Polarized Light Optical Microscopy Research Articles

Effect of Nano Spinel Ferrites Co0.9Cu0.1Fe2O4 on Non-Isothermal Cold Crystallization Behaviours and Kinetics of Its Composites with Polylactic Acid.

Nanoparticles of spinel ferrites with a composition of Co0.9Cu0.1Fe2O4 (AM NPs) were effectively synthesized via a hydrothermal route. The structure of ferrite nanoparticles was characterized with X-ray diffraction, which showed a single cubic spinel phase. Energy-dispersive X-ray (EDX) spectroscopy and field emission-scanning electron microscopy (FE-SEM) were employed to analyse elemental composition and surface morphology, respectively. Moreover, the effects of the Co0.9Cu0.1Fe2O4 on the morphology of [PLA = polylactic acid] nanocomposites were examined through polarized light optical microscopy (POM) and X-ray diffraction (XRD). The thermal behaviours for tested samples were studied through [DSC = differential scanning calorimetry] and [TGA = thermal gravimetric analysis]. A great number of minor PLA spherulites were detected using POM in the presence of the Co0.9Cu0.1Fe2O4 ceramic magnetic nanoparticles (AM), increasing with AM nanoparticle contents. X-ray diffraction (XRD) analysis showed that the presence of nanoparticles led to an increase in the intensity of diffraction peaks. The DSC findings implied that the crystallization behaviours for the efficient PLA as well as its nanocomposites were affected by the addition of AM nanoparticles. They act as efficient nucleating agents because they shift the temperature of crystallization to a lower value. The Avrami models were used to analyse kinetics data. The experimental data were well described using the Avrami method for all samples tested. The addition of AM to the PLA matrix resulted in a decrease in the crystallization half-time t1/2 values, indicating a faster crystallization rate. TGA data showed that the occurrence of AM nanoparticles decreased the thermal stability of PLA.

CHARACTERIZATION OF EARTH, LIME, AND GYPSUM MORTARS IN THE CONSTRUCTIONS OF THE 16TH, 17TH, AND 18TH CENTURIES

The historical mortars of three ecclesiastical assets of the Colonial Quito were analyzed, which by 1978 was declared as heritage by UNESCO. The emblematic works of Jesuits, Dominicans, and Franciscans, built between the 16th to 18th centuries have multiple constructive stages and interventions of which there is no technical record because of the historical and present space of worship, living and religious museum of Quito. The objective of the lining mortars characterization is to provide the clear information of the composition of the analyzed samples for better understand the constructive chronology of the churches and to determine which earth, lime, gypsum, etc. mortar was used frequently according to the epoch and religious order. A total of 48 samples of lining mortars of the interior and exterior of the temples were examined, with the protocols and norms on non-destructive essays suggested by the research team. The analysis comprising stereomicroscopy studies that were complemented with mineral characterization and quantitative analysis by X-ray diffraction, as well as polarized light optical microscopy and scanning electron microscopy with microanalysis of the samples, among others. The results in the laboratory allowed us to demonstrate the existence of earth mortars, lime and gypsum bastards, and gypsum mortars with carbonate aggregate, those elements have volcanic and metamorphic volcanic mineralogical composition, this allowed us to date into the constructive stages registered in the church. The results in the laboratory allowed us to demonstrate the existence of earth mortars, lime and gypsum bastards, and gypsum mortars with carbonate aggregate, those elements have volcanic and metamorphic volcanic mineralogical composition, this allowed us to date into the constructive stages registered in the church

Non-Linear Optical Activity of Chiral Bipyrimidine-Based Thin Films.

An original series of bipyrimidine-based chromophores featuring alkoxystyryl donor groups bearing short chiral (S)-2-methylbutyl chains in positions 4, 3,4 and 3,5, connected to electron-accepting 2,2-bipyrimidine rings, has been developed. Their linear and non-linear optical properties were studied using a variety of techniques, including one- and two-photon absorption spectroscopy, fluorescence measurements, as well as Hyper-Rayleigh scattering to determine the first hyperpolarizabilities. Their electronic and geometrical properties were rationalized by TD-DFT calculations. The thermal properties of the compounds were also investigated by a combination of polarized light optical microscopy, differential scanning calorimetry measurements and small-angle X-ray scattering experiments. The derivatives were found not to have mesomorphic properties, but to exhibit melting temperatures or cold crystallization behavior that enabled the isolation of well-organized thin films. The nonlinear optical properties of amorphous or crystalline thin films were studied by wide-field second harmonic generation and multiphoton fluorescence imaging, confirming that non-centrosymmetric crystal organization enables strong second and third harmonic generation. This new series confirms that our strategy of functionalizing 3D organic octupoles with short chiral chains to generate non-centrosymmetric organized thin films enables the development of highly second order nonlinear optical active materials without the use of corona-poling or tedious deposition techniques.

