Influence of Atmospheric Conditions on the Polymer Composite Based on NBR Rubber and Functionalized Protein Waste

The aim of this work is to characterize a biodegradable polymer composite based on butadiene-co-acrylonitrile rubber (NBR) and protein waste (ground leather). The biodegradable polymer composite was obtained by the mixing technique on a Brabender Plasti-Corder mixer and then on an electric roller (without heating), between its rollers, with sulfur vulcanization activators and Th accelerator, relative to 100 parts plasticized elastomer, obtaining 3-4 mm thick sheets, with strict observance of the technological recipe, but also of the established mode of operation. The obtained mixtures are then subjected to rheological characterization to determine the vulcanization time using the Monsanto rheometer (to determine the optimum temperature and vulcanization times in the laboratory electric press in specific molds for obtaining specimens to be subjected to subsequent characterization). Biodegradable polymeric composites based on butadiene-co-acrylonitrile rubber (NBR) and protein waste (leather waste from the footwear and leather goods industry) were made at optimal working parameters, and the characterization was performed on equipment specific to elastomers and according to standards in force for the footwear and consumer goods industry such as: plates for general purpose footwear soles as well as for water and mud environments, but also for the food industry, car mats, gaskets and components used under normal working conditions, technical plates, insoles, etc.

Lead(II) chloride effects on nuclear shielding capabilities of polymer composites

This work investigated the effects of using a new fabrication technique to prepare polymer composite on the wear-resistant performance of epoxy resin composites under dry friction conditions. Polymer composite samples with different weight contents of silicon carbide (SiC) particles were manufactured. This paper addresses the wear behavior of the obtained samples. With the suggested technique, the samples were prepared from epoxy/silicon carbide particles using a layer of thin kraft paper to prevent the sedimentation of the ceramic particles and to control the weight content of ceramic in the polymer. Kraft paper was used as a layer in the polymer composite. The hardness, wear resistance, and water absorption capacity of the produced epoxy composite samples prepared using the kraft paper technique were evaluated. The morphology of epoxy composite samples showed a significant improvement in the ceramic distribution and enhancement of interface bonding between ceramic and the polymer. The hardness values of the developed polymer composites were enhanced by up to 42.8%, which was obtained at 18 wt.% SiC particles. Increasing the ceramic content in the epoxy also led to the enhancement of wear resistance compared with pure epoxy. The results of the microstructure study also showed that the kraft paper layers helped in maintaining the distribution of the ceramic particles according to the previously specified content in each layer in the sample. Wear tests showed that the wear rate of the polymer composite decreased with the increase in the ceramic content. This study provides a new recycling method for using old kraft paper in polymer composite manufacturing to improve the distribution of ceramic particles in the polymer matrix.

The review examines the effect of radio-frequency superradiance during pulsed mechanochemical activation of polymer composites under high pressure. Mechanochemical activation is implemented in three modes: (a) rheological explosion of polymer composite under rapid uniaxial compression, when an elastic wave pulse occurs in a polymer composite sample and implements the physico-chemical transformations leading to the occurrence of a superradiance pulse; (b) parametric mode, when an elastic wave pulse is introduced from the outside through a waveguide into a composite sample; (c) the mode of rapid pressure release, which also leads to the occurrence of a superradiance pulse. Paramagnetic polymer composites—namely polystyrene–binuclear clusters Co(QH)2–O–Co(QH)2 or Mn(QH)2–O–Mn(QH)2, where QH is a ligand based on QH2–3,6-di-tert-butylpyrocatechin)—are considered as objects implementing such processes. These binuclear clusters exhibit the Dzyaloshinskii–Moriya effect, and polymer composites based on them exhibit multiferroic properties. A composite of a molecular magnet in polystyrene matrix (Eu(III)(SQ)3·bipy complex with four unpaired electrons on Eu(III) and on SQ ligands; SQ is 3,6-di-tert-butylquinolate paramagnetic ligand) is also considered. The binuclear clusters and europium complexes form 2D nano-objects in the polymer matrix with a diameter of 50–100 nm and a thickness of ~ 1–2 nm. The review considers the formalisms of Dicke, Lorentz, Landau–Lifshitz–Blombergen and Havriliak–Negami equations, which make it possible to conduct a time–frequency analysis of these processes, to obtain data on the relaxation processes of spin and charge density in objects responsible for the process of radio-frequency superradiation. It is also shown that the analysis of electron spin resonance data allows us to provide a probable quantum chemical scheme for the implementation of the radio-frequency superradiance process. The phenomenon of superradiation has a great deal of potential in such areas as energy-saving technologies, wireless power transmission and storage devices. The technique of studying fast mechanochemical processes considered in the review allows us to investigate the mechanisms of interaction of magnetic and electrical subsystems in multiferroics and molecular magnets, which expands the scientific base for the creation of new functional materials and enables the solving of related problems of condensed matter physics.

