoral scanning of totally edentulous maxillary arches does not affect the peripheral border registration.

Upcycling waste tempura flake-derived starch powder as an environment-friendly polymer matrix filler for thermoplastic starch compounds

Waste tempura flakes collected from local restaurants were upcycled to be utilized as a polymer filler material. The oil fraction in collected waste tempura flakes were extracted two times via centrifugal solid-liquid separation and organic solvent extraction. Then, oil-extracted residual starch was freeze-milled to produce fine powders. Waste tempura flake-derived starch powder was substituted with 1%, 3%, and 5% (wt%) of virgin starch powder to produce thermoplastic starch. Composition, X-ray diffraction, and Fourier transform infrared analyses showed that the mixture was successfully thermally plasticized. Substitution of waste tempura flake-derived starch decreased tensile strength while increasing elongation at break of some samples. Produced thermoplastic starch samples again were compounded with polylactic acid (PLA) and poly-butylene adipate-co-terephthalate (PBAT) following a mixing ratio of 3:5:2. The analyses indicated that thermoplastic starch, PLA, and PBAT were successfully compounded. The compound containing 1 wt% substituted thermoplastic starch showed the minimal mechanical strength decrease. This study revealed the possibility of upcycling waste fried food into a valuable bioplastic material. Waste tempura flakes can be utilized as both bio-jet fuel and bioplastic filler material.

Eco-Design and Additive Manufacturing of an Innovative Double-Casing Pedometer for Oestrus Detection in Dairy Cow

The analysis of motor activity has been revealed to be essential for monitoring dairy cows’ behavior, with the main aim of identifying the onset of oestrus in time. Pedometers used for oestrus detection have a current average working life on the market of about 5 years. At the end of that period, devices are disposed of, posing a relevant question regarding environmental sustainability. The present work proposed a method to achieve an eco-design of pedometers compliant with the guidelines of the Green Deal. Specifically, a new thermo-plastic organic compound made of polyamide 66 reinforced with organic hemp fibers (trade name SDS Nylon) was adopted. The feasibility, benefits, and performance of this material were assessed with a major emphasis on strength, lightweight, and surface finish. The material in addition to ensuring adequate chemical and mechanical resistance is biocompatible and recyclable. It assures better animal welfare and reduces both environmental impacts and management costs for farmers. Other innovations introduced in this study consisted of the adoption of a double casing. An external case was conceived with a protective function of the measurement system and fixed to a cow’s foreleg by an easy anchor system. An internal case was specifically designed to house the electronic components and to be moved from one cow to another after the pregnancy diagnosis. The solutions proposed in this research will contribute to guaranteeing pedometers a longer lifetime and better recyclability than existing commercial ones, consequently limiting the environmental load derived from their disposal.

Morphology, Thermal and Mechanical Property of Thermoplastic Starch Biocomposite

Thermoplastic starch bio-composite compound of cross-linked cassava starch has been produced by a twin screw extruder. Rice husk powder, bacterial cellulose fiber and glycerol were incorporated into the starch at various compositions. Bio-composite compounds were thermally compressed into a mechanical test specimen. Influences of reinforcing materials and plasticizer contents were investigated. An extrusion (160°C) and compression (200°C) at higher temperature produced a greater structural deformation of the cross-linked starch than a processing at lower temperature. Morphology of the bio-composite showed a homogeneous distribution of reinforcement in the matrix at high temperature processing and showed good adhesion between rice husk particle, bacterial cellulose fiber and starch matrix. Flexural and tensile mechanical properties of the bio-composite significantly improve with only 0.71%wt bacterial cellulose incorporation.

Preparation of high‐performance poly(butylene adipate‐co‐terephthalate)/thermoplastic starch compounds with epoxidized soybean oil as compatibilizer

AbstractBiodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) has excellent processing and mechanical properties. However, PBAT is expensive and its relatively slow biodegradation rate limits its wide application. In this paper, PBAT/thermoplastic starch (TPS) complexes were prepared by a two‐step process using epoxidized soybean oil (ESO) as a reactive compatibilizer. The compatibilizing ability of ESO was investigated by FT‐IR and GPC. Results showed ESO could form a chemical bonding interface with PBAT and TPS. Compared to PBAT/TPS, tensile strength, elongation at break and tear strength of PBAT/TPS/5%ESO composites increased by 84%, 53%, and 68%, respectively. The optical transparency of the PBAT/TPS/5%ESO film improved by 6% compared to the PABT/TPS film. This research offers a viable solution for the preparation of high performance, green PBAT/TPS complexes.