Formulating PBS/PLA/PBAT blends for biodegradable, compostable packaging: The crucial roles of PBS content and reactive extrusion

The use of biodegradable polymers such as Poly (lactic acid) (PLA), Poly(butylene succinate) (PBS), and Poly(butylene adipate-co-terephthalate) (PBAT) is constantly increasing to try to substitute non-biodegradable plastics. Blending is a viable option to improve the morphology and the mechanical and heat resistance properties of biodegradable polymers. Thus, in this work, a biodegradable and compostable PLA/PBAT blend was improved by adding PBS, leading to non-reactive, melt-mixed PLA/PBAT/PBS ternary blends. The PLA/PBAT ratio was fixed at 1:1, while the PBS varied from 0 to 40 wt%. Polarized Light Optical Microscopy (PLOM) imaging showed that micro-spherulitic PBS was localized at the interface between PLA and PBAT in the blend, acting as a compatibilizer, reducing the interfacial tension and refining the ternary blend's morphology. Consequently, the mechanical properties improved, such as the elongation at break, which increased from 70 to 300 %. However, these tertiary non-reactive blends were found to lack adequate rheological properties to be processed by blown film extrusion. Therefore, reactive blending was performed by adding peroxide and carbodiimide, leading to a finer morphology and improved rheological properties. Thus, these reactive blends were successfully processed by blown film extrusion. Two types of blown films were produced, Tubular and Champagne films (DDR/BUR ratio of 37.6 and 5.2, respectively). Both types of blown films exhibited adequate ductile mechanical properties for film packaging applications, as well as high seal strength and good thermal resistance. In addition, their specific mechanical properties were a function of blend composition and the degree of biaxial orientation produced during the extrusion-blowing process.

Influence of the hemisphere on Janus structures containing cyanobiphenyl units

ABSTRACT New Janus-type compounds were synthesised with two different hemispheres structures and properties. The structures contain cyanobiphenyl units linked with 3,4,5-tribenzyloxybenzene or 3,4,5-tridecyloxybenzene units. Also, the influence of the 1,3,4-thiadiazole heterocycle was studied. The mesomorphic properties were studied by differential scanning calorimetry, polarised light optical microscopy and thermal gravimetric analysis. The mesophases obtained depend on the structure of the hemispheres, even obtaining mesophases different from the initial ones. The new materials synthesised presented photoluminescent properties, which were studied in solution.

The stone artifacts of the National Archaeological Museum of Adria (Rovigo, Italy): a noteworthy example of heterogeneity

This paper reports on the results of the analyses of 56 stone samples from Roman and pre-Roman artifacts from the ancient town of Atria, currently preserved at the National Archaeological Museum of Adria. The city is located in the eastern Veneto lowlands, close to the Po River delta, and far from the main rock outcrops of the region. The objective of this research is to determine the provenance of the stones used in ancient Atria and their trade networks. The analytical techniques adopted include polarized-light optical microscopy (PLM), X-ray fluorescence (XRF), and quantitative phase analysis by X-ray powder diffraction (QPA-XRPD). The results reveal a widespread use of imported stones from the central-western territories of Veneto, primarily comprising trachyte from the Euganean Hills and the soft limestone Vicenza Stone from the Berici Hills/eastern Lessini Mounts. Rosso Ammonitico, Maiolica (Biancone) and Scaglia Rossa limestones are also documented. From neighbouring regions, the imported stone types include Aurisina limestone from the Trieste Karst and Istrian Stone. Sandstone was uniquely recognized in G. Popillius’s milestone. Moreover, advanced geochemical and mineralogical analyses performed on the Euganean trachytes allow tracking accurately the quarry sites, revealing an extensive exploitation of the main historical quarries of M. Oliveto, Monselice and M. Merlo, although some provenances from outcrops less systematically exploited were also detected. Notably, the use of rhyolite for manufacturing a pre-Roman gravestone provides new insights regarding the exploitation of Euganean stone resources before the Roman era.

