Correlation between degree of crystallinity and bluing of Zn1–Co Al2O4 (0≤x≤1) nanopowders prepared by soft chemistry route

A star polymer with a polyhedral oligomeric silsesquioxanne (POSS) core and poly(ethylene glycol) (PEG) vertex groups is incorporated in a polyurethane with flexible hard segments in-situ during the polymerization process. The blends are studied in terms of morphology, molecular dynamics, and charge mobility. The methods utilized for this purpose are scanning electron and atomic force microscopies (SEM, AFM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and to a larger extent dielectric relaxation spectroscopy (DRS). It is found that POSS reduces the degree of crystallinity of the hard segments. Contrary to what was observed in a similar system with POSS pendent along the main chain, soft phase calorimetric glass transition temperature drops as a result of plasticization, and homogenization of the soft phase by the star molecules. The dynamic glass transition though, remains practically unaffected, and a hypothesis is formed to resolve the discrepancy, based on the assumption of different thermal and dielectric responses of slow and fast modes of the system. A relaxation α′, slower than the bulky segmental α and common in polyurethanes, appears here too. A detailed analysis of dielectric spectra provides some evidence that this relaxation has cooperative character. An additional relaxation g, which is not commonly observed, accompanies the Maxwell Wagner Sillars interfacial polarization process, and has dynamics similar to it. POSS is found to introduce conductivity and possibly alter its mechanism. The study points out that different architectures of incorporation of POSS in polyurethane affect its physical properties by different mechanisms.

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Polyurethane Composite Foams Synthesized Using Bio-Polyols and Cellulose Filler

Materials ◽

10.3390/ma14133474 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3474

Author(s):

Katarzyna Uram ◽

Milena Leszczyńska ◽

Aleksander Prociak ◽

Anna Czajka ◽

Michał Gloc ◽

...

Keyword(s):

Cross Sections ◽

Raw Materials ◽

Polyurethane Foams ◽

Degree Of Crystallinity ◽

X Ray Diffraction ◽

Polyurethane Composite ◽

Composite Foams ◽

Closed Cell ◽

Ft Ir ◽

The Fourier Transform

Rigid polyurethane foams were obtained using two types of renewable raw materials: bio-polyols and a cellulose filler (ARBOCEL® P 4000 X, JRS Rettenmaier, Rosenberg, Germany). A polyurethane system containing 40 wt.% of rapeseed oil-based polyols was modified with the cellulose filler in amounts of 1, 2, and 3 php (per hundred polyols). The cellulose was incorporated into the polyol premix as filler dispersion in a petrochemical polyol made using calenders. The cellulose filler was examined in terms of the degree of crystallinity using the powder X-ray diffraction PXRD -and the presence of bonds by means of the fourier transform infrared spectroscopy FT-IR. It was found that the addition of the cellulose filler increased the number of cells in the foams in both cross-sections—parallel and perpendicular to the direction of the foam growth—while reducing the sizes of those cells. Additionally, the foams had closed cell contents of more than 90% and initial thermal conductivity coefficients of 24.8 mW/m∙K. The insulation materials were dimensionally stable, especially at temperatures close to 0 °C, which qualifies them for use as insulation at low temperatures.

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Estimation of the Age of Architectural Heritage Objects by Microstructural Changes of Calcite in Lime Mortars of Ancient Brickwork and Masonry

Buildings ◽

10.3390/buildings11060240 ◽

2021 ◽

Vol 11 (6) ◽

pp. 240

Author(s):

Vladimir Kotlyar ◽

Victoria Pishchulina ◽

Alexey N. Beskopylny ◽

Besarion Meskhi ◽

Yury Popov ◽

...

Keyword(s):

