scholarly journals (Bio)Degradable Polymeric Materials for Sustainable Future—Part 3: Degradation Studies of the PHA/Wood Flour-Based Composites and Preliminary Tests of Antimicrobial Activity

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2200
Author(s):  
Marta Musioł ◽  
Sebastian Jurczyk ◽  
Michał Sobota ◽  
Magdalena Klim ◽  
Wanda Sikorska ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Degradation Products ◽  
Wood Flour ◽  
Polymeric Materials ◽  
Wood Products ◽  
Ionization Mass ◽  
Degradable Polymers ◽  
Scanning Calorimetry ◽  
Bioactive Materials ◽  
Recycled Waste

The need for a cost reduction of the materials derived from (bio)degradable polymers forces research development into the formation of biocomposites with cheaper fillers. As additives can be made using the post-consumer wood, generated during wood products processing, re-use of recycled waste materials in the production of biocomposites can be an environmentally friendly way to minimalize and/or utilize the amount of the solid waste. Also, bioactive materials, which possess small amounts of antimicrobial additives belong to a very attractive packaging industry solution. This paper presents a study into the biodegradation, under laboratory composting conditions, of the composites that consist of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate)] and wood flour as a polymer matrix and natural filler, respectively. Thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy were used to evaluate the degradation progress of the obtained composites with different amounts of wood flour. The degradation products were characterized by multistage electrospray ionization mass spectrometry. Also, preliminary tests of the antimicrobial activity of selected materials with the addition of nisin were performed. The obtained results suggest that the different amount of filler has a significant influence on the degradation profile.

scholarly journals Forensic Engineering of Advanced Polymeric Materials—Part VII: Degradation of Biopolymer Welded Joints

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1167
Author(s):  
W. Sikorska ◽  
M. Zięba ◽  
M. Musioł ◽  
M. Kowalczuk ◽  
H. Janeczek ◽  
...  
Keyword(s):  
Degradation Products ◽  
Bond Cleavage ◽  
Hydrolytic Degradation ◽  
Welding Process ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Scanning Calorimetry ◽  
Forensic Engineering ◽  
The Impact ◽  
Welding Processes

Welding technology may be considered as a promising processing method for the formation of packaging products from biopolymers. However, the welding processes used can change the properties of the polymer materials, especially in the region of the weld. In this contribution, the impact of the welding process on the structure and properties of biopolymer welds and their ability to undergo hydrolytic degradation will be discussed. Samples for the study were made from polylactide (PLA) and poly(3-hydroxyalkanoate) (PHA) biopolymers which were welded using two methods: ultrasonic and heated tool welding. Differential scanning calorimetry (DSC) analysis showed slight changes in the thermal properties of the samples resulting from the processing and welding method used. The results of hydrolytic degradation indicated that welds of selected biopolymers started to degrade faster than unwelded parts of the samples. The structure of degradation products at the molecular level was confirmed using mass spectrometry. It was found that hydrolysis of the PLA and PHA welds occurs via the random ester bond cleavage and leads to the formation of PLA and PHA oligomers terminated by hydroxyl and carboxyl end groups, similarly to as previously observed for unwelded PLA and PHA-based materials.

Role of Zno Nanoparticles in Enhancing the Antimicrobial Property of Nitrocellulose Lacquer Wood Finish

2019 ◽  
Vol 12 (1) ◽  
pp. 91-98
Author(s):  
Shikhar Shukla ◽  
Shailendra Kumar ◽  
Ismita Nautiyal ◽  
Kishan Kumar V.S
Keyword(s):  
Antimicrobial Activity ◽  
Zno Nanoparticles ◽  
Antimicrobial Property ◽  
Economic Loss ◽  
Analysis Data ◽  
Wood Products ◽  
Mould Growth ◽  
Neem Oil ◽  
Nano Zno ◽  
Aesthetic Appearance