Influence of filler type and content on thermal conductivity and mechanical properties of thermoplastic compounds

AbstractCombining thermal conductivity with electrical isolation is a very interesting topic for electronic applications in order to transfer the generated heat. Typical approaches combine thermally conductive fillers with a thermoplastic matrix. The aim of this work was to investigate the influence of different fillers and matrices on the thermal conductivity of the polymer matrix composites. In this study, various inorganic fillers, including aluminum oxide (Al2O3), zinc oxide (ZnO), and boron nitride (BN) with different shapes and sizes, were used in matrix polymers, such as polyamide 6 (PA6), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethane (TPU), and polysulfone (PSU), to produce thermally conductive polymer matrix composites by compounding and injection molding. Using simple mathematical models (e.g., Agari model, Lewis–Nielson model), a first attempt was made to predict thermal conductivity from constituent properties. The materials were characterized by tensile testing, density measurement, and thermal conductivity measurement. Contact angle measurements and the calculated surface energy can be used to evaluate the wetting behavior, which correlates directly with the elastic modulus. Based on the aforementioned evaluations, we found that besides the volume fraction, the particle shape in combination with the intrinsic thermal conductivity of the filler has the greatest influence on the thermal conductivity of the composite.

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.

Hybrid joining of aluminum alloys and thermoplastic CFR‐PA12 manufactured by IR‐irradiation: Influence of pretreatment and aging on the mechanical properties

AbstractIn this work, a thermal direct joining process was applied to obtain hybrid composites of thermoplastic carbon fiber compounds and selected aluminum alloys. With the successful proof‐of‐concept, the aging behavior under hydrothermal and corrosive conditions is also investigated. Before joining, various linear surface topographies with a characteristic aspect ratio ranging from 0.1 to 2.0 were generated on the aluminum using a short‐pulsed near‐infrared (NIR) laser source. By using optimized NIR laser parameters, the achieved shear strength under tensile load can reach the maximum value corresponding to the interlaminar shear strength of the used carbon fiber‐reinforced thermoplastic polymer. In two aging regimes under hydrothermal and corrosive conditions, a rapid and sharp decrease in mechanical strength over time was observed exclusively under corrosive conditions.

Influence of Fiber Volume in Hybrid Short Glass/Cellulose Reinforced Thermoplastic Compounds

Glass fibers (GF) and regenerated cellulose fibers (RCF) are possible partners in the hybrid reinforcement of thermoplastics because of their different properties. Due to the weak bonding properties of polypropylene, coupling agents are used and the fiber volume content is set high to achieve high reinforcing effects. A lower fiber content of GF can raise the toughness properties of a reinforced polypropylene which is investigated in this study with different ratios of GF and RCF. The composites are tested in tensile tests, flexural tests and also in notched Charpy impact tests. The results can be used to compare whether a substitution of GF with RCF or the addition of more GF leads to higher mechanical properties. The tensile and Charpy impact results are compared with the Rule of Hybrid Mixtures (RoHM) to show the deviation to the prediction. Better results in terms of stiffness and strength are seen with a higher total fiber volume, while hybrid reinforced specimens show lower toughness values compared to the RCF reinforced reference specimens. Adding 5 vol% GF to 16 vol% RCF results in an increase in tensile strength by 26%, but also a significant decrease in elongation at break by 65%.

