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The development of biodegradable materials as food packaging material is important not only due to the reduction in environmental pollution but also because of an improvement in the functionality. Rice husk-reinforced biopolymers have offered a possible solution to waste-disposal problems associated with traditional petroleum-derived plastics. Rice husk-reinforced low density polyethylene (LDPE)-based biocomposites have been of great interest for their use as food packaging material. In this work, the LDPE/RH biocomposites with different rice husk (RH) content (10, 20, 30, 40 and 50 wt.%) were prepared by the melt mixing process in a laboratory Brabender mixer. The effect of RH content on the physical, thermal and mechanical properties of LDPE was investigated. More importantly, this work aimed to research the biodegradation of the LDPE/RH biocomposites as well as their effect on ‘Granny Smith’ apples’ respiration. The results showed that the incorporation of RH into the LDPE decreased the thermal stability of LDPE, increased water vapour permeability and water absorption, and increased the degree of crystallinity. The incorporation of RH increased the biodegradability of LDPE as well as the postharvest quality of ‘Granny Smith’ apples. The addition of RH in LDPE film significantly decreased fruit respiration and increased firmness as compared to LDPE film. The composting results showed that after the LDPE/RH biocomposite films were biodegraded for 21 days, the biocomposite films with the highest content of rice husks were the most degraded.

High-molecular-weight poly(butylene 2,4-furanoate) (2,4-PBF), an isomer of well-known poly(butylene 2,5-furanoate) (2,5-PBF), was synthesized through an eco-friendly solvent-free polycondensation process and processed in the form of an amorphous film by compression molding. Molecular characterization was carried out by NMR spectroscopy and GPC analysis, confirming the chemical structure and high polymerization degree. Thermal analyses evidenced a reduction of both glass-to-rubber transition and melting temperatures, as well as a detriment of crystallization capability, for 2,4-PBF with respect to 2,5-PBF. Nevertheless, it was possible to induce crystal phase formation by annealing treatment. Wide-angle X-ray scattering revealed that the crystal lattices developed in the two isomers are distinct from each other. The different isomerism affects also the thermal stability, being 2,4-PBF more thermally inert than 2,5-PBF. Functional properties, such as wettability, mechanical response, and gas barrier capability, were tested on both amorphous and semicrystalline 2,4-PBF films and compared with those of 2,5-PBF. Reduced hydrophilicity was determined for 2,4-isomer, in line with its lower average dipole moment, suggesting better chemical resistance to hydrolysis. Stress–strain tests have evidenced the higher flexibility and toughness of 2,4-PBF with respect to those of 2,5-PBF and the possibility of improving its mechanical resistance by annealing. Finally, the different isomerism deeply affects the gas barrier performance, being the O2- and CO2-transmission rates of 2,4-PBF 50 and 110 times lower, respectively, than those of 2,5-PBF. The gas barrier properties turned out to be outstanding under a dry atmosphere as well as in humid conditions, suggesting the presence of interchain hydrogen bonds. The gas blocking capability decreases after annealing because of the presence of disclination associated with the formation of crystals., Poly(butylene 2,4-furanoate) was obtained from 2,4-isomer of biobased furandicarboxylic acid, and isomerism further improved the key properties for sustainable packaging applications.

In this research, biodegradable blend of poly(ϵ-caprolactone) (PCL) and poly(lactic acid) (PLA) is proposed as a new material for the production of a printing plate for embossing process. Printing plates for embossing consist of raised printing elements and recessed nonimage elements. In production of printing plates, laser technology was used in order to form a relief printing plate. The embossing process is based on the principle of the pressure of the relief printing plate into the printing substrate, which causes the controlled deformation of the substrate and three-dimensional (3D) effect. Coir fibers (CFs) were added as a natural filler to PCL/PLA blends to improve and adjust the properties of produced blends. Scanning electron microscopy micrographs, dynamic mechanical analysis analysis, roughness, and hardness were measured on prepared materials, and 2D and 3D microscopy was conducted on laser engraved printing plates. Results have shown that the addition of CFs improved the mechanical properties of produced materials. DMA results indicate the semicrystalline structure of all prepared blends, and that the addition of CFs raises the elasticity of the composites. Laser engraving showed that it is possible to engrave the produced biodegradable materials and to use it as a material for production of printing plates.

TARAMAWOS WOS:000650538300001 TARAMASCOPUS Ethyl cyanoacrylate polymerizes at room temperature, and is often used as an adhesive in many areas for a wide variety of applications. In this study, the possibility of using poly(ethyl cyanoacrylate) in the field of wood modification was investigated. For this purpose, Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis) samples were impregnated with poly(ethyl cyanoacrylate) that was synthesized using acetone. Modified samples were characterized by Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (ESEM). Decay performance was done with white rot fungus (Trametes versicolor (L: Fr.) Pilat. (FFPRI 1030)) for beech wood and brown rot fungus Coniophera puteana for pine wood; the European standard EN113 FTIR analysis indicated that PECA could appreciably alter the chemical structure in modified wood. Thermal changes in modified wood were be minor compared to those of untreated wood. Samples treated with PECA had significantly lower mass losses than untreated samples as a result of fungal exposure to Coniophora puteana and T. versicolor.