This article mainly aims at experiments used for modifying unsaturated polyester resin (UPR), and trying to enhance the strengthening and toughening performance of nano-silica/UPR polymer composite in order to improve its integrated mechanical properties and to expand its field of application. Experiments were initially used to get high dispersibility nano-silica powder by adding silane coupling agent KH570 as a dispersant into commonly and commercially available nano-silica powder. Then, high dispersibility nano-silica powder was added as a filling with different mass fraction ratios into UPR and nano-silica/UPR polymer composite samples were fabricated. Infrared spectroscopy analysis, X-ray diffraction analysis, and scanning electron microscopy (SEM) analysis were conducted for high dispersibility nano-silica powder. Mechanical properties test and SEM observation of fracture morphology were investigated for nano-silica/UPR polymer composite samples. The results revealed that adding silane coupling agent KH570 with a mass fraction ratio 3% into nano-silica powder made nano-silica best dispersed after the modification reaction at a temperature of 80°C for 2 h. When the high dispersibility nano-silica powder was added into UPR with a mass fraction ratio 1.5%, the impact strength of nano-silica/UPR polymer composite improved greatly by 9.6%. However, when the high dispersibility nano-silica powder was added into UPR with a mass fraction ratio 2%, the tensile strength, bending strength and extension rate of nano-silica/UPR polymer composite improved greatly by 152%, 102%, and 167%, respectively.

Introduction: The article is the product of the research "Application of the ISO 9001 standard version 2015 in the leather, footwear and leather goods industry of the Restrepo sector, Bogotá D.C." developed at the Francisco José de Caldas district university during the years 2018 and 2019.
 Objective: Formulate strategies that allow SMEs to apply ISO 9001: 2015 in the leather, footwear and leather goods industry in SMEs of the Restrepo sector of the city of Bogotá-Colombia.
 Methodology: Surveys and a bibliographic inquiry were carried out to characterize the subject of the study; make a comparison at an international, national and local level; make a diagnosis of the application of the standard, and propose strategies for its implementation.
 Conclusion: About 78% of companies in the sector have the potential to be certified in the norm, although they must urgently implement information and communication technologies at the operational and documentary level, and those that are not legally formalized must register before the competent legal entities.
 Originality: Through this research, strategies for the implementation of ISO 9001: 2015 for SMEs in the Restrepo sector in Bogotá are formulated for the first time.
 Limitations: The results expose the problems found in a Bogotá cluster, which allow for making inferences for the case of Colombia, but it might not be the case for other countries with higher production or different conditions in the industry.

This work deals with gas–solid interactions between a high-alloyed steel powder and the surrounding atmosphere during continuous heating. It is motivated by the recently developed corrosion-resistant CrMnCN austenitic cast steels. Here, powder metallurgical processing would be desirable to manufacture highly homogeneous parts and/or novel corrosion-resistant metal-matrix composites. However, the successful use of this new production route calls for a comprehensive investigation of interactions between the sintering atmosphere and the metallic powder to prevent undesirable changes to the chemical composition, e.g., degassing of nitrogen or evaporation of manganese. In this study, dilatometric measurements combined with residual gas analysis, high-temperature X-ray diffraction (XRD) measurements, and thermodynamic equilibrium calculations provided detailed information about the influence of different atmospheric conditions on the microstructure, constitution, and densification behavior of a gas-atomized CrMnCN steel powder during continuous heating. Intensive desorption of nitrogen led to the conclusion that a vacuum atmosphere is not suitable for powder metallurgical (PM) processing. Exposure to an N2-containing atmosphere resulted in the formation of nitrides and lattice expansion. Experimental findings have shown that the N content can be controlled by the nitrogen partial pressure. Furthermore, the reduction of surface oxides because of a carbothermal reaction at elevated temperatures and the resulting enhancement of the powder’s densification behavior are discussed in this work.

