Characterisation of polyamide (PA)12 nanocomposites with montmorillonite (MMT) filler clay used for the incremental forming of sheets

In this paper, the preparation and characterisation of polymer materials suitable for single point incremental forming (SPIF) technology were performed. Three different kinds of mixtures were selected: a mixture of neat polyamide 12 (PA12), a nanocomposite with PA12 matrix and 1% clay (Cloisite 93A), and a nanocomposite with PA12 matrix and 3% clay (Cloisite 93A). Materials were produced using a melt intercalation method followed by compression moulding. According to the needs of SPIF technology, morphological and mechanical properties were investigated in the obtained mixtures. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize morphological properties. It was determined that the most desired obtained exfoliated structure of clay in the polymer matrix was achieved. Static tensile testing and dynamic mechanical analysis as well as the determination of glass transition temperature and crystallinity of all analysed materials were used to obtain mechanical and thermal properties of the mixtures. The results obtained for each mixture were compared with respect to the content of clay. The content of clay (Cloisite 93A) showed a strong influence on the properties of the obtained materials. The presence of clay (Cloisite 93A) affected the increase of tensile strength and Young's modulus, while its influence on the attained elongation was not unique.Ministry of Education, Youth and Sports of the Czech Republic (Program NPU I) [LO1504]; Slovenian Research AgencySlovenian Research Agency - Slovenia [P2-0248]; University of Rijeka [Uniri-tehnic-18-100-589]; Tomas Bata University in Zlin RVO

Barrier properties of PE, PP and EVA (nano) composites - the influence of filler type and concentration

Nanocomposite materials with layered clay used as nanofiller and polyethylene (PE), polypropylene (PP) and copolymer ethylene and vinyl acetate matrix (EVA, the content of VA component 19 wt. %) were prepared by compounding the individual components in Brabender kneader. The MMT Na+ and four types of commercial products such as Nanofil N 5 and N3000, Cloisite 93A and 30B were used as nanofillers. Next to the clays microprecipitated CaHCO3, nanosilica and Halloysite tubes were used. The quantity of all the above-mentioned (nano) fillers was 1, 3 and 5 wt. % in relation to the content of montmorillonite. The aim was to evaluate the influence of (nano) filler type and concentration on nanocomposite barrier properties. The morphology of nanocomposite samples was examined by means of XRD analysis illustrated by transmission electronic microscopy TEM. Furthermore, permeability for O-2 and CO2 were observed

Permeation properties of polymer/clay nanocomposites

The important characteristics of polymer/clay nanocomposites are stability, barrier properties and in the case of polyvinyl chloride also plasticizer migration into other materials. Therefore, the permeation properties of polymer/clay nanocomposites are discussed in this paper. The attention was focused to the polyethylene (PE) and polyvinyl chloride (PVC). Natural type of montmorillonite MMTNa+ and modified types of montmorillonite from Southern Clay Products were used as the inorganic phase. As the compounding machine, one screw Buss KO-kneader was employed. The principal aim is to fully exfoliate the clay into polymer matrix and enhanced the permeation properties. Prepared samples were tested for O-2 and CO2 permeability. Polymer/clay nanocomposite structure was determined on the base of X-ray diffraction and electron microscopy (TEM)

Changes of PVC nanocomposite properties connected with clay content

The polyvinylchloride (PVC) is an extensively used thermoplastic material, therefore the research were focused on this polymer. The aim of this work was to determinate the current development of nanocomposite materials based the polyvinylchloride and the influence of filler loading on their thermal and electrical properties. As nanofillers were used clays derived from montmorillonite (MMT): MMTNa+ and MMT30B. MMTNa+ presented sodium type of montmorillonite and MMT30 is organically modified type of MMT. Both of the clays were intercalated or cointercalated with plasticizer bis(2-ethylhexyl) phthalate (DEHP). As the compounder the Buss KO-kneader was selected. This type of compounder is suitable for processing temperature-sensitive polymers. The properties as thermal and electrical conductivity were evaluated in comparison to the structure