As a potential physical blowing agent, sodium bicarbonate (SB) is environmentally friendly and low in cost, but its low decomposition temperature cannot meet the requirements of polyolefin foam materials. Herein, for enhancing the thermal properties of SB, a modified way was offered to fabricate various SB-based capsules via suspension polymerization. As the modified SB-based capsules, epoxy resin (EP) accompanied with several organic acids was successfully coated on the surface of SB, serving as heat-insulation layer of SB. Various physicochemical characterizations provided reliable evidences for the good coating effect, and the thermal performance of the modified SB was improved. Further, the composite SB capsules were applied for the foaming of polypropylene (PP), and the foaming behavior of the SB-based capsules in PP was significantly improved, with more uniform distribution, smaller cell diameter, and higher cell density. In all, this work fully proved that the coated shells enhanced the thermal properties of SB, and the modified SB capsules significantly improved the foaming quality of foamed PP.

The current study investigates the reinforcement properties of novel nano-calcium carbonate (nano-CaCO3) synthesized from Achatina fulica snail shell. The shell was wet-milled to nanoparticle sizes using mechanochemical procedures. Epoxy nanocomposites prepared with nanofiller content ranges of 1–7 wt.% were fabricated using a conventional resin casting method. Thermal stability and degradation with mechanical properties such as tensile strength, impact strength, and the hardness properties of prepared nanocomposites were determined. It was observed that the reinforcement by the synthesized nano-CaCO3 improved the thermal stability and mechanical properties of neat epoxy irrespective of the filler content. Significantly, the inclusion of 1 w.% Achatina fulica snail shell nanoparticles increased the neat epoxy tensile strength by 75%, stiffness by over 25%, impact strength by 25%, and hardness 35%. These improved properties indicate that nano-CaCO3 synthesized from A. fulica snail shell possesses suitable reinforcement properties that can be used for nanocomposite fabrication.

We prepared bilayer films of iron yam–pea starch and corn zein to evaluate their potential application in the packaging of instant foods and condiments. We found that the water resistance and mechanical properties of bilayer films were improved after adding a layer of corn zein compared with the monolayer films of the starch materials. Scanning electron microscopy revealed that the bilayers were close and this was reflected in increased thermal stability and biocompatibility between layers with the addition of zein. Our experimental films showed greater elongation at break than the commercial biaxially oriented polypropylene polyethylene films. Based on the results of this study, the iron yam-pea starch/corn zein films have the mechanical strength and flexibility to be used for convenience food packaging materials, which are expected to provide consumers with clean products.

The effect of CaF2 addition on plasma resistance and thermal properties of CaO-Al2O3-SiO2 (CAS) glasses was investigated. The amount of SiO2 and Al2O3 was fixed to 42.9 and 9.1 (in mol%), respectively, while total amount of CaO and CaF2 was 48 mol% and the ratios of CaO:CaF2 were changed from 10:0 to 8:2. As the amount of CaF2 of CAS glass increased, CF4/O2/Ar plasma etch rate of glass decreased proportionally. In case of sample with CaO:CaF2 = 8:2, its etch rate had 5.04 ± 0.14 ㎚/min, which was about 20 times lower than that of quartz glass and was improved by more than 25% compared to the glass without CaF2. All glass samples maintained the initial surface and roughness even after plasma etching. In addition, the glass transition (Tg), crystallization (Tc), and the first melting temperature (Tf1) temperatures decreased with the amount of increased CaF2. F− ion in CAS glasses not only enhances the plasma resistance but also facilitates glass melting and forming operations.

Tetraacetylethylenediamine (TAED) activated hydrogen peroxide (H2O2) was tentatively used in the bleaching of scoured jute fibers, and the effects of this method on the physicomechanical properties, main chemical compositions, and structures during bleaching were evaluated and compared with conventional H2O2 bleaching. By comparing with H2O2 bleached jute fibers, the TAED-activated H2O2 bleached jute fibers were found to have a better storage stability of whiteness and yellowness, higher breaking tenacity, lower fineness value and breaking extension. The differences in morphological structure and thermogravimetric analysis showed that the TAED-activated H2O2 bleaching system had a stronger ability for the removal of noncellulosic materials than conventional H2O2 bleaching system. The changes in main chemical compositions and Fourier transform infrared spectra further indicated that the removal ability of TAED-activated bleaching for lignin was obviously stronger than that of conventional bleaching, but it had a similar removal ability for hemicellulose. Furthermore, when the whiteness and yellowness values were similar, the amount of H2O2, bleaching temperature, and time of TAED-activated H2O2 bleaching were obviously less than those of H2O2 bleaching.

Polyolefins used in building materials and furniture require the use of flame-retardant (FR) additives to improve their fire safety. Such additives should be safe to humans and the environment, and preferably bio-based. In the present work, the FR performance of unmodified and chemically modified technical lignins was compared to that of the ammonium polyphosphate/pentaerythritol (APP/PER) intumescent system in a polypropylene (PP) matrix. Micro-scale combustion calorimetry (MCC) was used to study the peak heat release rate (PHR), temperature at PHR (TPHR), total heat release (THR) and char yield upon thermal decomposition of milligram-scale specimens. The PP/lignin composites showed up to 41% lower PHR and up to 36% lower THR compared to pure PP as well as large char residues. Based on the same parameters, especially the PP/lignin composites made with modified lignins outperformed the reference PP/APP/PER system and the PP/APP/lignin composites where unmodified lignin was used with APP. The most promising PP/lignin composites were prepared with partially demethylated/demethoxylated and depolymerised kraft lignin (‘CatLignin’), modified by the Mannich reaction to a nitrogen content of 13.5%.

