Manufacture Of Plastic Products Research Articles

Effect of Fiber Content on Mechanical and Morphological Properties of Bamboo Fiber-Reinforced Linear Low-Density Polyethylene Processed by Rotational Molding

Rotational molding or rotomolding is a powder processing technique used for the manufacturing of hollow plastic products. The present work investigates the moldability of long bamboo fiber as the reinforcement for linear low-density polyethylene (LLDPE) matrix. The temperature of the mold, oven and internal air temperature of the mold has been recorded to study the heat transfer rate while processing composites with different weight percentage. Mechanical properties were found to be improved by 5% fiber addition, and beyond that, the properties were reverted. Morphological characterization was done to analyze the interfacial properties of fiber and matrix. The present work successfully incorporated long bamboo fibers with LLDPE powders and uniformly distributed these fibers along the sides of the mold without applying any external pressure. Thus, it is concluded that fiber incorporation is possible in the rotomolding process and homogenous randomly oriented fiber dispersion can also be achieved by the rotational molding process.

Occurrence of phthalic acid esters in marine organisms from Hangzhou Bay, China: Implications for human exposure

Owing to the wide application of phthalic acid esters (PAEs) in the manufacturing of plastic products, they are ubiquitous in the marine environment. However, the occurrence of various PAEs in marine organisms from China has not been well characterized. In this study, 341 marine organism samples (including fish, shrimp, crab, and shellfish) were collected from Hangzhou Bay, China and analyzed for 16 PAEs. Further, the human PAE exposure risks raised from the consumption of marine organisms were evaluated for adults and children. In total, eight PAEs were detected in collected organism samples, with the concentration of total PAEs (∑PAEs) ranging from 64 to 2840 ng/g (mean 238 ng/g). Crab (mean 811 ng/g) samples had the highest mean concentration of ∑PAEs, followed by fish (465 ng/g), shrimp (293 ng/g), and shellfish (261 ng/g) samples. Among detected PAEs, di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DBP), and di-ethylhexyl phthalate (DEHP) were the predominant PAEs, and they collectively accounted for 84–97% of the ∑PAEs concentrations in all samples. The estimated daily intakes of DiBP, DBP, and DEHP were more than one order of magnitude higher than remaining PAEs. Calculated hazard quotient values of PAEs were all <0.1, suggesting non-cancer risks for the general population through the consumption of marine organisms. Overall, for the first time, this study systematically examined the occurrence of multiple PAEs in four types of marine organisms from Hangzhou Bay, China.

181 Association between Polychlorinated Biphenyl (PCB) 153 Exposure and Serum Testosterone Levels: Analysis of the National Health and Nutrition Examination Survey

Polychlorinated biphenyls (PCB) 153 are a category of chlorinated aromatic hydrocarbon compounds manufactured for use in various commercial and industrial applications. PCBs are predominantly used as coolants and lubricants in electrical equipment, but is also utilized for the manufacturing of plastic and rubber products as well as pigments and dyes. As PCB and its metabolites have been recognized as potential health hazards, it is important for us to understand its implications on male fertility or the endocrine-related adverse effects associated with PCB exposure. We examined the effects of PCB 153 on serum testosterone levels as an independent variable, and in conjunction with other clinical, demographic and biochemical factors. We hypothesized that men with higher serum levels of PCB153 are associated with lower levels of testosterone, potentially suggesting the detrimental effects of PCB as an endocrine disruptor in humans. Using data collected from the 1999-2000 and 2001-2002 National Health and Nutrition Examination Survey (NHANES), we analyzed serum total testosterone and PCB153 levels, demographic data and comorbidities for men aged 18 years and older. Univariate and multivariate linear regression analysis was used to evaluate the association between total testosterone and serum PCB153.

Life Cycle of Products Made of Polymer Composite Materials

The life cycles of products made of metal and polymer composite materials are considered, and their common and distinctive features are determined. Using the mirror of a space antenna (made of carbon-filled plastic) as an example, we analyze the influence of auxiliary materials on the quality indices. A technique is developed to determine the influence of auxiliary materials on the phase composition (polymer matrix content is determined by thermogravimetry). A structure for forming carbon-filled plastic products using vacuum infusion and a system for the implementation of competitive design-technological solutions are presented for the manufacture of carbon-filled plastic products.

