Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.5
S. Jaerger, Daiane Nogueira, Douglas Santos de Oliveira, M. V. Machado, R. Marangoni
The presented work shows the synthesis and characterization of Zn/Ti layered double hydroxide (LDH) intercalated with carbonate and dodecyl sulfate ions following its application as a functional filler in LDPE in order to improve the thermal properties and resistance degradation in UV-Vis radiation. X-ray diffractogram patterns of Zn/Ti LDH-CO3 and Zn/Ti LDH-DDS present basal spacing value in the order of 6.81 Å and 38.09 Å, respectively, indicating success in layered compound synthesis. LDPE nanocomposite containing hydrophobic and hydrophilic LDH presented a very well dispersed nanocomposite, as demonstrated in XRD and DSC results. The addition of only 1 % of LDH as filler into LDPE causes an increase of 5.43 C in the thermal property. Zn/Ti LDH-DDS absorbs more light compared to the Zn/Ti LDH-CO3 due to the enhanced interlayer distance in the presence of DDS in the basal space of LDH, which further the intercalation process of polymer chains within the interlayer regions of LDH.
{"title":"Low-Density Polyethylene Nanocomposite Containing Zn/Ti Layered Double Hydroxide","authors":"S. Jaerger, Daiane Nogueira, Douglas Santos de Oliveira, M. V. Machado, R. Marangoni","doi":"10.6000/1929-5995.2021.10.5","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.5","url":null,"abstract":"The presented work shows the synthesis and characterization of Zn/Ti layered double hydroxide (LDH) intercalated with carbonate and dodecyl sulfate ions following its application as a functional filler in LDPE in order to improve the thermal properties and resistance degradation in UV-Vis radiation. X-ray diffractogram patterns of Zn/Ti LDH-CO3 and Zn/Ti LDH-DDS present basal spacing value in the order of 6.81 Å and 38.09 Å, respectively, indicating success in layered compound synthesis. LDPE nanocomposite containing hydrophobic and hydrophilic LDH presented a very well dispersed nanocomposite, as demonstrated in XRD and DSC results. The addition of only 1 % of LDH as filler into LDPE causes an increase of 5.43 C in the thermal property. Zn/Ti LDH-DDS absorbs more light compared to the Zn/Ti LDH-CO3 due to the enhanced interlayer distance in the presence of DDS in the basal space of LDH, which further the intercalation process of polymer chains within the interlayer regions of LDH.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90562283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.1
S. Scagliusi, Elizabeth C.L. Carvalho, A. B. Lugão
: Thermoplastic elastomers (TPEs), based in PP (Polypropylene) / EPDM (Ethylene Propylene Diene Monomer) have as purpose improving PP resistance and impact, aiming to a more comprehensive use in automotive market, among edifications, construction and packaging sectors, due to their recyclability properties. PP is a commodity, with a high melting point, high mechanical resistance and low density, posing a balance between physical and mechanical properties; in addition, it shows an easy processing, at low cost. In order to minimize this deficiency, EPDM, an impact modifier, can be used. Nevertheless, most of polymeric blends are incompatible and immiscible, i.e., show a mutual and limited solubility and in most of cases, a high interfacial tension. However, there is a relatively low interfacial tension (force which acts on transformation of a continuous structure in a dispersion) between PP and EPDM (approximately 0.3 mN.m -1 ), reducing the rate of breakup and facilitating the build-up of a continuous structure. This work aims to the study of compatibility of PP and EPDM blends and variation of mechanical properties, emphasizing that many properties of thermoplastic elastomers can be processed according with conventional thermoplastics methods: herein, PP/EPDM blends, 90/10, 80/20, 70/30 and 50/50 were characterized according to: Mechanical essays, Differential Scanning Calorimetry, Thermogravimetric Analyses, Melt Flow Index, Izod Impact Strength and Dynamic mechanical Analyses.