A novel and excellent composite film was fabricated by simply casting cassava silk fibroin (CSF), chitosan quaternary ammonium salt (HACC), and graphene oxide (GO) in an aqueous solution. Scanning electron microscope images showed that when GO was dispersed in the composite films, the surface of CSF-based composite film became rough, and a wrinkled GO structure could be found. When the content of GO was 0.8%, the film displayed a higher change with respect to the breaking strength and elongation, respectively, up to 97.69 ± 3.69 and 79.11 ± 1.48 MPa, keeping good thermal properties because of the incorporation of GO and HACC. Furthermore, the novel CSF/HACC/GO composite film demonstrates a lower degradation rate, implying the improvement of the resistance to the enzyme solution. Especially in the film with 0.8 wt% GO, the residual mass arrived at 64.35 ± 1.1% of the primary mass after 21 days compared with the CSF/HACC film. This would reclaim the application of silk-based composite films in the biomaterial field.

This study examines the influence of cellulose nanocrystal (CN) particles on the morphological, thermal, and thermo-mechanical properties of polylactide (PLA)/poly [(butylene succinate)-co-adipate] (PBSA) blend foams prepared by casting and particulate leaching method using fructose as porogen particles. The morphological analysis showed an interconnected open-cell structure, with porosity above 80%. The crystallinity of the prepared foams was disrupted by the inclusion of CN particles as observed from XRD analyses, which showed a decrease in PLA crystal peak intensity. With regards to neat blend foam, the onset thermal degradation increased with the addition of CN particles, which also increased the thermal stability at 50% weight loss. Furthermore, CN acted as a reinforcing agent in improving the stiffness of the prepared blend foam. Overall, completely environmentally friendly foams were successfully prepared, as a potential material that can replace the current existing foam materials that pose many environmental concerns. However, there is a need to develop an environmentally friendly processing technique.

In this work, a series of nanoencapsulated phase change materials (NanoPCMs) with paraffin wax (PW) as core and melamine-formaldehyde (MF) as shell were synthesized by the in-situ polymerization method. The morphology, chemical structure and thermal properties of prepared NanoPCMs were characterized by scanning electron microscope, Fourier transform infrared, differential scanning calorimetry and thermogravimertic analyzer. The results show that the PW is successfully encapsulated in the MF without chemical interaction, and the NanoPCMs present regular spherical shape with the average diameter of 260–450 nm. The encapsulation efficiency of the NanoPCMs increases with the augment of the supplied amount of core material. The maximum encapsulation efficiency of the NanoPCMs can reach up to approximately 75%. The NanoPCMs can maintain excellent thermal reliability and stability after 2000 thermal cycling. The prepared NanoPCMs can be well applied in the latent heat thermal energy storage and thermal management systems due to their remarkable encapsulation efficiency and thermal properties enable them to.

Made available in DSpace on 2020-12-12T02:45:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In the present study, biocomposite films from cellulose nanocrystals (CNCs) were obtained by the solution casting method. CNCs were isolated from pineapple crown using chemical treatments followed by sulfuric acid hydrolysis and added into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrix. The effect of freeze-dried CNC content (1, 3, and 5 wt%) on the structural, crystallization, thermal degradation lifetime prediction, and thermogravimetric simulation was investigated. An irreversible agglomeration observed after freeze-dried provided changes in the morphology and size of CNCs. Addition up to 3 wt% of CNCs increased the thermal stability, crystallization rate, and crystallinity index of PHBV, as showed by thermal and crystallinity analysis, respectively. The kinetic degradation study by thermogravimetric analysis (TGA) was done using the F-test method by statistically comparing degradation mechanisms in the solid-state. The most probable degradation mechanism was the autocatalytic reaction model for all samples (represented by Cn and Bna-types) with a suitable adjustment of the simulated curves. Lifetime prediction showed to be successfully applied based on the kinetic analysis, and PHBV reinforced with 3 wt% of CNCs presents the highest results for the isothermal temperature of 180 °C. Department of Materials and Technology Fatigue and Aeronautic Materials Research Group School of Engineering Sao Paulo State University (UNESP) Department of Materials and Technology Fatigue and Aeronautic Materials Research Group School of Engineering Sao Paulo State University (UNESP) CNPq: 153335/2018-1 FAPESP: 2011/14153-8 FAPESP: 2015/10386-9

All-organic high dielectric materials are highly required in the field of modern electronic industry and energy storage. In this work, all-organic polyimide/polysulfone composite films with different amounts of PSF (PI/PSF-X) were prepared by in situ polymerization followed by film casting and thermal treatment. The dielectric, mechanical and thermal properties of these PI/PSF-X composite films are characterized by dielectric measurement, tensile test, thermogravimetric analysis and dynamic mechanical analysis. The results suggest that the PI/PSF-X composite films have good dielectric properties, good mechanical properties and excellent thermal properties, which are suitable for applications in electronic devices in harsh environments, especially in high-temperature environments.