We report the synthesis and characterization of novel elastomeric nanocomposites containing polyhedral oligomeric silsesquioxanes (POSS) as both the cross‐linker and filler within a polydimethylsiloxane (PDMS) polymer matrix. These polymer composites were prepared through the reaction of octasilane‐POSS (OS‐POSS) with vinyl‐terminated PDMS chains using hydrosilylation chemistry. In addition, larger super‐POSS cross‐linkers, consisting of two pendant hepta(isobutyl)POSS molecules attached to a central octasilane‐POSS core, were also used in the fabrication of the PDMS composites. The chemical incorporation of these POSS cross‐linkers into the PDMS network was verified by solid‐state 1H magic angle spinning NMR. Based on dynamic mechanical analysis, the PDMS nanocomposites prepared with the octafunctional OS‐POSS cross‐linker exhibited enhanced mechanical properties relative to polymer systems prepared with the tetrafunctional TDSS cross‐linker at equivalent loading levels. The observed improvements in mechanical properties can be attributed to the increased dimensionality of the POSS cross‐linker. The PDMS elastomers synthesized from the larger super‐POSS molecule showed improved mechanical properties relative to both the TDSS and OS‐POSS composites due to the increased volume‐fraction of POSS filler in the polymer matrix. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2589–2596, 2009

Polylactic acid (PLA) is the first commodity polymer produced from annually renewable resources. Its degradation is caused by hydrolytic cleavage of the polymer backbone with or without enzymes. However, PLA is commontly termed as a biodegradation polymer. Schizostachyum funghomii McClure is also a biodegradable material. So polymer composite (PC) material based on PLA and fiber of Schizostachyum funghomii McClure is call green composite with mechanical properties depending remarkably on kind of fiber (untreated or treated fibers). Water absorption capacity of material was evaluated through weight gains while scanning electron microscope (SEM) was used to study the morphology of surface of sample after soaking in chemical or biological medium. Thermal degradation temperature of PC was slightly lower than that of pure PLA. The weight remaining of PLA in neat PLA or PC sample is a function of elapsing time while the weight remaining of PLA in both samples after soaking in biological medium decreased almost linearly with elapsing time. In all medium, the degradation of PLA in neat PLA was slower than that of in PC sample. Keywords: Green polymer composite, polylactic acid, Schizostachyum funghomii McClure.

Purpose: The aim of the article is to present the thermal, electrical and mechanical properties of the produced polymer composites with a filler in the form of charcoal powder. Design/methodology/approach: The tests were carried out on samples of pure polypropylene (PP) and polymer composites, the matrix of which is polypropylene (PP), and the filler was charcoal powder with a volume fraction of 10%, 20%, 30%, 40% and 50%. The tested polymer composites in the form of granules were produced by extrusion, and then standardised test profiles were made by injection moulding. Findings: The hardness of the tested composites was determined by the Shore D method, the grain size distribution of the filler used was determined using the laser method and its thermal stability was tested using the TGA thermogravimetric analysis. The volume and surface resistivity were also determined and the density was determined. It was found that the charcoal powder used as a filler is characterised by high thermal stability – up to 600°C – and with an increase in its volume share in the polymer matrix, the hardness and density of the produced composites increases. Practical implications: The tested composites can be used as structural composites for complex elements requiring high hardness and strength. Originality/value: The research results indicate the possibility of using charcoal as a filler in polymer matrix, which, due to its low production cost, may be an alternative to expensive carbon fillers.

This work presents the obtaining and characterization of elastomeric compounds based on butadiene-co-acrylonitrile rubber and NBR rubber waste (from the footwear industry) that replaces the active silicon dioxide filler. The rubber waste was cryogenically ground to micrometric dimensions and functionalized with monoethylene glycol (MEG). After grinding, it is functionalized with monoethylene glycol (MEG) in a proportion of 20% at a temperature of 60°C. By recycling and reusing vulcanized rubber waste (NBR), as well as by means of advanced technologies, it is possible to contribute to the improvement of product quality, the protection of the environment through waste recycling, and most importantly the protection of human health through the elimination of noxious substances during their burning and, of course, increasing the turnover of economic agents. The polymer compounds obtained after conditioning at ambient temperatures were characterized according to the standards in force for the footwear industry, in terms of physical-mechanical normal state and accelerated aging at 70°C for 168 h and FT-IR spectroscopy. The polymer composites based on NBR rubber and functionalized rubber waste present optimal values according to the standards and are used in the processing of general-purpose footwear.