RESEARCH OF THE STRESS-STRAIN STATE OF THE MAIN CYLINDER OF THE HYDRAULIC PRESS

In the article the stress-strain state of the main cylinder of the hydraulic press for the manufacturing of large-sized plastic products has been investigated using software of finite-element analysis. It is established that the stress-strain state is characterized by a general and local uneven distribution of stresses and displacements. The nature of the distribution of stresses, deformations, displacements, safety factors along the length of the cylinder allowed conditionally divide the cylinder into three characteristic zones: flange zone, Lame zone, bottom zone. In each of the zones we found the areas in which the maximum stresses and strains are observed. It was found that the maximum equivalent stresses calculated according to the Huber-Mises energy theory of strength are observed on the inner surface of the cylinder, and in their fillets in the zones of the bottom and flange. A comparative analysis of the stresses and displacements determined by the Lame formulas and the finite element method showed that in the Lame zone their values do not change significantly. Studies on the influence of the radius, which varied over a wide range, and the fillet angle, made it possible to establish the region of maximum principal and equivalent stresses and reduce their magnitude. The calculations revealed the fillet region in which the axial tensile stresses act and determine the fillet angle at which the axial stresses are equal in magnitude and sign The study allowed to change the geometry of the cylinder, reduce the stress in the cylinder fillet and its weight. The results of the study can be applied to improve the existing and design of new hydraulic presses of the chemical industry, as well as the basis for further research.

Structure of the global plastic waste trade network and the impact of China’s import Ban

Millions of tonnes (teragrams) of plastic waste are traded around the world every year, which plays an important role in partially substituting virgin plastics as a source of raw materials in plastic product manufacturing. In this paper, global plastic waste trade networks (GPWTNs) from 1988 to 2017 are established using the UN-Comtrade database. The spatiotemporal evolution of the GPWTNs is analyzed. Attention is given to the country ranks, inter- and intra-continental trade flows, and geo-visual communities in the GPWTNs. We also evaluate the direct and indirect impacts of China’s plastic waste import ban on the GPWTNs. The results show that the GPWTNs have small-world and scale-free properties and a core-periphery structure. The geography of the plastic waste trade is structured by Asia as the dominant importer and North America and Europe as the largest sources of plastic waste. China is the unrivaled colossus in the global plastic waste trade. After China’s import ban, the plastic waste trade flows have been largely redirected to Southeast Asian countries. Compared with import countries, export countries are more important for the robustness of GPWTNs. Clearly, developed countries will not announce bans on plastic waste exports; these countries have strong motivation to continue to shift plastic waste to poorer countries. However, the import bans from developing countries will compel developed countries to build new disposal facilities and deal with their plastic waste domestically.

Thermal and mechanical analysis for conformal cooling channel in plastic injection molding

Injection molding is widely used in plastic product manufacturing process. The product quality and the cost-effectiveness highly depend on the cooling step in the molding process. Thanks to the development of additive manufacturing techniques, conformal cooling channel (CCC) becomes a promising alternative for channel design. In this paper, three CCCs with different profiles and the same aspect ratio are designed for cooling a plastic product in its manufacturing process. The thermal and mechanical performance is presented by ANSYS Workbench. The simulation results are validated by the experimental data. The cooling performance under different coolant flow rate and different inlet temperature are simulated and compared. The thermal results show that compared with conventional straight channel, the designed CCCs can shorten the cooling time ranging from 10% to 57.1% and the temperature distribution of the plastic product is uniform as well. The mechanical results show that the fatigue life and von Mises stress of the designed CCCs can meet the industrial operating requirement.

Incorporation of life cycle emissions and carbon price uncertainty into the supply chain network management of PVC production

Emissions trading schemes have been widely implemented by many countries to enforce the “cap and trade” concept for mitigating CO2 emissions. Thus, the carbon price influences the manufacturing costs in all stages of production, recycling, and disposal. Consideration of the carbon price is especially important for the economic efficiency of the downstream manufacturing sectors, such as in plastic product manufacturing, to substantially reduce their costs through the design and management of networked supply chains, which results in purchasing feedstocks from different technological routes, as well as choosing plants, warehouses and various transportation modes with diverse CO2 emission intensities. Supporting the decision-making in such situations requires the integration of life cycle analysis and networked supply chain management methodologies with an analysis of the carbon-market uncertainties. Such approaches have not been sufficiently quantified in the existing literature. This study presents a stochastic mixed-integer linear programming model developed for polyvinyl chloride pipe manufacturing in China, which is used to evaluate the effects of the life cycle emissions of procurement on the whole supply chain under carbon market uncertainty. Our results illustrate that the carbon market uncertainty would not only significantly influence the carbon-intensive production sectors but also the downstream manufacturing sectors. The five scenarios with carbon price variation exhibit distinctively different choices in procurement and supply chain configurations, as well as in their performances regarding total emissions and associated costs.