Результати досліджень для визначення впливу наночастинок діоксиду титану (nanoTiO2), тонкодисперсної кристалічної лінії анатазу діоксиду титану (anatazTiO2) та поверхнево-активних речовин (ПАР) на міцність на стиск, ступінь проникності та термостійкість зразків бетону представлений. Додавання до цементу частинок нанотитану, анатазу титану та ПАР до 2% прискорює процес гідратації та збільшує міцність бетону, а також сильно впливає на його мікроструктуру. В результаті досліджень експериментально доведено, що міцність бетону на стиск зростає з додаванням наночастинок діоксиду титану (nanoTiO2) на 23,2%, тонкодисперсного кристалічного діоксиду титану анатазу (anatazTiO2) на 21,7% до 5% по масі. Крім того, введення цих добавок знижує проникність бетону. Це пов’язано зі зменшенням поглинання бетону водою з додаванням нанотитану та анатазу титану. Введення добавок від 1% до 5% по масі в бетон зменшує глибину проникнення хлориду в 10–15 разів порівняно з контролем. Використання методу запрограмованої температурою десорбційної мас-спектрометрії (TPD-MS) показало, що збільшення відсотка наночастинок TiO2 до 5% у бетонних сумішах корелює зі збільшенням мікропористості та рівня дисперсії цих сумішей, що спричиняє зміщення піки інтенсивного виділення газу із зразків при нагріванні до бокових низьких температур (наприклад, вуглекислий газ CO2). Отримані зразки бетону планується використовувати для виготовлення підлог у тваринницьких будівлях. Введені добавки вибирають, оскільки вони не є токсичними речовинами і, контактуючи з біологічним середовищем тваринницьких будівель (сеча, кал), не будуть з ними реагувати. Приведены результаты исследований по определению влияния наночастиц диоксида титана (nanoTiO2), мелкодисперсного кристаллического диоксида титана анатаза (anatazTiO2) и поверхностно-активных веществ (ПАВ) на прочность на сжатие, степень проницаемости и термостойкость бетонных образцов. Добавление в цемент частиц нанотитана, анатаза титана и поверхностно-активных веществ до 2% ускоряет процесс гидратации и увеличивает прочность бетона, а также сильно влияет на его микроструктуру. В результате исследований экспериментально доказано, что прочность бетона на сжатие увеличивается при добавлении наночастиц диоксида титана (nanoTiO2) на 23,2%, мелкодисперсного кристаллического диоксида титана анатаза (anatazTiO2) на 21,7% до концентрации 5% по массе. Кроме того, введение этих добавок снижает проницаемость бетона. Это связано с уменьшением впитывания бетона водой при добавлении нанотитана и анатаза титана. Введение в бетон добавок от 1% до 5% по массе снижает глубину проникновения хлоридов в 10–15 раз по сравнению с контролем. Использование метода термопрограммируемой десорбционной масс-спектрометрии (TPD-MS) показало, что увеличение процентного содержания наночастиц TiO2 до 5% в бетонных смесях коррелирует с увеличением микропористости и уровня дисперсности этих смесей, что вызывает сдвиг в пики интенсивного газовыделения из образцов при нагреве в сторону низких температур (например, углекислый газ СО2). Полученные образцы бетона планируется использовать для изготовления полов в животноводческих помещениях. Вводимые добавки выбраны потому, что они не являются токсичными веществами и при контакте с биологической средой животноводческих помещений (моча, фекалии) не вступают с ними в реакцию. The results of studies to determine the effect of titanium dioxide nanoparticles (nanoTiO2), finely dispersed anatase crystal¬line titanium dioxide (anatazTiO2) and surface-active substances (surfactants) on the compressive strength, degree of permeability and thermal stability of concrete samples are presented. Adding particles of nanotitanium, anatase titanium and surfactants up to 2 % to cement accelerates the hydration process and increases the strength of concrete, and also has a strong effect on its microstructure. As a result of the studies, it is experimentally proved that the compressive strength of concrete increases with the addition of titanium dioxide (nanoTiO2) nanoparticles by 23.2 %, finely dispersed anatase crystalline titanium dioxide (anatazTiO2) by 21.7 % to 5 % concentration by weight. In addition, the introduction of these additives reduces the permeability of concrete. This is due to a decrease in the absorp¬tion of concrete by water with the addition of nanotitanium and anatase titanium. The introduction of additives from 1 % to 5 % by weight in concrete reduces the depth of chloride penetration by 10–15 times, compared with the control. The use of temperature-programmed desorption mass spectrometry (TPD-MS) method has shown that an increase in the percentage of TiO2 nanoparticles to 5 % in concrete mixtures correlates with an increase in microporosity and dispersion level of these mixtures, which causes a shift in the peaks of intense gas evolution from the samples when heated to the side low temperatures (for example, carbon dioxide CO2). The resulting concrete samples are planned to be used for the manufacture of floors in livestock buildings. The injected additives are selected because they are not toxic substances and, in contact with the biological environment of livestock buildings (urine, feces), will not react with them.

This study aimed to prepare poly (3-hydroxybutyrate-co-3-hydroxyvalerate), biocomposites with incorporating various percentages of calcium carbonate using extrusion processing. Calcium carbonate was synthesized in the absence and presence of poly(vinyl sulfonic acid). The polymorph and morphology of calcium carbonate chanced with the introduction of poly(vinyl sulfonic acid). The rhombohedral calcite was obtained in the absence of poly(vinyl sulfonic acid). Rhombohedral calcite transformed into spherical vaterite with the addition of poly(vinyl sulfonic acid). The influence of filler contents on the properties of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) composites was studied. The structure and properties of poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/ calcium carbonate biocomposites were investigated by XRD, FTIR, TGA, DSC, SEM, OTR and DMA. The nucleation effect of the calcium carbonate on the crystallization of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) was observed in the DSC and XRD measurements by increasing crystallinity of poly (3-hydroxybutyrate-co-3-hydroxyvalerate). It was shown that the variation of the barrier properties of biocomposites was influenced by polymorph and morphology of calcium carbonate. The addition of 0.5 wt% of the rhombohedral calcite and spherical vaterite increased the barrier properties by 25% and 12%, respectively compared to neat polymer. The dynamic mechanical properties of composites based on rhombohedral calcite and spherical vaterite in poly (3-hydroxybutyrate-co-3-hydroxyvalerate) matrix were investigated. The storage modulus increases by adding both particles in the composites over a wide range of temperature (-30 to 150 °C) where the reinforcing effect of calcite and vaterite was confirmed. At the same loading level, rhombohedral calcite led to more increase in the storage modulus, while less increase in storage modulus was observed in the presence of spherical vaterite particles.

