Thermoplastic Industry Research Articles

Safe(r)-by-design principles in the thermoplastics industry: guidance on release assessment during manufacture of nano-enabled products.

The application of nanomaterials (NMs) and nano-enabled products (NEPs) across many industries has been extensive and is still expanding decades after first being identified as an emerging technology. Additive manufacturing has been greatly impacted and has seen the benefits of integrating NMs within products. With the expansion of nanotechnology, there has been a need to develop more adaptive and responsive methods to ascertain risks and ensure technology is developed safely. The Safe(r)-by-Design (SbD) concept can be used to establish safe parameters and minimise risks during the materials' lifecycle, including the early stages of the supply chain. Exposure monitoring has advanced in recent years with the creation of standardised protocols for occupational exposure assessment of nano-objects and their aggregates and agglomerates (NOAA). To aid in the development of an online SbD-supporting platform by the EU-funded project SAbyNA, we adopt a Europe Standard for monitoring release of NOAA to identify if a greater release of NOAA is associated with incorporation of NMs within NEPs compared to a polymer matrix alone. Case studies included filaments of polypropylene (PP) with nano-Ag or polycarbonate (PC) with single-walled carbon nanotubes (SWCNTs). NMs were received in masterbatch, and therefore previously modified to align with SbD interventions. Results were collected in line with European Standard recommendations: monitoring particle concentrations using direct reading instruments (DRI), sampling for offline chemical and morphological analysis, and collecting contextual information. Based on the criteria described in the European standard (BS EN 17058), data from both case studies identified that inhalation exposure relating to NM was "unlikely". Despite this, during the production of the SWCNT-PC filaments, some noteworthy observations were made, including several DRI activity measurements shown to be higher than background levels, and material morphologically similar to the reference SWCNT/polymeric masterbatch observed in offline analysis. The data collected during this campaign were used to discuss choices available for data interpretation and decision-making in the European Standard for monitoring release of NOAA and also to facilitate the development of SAbyNA's user-friendly industry platform for the SbD of NMs and NEPs.

Improvement in the Thermomechanical Properties and Adhesion of Wood Fibers to the Polyamide 6 Matrix by Sequential Ball Milling Technique

Improvement in the Thermomechanical Properties and Adhesion of Wood Fibers to the Polyamide 6 Matrix by Sequential Ball Milling Technique

A rare case of thermoplastic pneumoconiosis: polyvinyl chloride pneumoconiosis: a case report

Polyvinyl chloride is a widely used synthetic plastic polymer worldwide. Today, it is used in many areas, such as health, electricity, electronics, and construction, especially in the building sector. It is known to have many harms to human health. Our case is a 39-year-old male patient who has been working in the plastics industry for 16 years. The patient, who was diagnosed with a gastric neuroendocrine tumor while working, applied to us to investigate the relationship between his tumor and work. Although a clear relationship could not be established, it was found that he had pneumoconiosis during the examination. It was thought this was due to the polyvinyl chloride he had been exposed to for years. As a result, pneumoconiosis can also be seen in people working in the thermoplastic industry, apart from classical pneumoconiosis-forming dust such as silica, silicate and coal. It is very important to detect these patients early with screening and prevent exposure.

Dynamic shop-floor scheduling using real-time information: A case study from the thermoplastic industry

Practical production planning and scheduling systems must promptly respond to major real-time events and adjust their plans and schedules accordingly. To highlight the importance of concurrency in such systems, this paper addresses the problem of dynamic shop-floor scheduling using real-time information in a case study from the thermoplastic industry. The considered production line is organized as unrelated parallel production cells with a set of identical parallel machines in each cell. Parts are produced in batches using different molds on specific machines. Due to the size and complicated design of the molds, they require extended recovery periods (i.e., maintenance) in case of major failures. Therefore, previously developed plans and schedules need to be revised using real-time information every time a mold’s major failure occurs. The production process is subject to the following constraints: batch processing, safety stocks, dedicated machines, machine-dependent setup times, precedence constraints, mold failures, and real-time updates. The problem is formulated as a mixed-integer programming model to minimize a weighted cost function that includes tardiness and operating costs. To solve the problem, a predictive-reactive scheduling approach is introduced based on a modified simulated annealing (SA) algorithm. The developed approach utilizes an event-driven rescheduling policy. It also embeds a problem-specific neighborhood structure and solution evaluation into the modified SA algorithm. The experimental study indicates that the proposed approach generates better real-life planning and scheduling results than the methods based on dispatching rules. The findings demonstrate that the proposed SA-based predictive-reactive scheduling approach generates the solutions with about a 26.1% less tardiness cost and a 6.99% less total weighted cost (on average). In addition, the results also show the competitiveness of the proposed SA-based predictive-reactive scheduling approach compared to two other approaches based on an iterated greedy (IG) algorithm and a Tabu Search (TS) algorithm from the literature.