Obtention of New Edible Biofilms from Water Kefir Grains in Comparison with Conventional Biofilms from Taro (Colocasia esculenta) and Cassava (Manihot esculenta) Starch

Microorganism biomass is a sustainable and innovative source of biopolymers, such as proteins and polysaccharides, that is suitable for the development of biodegradable films. The aim of this research was to evaluate the synthesis, morphology, rheology, and morphological and mechanical properties on the production of edible biofilms based on water kefir grains, and compare them with edible films based on thermoplastic compounds from starch (TPS) obtained from taro (Colocasia esculenta) and cassava (Manihot esculenta). Edible biofilms were prepared in solution with 30% wt/wt glycerol relative to starch mass and kefir grain biofilms using the casting method. A stationary rheological analysis was performed on the film-forming suspensions of kefir, taro starch, and cassava starch. Once the films were obtained, a physicochemical and morphological characterization was carried out. Results of the characterization showed the following main aspects: The results indicated an increase in biomass production using muscovado and pineapple peel. The film-forming suspensions had a dilating behavior; however, the results obtained not only show the viscoelastic behavior but also the elastic limit (σ0), which varied from 0.077 to 0.059 Pa for suspensions of water kefir grains and from 0.077 to 0.072 Pa for starch suspensions. These elastic limit variations can be defined as the minimum shear stress required to start the flow, and all these rheological data were adjusted to the Herschel–Bulkley model; the morphological and mechanical characterization of the films obtained showed homogeneous surfaces with transparency and without cracks; regarding the water activity, values lower than 6 were obtained, which indicates that there will be no growth of any microorganism, and the hardness data showed differences between those obtained from kefir and taro and cassava starch. The similar results of the rheological characterization in the formation of the kefir biofilm and the conventional edible starch films, in addition to the similar results in the water activity below 6 and the hardness, points to an attractive alternative capable of replacing the conventional materials with a mass production of biofilms of probiotic microorganisms. The results also revealed that water kefir grains biomass is a viable and innovative source of biodegradable materials, and these grains can be an alternative to conventional established starch materials.

Surface Defects of TPO Injected Foam Parts for Automotive Applications

Abstract Benefits of reduced vehicle weight can have an important environmental impact since there is a 6 to 8% improvement in fuel efficiency for every 10% in weight reduction. In this work, foaming technology is used to produce injection molded TPO parts (thermoplastic olefin compounds) for the automotive industry with a minimum of 20% weight reduction while retaining a glossy surface quality. It was found by Guo et al. (2006, 2007) that the best strategy to raise the surface quality was to decrease the shot size, the cycling time and the temperature of the injected melt. However, the targeted objective of a minimum of 20% weight reduction was not achieved in these preliminary experiments. Therefore, in this work a blend of TPO and maleic anhydride modified polypropylene (PP-g-MA) was used in order to promote TPO foamability and improve the surface quality of injected parts. Under these conditions, we managed to produce injected molded TPO samples with a 24% weight reduction and good surface quality. Moreover, we investigated the effect of PP-g-MA in the TPO system by performing rheological measurements and photoacoustic Fourier transform infrared (PA-FTIR) analysis to characterize the PP-g-MA physico-chemical interactions with TPO.

Recycling of 3D Printable Thermoplastic Cellulose-Composite

3D printing enables sustainable product innovations through novel design, reduced use of materials, and local manufacturing. Sustainable 3D printing can further be realized using recyclable materials. Cellulose is an abundantly available renewable material. Modified celluloses, such as thermoplastic cellulose esters, are widely used in injection molding applications. The aim of this research was to study the properties of a cellulose-based composite (cellulose acetate propionate (CAP) polymer matrix with 20 wt. % microcellulose) in injection molding and granular extrusion-based 3D printing processes over multiple recycles. The impact of the processing methods on the composite’s properties were investigated. Both injection molded and 3D printed samples were ground with plastic grinding mill to particle sizes below 3 mm after each preparation stage and reused as such in the next process cycle. Morphology, mechanical and thermal properties, and material degradation were analyzed. The thermoplastic cellulose-based compound was found to be directly recyclable for both processes without the need for any additional compounding steps. The polymer matrix was able to withstand at least seven processing cycles without degradation. However, microcellulose was found to be more sensitive to thermal stress. The mechanical and thermal properties of the cellulose-based composites remained close to initial levels throughout.