Made available in DSpace on 2020-12-12T02:37:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Buckwheat starch is an alternative source to supply the high global demand for starch. The properties of starch can be modified through chemical and physical methods; one of them is the milling process, which can be considered as green method according with the green chemistry principles. Thus, this work aims to use the milling process and study its effects on thermal and crystalline properties of starch extracted from common buckwheat (Fagopyrum esculentum). It was observed in differential scanning calorimetry and X-ray powder diffraction that after the milling process, the starch losted its crystallinity and was pre-gelatinized. Nevertheless, the samples showed similar decomposition, dehydration and oxidation profiles, as observed by thermogravimetry and differential thermal analysis curves. The thermal stability did not show considerable difference (less than 5 °C) after the milling process. Moreover, the medium infrared spectroscopy showed that the milling process did not change the functional groups of starch. The morphology of the starch granules, as observed by scanning electron microscope presented surface roughness, and also the decrease of the average diameter of the modified starch was observed. State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748 UNESP - Chemistry Department School of Sciences São Paulo State University UNESP - Chemistry Department School of Sciences São Paulo State University

The paper is focused on measurements of electric and thermal properties of alkali-activated aluminosilicates (AAAs) with a carbon nanotube (CNT) admixture. Such composites, fabricated from blast-furnace slag, quartz sand, water glass as an alkali activator, a small amount of electrically conductive CNT admixture and water exhibit better electric and thermal properties than the reference material without the CNT. Such an enhancement opens new practical applications, such as designing snow-melting, de-icing or self-sensing systems that do not need any external sensors to detect the current condition of the building's materials. Moreover; the economic aspect is more favourable in the case of AAA than that of Portland cement-based materials. The DC (direct current) electric properties are determined experimentally from the current-voltage (I-V) characteristics, the dielectric properties by means of impedance spectroscopy. Dielectric measurements allow us to determine the contribution of the individual components to the conductivity of the composite. The electric and thermal conductivities in the transverse direction were 16.16 mu S.m(-1) and 0.907 W.m(-1).K-1 for 0 % of CNT and 34.46 mu S.m(-1) and 1.298 W.m(-1).K-1 for 0.4 % of CNT, respectively.

In this study, the influence of nanosilicon(IV)-oxide (with hydrophobic and hydrophilic functionalized surfaces) on the properties of siloxane elastomers was studied. The elastomers were prepared from vinyl and hydrogen oligosiloxanes, while the nanocomposites were obtained by addition of nanofillers at different concentrations (1, 5, 10 and 20 wt%). The chemical structure of the obtained materials was analyzed by Fourier transform infrared spectroscopy. Transmission electron microscopy confirmed good dispersion of the hydrophobic filler within the polymer matrix, while the hydrophilic filler formed a net on the siloxane sample. Type of the filler modification did not affect hardness of the siloxane hybrid materials, while the samples with the highest content of hydrophobic nanosilica have shown the highest value of tensile strength. Influence of the nanosilica type on thermal degradation of elastomeric materials was investigated by using thermogravimetric analysis, while the influence of the fillers on the phase transition temperature was analyzed by differential scanning calorimetry. Lower compatibility of the hydrophobic matrix and hydrophilic filler caused a decrease in the crystalline melting temperature with the lowest value determined for the sample with the highest filler loading. Increase in the nanofiller content resulted in the improved thermal stability of the obtained hybrid materials.

A racemic mixture of two stereoregular polylactides (PLAs) (i.e. PLLA and PDLA) allows obtaining wholly amorphous stereocomplex PLA films by solvent casting method. The amorphous phase behavior of stereocomplex PLA is compared with that of PLLA and PDLA by advanced thermal analysis, such as Fast Scanning Calorimetry (FSC) and Dielectric Relaxation Spectroscopy (DRS). FSC allows us to quench at very high cooling rate (up to 4000 K・s–1) the studied polymers and to obtain glassy amorphous phases with high excess of enthalpy. It is shown that stereocomplexation has no influence on the glass transition temperature, the physical aging and on the cooperativity. The α and β processes were examined to study the dielectric properties, such as relaxation time, dielectric strength, and fragility. The results of FSC and DRS are correlated to determine the values of cooperativity length which are found to be similar in a wide temperature range. It is found that the studied polymers have the similar dielectric properties independently on their tacticity.