Enhanced thermally conductive TPU/graphene filaments for 3D printing produced by melt compounding

AbstractConducting polymers are a potential solution to the issue of wide‐range manufacture of flexible electronics, since many polymers are suitable to advanced fabrication methods, such as fused deposition modeling (FDM) 3D printing. Therefore, it is proposed in this work a ductile thermoplastic polyurethane (TPU)/graphene nanocomposite with enhanced thermal conductivity that would be suitable for additive manufacturing processes. The nanocomposites were produced by melt compounding technique, which does not require the use of toxic solvents and is characteristic of being used by the thermoplastic industry. The filaments were then analyzed in terms of graphene dispersion, microstructural changes, mechanical behavior, and thermal conductivity. It was verified that graphene does not have a good interaction with the TPU matrix, presenting voids at the interface and forming agglomerates at higher contents. However, it was able to affect the TPU's hard segments organization, leading to a more ordered structure up to 1.0 wt%. Consequently, the thermal conductivity was enhanced up to the graphene concentration by about 14% in relation to neat TPU. Additionally, even though the system presented a poor interface, no mechanical properties were lost, that is, the composite remained ductile even after graphene insertion, which is extremely interesting for additive manufacturing processes.

Evaluation of maintenance management of a thermoplastic industry using maintenance maturity model

The present work focuses on a case study applying a maintenance management system model based on the degree of maturity in a thermoplastic industry that operates in the Industrial Pole of Manaus, in the state of Amazonas (Brazil). The system must support the decisions of the organization and promote progress in the company's continuous improvement system. The study was based on the answers to a questionnaire submitted to the maintenance, production and process engineering sectors. Internal perception was compared with external perception, in order to perform an analysis of the field of view of the three sectors on the current position of the maintenance sector in relation to the maturity model used for this analysis. From the application of the model, it was possible to develop a strategic action plan, based on lean practices, so that the maintenance areas advance towards the higher levels of the maturity scale, aiming to reach and maintain performance levels recognized as excellence.

Failure Mode and Effect Analysis and Analytic Hierarchical Process Applied for Reduction of Environmental Risk in Supplier Selection to Thermoplastic Industry

Failure Mode and Effect Analysis and Analytic Hierarchical Process Applied for Reduction of Environmental Risk in Supplier Selection to Thermoplastic Industry

ATRIBUTOS TERRITORIAIS: DAS INOVAÇÕES AO MERCADO LATINO AMERICANO NAS INDÚSTRIAS TERMOPLÁSTICAS DO SUL DO BRASIL

The Brazilian thermoplastic industry consolidated from the 1970s with the urbanization intensification and industrialization of the country. In that area, technical progress is crucial for competitiveness; however, there is a certain maturity in the development of technologies. On the other hand, the international trade is centered on equipment and raw material since finished plastic does not compose large exponents in trade balances. Thus, the article’s aim is to identify technical progress and international trade of thermoplastic industries, in southern Brazil. The study developed from the literature review on innovation, in the plastic industry, along with data obtained from the Brazilian foreign trade. After that, it was possible to identify the potential and the dynamic territorial attributes of thermoplastic industries in the South region, especially, the ability to invest in potential markets of Latin America.