Tensile, compressive, flexural and wear resistance properties of Hibiscus sabdariffa fiber-reinforced phenolic (Resorcinol Formaldehyde) resin matrix-based composites were evaluated to assess the possibility of using these fibers as a new eco-friendly material in engineering applications. Polymer composite samples were fabricated by a compression-molding technique developed in our laboratory. The effect of fiber dimension on mechanical properties was evaluated. The interfacial bonding between Hibiscus sabdariffa fiber and the polymer matrix has been found to affect the mechanical properties of the resorcinol formaldehyde resin matrix. It has been observed that particle-reinforced polymer composites exhibit better mechanical properties as compared to short and long fiber-reinforced polymeric composites. These composites were further subjected to an evaluation of morphological, thermal, physical (swelling and moisture absorption) and chemical properties.

Introduction: the research addressed the situation of leather goods companies in the municipality of Belén, Nariño, which faced limitations related to lack of innovation, market knowledge and positioning strategies. These problems impacted their ability to differentiate themselves in a competitive environment. Given that the leather goods industry was one of the main economic activities in the municipality, it was considered essential to analyze its market orientation as a tool for commercial strengthening.Development: the study was based on international, national and regional antecedents that demonstrated the relationship between market orientation and organizational performance. It was found that companies with greater integration between marketing, design and innovation obtained better results in terms of competitiveness and sustainability. At the local level, it was identified that the sector had governmental and institutional support; however, many companies did not take advantage of these opportunities due to a lack of strategic train ing. The theories consulted highlighted the importance of implementing market intelligence, adaptability and modern marketing channels.Conclusions: it was concluded that market orientation represented a key factor for the transformation of the Bethlehem leather goods industry. Companies needed to adopt a customer-centric strategic approach, foster innovation and improve their organizational capacity. Only through the implementation of these strategies could they achieve brand recognition, increased profitability and a more prominent participation in regional and national markets.

The viscoelastic properties of a halogen-free polymer composition for cable products have been investigated. The influence of temperature parameters, shear rate on the die-swell ratio of the polymer composition has been determined; the dependence of the melt density on a temperature was investigated. The polymer matrix is a mixture of polyolefins (linear low density polyethylene; polyolefin elastomer and maleic anhydride modified linear low density polyethylene) as a flame retardant filler for the polymer composition is trihydrate alumina. The content of flame retardant filler in the polymer composition is 60 %. The polymer composition was manufactured on the compounding line of X-Compound, Switzerland. The investigation of both melt density and die-swell ratio of the polymer composition has been conducted with help of capillary viscometer type IIRT-AM. To determine the density of the melt the ratio of capillary length to diameter L/D=8/2 was used. The results of the study of the dependence of the melt density of the polymer matrix from a temperature of 150–190 °C at different loads showed that this parameter decreases from 789 to 744 kg/m3 and for polymer composition from 1309 to 1268 kg/m3. The die-swell ratio in the case of an increase of the shear rate at temperatures of 150–190°C for the polymer matrix increases from 1,102 to 1,520, and for the polymer composition decreases from 1,056 to 1,018. The investigation results of the dependence of both die-swell ratio of the polymer matrix and the polymer composition on the ratio of the length of the forming tool to the diameter indicates that the die-swell ratio for the polymer matrix was reduced from 1,296 to 1,152, and for the polymer composition from 1,045 to 1,01. It was established that the viscoelastic properties of the halogen-free polymer composition are significantly influenced by: processing temperature, shear rate, melt density, the ratio of the length of the forming tool to the diameter. The research results give a possibility for a reasonable approach for the determination of technological parameters of an insulation, sheathing of power cables and optical cables of microtube construction. It will also allow to quickly adjust the geometrical parameters of the forming tool of cable heads.

Foaming of the biodegradable polymer composites and melting of the gas-filled materials were studied using thermal microscopy. Composite materials under investigation were based on the low density polyethylene and natural products used as the polymer composite fillers: wood flour and corn starch. Porous structure of the composite material was obtained using a chemical porogen “Hydrocerol BIF”. It has been shown that the foaming and melting processes occur differently in the polymer composite samples containing either different amount of the fillers or the same content of the filler with different particle size fractions. Thermal behavior of the composite samples was shown to be different from the behavior of pure polyethylene, which indicates non-additivity (superadditivity) of the contribution of the above components to the thermal behavior of the final composite material. All the results obtained using heating stage (hot stage) microscopy were in good agreement with the SEM and DSC data.