18Th Century ◽

Degree Of Crystallinity ◽

Architectural Heritage ◽

Natural Conditions ◽

Relative Age ◽

Lime Mortars ◽

Powder Samples ◽

Diffraction Patterns ◽

Cultural Monuments ◽

The Degree Of Crystallinity

Determining the age of ancient architectural and cultural monuments is a significant scientific problem. An approach based on the transformation of portlandite into calcite and subsequent recrystallization of calcite is considered, which allows for estimating the relative age of ancient brickworks for local groups of historic buildings based on the results of diffraction studies of powder samples of carbonate mortars and measurements of samples with a known age. This article presents the results of the study of lime mortars of ancient brickwork. Under natural conditions, the process of transformation of portlandite into calcite takes from 100 to 200 years. The rate of this process is influenced by temperature, humidity, peculiarities of interaction with carbon dioxide contained in the air, etc. Examples show that portlandite is completely transformed into calcite in masonry mortars of the 18th century and that portlandite is not found in older mortars. It was determined that after the transformation of portlandite into calcite, an increase in the degree of recrystallization of calcite is observed, which manifests itself in powder diffraction patterns in the relative broadening of the diffraction peak of calcite hkl 104. In a detailed study, an estimate of the peak width at half maximum (FWHM) associated with the degree of crystallinity is effective. The actual data are given, which show that in older lime mortars the degree of recrystallization of calcite is higher than in younger ones. This fact makes it possible to indirectly determine the relative age of brickwork and masonry of various buildings of architectural heritage, which is especially relevant for the objects with the use of lime mortars of the northern provinces of the Byzantine Oecumene and other periods of various cultures.

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Characterizing Bacterial Cellulose Produced byKomagataeibacter sucrofermentans H-110 on Molasses Medium and Obtaining a Biocomposite Based on It for the Adsorption of Fluoride

Polymers ◽

10.3390/polym13091422 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1422

Author(s):

Viktor V. Revin ◽

Alexander V. Dolganov ◽

Elena V. Liyaskina ◽

Natalia B. Nazarova ◽

Anastasia V. Balandina ◽

...

Keyword(s):

Composite Material ◽

Adsorption Capacity ◽

Bacterial Cellulose ◽

Functional Materials ◽

Degree Of Crystallinity ◽

Maximum Adsorption Capacity ◽

Fluoride Ions ◽

Sorption Ability ◽

Wide Range ◽

Biocomposite Material

Currently, there is an increased demand for biodegradable materials in society due to growing environmental problems. Special attention is paid to bacterial cellulose, which, due to its unique properties, has great prospects for obtaining functional materials for a wide range of applications, including adsorbents. In this regard, the aim of this study was to obtain a biocomposite material with adsorption properties in relation to fluoride ions based on bacterial cellulose using a highly productive strain of Komagataeibacter sucrofermentans H-110 on molasses medium. Films of bacterial cellulose were obtained. Their structure and properties were investigated by FTIR spectroscopy, NMR, atomic force microscopy, scanning electron microscopy, and X-ray structural analysis. The results show that the fiber thickness of the bacterial cellulose formed by the K. sucrofermentans H-110 strain on molasses medium was 60–90 nm. The degree of crystallinity of bacterial cellulose formed on the medium was higher than on standard Hestrin and Schramm medium and amounted to 83.02%. A new biocomposite material was obtained based on bacterial cellulose chemically immobilized on its surface using atomic-layer deposition of nanosized aluminum oxide films. The composite material has high sorption ability to remove fluoride ions from an aqueous medium. The maximum adsorption capacity of the composite is 80.1 mg/g (F/composite). The obtained composite material has the highest adsorption capacity of fluoride from water in comparison with other sorbents. The results prove the potential of bacterial cellulose-based biocomposites as highly effective sorbents for fluoride.

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Synthesis and Characterization of Nano-Sized 4-Aminosalicylic Acid–Sulfamethazine Cocrystals

Pharmaceutics ◽

10.3390/pharmaceutics13020277 ◽

2021 ◽

Vol 13 (2) ◽

pp. 277 ◽

Cited By ~ 1

Author(s):

Ala’ Salem ◽

Anna Takácsi-Nagy ◽

Sándor Nagy ◽

Alexandra Hagymási ◽

Fruzsina Gősi ◽

...

Keyword(s):

High Power ◽

Active Pharmaceutical Ingredient ◽

Polymorphic Form ◽

Degree Of Crystallinity ◽

Dissolution Enhancement ◽

Aminosalicylic Acid ◽

Nano Technology ◽

Power Ultrasound ◽

High Power Ultrasound ◽

High Degree

Drug–drug cocrystals are formulated to produce combined medication, not just to modulate active pharmaceutical ingredient (API) properties. Nano-crystals adjust the pharmacokinetic properties and enhance the dissolution of APIs. Nano-cocrystals seem to enhance API properties by combining the benefits of both technologies. Despite the promising opportunities of nano-sized cocrystals, the research at the interface of nano-technology and cocrystals has, however, been described to be in its infancy. In this study, high-pressure homogenization (HPH) and high-power ultrasound were used to prepare nano-sized cocrystals of 4-aminosalysilic acid and sulfamethazine in order to establish differences between the two methods in terms of cocrystal size, morphology, polymorphic form, and dissolution rate enhancement. It was found that both methods resulted in the formation of form I cocrystals with a high degree of crystallinity. HPH yielded nano-sized cocrystals, while those prepared by high-power ultrasound were in the micro-size range. Furthermore, HPH produced smaller-size cocrystals with a narrow size distribution when a higher pressure was used. Cocrystals appeared to be needle-like when prepared by HPH compared to those prepared by high-power ultrasound, which had a different morphology. The highest dissolution enhancement was observed in cocrystals prepared by HPH; however, both micro- and nano-sized cocrystals enhanced the dissolution of sulfamethazine.