Evaluation of experimental resin infiltrant containing nanohydroxyapatite on color stability and microhardness in demineralized enamel.

The aim of the study was to evaluate the effect of the addition of 10% nanohydroxyapatite in an experimental resin infiltrant on color stability and mineral loss. Bovine enamel blocks were randomized into five groups (n = 27/group): SE (sound enamel); ICL (initial caries lesion); I (Icon®); E (experimental infiltrant); EH (experimental infiltrant containing 10% nanohydroxyapatite). Color evaluation (n = 15) was performed and CIEL*a*b* values were obtained at points T0 (baseline), T1 (14days immersed on coffee solution), and T2 (28days immersed) and data were calculated ∆E00, ∆WID, ∆L*, ∆a*, and ∆b*. Cross-sectional microhardness (n = 12) was performed and lesion area (∆S) was calculated. Images were obtained with polarized light optical microscopy at 40 × magnification (n = 5). In color stability results, there was significant difference between time (14 and 28days); ICL demonstrated significant difference among treated groups in all measures (∆L*, ∆a*, ∆b*, ∆E00, ∆WID) regardless of time; I and E demonstrated similar behavior on those measures and EH differed from I in ∆L*. For ∆S, ICL group showed a significant difference compared to I and EH groups, but did not differ from E. The nanohydroxyapatite incorporation suggested an effective mineral recovery on initial caries lesion in depth; however, it showed high color variation, such as Icon. In terms of ∆S, I and EH had lower mineral loss, suggesting a reinforcement on initial caries lesion. Commercial and experimental infiltrants containing nanohydroxyapatite present low color stability and might reinforce mineral in initial caries lesion.

Eco-Innovative Concrete for Infrastructure Obtained with Alternative Aggregates and a Supplementary Cementitious Material (SCM)

Concrete is a heterogeneous material, one of the most widely used materials on the planet, and a major consumer of natural resources. Its carbon emissions are largely due to the extensive use of cement in its composition, which contributes to 7% of global CO2 emissions. Extraction and processing of aggregates is another source of CO2 emissions. Many countries have succeeded in moving from a linear economy to a circular economy by partially or fully replacing non-renewable natural materials with alternatives from waste recycling. One such alternative consists of partially replacing cement with supplementary cementitious materials (SCMs) in concrete mixes. Thus, this work is based on the experimental investigation of the fresh and hardened properties of road concrete in which crushed river aggregates were replaced with recycled waste aggregates of uncontaminated concrete. At the same time, partial replacement of cement with a SCM material in the form of glass powder improved the durability characteristics of this sustainable concrete. The microstructure and compositional features of the selected optimum mix have also been investigated using polarized light optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction by the Powder method (PXRD) for the qualitative analysis of crystalline constitutive materials.

Fractal Analysis of Four Xerogels Based on TEGylated Phenothiazine and Chitosan

The present article describes novel massive materials (in the solid phase) based on TEGylated phenothiazine and chitosan that possess great capability to recover mercury ions from constituent aqueous solutions. These were produced by chitosan hydrogelation accompanied by formyl subsidiary item of TEGylated phenothiazine, attended by lyophilization. The delineation and structure description of the obtained material or supramolecular assembly were realized by FTIR (Fourier transform infrared) spectroscopy, X-ray diffraction, and POM (Polarized Light Optical Microscopy). The morphology of their texture was kept under observation by SEM (Scanning Electron Microscopy). The obtained SEM images were evaluated by fractal analysis. The fractal parameters of interest were calculated, including the fractal dimension and lacunarity.

Organogel of Acai Oil in Cosmetics: Microstructure, Stability, Rheology and Mechanical Properties.

Organogel (OG) is a semi-solid material composed of gelling molecules organized in the presence of an appropriate organic solvent, through physical or chemical interactions, in a continuous net. This investigation aimed at preparing and characterizing an organogel from acai oil with hyaluronic acid (HA) structured by 12-hydroxystearic acid (12-HSA), aiming at topical anti-aging application. Organogels containing or not containing HA were analyzed by Fourier-transform Infrared Spectroscopy, polarized light optical microscopy, thermal analysis, texture analysis, rheology, HA quantification and oxidative stability. The organogel containing hyaluronic acid (OG + HA) has a spherulitic texture morphology with a net-like structure and absorption bands that evidenced the presence of HA in the three-dimensional net of organogel. The thermal analysis confirmed the gelation and the insertion of HA, as well as a good thermal stability, which is also confirmed by the study of oxidative stability carried out under different temperature conditions for 90 days. The texture and rheology studies indicated a viscoelastic behavior. HA quantification shows the efficiency of the HA cross-linking process in the three-dimensional net of organogel with 11.22 µg/mL for cross-linked HA. Thus, it is concluded that OG + HA shows potentially promising physicochemical characteristics for the development of a cosmetic system.