Background: Mould growth on coated wood products during shipment is the foremost apprehension for most of the wood industries in India. Well finished wood products tend to get deposited by staining moulds superficially in high humidity conditions during shipment. Though wood disfiguring fungi (stain moulds) normally have no significant effect on the mechanical properties of timber, they only affect the aesthetic appearance of the material without destructing the wood cell wall. This causes a huge economic loss to the manufacturer due to disfigurement of the appearance of wood products. Methods: The aim of this work is to test and enhance antimicrobial property of Nitrocellulose lacquer wood finish to prevent mould deposition on coated wood products. The work was carried out to screen and evaluate the antimicrobial activity of commercial Nitrocellulose lacquer. Several patents regarding antimicrobial activity of nano metal oxides have been visited. In order to enhance the mould resistance of this coating, its combinations with neem oil and ZnO nanoparticles were prepared and tested against the growth of staining moulds: Aspergillus niger and Penicillium sp. on the wood substrate of Melia dubia. The study was carried out for 500 hours under favorable conditions (Temperature and Relative Humidity (RH)) for the mould growth. The growth was analysed on the basis of surface area affected by stain moulds on coated wood samples. Results: The growth analysis data inferred that the ZnO nanoparticles had significant effect against the growth of stain moulds. The presence of ZnO nanoparticles increased the mould growth resistance of Nitrocellulose lacquer coating to a great extent compared to the ability of neem oil for the same. This finding demonstrates the potential use of nano ZnO for increasing the effectiveness of NC lacquer against mould growth without hampering its other properties. Conclusion: 1 % nano ZnO concentration in Nitrocellulose lacquer wood coating increased its efficacy against staining mould growth by 95 %.

scholarly journals Proof-of-Concept of Detection of Counterfeit Medicine through Polymeric Materials Analysis of Plastics Packaging

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2185
Author(s):  
Mohammad Salim ◽  
Riyanto Teguh Widodo ◽  
Mohamed Ibrahim Noordin
Keyword(s):  
Polymeric Materials ◽  
Proof Of Concept ◽  
Scanning Calorimetry ◽  
Counterfeit Drug ◽  
Drug Products ◽  
Counterfeit Medicines ◽  
Counterfeit Medicine ◽  
Counterfeit Pharmaceuticals ◽  
Purge Gas ◽  
Sample Set

The detection of counterfeit pharmaceuticals is always a major challenge, but the early detection of counterfeit medicine in a country will reduce the fatal risk among consumers. Technically, fast laboratory testing is vital to develop an effective surveillance and monitoring system of counterfeit medicines. This study proposed the combination of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Differential Scanning Calorimetry (DSC) for the quick detection of counterfeit medicines, through the polymer analysis of blister packaging materials. A sample set containing three sets of original and counterfeit medicine was analyzed using ATR-FTIR and DSC, while the spectra from ATR-FTIR were employed as a fingerprint for the polymer characterization. Intending to analyze the polymeric material of each sample, DSC was set at a heating rate of 10 °C min−l and within a temperature range of 0- 400 °C, with nitrogen as a purge gas at a flow rate of 20 ml min−an. The ATR-FTIR spectra revealed the chemical characteristics of the plastic packaging of fake and original medicines. Further analysis of the counterfeit medicine’s packaging with DSC exhibited a distinct difference from the original due to the composition of polymers in the packaging material used. Overall, this study confirmed that the rapid analysis of polymeric materials through ATR-FTIR and comparing DSC thermograms of the plastic in their packaging effectively distinguished counterfeit drug products.

scholarly journals Biofilm on the polymer composites - qualitative and quantitative microbiological analysis

2021 ◽  
Author(s):  
Dobrochna Ginter-Kramarczyk ◽  
Izabela Kruszelnicka ◽  
Michał Michałkiewicz ◽  
Przemysław Muszyński ◽  
Stanisław Zajchowski ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Wood Flour ◽  
Biological Membrane ◽  
Polymeric Materials ◽  
Active Surface ◽  
Modern Technology ◽  
Biofilm Reactor ◽  
Active Surface Area ◽  
Microbiological Analysis ◽  
Wood Polymer