Sigma Level Verification of a Thermoplastic Industry with the Support of DMAIC Method

This study aims to determine the sigma level of the production process of a thermoplastics industry with the implementation of DMAIC approach. To achieve this purpose it was conducted interviews to know the production system, analysing the non-conformities in the produced forks. It was found that the industry has a sigma level that is the reality of industries in general, however, this level still does not equal to what is presented by large industries. The paper contributed to the improvement of industrial quality control, and the proposed method it is being evaluated so that other improvements can be implemented.

Comparative study of lignins isolated from Alfa grass ( Stipa tenacissima L.)

Soda lignin, dioxane lignin and milled lignin were isolated from Alfa grass ( Stipa tenacissima L.). The physico-chemical characterization of three different lignins: one industrial lignin precipitated from soda spent liquor and two lignin preparations isolated under laboratory conditions from Alfa grass (also know as Esparto grass) was performed. The structures of lignins were studied by three non-destructive (FT-IR, solid state 13C NMR and UV/visible spectroscopy) and two destructive (nitrobenzene oxidation and thermogravimetric analysis) methods. Elemental analysis and the methoxyl content determination were performed in order to determine the C 9 formulae for the studied lignins. The total antioxidant capacity of the studied lignins has been determined and compared to commercial antioxidants commonly used in thermoplastic industry.

Synthetic polymers in the marine environment: A rapidly increasing, long-term threat

Synthetic polymers, commonly known as plastics, have been entering the marine environment in quantities paralleling their level of production over the last half century. However, in the last two decades of the 20th Century, the deposition rate accelerated past the rate of production, and plastics are now one of the most common and persistent pollutants in ocean waters and beaches worldwide. Thirty years ago the prevailing attitude of the plastic industry was that “plastic litter is a very small proportion of all litter and causes no harm to the environment except as an eyesore” [Derraik, J.G.B., 2002. The pollution of the marine environment by plastic debris: a review. Mar. Pollut. Bull. 44(9), 842–852]. Between 1960 and 2000, the world production of plastic resins increased 25-fold, while recovery of the material remained below 5%. Between 1970 and 2003, plastics became the fastest growing segment of the US municipal waste stream, increasing nine-fold, and marine litter is now 60–80% plastic, reaching 90–95% in some areas. While undoubtedly still an eyesore, plastic debris today is having significant harmful effects on marine biota. Albatross, fulmars, shearwaters and petrels mistake floating plastics for food, and many individuals of these species are affected; in fact, 44% of all seabird species are known to ingest plastic. Sea turtles ingest plastic bags, fishing line and other plastics, as do 26 species of cetaceans. In all, 267 species of marine organisms worldwide are known to have been affected by plastic debris, a number that will increase as smaller organisms are assessed. The number of fish, birds, and mammals that succumb each year to derelict fishing nets and lines in which they become entangled cannot be reliably known; but estimates are in the millions. We divide marine plastic debris into two categories: macro, >5 mm and micro, <5 mm. While macro-debris may sometimes be traced to its origin by object identification or markings, micro-debris, consisting of particles of two main varieties, (1) fragments broken from larger objects, and (2) resin pellets and powders, the basic thermoplastic industry feedstocks, are difficult to trace. Ingestion of plastic micro-debris by filter feeders at the base of the food web is known to occur, but has not been quantified. Ingestion of degraded plastic pellets and fragments raises toxicity concerns, since plastics are known to adsorb hydrophobic pollutants. The potential bioavailability of compounds added to plastics at the time of manufacture, as well as those adsorbed from the environment are complex issues that merit more widespread investigation. The physiological effects of any bioavailable compounds desorbed from plastics by marine biota are being directly investigated, since it was found 20 years ago that the mass of ingested plastic in Great Shearwaters was positively correlated with PCBs in their fat and eggs. Colonization of plastic marine debris by sessile organisms provides a vector for transport of alien species in the ocean environment and may threaten marine biodiversity. There is also potential danger to marine ecosystems from the accumulation of plastic debris on the sea floor. The accumulation of such debris can inhibit gas exchange between the overlying waters and the pore waters of the sediments, and disrupt or smother inhabitants of the benthos. The extent of this problem and its effects have recently begun to be investigated. A little more than half of all thermoplastics will sink in seawater.