In this study, poly(vinyl alcohol) (PVA)-modified Saudi bentonite nanocomposite films were prepared using the solution method. Two surfactants, cetylpyridinium chloride and tetrabutyl phosphonium bromide, were used to modify the clay after the ion-exchange process by Na+ ions. The effect of the addition of modified Saudi bentonite (2.5%) on the thermal and flammability properties of the nanocomposite films was investigated. The prepared samples were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Thermogravimetric analysis and differential scanning calorimetry were carried out to observe the thermal behaviour of the PVA-based nanocomposite films. Vertical flammability tests (UL94 VB) were also carried out to study the flame retardancy behaviour of the nanocomposite films. The nanocomposite films showed better flammability than pure PVA, wherein the ignition time of the nanocomposites increased and flame propagation rate decreased. The thermal stability of the nanocomposites increased by approximately 10% for the onset and endset temperature of decomposition. The type of surfactant played an important role in dispersion of the clay into the polymeric matrix and enhancing the flammability properties of the films wherein the tetrabutyl phosphonium bromide was better flame retardant than cetylpyridinium chloride.

Protein films can be applied to improve food quality and to reduce packaging waste. To overcome their poor water barrier properties, lipids are often incorporated. The function of incorporated lipid depends on the interface between filler and matrix. This study aimed to tailor the properties of a protein–lipid film by designing the oil/water interface to see if the concept of inactive/active filler is valid. Therefore, we varied the emulsifier stabilizing solid lipid nanoparticles (SLN) to promote (viaβ-lactoglobulin) or to minimize (via Tween 20) interactions between particle surface and protein. SLN were incorporated into protein films and film properties were determined. Addition of SLN led to significantly decreased water vapor permeability (WVP) of protein films. However, WVP was mainly affected by the emulsifiers and not by the lipid. Protein-stabilized SLN (BS) replaced a lacking protein in the protein network and therefore did not influence the mechanical properties of the films at ambient temperature. BS-composite films were temperature sensitive, as lipid and sucrose palmitate melted at temperatures above 40°C. Tween 20-stabilized SLN(TS) led to reduced tensile strengths, probably due to perturbative effects of TS and plasticizing effects of Tween 20. Dynamic mechanical analysis showed that TS and Tween 20 increased film mobility. Melting of lipid and emulsifiers, and temperature-dependent behavior of Tween 20 led to a strong temperature dependence of the film stiffness. By designing the interface, particles can be used to tailor mechanical properties of protein films. Tuned edible films could be used to control mass transfers between foods.

A novel microencapsulated phase change material was prepared by sol-gel method using lauric acid (LA) as core material and titanium dioxide (TiO2) as shell material. The composites were characterized by field emission scanning electron microscope (FE-SEM), Fourier transformation infrared spectrometer (FT-IR), differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The results of the FE-SEM and FT-IR indicated that LA was well coated in the shell of TiO2 and no chemical reaction occurred between them. The results of the DSC denoted that the composites with 43.5 % encapsulation ratio of the LA melted at 44.39 ℃ with the melting enthalpy of 67.54 J/g and solidified at 43.64 ℃ with the solidification enthalpy of 65.17 J/g. The results of the TGA signified that the thermal stability and fire resistance of the microcapsules were greatly enhanced under the protection barrier of TiO2. The thermal decomposition of the microencapsulated LA with TiO2 shell hardly occurred under 200 ℃. That is to say, the composites possess good thermal stability in the operating temperature range. In conclusion, the prepared microencapsulated composites can be incorporated into solar energy storage like solar air heaters and into electronic devices as heat sinks.

Poly(ethylene glycol) diacrylate (PEGDA) of different molecular weights (Mn = 575 and 700) was used as crosslinking agent for the photopolymerization of 2-hydroxyethyl methacrylate (HEMA) in order to obtain HEMA/PEGDA-based hydrogels. Composites were synthesized in situ employing a new methodology that implies the addition of different quantities of silver nitrate aqueous solution to the monomer mixture with the finality to obtain hydrogels with different silver nanoparticles’ spatial density and distribution. Samples were characterized by thermal, optical, spectroscopic and structural/morphological methods. Thermal studies showed that the increase of PEGDA molecular weight and the AgNO3 concentration in the reaction mixture enhance the glass transition temperature and the thermal stability of the composites. This behavior could be related to the silver coordination with the polymer network. Infrared spectroscopy with Fourier transform and Raman analyses were realized in order to corroborate the sample chemical structure by the identification of specific functional groups. Surface hydrogel morphology was visualized with scanning electron microscopy analysis, detecting a homogeneous micro-porous surface for the samples obtained from high molecular weight PEGDA. Presence of silver nanoparticles was established by X-ray fluorescence spectroscopy and UV/Vis methods. In this last case, the characteristic silver nanoparticle plasmon was observed. Using Transmission Electron Microscopy it was possible to visualize a homogeneous spatial distribution of spherical silver nanoparticles with very narrow diameter distribution that rounds about 14–21 ± 5 nm. In general, the silver nanoparticle presence in the compounds enhances considerably their thermal/morphological characteristics. Keywords: Silver nanoparticles, HEMA/PEGDA hydrogel, Thermal properties, Crosslinking agent

Pineapple crown leaf fiber (PCLF) is one of the major biomass wastes from pineapple processing plants. It consists mostly of carbohydrate polymers, such as cellulose, hemicellulose, and lignin. It can be further processed to form a more valuable and widely used nanocrystalline cellulose (NCC). This study investigates the effect of hydrolysis time on the properties of the produced NCC. The acid hydrolysis was conducted using 1 M of sulfuric acid at hydrolysis times of 1–3 h. The resulting NCCs were then characterized by their morphology, functional groups, crystallinity, thermal stability, elemental composition, and production yield. The results show that the NCC products had a rod-like particle structure and possessed a strong cellulose crystalline structure typically found in agricultural fiber-based cellulose. The highest NCC yield was obtained at 79.37% for one hour of hydrolysis. This NCC also displayed a higher decomposition temperature of 176.98 °C. The overall findings suggest that PCLF-derived NCC has attractive properties for a variety of applications.