{"title":"Introduction to the Study of Mechanical Properties of Terpolymer PP/EPDM Mixtures","authors":"S. Scagliusi, Elizabeth C.L. Carvalho, A. B. Lugão","doi":"10.6000/1929-5995.2021.10.1","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.1","url":null,"abstract":": Thermoplastic elastomers (TPEs), based in PP (Polypropylene) / EPDM (Ethylene Propylene Diene Monomer) have as purpose improving PP resistance and impact, aiming to a more comprehensive use in automotive market, among edifications, construction and packaging sectors, due to their recyclability properties. PP is a commodity, with a high melting point, high mechanical resistance and low density, posing a balance between physical and mechanical properties; in addition, it shows an easy processing, at low cost. In order to minimize this deficiency, EPDM, an impact modifier, can be used. Nevertheless, most of polymeric blends are incompatible and immiscible, i.e., show a mutual and limited solubility and in most of cases, a high interfacial tension. However, there is a relatively low interfacial tension (force which acts on transformation of a continuous structure in a dispersion) between PP and EPDM (approximately 0.3 mN.m -1 ), reducing the rate of breakup and facilitating the build-up of a continuous structure. This work aims to the study of compatibility of PP and EPDM blends and variation of mechanical properties, emphasizing that many properties of thermoplastic elastomers can be processed according with conventional thermoplastics methods: herein, PP/EPDM blends, 90/10, 80/20, 70/30 and 50/50 were characterized according to: Mechanical essays, Differential Scanning Calorimetry, Thermogravimetric Analyses, Melt Flow Index, Izod Impact Strength and Dynamic mechanical Analyses.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79134739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.3
Francisco M. dos Santos, L. A. Oliveira, A. Bueno, R. Freire, Leandro José da Silva, G. Pino, T. Panzera
: A full factorial design is carried out to investigate the effects of different surface treatments, the inclusion of silica microparticles and the use of wash primer on the apparent shear strength and adherent strength of single-lap aluminium joints. Scanning electron microscopy, surface energy and roughness measurements are performed to characterise the aluminium surface. The results show that the use of wash primer decreases the apparent shear strength of the joints significantly. The cohesive failure of the primer is the main cause of the reduction in strength. On the other hand, the inclusion of 10 wt.% of silica microparticles in the adhesive layers increases the shear strength by 26%. Surfaces treated with NaOH for one minute, without using a wash primer, result in the most resistant joint. In contrast to the apparent shear strength, adherent strength is most effective when only degreasing is considered.
{"title":"The Effect of Aluminium Surface Treatments on the Bonding Properties of Silica-Modified Epoxy Adhesive Joints: A Statistical Approach","authors":"Francisco M. dos Santos, L. A. Oliveira, A. Bueno, R. Freire, Leandro José da Silva, G. Pino, T. Panzera","doi":"10.6000/1929-5995.2021.10.3","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.3","url":null,"abstract":": A full factorial design is carried out to investigate the effects of different surface treatments, the inclusion of silica microparticles and the use of wash primer on the apparent shear strength and adherent strength of single-lap aluminium joints. Scanning electron microscopy, surface energy and roughness measurements are performed to characterise the aluminium surface. The results show that the use of wash primer decreases the apparent shear strength of the joints significantly. The cohesive failure of the primer is the main cause of the reduction in strength. On the other hand, the inclusion of 10 wt.% of silica microparticles in the adhesive layers increases the shear strength by 26%. Surfaces treated with NaOH for one minute, without using a wash primer, result in the most resistant joint. In contrast to the apparent shear strength, adherent strength is most effective when only degreasing is considered.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73624213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.4
E. Cardoso, D. F. Parra, S. Scagliusi, L. G. H. Komatsu, A. B. Lugão
: Bio-filler from eggshells as reinforcement of bio-based polymers are based on their benefits as adequate strength and stiffness, besides friendly, degradable and renewable environment. Eggshell is an agricultural waste considered as garbage, contributing to pollution; nevertheless, it can be transformed into bio-calcium carbonate, acquiring new values. As biodegradable polymers, there were chosen PLA (poly-lactic-acid) and PBAT (butylene adipate co-terephthalate), thermoplastics capable to be processed via conventional methods. PLA is a linear, aliphatic thermoplastic polyester, high in strength and modulus, but brittle. PBAT is a synthetic polymer, very flexible, based on fossil resources with high elongation at break, but low strength. It will be required the use of compatibilizers, for reducing interfacial tension exhibited by PLA/PBAT immiscible blend, considering their extreme glass transition temperatures: 62 o C for PLA and – 30 o C for PBAT. Herein it was used ionizing radiation for inducing compatibilization by free radicals, improving dispersion and adhesion of blend phases, without using chemical additives, at room temperature. PLA, acting as compatibilizer, was previously e-beam and gamma radiated, at 150 kGy. PBAT/PLA 50/50 blend with 15 phr of bio- filler from avian eggs 125 µ m particle size and both compatibilizers were homogeneized in a co-rotating twin-screw extruder, within a temperature profile 120 to 145 o C, from hopper to die. Characterization involved: Differential Scanning Calorimeter, Thermogravimetric Analyses, Fourier Transform Infrared Spectroscopy, Wide Angle X-Ray Diffraction, Tensile Strength and Elongation at Break.