Graphite/Polyaniline (GP) composites: Synthesis and characterization

Ever since the discovery of inherently conducting polymers (ICPs), research dealing with the applications of these unique materials continues to grow. The use of ICPs, especially polyaniline (PANi) and polypyrrole (PPy), and carbon black (CB) as conductive additives in the thermoplastics industry have been limited due to undesirable properties of each at high temperatures. Carbon black-ICP composites, however, have shown improved properties at higher temperatures. The applications of these composites are still limited because the conductivities are below that of carbon black alone and about the same order of magnitude as PANi. Graphite/ICP composites have also been touted as possible electrode materials in rechargeable batteries and have numerous other applications. The exploration of graphite/PANi composites in our research lab has yielded conducting composites which exhibit conductivities greater than the graphite or PANi alone. In addition to higher conductivities, these graphite/PANi composites exhibit controllable conductivities as a function of pH.

Surface chemistry changes of weathered HDPE/wood-flour composites studied by XPS and FTIR spectroscopy

The use of wood-derived fillers by the thermoplastic industry has been growing, fueled in part by the use of wood-fiber–thermoplastic composites by the construction industry. As a result, the durability of wood-fiber–thermoplastic composites after ultraviolet exposure has become a concern. Samples of 100% high-density polyethylene (HDPE) and HDPE filled with 50% wood-flour (WF) were weathered in a xenon arc-type accelerated weathering apparatus for 2000 h. Changes in surface chemistry were studied using spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) was used to verify the occurrence of surface oxidation. Fourier transform infrared (FTIR) spectroscopy was used to monitor the development of degradation products, such as carbonyl groups and vinyl groups, and to determine changes in HDPE crystallinity. The results indicate that surface oxidation occurred immediately after exposure for both the neat HDPE and WF/HDPE composites; the surface of the WF/HDPE composites was oxidized to a greater extent than that of the neat HDPE. This suggests that the addition of WF to the HDPE matrix results in more weather-related damage. The results also show that while neat HDPE may undergo crosslinking in the initial stages of accelerated weathering, WF may physically hinder the ability of HDPE to crosslink, resulting in the potential for HDPE chain scission to dominate in the initial weathering stage.

Group 4 Metallocenes: Supported and Unsupported

The global thermoplastics industry is made up of 74% commodity resins, one-third of which is accounted for by polyethylene alone [1]. It was only in 1933 that polyethylene was discovered by Fawcett and Gibson [2] and it was not until 1953 that Karl Ziegler [3–5], Guilio Natta [6–8], and Paul Hogen [9] discovered the revolutionary first-generation Ziegler-Natta transition metal catalyst system. The second-generation MgCI, and/or donorsupported Ziegler-Natta transition metal catalyst system, which was at least 100 times more active, led to the development of the low-pressure polymerization process for polyolefins and synthetic elastomers [10]. This revolutionary catalyst system resulted in the development of simplified gas-phase low-pressure polymerization plant operation without the need for the removal of residual trace catalyst from the polymer.

A design of experiments study on the factors affecting variability in the melt index measurement

Melt index (MI) is universally accepted as the primary specification in the thermoplastics industry. The standard according to which the MI measurement is made is ASTM D-1238. However, some variation in the MI measurement is possible, even when all ASTM D-1238 specifications are met. A thorough understanding of the sources and magnitude of variation is essential, since measurement error can have significant economic implications. Error in the MI measurement can cause a resin lot (about 190,000 pounds) to be erroneously classified as off-spec (leading to a loss of over US $20,000). A Resolution IV, six-factor, 1/4 fractional factorial design of experiments (DOE) study [with three replicates] was done to quantify the effect of various factors affecting variability in the MI measurement using two high-density polyethylene monitor resins with MI of 1.91 g/10 min (“low” MI) and 36.4 g/10 min (“high” MI). A major challenge was dealing with qualitative (e.g., “cleanliness”) and quantitative (e.g., “sample mass” or “temperature”) factors in the same DOE. For the high MI monitor, among the factors considered, the most significant (for the ranges considered) were found to be (in the order of importance): die orifice diameter, temperature, die cleanliness, barrel cleanliness, and sample mass. The following factors were also considered but not found (in the ranges considered) to be as significant: piston land (tip) diameter, load, piston cleanliness, preheat time, and piston curvature. For the low MI monitor, among the factors considered, the two most significant (for the ranges considered) were temperature and barrel cleanliness. This article gives practical and useful information for those who make and/or use MI measurements. As others have pointed out, much of such discussion related to melt indexers is also applicable to more sophisticated capillary rheometers. © John Wiley & Sons, Inc. J Appl Polym Sci 65:277–288, 1997