Development of lightweight structural components based on low-cost processes for application in eco-efficient means of transport

The main objective of the LIGHTRANS project is the design and development of lightweight multi-material structures, through the development of optimized and low-cost manufacturing and joining processes. Which should allow its application in eco-efficient road transport vehicles. More specifically, within the framework of this project, the redesign  of a bus superstructure as well as an electric three-wheeled  vehicle will      be developed. Within the LIGHTRANS project, due to the needs of the market, it is proposed to strategically combine materials of different nature in such a way that the resulting structures present a weight reduction but without affecting the properties of the final components. The multimaterial structurals developed within the framework of the project, for both study cases, are based on thermosetting and thermoplastic compounds, cellular polymers and steel. Throughout this article, the mechanical characterization of the materials used for the manufacture of the components of both study cases, the manufacture of all the proposed components, as well as the evaluation of each of them in the final structures through tests will be presented. field.

ECOFUNEL: New Ad-hoc injection molding composites with enhanced electrical features for airborne systems

The European Commission has a strong compromise in matter of developing eco-friendly designs for airborne systems to reduce both manufacturing and in-service contamination related to those elements. One of the main approaches in this sense is to substitute metal parts by stiff, light-weight, multifunctional and recyclable polymer-based compounds which allow eliminating hazardous surface treatments and also permit reusing the materials at the end of life of the components. In this framework, ECOFUNEL project was launched by Liebherr Aerospace SAS with the consortium formed by FIDAMC, CTAG and CANOE, and with the financial support of the European Commission under the Clean Sky 2 initiative. The work aims to giving alternatives to current metal valve bodies of air conditioning systems for aircraft, by investigating the use of thermoplastic while addressing the challenge of keeping sufficient electrical conductivity and mechanical properties of the part. The research line put the focus on the development of new functionalized material formulations based on high performance injection molding thermoplastic compounds with enhanced electrical feature. New formulations are designed, produced and studied systematically within ECOFUNEL and a final prototype element will be created employing the ad-hoc own-designed materials.

Simulation of Thermoplastic Powder Cold Spraying

The work is devoted to the deposition of composite powder materials by cold spray method. As a spraying material, a thermoplastic compound «WAY» for marking the roadway was used. An asphalt concrete was used as a substrate. As a result of experimental studies, the dependence of the deposition efficiency on the stagnation temperature of the working air in the ejector nozzle was obtained. The ANSYS Fluent package was used for evaluative modeling of the cold spraying process. Gas flow patterns were obtained in the computational domain without particles and taking into account the interaction of the flow with particles. The trajectory of the particles was calculated for various spraying parameters

Biodegradable polymer film based on pbat and cassava starch: research and preparation

Thermoplastic starch compounds were prepared from cassava starch, glycerol, and tartaric acid by the twin-screw extruder. Fouriertransform infrared spectroscopy (FTIR) analysis demonstrated the formation of ester bonds during starch modification through absorption peaks at characteristic wavelengths of C=O bonding and C—O bonding. Biodegradable polymer were fabricated from thermoplastic starch (TPS) and polybutylene adipate terephthalate (PBAT) by the twin-screw extruder and then a blown film extrusion process. Scanning electron microscopy (SEM) images showed that when using modified thermoplastic starch (MTPS), the material showed a more homogeneous structure. Besides, this study also selected the optimal content of tartaric acid as a compatibilizer, screw speed, and talc powder content used in the blend when determining the tensile properties and melt flow index (MFI) of the material.

A review study in ultrasonic-welding of similar and dissimilar thermoplastic polymers and its composites

Due to the use of integrated materials in aerospace, automotive, sportswear, wind turbine and other fields, the industry is demanding new technologies and is rapidly adapting to more complex composite structures. In the last several years, unlike traditional welding methods, ultrasonic joining has become an important relevance in many applications areas. The random distribution and poor mechanical characteristics of grain always make it difficult to connect dissimilar materialsin the conventional welding process. The Ultrasonic-Welding technology for joining thermoplastic (TP) compounds is fast and energy efficient. Compared to other joining processes (adhesive, mechanical etc.), this welding method is more economical. This review's key features are the Ultrasonic-Welding process, theory, advantages, and limitations, process parameter, the effect of Energy director (EDs), Ultrasonic-Welding (UW) of similar and dissimilar TP composites and TP. The present state of UW and future viewpoints of TP composites are also explored.