{"title":"Effect of Ionizing Radiation Applied to PLA Used as Compatibilizing Agent in Reinforced eGG Shell PBAT/PLA Bio-Based Composites","authors":"E. Cardoso, D. F. Parra, S. Scagliusi, L. G. H. Komatsu, A. B. Lugão","doi":"10.6000/1929-5995.2021.10.4","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.4","url":null,"abstract":": Bio-filler from eggshells as reinforcement of bio-based polymers are based on their benefits as adequate strength and stiffness, besides friendly, degradable and renewable environment. Eggshell is an agricultural waste considered as garbage, contributing to pollution; nevertheless, it can be transformed into bio-calcium carbonate, acquiring new values. As biodegradable polymers, there were chosen PLA (poly-lactic-acid) and PBAT (butylene adipate co-terephthalate), thermoplastics capable to be processed via conventional methods. PLA is a linear, aliphatic thermoplastic polyester, high in strength and modulus, but brittle. PBAT is a synthetic polymer, very flexible, based on fossil resources with high elongation at break, but low strength. It will be required the use of compatibilizers, for reducing interfacial tension exhibited by PLA/PBAT immiscible blend, considering their extreme glass transition temperatures: 62 o C for PLA and – 30 o C for PBAT. Herein it was used ionizing radiation for inducing compatibilization by free radicals, improving dispersion and adhesion of blend phases, without using chemical additives, at room temperature. PLA, acting as compatibilizer, was previously e-beam and gamma radiated, at 150 kGy. PBAT/PLA 50/50 blend with 15 phr of bio- filler from avian eggs 125 µ m particle size and both compatibilizers were homogeneized in a co-rotating twin-screw extruder, within a temperature profile 120 to 145 o C, from hopper to die. Characterization involved: Differential Scanning Calorimeter, Thermogravimetric Analyses, Fourier Transform Infrared Spectroscopy, Wide Angle X-Ray Diffraction, Tensile Strength and Elongation at Break.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74721792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.6
Sayra Oliveira Silva, L. A. Teixeira, A. Gontijo, S. Luz
: Quality control to obtain composite laminates is frequently applied to synthetic fibers/epoxy prepregs. The gel time test, resin, volatiles and fiber content, drape measurement and tack tests together with water absorption capacity are methods currently employed. However, for natural fibers prepregs there is a gap in the literature, which makes their application difficult. Thus this work will investigate sisal fibers, which have low cost, high biodegradability and low specific weight, following the common methods to manufacture composites from natural fibers/epoxy prepregs. First, the prepregs were prepared by hand lay-up, aligning the fibers with epoxy, keeping 15% by weight content of fiber. After the quality control characterization, 3 mm thickness composite was prepared by using a press, and tensile tests and scanning electron microscopy (SEM) were applied. As a result, the resin fraction values and the solid content of the matrix showed little variation between the different samples. The natural fibers prepregs absorbed water quickly in the initial stage until reaching the saturation level. The NaOH-treated sisal/epoxy prepreg had a tension of 71.06 ± 8.28 kPa for the tack test and tensile strength of 69.24 ± 11.69 MPa. Finally, the NaOH-treated sisal 15 wt%/epoxy resulted in composites with a better performance than the neat epoxy resin. There was good adhesion between the fibers and matrix, as confirmed by SEM and mechanical tests.