Thermal analysis of postcured aramid fiber/epoxy composites

In this study, aramid fiber-reinforced polymer (AFRP) composites were prepared and then postcured under specific heating/cooling rates. By dynamic mechanical analysis, the viscoelastic properties of the AFRP composites at elevated temperatures and under various frequencies were determined. Thermomechanical analysis (TMA), in the modes of creep-recovery and stress-relaxation tests, was also performed. Furthermore, differential scanning calorimetry was also used, and the decomposition of the AFRP composites, aramid fibers, and pure postcured epoxy, in two different atmospheres, namely, air atmosphere and nitrogen (N2) atmosphere, was explored by the thermogravimetric analysis (TGA). From this point of view, the aramid fibers showed remarkably thermal resistance, in N2 atmosphere, and the volume fraction of fibers (φf) was calculated to be φf = 51%. In the TGA experiments, the postcured AFRP composites showed very good thermal resistance, both in air and N2 atmosphere, and this characteristic in conjunction with their relatively high Tg, which is in the range of 85-95°C, depending on the frequency and the determination method, classifies these composites as potential materials in applications where the resistance in high temperatures is a required characteristic. © 2021 Konstantinos Karvanis et al., published by De Gruyter 2021.TBU in Zlin [IGA/FT/2021/006]IGA/FT/2021/00

Applications of clays in nanocomposites and ceramics

Clays and clay minerals are common natural materials, the unique properties of which have attracted the interest of the industry, especially because these materials are easily available, cheap, and non-toxic. Clays and clay minerals are widely used in many applications, such as in ceramic production, in the clarification of liquids, pollutant adsorbers, filler in composites and nanocomposites, soil amendments, in pharmacy, etc. This review assesses the development in the area of clay application in nanocomposites and ceramics. The first part of this study covers polymer/clay nanocomposites. Topics of interest include nanofiller sources for polymer nanocomposites, the possible ways of clay modification, polymer/clay nanocomposite classification and their processing, and polymer matrix overview with possible enhancement of nanocomposite properties. Some of the applications have already been commercialized. Approximately 80% of the polymer/clay nanocomposites are destined for the automotive, aeronautical, and packaging industries. The second part of this study describes ceramic materials with a focus on silicate ceramics. Talc and kaolinite represent the main natural raw materials for traditional ceramic applications. Less traditional cordierite, steatite, and forsterite could offer property enhancement and seem to be useful in electronics, electrical engineering, catalysts, solar thermal storage, or medical applications.Tomas Bata University in Zlin, Faculty of Technology [IGA/FT/2023/008, IGA/FT/2024/008]; Jan Amos Komensky Operational Program - EU; State budget of the Czech Republic [CZ.02.01.01/00/22_008/0004631]; EU under the REFRESH-project via the Operational Programme "Just Transition" [CZ.10.03.01/00/22_003/0000048

Tribo-mechanical properties of the antimicrobial low-density polyethylene (LDPE) nanocomposite with hybrid ZnO–vermiculite–chlorhexidine nanofillers

Materials made from low-density polyethylene (LDPE) in the form of packages or catheters are currently commonly applied medical devices. Antimicrobial LDPE nanocomposite materials with two types of nanofillers, zinc oxide/vermiculite (ZnO/V) and zinc oxide/vermiculite_chlorhexidine (ZnO/V_CH), were prepared by a melt-compounded procedure to enrich their controllable antimicrobial, microstructural, topographical and tribo-mechanical properties. X-ray diffraction (XRD) analysis and Fourier transform infrared spectroscopy (FTIR) revealed that the ZnO/V and ZnO/V_CH nanofillers and LDPE interacted well with each other. The influence of the nanofiller concentrations on the LDPE nanocomposite surface changes was studied through scanning electron microscopy (SEM), and the surface topology and roughness were studied using atomic force microscopy (AFM). The effect of the ZnO/V nanofiller on the increase in indentation hardness (HIT) was evaluated by AFM measurements and the Vickers microhardness (HV), which showed that as the concentration of the ZnO/V nanofiller increased, these values decreased. The ZnO/V and ZnO/V_CH nanofillers, regardless of the concentration in the LDPE matrix, slightly increased the average values of the friction coefficient (COF). The abrasion depths of the wear indicated that the LDPE_ZnO/V nanocomposite plates exhibited better wear resistance than LDPE_ZnO/V_CH. Higher HV and HIT microhardness values were measured for both nanofillers than the natural LDPE nanocomposite plate. Very positive antimicrobial activity against S. aureus and P. aeruginosa after 72 h was found for both nanofiller types. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.[SP2020/08

Synergistic effect between polyhedral oligomeric silsesquioxane and flame retardants