Abstract Background Modern technology, which has been getting more and more recognition in the world for the last several years, is the moving bed biofilm reactor (MBBR) technology. Currently, movable biofilters made of basic polymeric materials, polyethylene and polypropylene. Methods An innovative solution in the field, mainly because of the large active surface area for biological membrane can be wood polymer composites (WPC). In the research polypropylene (PP) and polyvinyl chloride (PVC) was used as the matrix. Two types of commercial wood flour also, selected from conifers, were selected for the study: Lignocel C 120 with particle sizes in the range of 70 μm–150 μm and L9 with dimensions of 0.8–1.1 mm and wood chips, which are used on an industrial scale for the production of chipboards, were used as a filler. A quantitative and qualitative analysis of newly formed biofilms was performed. Results The study showed a direct effect of the filler and its particle size on the susceptibility to the formation of the biofilm of on the composites surface. Conclusions Polypropylene PPH 648 T and 40% wt. of L9 type wood flour was the most susceptible to biofilm formation. Pure polypropylene PPH 648 T was the least susceptible material.

scholarly journals The formation of formates: 3a review of metal formates on heritage objects

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Gerhard Eggert ◽  
Andrea Fischer
Keyword(s):  
Degradation Products ◽  
Dominant Role ◽  
Copper Alloys ◽  
Wood Products ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Irreversible Damage ◽  
Preventive Conservation ◽  
Calcium Formate ◽  
Metal Formates

AbstractMetal formates sometimes occur as degradation products on heritage objects due to the use of wood products or other sources of formic acid and formaldehyde. They are often related to alkaline surfaces which transform formaldehyde directly into formate. The dominant role of formate on alkaline surfaces, for example in glass-induced metal corrosion (GIM) or calcium carbonate degradation, was explored in the Stuttgart research on rare heritage corrosion products. This review discusses these findings together with those from the literature: ocurrences of sodium and potassium formate on glass, calcium formate and calcium acetate-formate phases on calcareous materials, magnesium formate on Sorel cement and dolomitic sandstone, lead formate on metal and pigments, cadmium formate on coated objects, as well as various copper and zinc formates on copper alloys. In the latter cases, formates dominate as glass-induced metal corrosion products. The formation of formates constitutes irreversible damage, degrading the material of heritage objects. Therefore, preventive conservation needs to remove all sources of carbonyl pollutants in order to avoid such corrosion.

Sensitization of nitrocompounds by amines

1992 ◽  
Vol 339 (1654) ◽  
pp. 403-417 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Charge Transfer ◽  
Nitro Group ◽  
Picric Acid ◽  
Isotope Analysis ◽  
Ionization Mass ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Rate Determining Step ◽  
The Impact

A study has been carried out of the sensitization of nitromethane, trinitrotoluene, trinitrobenzene, picric acid and tetryl by the addition of small amounts of amines. The sensitization has been confirmed using dropweight impact experiments and a new method has been found, using differential scanning calorimetry, of making reproducible and quantitative measurements of the effect. It is found that the nitrocompound-amine mixtures decompose at temperatures lower than those of either of the pure components and show a drop in the impact energy required to cause initiation of ignition. The thermal decomposition experiments also yield substantially lower activation energies and an empirical sensitization factor (defined in the text) for nitromethane mixtures that decreases as the nitromethane aci-anion concentration increases. Kinetic deuterium isotope analysis points to C-N bond scission as the rate-determining step in the thermal decomposition of nitromethane and nitromethane-amine mixtures. Laser ionization mass analyses of the solid nitrocompound-amine mixtures indicate significant changes in the fragmentation patterns, with removal of the nitro-group occurring in all cases as the first step in the breakdown of the mixtures, which is not the case for the pure materials. Absorption bands appear in the UV / visible spectra of all the sensitized materials. These bands are ascribed to an intermolecular charge transfer from the nitrogen of an amine group to the antibonding orbital of the nitro-group. It is shown that, with small amounts of amines present, each amine molecule can form a complex with as many nitrocompound molecules as there are amine groups on it. The formation of this charge transfer complex is shown to weaken the nitrocompound C-N bond involved. The weakening of the C-N bond increases directly with increasing binding energy of the complex. Combined with the knowledge that the C-N bond breakage is the rate- ­determining step in the thermal decomposition of these materials and the suggestion that the dominant mechanism in their ignition/detonation is most likely thermal in origin, the sensitization is explained. This explanation deviates from the theories which have been previously proposed.

scholarly journals Eco-Friendly Approach and Potential Biodegradable Polymer Matrix for WPC Composite Materials in Outdoor Application