{"title":"Processing Characterization of Sisal/Epoxy Prepregs","authors":"Sayra Oliveira Silva, L. A. Teixeira, A. Gontijo, S. Luz","doi":"10.6000/1929-5995.2021.10.6","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.6","url":null,"abstract":": Quality control to obtain composite laminates is frequently applied to synthetic fibers/epoxy prepregs. The gel time test, resin, volatiles and fiber content, drape measurement and tack tests together with water absorption capacity are methods currently employed. However, for natural fibers prepregs there is a gap in the literature, which makes their application difficult. Thus this work will investigate sisal fibers, which have low cost, high biodegradability and low specific weight, following the common methods to manufacture composites from natural fibers/epoxy prepregs. First, the prepregs were prepared by hand lay-up, aligning the fibers with epoxy, keeping 15% by weight content of fiber. After the quality control characterization, 3 mm thickness composite was prepared by using a press, and tensile tests and scanning electron microscopy (SEM) were applied. As a result, the resin fraction values and the solid content of the matrix showed little variation between the different samples. The natural fibers prepregs absorbed water quickly in the initial stage until reaching the saturation level. The NaOH-treated sisal/epoxy prepreg had a tension of 71.06 ± 8.28 kPa for the tack test and tensile strength of 69.24 ± 11.69 MPa. Finally, the NaOH-treated sisal 15 wt%/epoxy resulted in composites with a better performance than the neat epoxy resin. There was good adhesion between the fibers and matrix, as confirmed by SEM and mechanical tests.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86202747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-26DOI: 10.6000/1929-5995.2021.10.2
V. Lacerda, Salvador n Barbalho, Zip Code Brazil Ba, A. R. Conceição, Catarina da N. Scherer, Michel G. Santos, M. Leao
The use of composite materials is increasingly present not only in several industrial areas but also in daily life. With the escalating environmental concern, it is necessary the search for materials that prove to be ecologically sustainable and economically viable. Vegetable fibers have been presenting themselves as an excellent alternative, however, because their disadvantage of having a high moisture absorption capacity, the introduction of synthetic fibers, forming hybrid composites, is a good solution since it combines the characteristics of both types of reinforcements. The present research aims to carry out a comparative study between two types of laminated polymer composites, one reinforced with Jute fibers and the other hybrid, composed of Jute and E-glass fibers. The mechanical performances of the composites submitted to the Uniaxial Tensile, Three-point Flexural and Shear tests were evaluated, as well as fracture analyzes. A comparative study to analyze the influence of hybridization on moisture absorption was carried out. The results showed that the hybridized composite showed an increase in the elastic modulus, as well as in its resistance to flexion and shear, which shows the formation of a more rigid material. Hybridization also changed the moisture content of the composite.
{"title":"Influence of Hybridization on Mechanical Properties and Water Absorption in Jute and Jute /E-Glass Reinforced Composites","authors":"V. Lacerda, Salvador n Barbalho, Zip Code Brazil Ba, A. R. Conceição, Catarina da N. Scherer, Michel G. Santos, M. Leao","doi":"10.6000/1929-5995.2021.10.2","DOIUrl":"https://doi.org/10.6000/1929-5995.2021.10.2","url":null,"abstract":"The use of composite materials is increasingly present not only in several industrial areas but also in daily life. With the escalating environmental concern, it is necessary the search for materials that prove to be ecologically sustainable and economically viable. Vegetable fibers have been presenting themselves as an excellent alternative, however, because their disadvantage of having a high moisture absorption capacity, the introduction of synthetic fibers, forming hybrid composites, is a good solution since it combines the characteristics of both types of reinforcements. The present research aims to carry out a comparative study between two types of laminated polymer composites, one reinforced with Jute fibers and the other hybrid, composed of Jute and E-glass fibers. The mechanical performances of the composites submitted to the Uniaxial Tensile, Three-point Flexural and Shear tests were evaluated, as well as fracture analyzes. A comparative study to analyze the influence of hybridization on moisture absorption was carried out. The results showed that the hybridized composite showed an increase in the elastic modulus, as well as in its resistance to flexion and shear, which shows the formation of a more rigid material. Hybridization also changed the moisture content of the composite.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83345007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.6000/1929-5995.2020.09.10
Md Nur Karim, M. Patwary, S. Abedin, Md Riaj Hossen, Md Saifur Rahman
Carbon nanotubes(CNTs) have achieved attention in recent times because of their extraordinary physicochemical properties like strength, flexibility, sensors, conducting etc. Carbon nanotubes(CNTs) are known as nano-architectured allotropes of carbon, having graphene sheets which are rolled up into cylinder that forms carbon nanotubes. In the field of nanotechnology, carbon nanotubes are the one of the most unique invention. The eye-catching features of carbon nanotubes are their electronic, mechanical, optical and chemical characteristics, which open a way to future applications. Carbon nanotubes can be single walled and multi walled which can be produced in various ways. The most common techniques used nowadays are: arc discharge, laser ablation and chemical vapour deposition. In this review article,the applications of CNTs in various technologically important fields are discussed in detail.