The present study deals with the formation of a phosphorylated polyvinyl alcohol (PPVA)-Aluminum Phosphate (AlPO4) nanocomposite, changing the pH solution under the two-step process involving the phosphorylation of polyvinyl alcohol (PVA) followed by the conjugation with AlPO4. The composite was formed by varying the pH of the solution in the range of 7–12 and the reflected changes in the product’s morphology, crystallinity, surface nature, thermal stability, etc. were recorded using FESEM, XRD, FTIR, UV-Vis spectroscopy, TGA, etc. From the analysis, it was found that the particles formed with two different sizes of the probed pH, and at pH 10 they were homogeneously distributed. In addition, the morphology of the PPVA-AlPO4 composite also seems to be altered with respect to the pH and this is due to the differences in the amount of H+ and OH− anions. Thus, from the overall analysis, it can be indicated that pH 10 needs to be maintained for the formation of a spherical shape and uniformly distributed PPVA-AlPO4 nanocomposite.

The TiO2 NPs have been successfully synthesized by sol-gel method and the SWCNTs/TiO2 nanostructures have been fabricated by a simple mixing technique. By a solution casting process, pure CMC/PEO and SWCNTs/TiO2 nanohybrid doped CMC/PEO polymer blend films have been prepared. The influence of SWCNTs/TiO2 nanohybrid loading on the thermal, optical, and conductivity properties of the polymer blend has been discussed. The XRD pattern shows that the average crystallite size of the nanoparticles for TiO2 and SWCNTs/TiO2 is 20 nm and 15 nm, respectively, and a change in crystallinity was observed with an increase in doping. The interaction between CMC/PEO chains and SWCNTs/TiO2 nanohybrid is confirmed by FTIR spectra. The optical absorption spectrum shows that the energy gap reduces with the dopant increase. The miscibility between the CMC and PEO was confirmed by DSC thermograms. With an increase in dopant content, the TGA study demonstrates that the system's thermal stability improves. The maximum value of the blend's AC conductivity is 4.77 10−6 S/m, and by increasing the loading of SWCNTs/TiO2 to 3.2 (wt%) increased to 9.23 10−4 S/m. The conduction mechanism changed with SWCNTs/TiO2 loading from the correlated barrier hopping, in the prepared samples. Usage of these nanocomposite films in the semiconductor industry is encouraged by the observed improvements in optical, thermal, and AC conductivity.

The advanced tendencies in building materials development are related to the design of cement composites with a reduced amount of Portland cement, contributing to reduced CO2 emissions, sustainable development of used non-renewal raw materials, and decreased energy consumption. This work deals with water cured for 28 and 120 days cement composites: Sample A—reference (white Portland cement + sand + water), Sample B—white Portland cement + marble powder + water, and Sample C white Portland cement + marble powder + polycarboxylate-based water reducer + water. By powder X-ray diffraction and FTIR spectroscopy, the redistribution of CO32−, SO42−, SiO44−, AlO45−, and OH− (as O-H bond in structural OH− anions and O-H bond belonging to crystal bonded water molecules) from raw minerals to newly formed minerals have been studied, and the scheme of samples hydration has been defined. By thermal analysis, the ranges of the sample’s decomposition mechanisms were distinct: dehydration, dehydroxylation, decarbonation, and desulphuration. Using mass spectroscopic analysis of evolving gases during thermal analysis, the reaction mechanism of samples thermal decomposition has been determined. These results have both practical (architecture and construction) and fundamental (study of archaeological artifacts as ancient mortars) applications.

[EN] An eco-friendly strategy for the modification of polylactic acid (PLA) surface properties, using a solvent-free process, is reported. Reactive extrusion (REX) allowed the formation of new covalent bonds between functional molecules and the PLA polymeric matrix, enhancing its mechanical properties and modifying surface hydrophobicity. To this end, the PLA backbone was modified using two alkoxysilanes, phenyltriethoxysilane and N-octyltriethoxysilane. The reactive extrusion process was carried out under mild conditions, using melting temperatures between 150 and 180 degrees C, 300 rpm as screw speed, and a feeding rate of 3 kg center dot h(-1). To complete the study, flat tapes of neat and functionalized PLA were obtained through monofilament melt extrusion to quantify the enhancement of mechanical properties and hydrophobicity. The results verified that PLA modified with 3 wt% of N-octyltriethoxysilane improves mechanical and thermal properties, reaching Young's modulus values of 4.8 GPa, and PLA hydrophobic behavior, with values of water contact angle shifting from 68.6 degrees to 82.2 degrees., This research work was funded by the Conselleria d'Economia Sostenible, Sectors Productius, Comerc i Treball de la Generalitat Valenciana through IVACE. Project references: GREENFILS, IMAMCI/2019/1 and BIOREX, IMAMCI/2020/1.