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Alessia Quitadamo ◽  
Valerie Massardier ◽  
Marco Valente
Keyword(s):  
Polymer Blend ◽  
Glycidyl Methacrylate ◽  
Wood Flour ◽  
Random Copolymer ◽  
Tensile Tests ◽  
Poly Lactic Acid ◽  
Polymer Interfaces ◽  
Scanning Calorimetry ◽  
Future Studies ◽  
Outdoor Application

Blends based on high-density polyethylene (HDPE) and poly(lactic) acid (PLA) with different ratios of both polymers were produced: a blend with equal amounts of HDPE and PLA, hence 50 wt.% each, proved to be a useful compromise, allowing a high amount of bioderived charge without this being too detrimental for mechanical properties and considering its possibility to biodegradation behaviour in outdoor application. In this way, an optimal blend suitable for producing a composite with cellulosic fillers is proposed. In the selected polymer blend, wood flour (WF) was added as a natural filler in the proportion of 20, 30, and 40 wt.%, considering as 100 the weight of the polymer blend matrix. There are two compatibilizers to modify both HDPE-PLA blend and wood-flour/polymer interfaces, i.e., polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate. The most suitable percentage of compatibilizer for HDPE-PLA blends appears to be 3 wt.%, which was selected also for use with wood flour. In order to evaluate properties of blends and composites tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, and infrared spectroscopy have been performed. Wood flour seems to affect heavy blend behaviour in process production of material suggesting that future studies are needed to reduce defectiveness.

scholarly journals Isolation and Structure Determination of Echinochrome A Oxidative Degradation Products

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4778
Author(s):  
Natalia P. Mishchenko ◽  
Elena A. Vasileva ◽  
Andrey V. Gerasimenko ◽  
Valeriya P. Grigorchuk ◽  
Pavel S. Dmitrenok ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Degradation Products ◽  
Lethal Dose ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Ionization Mass ◽  
Echinochrome A ◽  
Esi Ms

Echinochrome A (Ech A, 1) is one of the main pigments of several sea urchin species and is registered in the Russian pharmacopeia as an active drug substance (Histochrome®), used in the fields of cardiology and ophthalmology. In this study, Ech A degradation products formed during oxidation by O2 in air-equilibrated aqueous solutions were identified, isolated, and structurally characterized. An HPLC method coupled with diode-array detection (DAD) and mass spectrometry (MS) was developed and validated to monitor the Ech A degradation process and identify the appearing compounds. Five primary oxidation products were detected and their structures were proposed on the basis of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 7-ethyl-2,2,3,3,5,7,8-heptahydroxy-2,3-dihydro-1,4-naphthoquinone (2), 6-ethyl-5,7,8-trihydroxy-1,2,3,4-tetrahydronaphthalene-1,2,3,4-tetraone (3), 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone (4), 2,3,4,5,7-pentahydroxy-6-ethylinden-1-one (5), and 2,2,4,5,7-pentahydroxy-6-ethylindane-1,3-dione (6). Three novel oxidation products were isolated, and NMR and HR-ESI-MS methods were used to establish their structures as 4-ethyl-3,5,6-trihydroxy-2-oxalobenzoic acid (7), 4-ethyl-2-formyl-3,5,6-trihydroxybenzoic acid (8), and 4-ethyl-2,3,5-trihydroxybenzoic acid (9). The known compound 3-ethyl-2,5-dihydroxy-1,4-benzoquinone (10) was isolated along with products 7–9. Compound 7 turned out to be unstable; its anhydro derivative 11 was obtained in two crystal forms, the structure of which was elucidated using X-ray crystallography as 7-ethyl-5,6-dihydroxy-2,3-dioxo-2,3-dihydrobenzofuran-4-carboxylic acid and named echinolactone. The chemical mechanism of Ech A oxidative degradation is proposed. The in silico toxicity of Ech A and its degradation products 2 and 7–10 were predicted using the ProTox-II webserver. The predicted median lethal dose (LD50) value for product 2 was 221 mg/kg, and, for products 7–10, it appeared to be much lower (≥2000 mg/kg). For Ech A, the predicted toxicity and mutagenicity differed from our experimental data.

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