Integración de Actuadores Hidráulicos para los Sistemas Secundarios de Moldeo y Liberación en Moldes de Inyección de Plástico

The manufacture of plastic products in the current markets demands the use of technologies that allow the molding of components with highly complex geometries and every time the time to manufacture is reduced. The presence of subsystems for the molding and release of negative structures increases the complexity of the mould, as well as the time required for the manufacture and adjust of the mould, since it is traditionally used mechanisms with angular pins. In this work the design of an injection mould is made for a component with negatives, which uses a system with actuator for the secondary molding and release of the negative structure according to the mould partition line. The mold is also design for the same component with the use of a secondary system of moulding totally mechanical and of conventional use. The analysis of the design and operation between a secondary mechanical molding system and a system with actuator for molding and releasing negative structures in plastic injection molds, alternative for reducing costs and times of Manufacturing.

Analysis of productivity improvement in hard disc spare parts production machines based on OEE, FMEA, and fuzzy value in Batam

Increasing productivity is very important for companies to achieve success in their business processes. The company studied in this study was in Batam, a manufacturing company engaged in the manufacture of plastic products. The purpose of this study was to determine the value of OEE from machines that produce Hard Disc Drive products in order to increase the effectiveness of the machine. Knowing the main root causes that often occured damage to the machine and to find out how to solve problems that can increase machine productivity. This study uses the Overall Equipment Effectiveness (OEE) and Fuzzy Failure Mode and Effects Analysis methods. The results of the calculation and discussion get the OEE (Overall Equipment Effectiveness) value for April 2018, which is 63.87%. The difference in OEE values obtained is still below the standard value of the OEE classification that makes OEE not reach the target. The main cause of damage to DC machines is 60 tons, namely the low Performance Rate with an average value of 71.71%, this is due to the value of Reduced Speed Losses which has the largest contribution in the six big losses (losses) with a loss of 91.97 the clock which resulted in a DC 60 ton machine not working optimally. The FRPN value of 277 was obtained in the DC 60 ton machine factor so that repairs were needed.

Atmospheric levels of BPA associated with particulate matter in an urban environment

Bisphenol A (BPA) is an Endocrine disruptor compound (EDC), capable of interfering with hormone related pathways and cause adverse effects, for example, in the reproductive system in wildlife and humans. As it has multiple applications and uses, mainly in the manufacturing of plastic and resin products, increasing amounts are being released into the environment with resulting enhanced exposure pathways. Since negative effects have been demonstrated even at low doses, it has been increasingly studied. However, these investigations have focused on BPA leaching from food cans, drinks and other consumer products as the oral exposure route is believed to be the most important. Consequently, the potential hazards of dermal or inhalation exposure resulting from the current levels of BPA in the atmosphere are poorly understand. Of the few studies reporting BPA occurrence in air, none of these were carried out in South American countries. Thus, the aim the present investigation was to assess BPA current levels in particulate matter in an urban environment (Córdoba, Argentina) and to analyze its spatial-temporal trends and the influence of meteorological parameters using a medium volume air sampler. Our results suggested a spatial trend that decreased according to the distance to emission sources in the order: Industrial area > City Centre > University campus, whose levels were comparable to other urban cities and with the temporal trend showing a higher prevalence of the compound in the colder months. Wind speed (WS), temperature (T), atmospheric pressure (AP) and relative humidity (RL) were the most influenced variables. However daily values are unpredictable and depend mainly on the emission sources and punctual events that release BPA into the atmosphere.No risk factor could be quantified since there is no reference value for this exposure route; Nevertheless, this study represents the first approach and provides data about this emergent pollutant in and Argentinean city, thus contributing to global BPA studies.

Neurotoxicity of BPA, BPS, and BPB for the hippocampal cell line (HT-22): An implication for the replacement of BPA in plastics

Bisphenol A (BPA), a plastic additive, is ubiquitous in the environment and has endocrine disrupting effects. As many countries have prohibited the manufacture and sale of plastic products with BPA, BPA analogs have been used to replace BPA during production, including bisphenol S (BPS) and bisphenol B (BPB). To investigate the toxicities of BPA and its analogs on neurons, reactive oxygen species (ROS) assay, Annexin V-FITC (fluorescein) apoptosis detection assay, lactate dehydrogenase (LDH) cytotoxicity assay, and Cell Counting Kit-8 assay were conducted to comprehensively assess the influence of different concentrations of BPA, BPB, and BPS on ROS, apoptosis, damage, and proliferation for hippocampal HT-22 cells, respectively. Results showed that 6 h of exposure to bisphenols (BPs) could increase the ROS levels, 24 h and 48 h of exposure could induce higher apoptosis and LDH leakage rates for HT-22 cells, and 7 d of exposure could inhibit the cell proliferations. In addition, non-monotonic dose-response relationships were observed between the concentrations of bisphenols and the toxic effects mentioned above. The neurotoxic effects of BPA, BPB and BPS on HT-22 cells were in the increasing order of BPS, BPA, and BPB. In conclusion, these results showed that exposure to BPA and its analogs may result in adverse effects on hippocampal neuronal cell lines. BPS is a surrogate with lower neurotoxicity to replace BPA in production of plastic utensils.