Microscopic and Small-/Wide-Angle Microbeam X-ray Analyses on Dendritic Crystals in Poly(butylene succinate)

A unique composite dendritic spherulite is detected in a specific crystallization temperature range (Tc = 60–78 °C), whose assembly is probed using microscopy techniques and powerful synchrotron X-ray microbeam analyses. Composite dendritic spherulites composed of feather-like and fern-like branches in poly(butylene succinate) (PBSu) crystallized with poly(ethylene oxide) diluent are analyzed on top surface morphologies correlating with interior-dissected assembly, concurrently through polarized-light optical microscopy, scanning electron microscopy, and synchrotron-radiation X-ray microbeam analysis. The feather-like branch is composed of fully edge-on crystal plates, while the fern-like branch is composed of flat-on crystal plates. These branches originate from a common nucleus with different growth rates. For the first time, the dendritic PBSu spherulite serves as a convenient model for understanding the mechanisms how edge-on and flat-on crystal orientations can alternate not only in a serial mode to form ring bands but also in a parallel mode to form straight dendrites. Morphology evidence and detailed microbeam techniques collectively prove that these discontinuous lamellar plates discretely and gradually tilt and bend to transform from a vertical to a horizontal crystal plate with a corresponding alteration in birefringence.

Cationized dialdehyde cellulose synthesized with deep eutectic-like solvents: Effects on sheet dewatering and mechanical properties when used as wet-end additive

The ability of cationized dialdehyde cellulose to improve the mechanical properties of paper was evaluated. The majority of cationized additives are synthesized by introducing cationic groups through chemical reactions. Here, cationized additives were produced in a more environmentally friendly manner by use of non-toxic and readily biodegradable deep eutectic-like solvent mixtures (DESs). The modified cellulose’s properties were characterized by FTIR, polarized-light optical microscopy, charge titrations, and SEM/EDX. The cationized additives were investigated as strength additives for papermaking. Three different amounts of cationic additive (2%, 5%, and 10%) were added to the pulp, and the properties of handsheets were studied. Because increasing the additive content can affect dewatering of the process, the dewatering capabilities of the pulps with additives were evaluated by Schopper-Riegler (°SR) value, water retention value (WRV), and vacuum dewatering. Finally, the recyclability of the DES was assessed in terms of cationization reaction efficiency and their effect on paper mechanical properties.

Phase transition behavior of pentylcyanobiphenyl liquid crystal containing n-dodecyl-2-hydroxy-1-naphthaldimine

The present work focuses on the phase transition behavior of a thermotropic liquid crystal incorporating a Schiff base having a terminal alkyl chain of 12 carbons, such as, n-dodecyl-2-hydroxy-1-naphthaldimine (SB). Given its interesting molecular structure, the SB was chosen as doping agent for a liquid crystal of cyano-biphenyl type, such as, 4-cyano-4′-n-pentyl-biphenyl (5CB). The study of the guest–host systems, at different concentrations of the solute, was performed using differential scanning calorimetry and UV–visible spectroscopy, equipped with the hot compartment. The fusion and the nematic – isotropic transition temperatures as well as the enthalpies ΔH 0 and entropies ΔS 0 variations of the 5CB-based systems were determined from their spectral data. The thermal properties and orientational order parameters were also determined for the pure and SB doped 5CB, as well as the activation energy for the guest system. The filamentary texture was observed by polarized light optical microscopy for both the pure and Schiff base-doped 5CB.

Curly morphology of β’-crystals of poly(butylene-2,6-naphthalate)

Crystallization of PBN at high temperature leads to growth of highly non-isometric β’-crystals, with their long and short dimensions being several µm and 10–20 nm, respectively. In the needle-like or lamellar crystals, molecular segments/stems are oriented parallel to their short dimension, as concluded from polarized-light optical microscopy (POM). In the early stage, the growth of β’-crystals is straight while in the later stages, when exceeding a critical length, distinct bending and circular growth occurs. These features cause an unusual appearance of the semicrystalline structure when viewed by POM. The spherulitic growth is uneven in the various directions of space, the spherulite surface appears frayed due to missing space-filling and reduced branching, and the finally curly crystal morphology yields a spotty decoration. The analysis of the morphology of β’-crystals of PBN is expected yielding an improved understanding of structure–property-relations, as these crystals may form at specific melt-processing conditions.