In the present study, 100% bio-based polyesters of 2,5-thiophenedicarboxylic acid were synthesized via two-stage melt polycondensation using glycols containing 3 to 6 methylene groups. The so-prepared samples were characterised from the molecular point of view and processed into free-standing thin films. Afterward, both the purified powders and the films were subjected to structural and thermal characterisation. In the case of thin films, mechanical response and barrier properties to O2 and CO2 were also evaluated. From the results obtained, it emerged that the length of glycolic sub-units is an effective tool to modulate the chain mobility and, in turn, the kind and amount of ordered phases developed in the samples. In addition to the usual amorphous and 3D crystalline phases, in all the samples investigated it was possible to evidence a further phase characterised by a lower degree of order (mesophase) than the crystalline one, whose amount is strictly related to the glycol sub-unit length. The relative fraction of all these phases is responsible for the different mechanical and barrier performances. Last, but not least, a comparison between thiophene-based homopolymers and their furan-based homologues was carried out.

Polylactic acid (PLA) was melt-blended with epoxy resin to study the effects of the reaction on the mechanical and thermal properties of the PLA. The addition of 0.5% (wt/wt) epoxy to PLA increased the maximum tensile strength of PLA (57.5 MPa) to 67 MPa, whereas the 20% epoxy improved the elongation at break to 12%, due to crosslinking caused by the epoxy reaction. The morphology of the PLA/epoxy blends showed epoxy nanoparticle dispersion in the PLA matrix that presented a smooth fracture surface with a high epoxy content. The glass transition temperature of PLA decreased with an increasing epoxy content owing to the partial miscibility between PLA and the epoxy resin. The Vicat softening temperature of the PLA was 59 °C and increased to 64.6 °C for 0.5% epoxy. NMR confirmed the reaction between the -COOH groups of PLA and the epoxy groups of the epoxy resin. This reaction, and partial miscibility of the PLA/epoxy blend, improved the interfacial crosslinking, morphology, thermal properties, and mechanical properties of the blends.

Biodegradable packaging prepared from starch is an alternative to fossil-based plastic packaging. However, the properties of starch packaging do not comply with the necessary physicochemical properties to preserve food. Hence, in a previous study, we reported the preparation of a composite polymer material based on starch-chitosan-pluronic F127 that was found to be an adequate alternative packaging material. In this study, we modified the physicochemical properties of this material by storing it for 16 months under ambient conditions. The results indicate that the incorporation of pluronic F127 in the blend polymer can help avoid the retrogradation of starch. Moreover, at higher concentrations of pluronic F127, wettability is reduced. Finally, after storage, the materials exhibited surface modification, which is related to a color change and an increase in solubility, as well as a slight increase in stiffness.

Over the last few decades, bio-based polymers have attracted considerable attention from both academic and industrial fields regarding the minimization of the environmental impact arising from the excessive use of petrochemically-based polymeric materials. In this context, poly(ethylene vanillate) (PEV), an alipharomatic polyester prepared from 4-(2-hydroxyethoxy)-3-methoxybenzoic acid, a monomer originating from lignin-derived vanillic acid, has shown promising thermal and mechanical properties. Herein, the effects of three different catalysts, namely titanium butoxide (TBT), titanium isopropoxide (TIS), and antimony trioxide (Sb2O3), on the synthesis of PEV via a two-stage melt polycondensation method are investigated. The progress of the reaction is assessed using various complementary techniques, such as intrinsic viscosity measurement (IV), end group analysis (AV), nuclear magnetic resonance spectroscopy (NMR), Fourier-transformed infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The thermal stability of the produced polyesters is studied by evolved gas analysis mass spectrometry (EGA-MS). Moreover, as the discoloration in polymers affects their applications, color measurement is performed here. Finally, theoretical kinetic studies are carried out to rationalize the experimental observations.

This work investigates the effects of modification of polylactide (PLA) using dicumyl peroxide (DCP) as a crosslinker and Joncryl as a chain extender on boehmite distribution. The PLA/boehmite (PLA/BA) composites at various concentrations were prepared via a twin-screw extruder. Transmission electron microscopy showed more agglomerations of BA particles when Joncryl and DCP were added individually to the PLA matrix, with lesser agglomeration upon simultaneous addition of DCP and Joncryl, which led to an enhancement of 10.7% of the heat distortion temperature and 8.8% of the modulus. The existence of fine dispersed BA particles in the BA3 sample improved the cold crystallization by 4 °C. Moreover, the maximum reinforcing effect in increasing the storage modulus of the prepared system was observed upon concurrent addition of DCP and Joncryl, with minimum reinforcing effect upon individual addition of DCP and Joncryl. In general, a bio-based PLA composite base BA with enhanced properties was successfully prepared for various applications.

Lyocell fabrics are widely applied in textiles, however, its high flammability increases the risk of fire. Therefore, to resolve the issue, a novel biomass-based flame retardant with phosphorus and nitrogen elements was designed and synthesized by the reaction of arginine with phosphoric acid and urea. It was then grafted onto the lyocell fabric by a dip-dry-cure technique to prepare durable flame-retardant lyocell fabric (FR-lyocell). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the flame retardant was successfully introduced into the lyocell sample. Thermogravimetric (TG) and Raman analyses confirmed that the modified lyocell fabric featured excellent thermal stability and significantly increased char residue. Vertical combustion results indicated that FR-lyocell before and after washing formed a complete and dense char layer. Thermogravimetric Fourier-transform infrared (TG-FTIR) analysis suggested that incombustible substances (such as H2O and CO2) were produced and played a significant fire retarding role in the gas phase. The cone calorimeter test corroborated that the peak of heat release rate (PHRR) and total heat release (THR) declined by 89.4% and 56.4%, respectively. These results indicated that the flame retardancy of the lyocell fabric was observably ameliorated.

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).