Inhibitory effect of Bisphenol A on in vitro feline uterine contractions

Bisphenol A (BPA) is an environmental pollutant used as a plasticizer in the manufacture of many plastic products, such as packaging, containers, and water and beverage bottles. There are deleterious effects of BPA on metabolic, endocrine, nervous, and reproductive systems. This is the first study in which there was investigation of the in vitro effect of BPA on the spontaneous contractions of the cat uterus. The tubal uterine segments (1 cm) collected from queens in estrus were suspended in an isolated organ bath. Following tissue stabilization, spontaneous contractions were recorded for 10 min to constitute the control group. The effects of the solvent (alcohol) and BPA at different concentrations (1, 10, and 100 μM) on uterine contractions were subsequently evaluated at 10 min intervals in terms of frequency and mean amplitude variables. The ethanol vehicle did not alter the uterine contractions compared to the control group. All concentrations of BPA used in the study resulted in a reduction (P < 0.05) in amplitude of uterine contractions in a dose-dependent manner, while only the largest dose of BPA decreased the frequency of contractions (P < 0.05). In reproductive physiology, regular uterine contractions facilitate successful fertilization, migration, implantation, and maintenance of pregnancy, as well as fetus expulsion. The results of this study indicate BPA has an inhibitory effect on spontaneous contractions of the cat uterus. It is proposed that this suppressive effect of BPA on uterine contractions might lead to queen infertility.

Metabolism Disrupting Chemicals and Alteration of Neuroendocrine Circuits Controlling Food Intake and Energy Metabolism.

The metabolism-disrupting chemicals (MDCs) are molecules (largely belonging to the category of endocrine disrupting chemicals, EDCs) that can cause important diseases as the metabolic syndrome, obesity, Type 2 Diabetes Mellitus or fatty liver. MDCs act on fat tissue and liver, may regulate gut functions (influencing absorption), but they may also alter the hypothalamic peptidergic circuits that control food intake and energy metabolism. These circuits are normally regulated by several factors, including estrogens, therefore those EDCs that are able to bind estrogen receptors may promote metabolic changes through their action on the same hypothalamic circuits. Here, we discuss data showing how the exposure to some MDCs can alter the expression of neuropeptides within the hypothalamic circuits involved in food intake and energy metabolism. In particular, in this review we have described the effects at hypothalamic level of three known EDCs: Genistein, an isoflavone (phytoestrogen) abundant in soy-based food (a possible new not-synthetic MDC), Bisphenol A (compound involved in the manufacturing of many consumer plastic products), and Tributyltin chloride (one of the most dangerous and toxic endocrine disruptor, used in antifouling paint for boats).

An Integrated Approach for Design and Manufacture of Plastic Products

An Integrated Approach for Design and Manufacture of Plastic Products

Stop eating plastic, molecular signaling of bisphenol A in breast cancer.

Breast cancer is the second most common fatal cancer in women. Developing a breast cancer is a multi-factorial and hormonal-dependent process, which may be triggered by many risk factors. An endocrine disrupting substance known as bisphenol A (BPA), that is used greatly in the manufacture of plastic products, was suggested as a possible risk factor for developing breast cancer. BPA has a strong binding affinity to non-classical membrane estrogen receptors like estrogen-related and G protein-coupled (GPER) receptors. Based on animal and in vitro studies, results showed a link between BPA exposure and increased incidence of breast cancer. BPA has the ability to alter multiple molecular pathways in cells namely, G protein-coupled receptor (GPER) pathway, estrogen-related receptor gamma (ERRγ) pathway, HOXB9 (homeobox-containing gene) pathway, bone morphogenetic protein 2 (BMP2) and (BMP4), immunoregulatory cytokine disturbance in the mammary gland, EGFR-STAT3 pathway, FOXA1 in ER-breast cancer cells, enhancer of zeste homolog 2 (EZH2), and epigenetic changes. Thus, the aforementioned alterations cause undesired gene stimulation or repression that increase risk of developing breast cancer. So, restricting exposure to BPA should be considered to aid in lowering the risk of developing breast cancer.