{"title":"A Review on Carbon Nanotubes: Preparation, Properties and Applications","authors":"Md Nur Karim, M. Patwary, S. Abedin, Md Riaj Hossen, Md Saifur Rahman","doi":"10.6000/1929-5995.2020.09.10","DOIUrl":"https://doi.org/10.6000/1929-5995.2020.09.10","url":null,"abstract":"Carbon nanotubes(CNTs) have achieved attention in recent times because of their extraordinary physicochemical properties like strength, flexibility, sensors, conducting etc. Carbon nanotubes(CNTs) are known as nano-architectured allotropes of carbon, having graphene sheets which are rolled up into cylinder that forms carbon nanotubes. In the field of nanotechnology, carbon nanotubes are the one of the most unique invention. The eye-catching features of carbon nanotubes are their electronic, mechanical, optical and chemical characteristics, which open a way to future applications. Carbon nanotubes can be single walled and multi walled which can be produced in various ways. The most common techniques used nowadays are: arc discharge, laser ablation and chemical vapour deposition. In this review article,the applications of CNTs in various technologically important fields are discussed in detail.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90493660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.6000/1929-5995.2020.09.09
M. Tavares, J. C. D. Filho, Tais Nascimento, G. Iulianelli, Pedro Paulo Merat
The purpose of this work was to study the molecular dynamics, morphology, mechanical and thermal performance of nanomaterials formed by poly(vinyl alcohol) and molybdenum trioxide (PVA/MoO3) obtained through solution casting method, focusing new materials with therapeutic applications since the molybdenum trioxide exhibit an excellent antibacterial activity and could be a pathway to prevent viruses. The obtaining materials were characterized by conventional techniques as X-ray diffraction, thermogravimetric and dynamical-mechanical analysis. The unconventional low-field NMR relaxometry was used to evaluate the molecular dynamic and morphology of these systems. The results obtained showed that the MoO3 addition into PVA matrix promote an increase on the thermal stability at higher temperatures and a progressive increase on the rigidity of the PVA systems. Also changes in the molecular mobility of nanomaterials determined through the proton spin-lattice relaxation time showed that low proportion of molybdenum trioxide increased the intercalation of the poly(vinyl alcohol) chains between oxide lamellae while higher quantity of molybdenum trioxide caused an inverse effect on the oxide lamellae delamination. From those results the nanomaterials presented a mixed structural organization as intercalated and exfoliated morphologies. According to these first results, the nanocomposites obtained promise to be antimicrobial and antiviral agent to prevent COVID-19 and similar viruses.
{"title":"Effect of Molybdenum Trioxide in the Behavior of Poly(vinyl alcohol) Nanocomposites Systems Focusing New Systems for Protection against COVID-19","authors":"M. Tavares, J. C. D. Filho, Tais Nascimento, G. Iulianelli, Pedro Paulo Merat","doi":"10.6000/1929-5995.2020.09.09","DOIUrl":"https://doi.org/10.6000/1929-5995.2020.09.09","url":null,"abstract":"The purpose of this work was to study the molecular dynamics, morphology, mechanical and thermal performance of nanomaterials formed by poly(vinyl alcohol) and molybdenum trioxide (PVA/MoO3) obtained through solution casting method, focusing new materials with therapeutic applications since the molybdenum trioxide exhibit an excellent antibacterial activity and could be a pathway to prevent viruses. The obtaining materials were characterized by conventional techniques as X-ray diffraction, thermogravimetric and dynamical-mechanical analysis. The unconventional low-field NMR relaxometry was used to evaluate the molecular dynamic and morphology of these systems. The results obtained showed that the MoO3 addition into PVA matrix promote an increase on the thermal stability at higher temperatures and a progressive increase on the rigidity of the PVA systems. Also changes in the molecular mobility of nanomaterials determined through the proton spin-lattice relaxation time showed that low proportion of molybdenum trioxide increased the intercalation of the poly(vinyl alcohol) chains between oxide lamellae while higher quantity of molybdenum trioxide caused an inverse effect on the oxide lamellae delamination. From those results the nanomaterials presented a mixed structural organization as intercalated and exfoliated morphologies. According to these first results, the nanocomposites obtained promise to be antimicrobial and antiviral agent to prevent COVID-19 and similar viruses.","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78676506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-21DOI: 10.6000/1929-5995.2020.09.08
S. Zaitsev, I. S. Zaitsev, I. Milaeva