A design of experiments study on the factors affecting variability in the melt index measurement

Melt index (MI) is universally accepted as the primary specification in the thermoplastics industry. The standard according to which the MI measurement is made is ASTM D-1238. However, some variation in the MI measurement is possible, even when all ASTM D-1238 specifications are met. A thorough understanding of the sources and magnitude of variation is essential, since measurement error can have significant economic implications. Error in the MI measurement can cause a resin lot (about 190,000 pounds) to be erroneously classified as off-spec (leading to a loss of over US $20,000). A Resolution IV, six-factor, 1/4 fractional factorial design of experiments (DOE) study [with three replicates] was done to quantify the effect of various factors affecting variability in the MI measurement using two high-density polyethylene monitor resins with MI of 1.91 g/10 min (“low” MI) and 36.4 g/10 min (“high” MI). A major challenge was dealing with qualitative (e.g., “cleanliness”) and quantitative (e.g., “sample mass” or “temperature”) factors in the same DOE. For the high MI monitor, among the factors considered, the most significant (for the ranges considered) were found to be (in the order of importance): die orifice diameter, temperature, die cleanliness, barrel cleanliness, and sample mass. The following factors were also considered but not found (in the ranges considered) to be as significant: piston land (tip) diameter, load, piston cleanliness, preheat time, and piston curvature. For the low MI monitor, among the factors considered, the two most significant (for the ranges considered) were temperature and barrel cleanliness. This article gives practical and useful information for those who make and/or use MI measurements. As others have pointed out, much of such discussion related to melt indexers is also applicable to more sophisticated capillary rheometers. © John Wiley & Sons, Inc. J Appl Polym Sci 65:277–288, 1997

INCREASED ISOTRANSFERRIN RATIO AND REDUCED ERYTHROCYTE AND PLATELET VOLUMES IN BLOOD FROM THERMOPLASTIC INDUSTRY WORKERS

Ten women (aged 31-61 years) and five men (aged 20-59 years) occupationally exposed to welding fumes of polyacetate containing diethylphthalate in a thermoplastic industry were studied. They had been employed 1-33 years (median: 11 years). Seven women (aged 35-55) and eight men (aged 26-73) acted as unexposed controls. The exposed persons showed increased isotransferrin ratio in blood serum and reduced volumes of erythrocytes and platelets in blood.

Injection mould design (fourth edition): An introduction and design manual for the thermoplastic industry R. G. W. Pye, Longman Scientific and Technical, Essex, UK in association with the Plastics and Rubber Institute, London, copublished by John Wiley &amp; Sons Inc., New York, 1989. pp. xii + 754, price £31·00. ISBN 0–582–01611–8

Injection mould design (fourth edition): An introduction and design manual for the thermoplastic industry R. G. W. Pye, Longman Scientific and Technical, Essex, UK in association with the Plastics and Rubber Institute, London, copublished by John Wiley &amp; Sons Inc., New York, 1989. pp. xii + 754, price £31·00. ISBN 0–582–01611–8

Application Research in the Thermoplastics Industry

To maintain the necessary close relation between producer and fabricator of plastics molding powders, the application research activities have been segregated from the research laboratory and placed in the hands of a technical service group RESEARCH, production, and sales, the three major divisions of a company, have, in general, filled the needs for such companies as those dealing in basic chemicals. In contrast to chemicals, the successful marketing of plastics molding powders requires that the producer furnish adequate technical assistance to the fabricator to assure good results with the given material. This is true for new types of plastics requiring different molding conditions and may also be true for an old plastic in a new application where tough molding problems arise. The producer's interests oblige him to help the fabricator use his plasties in the right application and mold them efficiently to assure consumer satisfaction and increase demand for the base plastic. Technical service ...