Effects of bisphenol A in soil on growth, photosynthesis activity, and genistein levels in crop plants (Vigna radiata)

The compound bisphenol A (BPA), an endocrine-disrupting compound that can act as an estrogen, is widely used in the industrial manufacture of plastic products and epoxy resins. Because of the widespread use of the compound and its use in soil amendments, there is concern regarding its effects on crop plants, although comparatively little information is available on the ecotoxicity and potential risk of bisphenol. Here, we investigated the toxicity of BPA on mung bean (Vigna radiata) by evaluating growth, photosynthesis parameters, and phytoestrogen changes. Adverse effects on shoot growth were observed at a dose of 750 mg BPA/kg dry soil after acute (14 days) and chronic (21 days) exposure, and inhibition of root development was confirmed at a dose of 1000 mg BPA/kg dry soil. Chlorophyll content and stomatal size decreased at doses of 250 and 500 mg BPA/kg dry soil, respectively, and leaf spots due to leaf necrosis were observed in the groups that received 250 mg BPA/kg dry soil. Photosynthetic activity appeared to decrease in the groups that received the highest exposure, although it was not statistically significant. Meanwhile, exposure to bisphenol A increased the level of the phytoestrogen genistein. We propose that changes in genistein levels due to endocrine-disrupting compounds can be considered as a specific toxicity endpoint for endocrine-disrupting chemicals; further studies should explore this effect. This study confirmed the phytotoxicity of BPA at various endpoints and the results provide a basis for future ecological risk assessment for BPA.

Minimum wage in Croatia: sectoral and regional perspectives

In this paper, we identify the sectors and regions in Croatia most affected by minimum wage changes. By using four criteria, we identify 13 low‐wage sectors. The analysis also reveals five regions (counties) in which the minimum wage can play an important role. Low‐wage sectors in Croatia are found to be manufacture of textiles, manufacture of clothing, manufacture of leather and related products, manufacture of wood and of products of wood, manufacture of rubber and plastic products, manufacture of furniture, construction of buildings, specialised construction activities, retail trade, food and beverage services, security and investigation activities, services to buildings (cleaning etc.) and personal services. We analyse the employment and wage changes for these low‐wage sectors in the period 2009–2015. It turns out that tradable low‐wage sectors are highly affected by minimum wage changes due to a high concentration of employees with wages just above the minimum wage. However, during the recession, these sectors had a smaller employment decline and higher wage growth compared with both the manufacturing industry as a whole and non‐tradable low‐wage sectors.

Plastik Ürün Üretiminde Tehlikeli Atıkların Azaltılması için Mevcut En İyi Teknikler

Plastik Ürün Üretiminde Tehlikeli Atıkların Azaltılması için Mevcut En İyi Teknikler

Disruption of the Reproductive Axis in Freshwater Fish, Catla catla, After Bisphenol-A Exposure

Environmental estrogens such as bisphenol-A (BPA) cause reproductive disorders in many vertebrate species, especially fish. BPA is used extensively in the manufacture of plastic and plastic products, epoxy resins, and dental sealants. The presence of BPA in sewage and surface water raises a potential threat to aquatic populations. In the present study, we investigated the effects of BPA on ovarian histology and transcription of key genes involved in reproduction. Adult female Catla catla were exposed to graded concentrations of BPA (10, 100, 1000 µg/l) for 14 days. Ovary histology and expression of steroidogenic acute regulatory protein (star), ovary aromatase (cyp19a), follicle-stimulating hormone receptor (fshr), and luteinizing hormone receptor (lhr) were evaluated in ovary of female fish after 14 days. Fish ovaries from the control and 10 µg/l BPA exposed groups included primary oocytes (POCs), while fish exposed to higher concentrations of BPA (100 and 1000 µg/l) contained tertiary and mature oocytes with increased numbers of atretic follicles. Significant increases in mRNA transcripts of star were observed in fish exposed to 100 and 1000 µg/l BPA. A 15-fold increase in the expression of ovary aromatase (cyp19a) was detected in fish exposed to 100 µg/l BPA. fshr increased in a dose-dependent manner. Increases in the expression of lhr, although not statistically significant, were observed in fish exposed to 100 and 1000 µg/l BPA when compared to control. The results of the present study indicate that BPA causes alterations in the expression patterns of genes involved in the reproductive pathway, which may lead to negative effects on the reproductive system in female fish.