The aim of this work was to study the interaction of lipases (as an important biopolymer) with models of biomembranes based on the phospholipid and cholesterol. Lipases (triacylglycerolacyl hydrolases) are widely distributed enzymes and well-known by their hydrolytic activity. The study of the lipase interactions with lipid vesicles in aqueous dispersions is of fundamental and practical interest. The pure phosphatidylcholine from egg yolk (ePC) and cholesterol (Chol) were obtained from Sigma-Aldrich. Lipase was obtained from hog pancreas. Measurements of the current and equilibrium surface tension (ST and eST) values were carried out using a BPA-1P device and ADSA program. The particle sizes in the prepared colloidal solutions were determined by the method of dynamic light scattering. An addition of lipase led to some decrease both, of ST and eST for the samples of ePC:Chol (in the ratios from19:1 to 1:1). The mean particle diameter (MPD) and effective particle diameter (EPD) values for the samples of ePC:Chol changed drastically by lipase addition. The EPD/MPD ratios increased from 1.7 to 2.0, from 1.8 to 2.6, from 2.3 to 6.5, from 1.5 to 2.9 for the samples of ePC:Chol at the ratios of 19:1, 14:1, 9:1, 7:1, respectively by lipase concentration increase. This general tendency can be explained by strong interaction of lipase with lipid membrane that leads to the formation of the mixed particles ePC:Chol:lipase with more narrow particle size distribution as compared to the initial EPD/MPD ratio (for the ePC:Chol mixture without lipase).
{"title":"Interaction of Lipase with Lipid Model Systems","authors":"S. Zaitsev, I. S. Zaitsev, I. Milaeva","doi":"10.6000/1929-5995.2020.09.08","DOIUrl":"https://doi.org/10.6000/1929-5995.2020.09.08","url":null,"abstract":"The aim of this work was to study the interaction of lipases (as an important biopolymer) with models of biomembranes based on the phospholipid and cholesterol. Lipases (triacylglycerolacyl hydrolases) are widely distributed enzymes and well-known by their hydrolytic activity. The study of the lipase interactions with lipid vesicles in aqueous dispersions is of fundamental and practical interest. The pure phosphatidylcholine from egg yolk (ePC) and cholesterol (Chol) were obtained from Sigma-Aldrich. Lipase was obtained from hog pancreas. Measurements of the current and equilibrium surface tension (ST and eST) values were carried out using a BPA-1P device and ADSA program. The particle sizes in the prepared colloidal solutions were determined by the method of dynamic light scattering. An addition of lipase led to some decrease both, of ST and eST for the samples of ePC:Chol (in the ratios from19:1 to 1:1). The mean particle diameter (MPD) and effective particle diameter (EPD) values for the samples of ePC:Chol changed drastically by lipase addition. The EPD/MPD ratios increased from 1.7 to 2.0, from 1.8 to 2.6, from 2.3 to 6.5, from 1.5 to 2.9 for the samples of ePC:Chol at the ratios of 19:1, 14:1, 9:1, 7:1, respectively by lipase concentration increase. This general tendency can be explained by strong interaction of lipase with lipid membrane that leads to the formation of the mixed particles ePC:Chol:lipase with more narrow particle size distribution as compared to the initial EPD/MPD ratio (for the ePC:Chol mixture without lipase).","PeriodicalId":16998,"journal":{"name":"Journal of Research Updates in Polymer Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76184519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-11DOI: 10.6000/1929-5995.2020.09.07
C. Velásquez, L. R. Avelizapa
The antifungal activity of the chitosan biopolymer has been extensively studied for several decades. However, the mechanisms of action associated with this process have not been fully clarified yet. To a large extent, this situation is due to the lack of systematization with which, in general terms, the subject has been approached. However, it seems to have begun to change in recent years with the appearance of several papers reviewing the accumulated knowledge on the beneficial effects shown by chitosan in agricultural applications and putting forward it in a more systematic mode. In this work, the most relevant mechanisms of action proposed for chitosan regarding its antifungal activity will be briefly presented, i.e., disruption and changes in the fungal plasma membrane, alteration of gene expression, inhibition of RNA and protein synthesis, Ca2+ channel blocker, to then address the main factors that influence this antifungal activity, observed mainly in studies focused on phytopathogenic species, which have been grouped into three main blocks: those related exclusively to the chitosan molecules, those associated to the fungal itself and those having to do with the environment where the processes take place. Additionally, a brief section addressing some possibilities on which future studies on this topic should focus is also included.
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