Synergistic effect was observed between two types of flame retardant and two types of polyhedral oligomeric silsesquioxanes (POSS). The polymer matrix was represented by low density polyethylene Bralen RB 2-62 (Slovnaft). The polyethylene was mixed with nanofillers OctaIsobutyl POSS and TriSilanolIsobutyl POSS. The flame retardants was represented by ADK STAB (R) FP 2200 and Exolite (R) APP 722. The flammability was investigated by UL-94 test. The results showed that the APP/POSS system had important flame retardant and anti-dripping abilities for LDPE

The Effect of processing on the PVC/Clay Nanocomposites Structure

Reported nanocomposites of poly(vinyl chloride) have been prepared using bentonite-based clay, Na-montmorillonite (nature clay) and organophilic clay 30B. Polymer nanocomposites of differing compositions were produced using Buss KO-kneader via melt intercalation method. The effect of different type of plasticizer (both low molecular and high molecular) and compounding conditions on the structure of PVC/clay nanocomposites was investigated. Different compounding conditions were tested to study their influence on nanoparticles dispersion, orientation and exfoliation in PVC/clay nanocomposites. The structure of PVC/MMT nanocomposites was observed using X-ray diffraction, transmission electron microscopy (TEM) and AFM (Atomic Force Microscopy). It was found that the Na-montmorillonite offer low exfoliation level, while 30B modified by plasticizer exhibits fine dispersion of partial to nearly full exfoliated MMT. Moreover the processing conditions play also important role in nanocomposite production

The effect of application of chicken gelatin on reducing the weight loss of beef sirloin after thawing

Freezing is one of the oldest and most-often-used traditional methods to prolong the shelf life of meat. However, the negative phenomenon of this process is the weight loss of water that occurs after the meat is thawed. Together with the water that escapes from the meat during thawing, there are large weight losses in this valuable raw material. Another negative aspect is that mineral and extractive substances, vitamins, etc. also leave the meat, resulting in irreversible nutritional losses of nutrients in the meat, which are subsequently missing for use by the consumer of the meat. The main goal of this work is to reduce these losses by using gelatin coatings. Gelatin was prepared from chicken paws according to a patented biotechnological procedure, which uses the very gentle principle of obtaining gelatin with the usage of enzymes. This unique method is friendly to the environment and innocuous for the product itself. At the same time, it ensures that the required principles achieve a circular economy with the use of the so far very-little-used slaughter byproducts, which in most parts of the world end up in uneconomic disposal by burning or landfilling without using this unique potential source of nutrients. Gelatin coatings on the surface of the beef steak were created by immersing the meat in a solution based on gelatin of different composition. A coating containing 3%, 5% or 8% gelatin with 10% or 20% glycerol (by weight of gelatin) and 1% glutaraldehyde crosslinker (by weight of gelatin) has proved to be effective. The amount of glutaraldehyde added to the coating is guaranteed not to exceed the permitted EU/U.S. legislative limits. In addition to weight loss, meat pH, color and texture were also measured. Freezing was done in two ways; some samples were frozen at a normal freezing temperature of -18 degrees C and the other part of the experiment at deep (shock) freezing at -80 degrees C. Defrosting took place in two ways, in the refrigerator and in the microwave oven, in order to use the common defrosting methods used in gastronomy. A positive effect of this coating on weight loss was observed for each group of samples. The most pronounced effect of coating was found for the least gentle method of freezing (-18 degrees C) and thawing (microwave), with the average weight loss of the coated samples differing by more than 2% from that of the uncoated sample. No negative effect of the coating was observed for other meat properties tested, such as pH, Warner-Bratzler Shear Force (WBSF) or color. Gelatin-based coating has a positive effect on reducing the weight loss of meat after thawing. Chicken gelatin prepared by a biotechnological process has a new application in improving the quality of meat due to the retention of water and nutrients in frozen and subsequently thawed beef, which can contribute to the better quality of the subsequently gastronomically prepared dish, while maintaining the weight and nutritional quality. This also results in economic savings in the preparation of highly-valued parts of beef.Internal Grant Agency of the Faculty of Technology, Tomas Bata University in Zlin [IGA/FT/2021/007, IGA/FT/2022/003]; National Agency for Agriculture Research project [QK1920190]QK1920190; Tomas Bata University in Zlin, TBU: IGA/FT/2021/007, IGA/FT/2022/00