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Crystallization Behavior and Mechanical Properties of Poly(ε-caprolactone) Reinforced with Barium Sulfate Submicron Particles

Materials ◽

10.3390/ma14092368 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2368

Author(s):

Hegoi Amestoy ◽

Paul Diego ◽

Emilio Meaurio ◽

Jone Muñoz ◽

Jose-Ramon Sarasua

Keyword(s):

Barium Sulfate ◽

Thermal Studies ◽

Polarized Light ◽

Optical Microscope ◽

Submicron Particles ◽

Degree Of Crystallinity ◽

Scanning Calorimetry ◽

Nucleation Effect ◽

Crystal Fraction ◽

Light Optical Microscope

Poly(ε-caprolactone) (PCL) was mixed with submicron particles of barium sulfate to obtain biodegradable radiopaque composites. X-ray images comparing with aluminum samples show that 15 wt.% barium sulfate (BaSO4) is sufficient to present radiopacity. Thermal studies by differential scanning calorimetry (DSC) show a statistically significant increase in PCL degree of crystallinity from 46% to 52% for 25 wt.% BaSO4. Non-isothermal crystallization tests were performed at different cooling rates to evaluate crystallization kinetics. The nucleation effect of BaSO4 was found to change the morphology and quantity of the primary crystals of PCL, which was also corroborated by the use of a polarized light optical microscope (PLOM). These results fit well with Avrami–Ozawa–Jeziorny model and show a secondary crystallization that contributes to an increase in crystal fraction with internal structure reorganization. The addition of barium sulfate particles in composite formulations with PCL improves stiffness but not strength for all compositions due to possible cavitation effects induced by debonding of reinforcement interphase.

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Emergence and Evolution of Crystallization in TiO2 Thin Films: A Structural and Morphological Study

Nanomaterials ◽

10.3390/nano11061409 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1409

Author(s):

Ofelia Durante ◽

Cinzia Di Giorgio ◽

Veronica Granata ◽

Joshua Neilson ◽

Rosalba Fittipaldi ◽

...

Keyword(s):

Thin Films ◽

Film Thickness ◽

Transition Metal Oxides ◽

Annealing Temperature ◽

Morphological Properties ◽

Degree Of Crystallinity ◽

Tio2 Thin Films ◽

Force Microscopy ◽

Heat Treated ◽

Complementary Techniques

Among all transition metal oxides, titanium dioxide (TiO2) is one of the most intensively investigated materials due to its large range of applications, both in the amorphous and crystalline forms. We have produced amorphous TiO2 thin films by means of room temperature ion-plasma assisted e-beam deposition, and we have heat-treated the samples to study the onset of crystallization. Herein, we have detailed the earliest stage and the evolution of crystallization, as a function of both the annealing temperature, in the range 250–1000 °C, and the TiO2 thickness, varying between 5 and 200 nm. We have explored the structural and morphological properties of the as grown and heat-treated samples with Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Diffractometry, and Raman spectroscopy. We have observed an increasing crystallization onset temperature as the film thickness is reduced, as well as remarkable differences in the crystallization evolution, depending on the film thickness. Moreover, we have shown a strong cross-talking among the complementary techniques used displaying that also surface imaging can provide distinctive information on material crystallization. Finally, we have also explored the phonon lifetime as a function of the TiO2 thickness and annealing temperature, both ultimately affecting the degree of crystallinity.

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Chemical and Structural Characterization of Maize Stover Fractions in Aspect of Its Possible Applications

Materials ◽

10.3390/ma14061527 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1527

Author(s):

Magdalena Woźniak ◽

Izabela Ratajczak ◽

Dawid Wojcieszak ◽

Agnieszka Waśkiewicz ◽

Kinga Szentner ◽

...

Keyword(s):

Structural Characterization ◽

Biogas Production ◽

Structural Parameters ◽

C:N Ratio ◽

Crystallinity Index ◽

Degree Of Crystallinity ◽

Cellulose Content ◽

X Ray Diffraction ◽

Maize Stover

In the last decade, an increasingly common method of maize stover management is to use it for energy generation, including anaerobic digestion for biogas production. Therefore, the aim of this study was to provide a chemical and structural characterization of maize stover fractions and, based on these parameters, to evaluate the potential application of these fractions, including forbiogas production. In the study, maize stover fractions, including cobs, husks, leaves and stalks, were used. The biomass samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction and analysis of elemental composition. Among all maize stover fractions, stalks showed the highest C:N ratio, degree of crystallinity and cellulose and lignin contents. The high crystallinity index of stalks (38%) is associated with their high cellulose content (44.87%). FTIR analysis showed that the spectrum of maize stalks is characterized by the highest intensity of bands at 1512 cm−1 and 1384 cm−1, which are the characteristic bands of lignin and cellulose. Obtained results indicate that the maize stover fraction has an influence on the chemical and structural parameters. Moreover, presented results indicate that stalks are characterized by the most favorable chemical parameters for biogas production.

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Cr-Substituted Mesoporous Aluminophosphate Molecular Sieve: Synthesis, Characterization, Crystallization Kinetics and Catalytic Activity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.316-317.1018 ◽

2013 ◽

Vol 316-317 ◽

pp. 1018-1023

Author(s):

Xin Zhu Li ◽

Ji Shi Zhang

Keyword(s):

Activation Energy ◽

Catalytic Activity ◽

Crystal Growth ◽

Crystallization Kinetics ◽

Molecular Sieve ◽

Arrhenius Equation ◽

Degree Of Crystallinity ◽

Tert Butylhydroperoxide ◽

Growth Activation ◽

Cr Map

Cr-substituted mesoporous aluminophosphate molecular sieve (Cr-MAP) was synthesized and characterized. Crystallization kinetics curves measured as an index to the relative degree of crystallinity, according to the Arrhenius equation to calculate the apparent nucleation activation energy and crystal growth activation energy of Cr-MAP, which was 63.7 and 14.7 kJ• mol-1, respectively. Cr-MAP had highly catalytic activity for fabricating acetophenone by selectively oxizing ethylbenzene. Using tert-butylhydroperoxide as oxidant and chlorobenzene as solvent at 100 °C for 8 h, acetophenone selectivity, acetophenone yield and ethylbenzene conversion reaches 85.4, 62.2 and 72.8 %, respectively.

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Impact of Macrodiols on the Morphological Behavior of H12MDI/HDO-Based Polyurethane Elastomer

Polymers ◽

10.3390/polym13132060 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2060

Author(s):

Shazia Naheed ◽

Mohammad Zuber ◽

Mahwish Salman ◽

Nasir Rasool ◽

Zumaira Siddique ◽

...

Keyword(s):

Molecular Weight ◽

Contact Angle ◽

Chain Length ◽

Microphase Separation ◽

Soft Segment ◽

Group Identification ◽

Degree Of Crystallinity ◽

Polyurethane Elastomers ◽

Hard Segments ◽

Morphological Behavior

In this study, we evaluated the morphological behavior of polyurethane elastomers (PUEs) by modifying the soft segment chain length. This was achieved by increasing the soft segment molecular weight (Mn = 400–4000 gmol−1). In this regard, polycaprolactone diol (PCL) was selected as the soft segment, and 4,4′-cyclohexamethylene diisocyanate (H12MDI) and 1,6-hexanediol (HDO) were chosen as the hard segments. The films were prepared by curing polymer on Teflon surfaces. Fourier transform infrared spectroscopy (FTIR) was utilized for functional group identification in the prepared elastomers. FTIR peaks indicated the disappearance of −NCO and −OH groups and the formation of urethane (NHCOO) groups. The morphological behavior of the synthesized polymer samples was also elucidated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The AFM and SEM results indicated that the extent of microphase separation was enhanced by an increase in the molecular weight of PCL. The phase separation and degree of crystallinity of the soft and hard segments were described using X-ray diffraction (XRD). It was observed that the degree of crystallinity of the synthesized polymers increased with an increase in the soft segment’s chain length. To evaluate hydrophilicity/hydrophobicity, the contact angle was measured. A gradual increase in the contact angle with distilled water and diiodomethane (38.6°–54.9°) test liquids was observed. Moreover, the decrease in surface energy (46.95–24.45 mN/m) was also found to be inconsistent by increasing the molecular weight of polyols.

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