Effect of self-nucleation on the crystallization kinetics and the microstructure of polypropylene parts manufactured by Laser Powder Bed Fusion

Laser Powder Bed Fusion (LPBF) of thermoplastic polymers is an additive manufacturing (AM) technique experiencing a remarkable growth in the recent years. Nowadays the most widely used materials are polyamides (PA12, PA11…) but massively available LPBF-compatible polyolefin powders recently arrived on the market. The need of understanding the crystallization process for these new materials is essential and this was addressed in the present work. Isothermal and non-isothermal crystallization kinetics was investigated by differential scanning calorimetry and parts microstructure was analyzed using polarized light optical microscopy, scanning electron microscopy, transmission electron microscopy and wide-angle X-rays diffraction experiments. It was shown that it is important to consider the significant nucleating effect of the sub-surface layers solidification during the building stage. Indeed, half-crystallization times of the PP material are consistent with experimental observations and time range in LPBF only if crystallization occurs from a self-nucleated molten state. Evidence of the presence of nuclei were given thanks to microscopic and wide-angle X-rays diffraction (WAXD) techniques. Alternate patterns of very finely microstructured, oriented transcrystalline regions and isotropic spherulitic regions every 100 µm ( i.e. the layer thickness during printing) were highlighted.

Polymorphic structure in ultrasonic microinjection-molded poly(butylene-2,6-naphthalate)

The formation and distribution of different crystal forms in ultrasonic microinjection-molded poly(butylene 2,6-naphthalate) (PBN) samples prepared using different mold temperatures were investigated by microfocus wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized-light optical microscopy (POM). The relative fractions of liquid-crystalline (LC) mesophase, α-phase and β′-phase along the thickness direction of microinjection-molded samples were obtained via a decomposition of the WAXD curves. The results indicate that the mold temperature affects the formation of the LC mesophase and α-crystals, but not the formation of β′-crystals. Moreover, the LC mesophase and α-phase were detected in both skin and core regions of the microinjection-molded PBN samples, while the β′-crystals were only observed in the skin layer. In the heating process, the crystals in the core region and skin layer began to melt at temperatures of about 240 and 250 °C, respectively, which is consistent with the different thermal stabilities of the α- and β′-phases. It is inferred that the β′-phase is able to form under a certain high shear flow, implying that the polymorphic structure of injection-molded parts of PBN can be tailored by variation of the molding conditions. • PBN tensile bars were prepared using an ultrasonic microinjection-molding machine. • The LC mesophase and α-phase were detected in both skin and core regions. • The β′-crystals were only observed in the skin layer. • Formation of β′-phase is influenced more by the shear flow than by the cooling rate. • Polymorphic structure of PBN can be tailored by variation of the molding conditions.

Effect of the TrFE Content on the Crystallization and SSA Thermal Fractionation of P(VDF-co-TrFE) Copolymers.

In this contribution, we study the effect of trifluoro ethylene (TrFE) comonomer content (samples with 80/20, 75/25, and 70/30 VDF/TrFE molar ratios were used) on the crystallization in P(VDF-co-TrFE) in comparison with a PVDF (Poly(vinylidene fluoride)) homopolymer. Employing Polarized Light Optical Microscopy (PLOM), the growth rates of spherulites or axialites were determined. Differential Scanning Calorimetry (DSC) was used to determine overall crystallization rates, self-nucleation, and Successive Self-nucleation and Annealing (SSA) thermal fractionation. The ferroelectric character of the samples was explored by polarization measurements. The results indicate that TrFE inclusion can limit the overall crystallization of the copolymer samples, especially for the ones with 20 and 25% TrFE. Self-nucleation measurements in PVDF indicate that the homopolymer can be self-nucleated, exhibiting the classic three Domains. However, the increased nucleation capacity in the copolymers provokes the absence of the self-nucleation Domain II. The PVDF displays a monomodal distribution of thermal fractions after SSA, but the P(VDF-co-TrFE) copolymers do not experience thermal fractionation, apparently due to TrFE incorporation in the PVDF crystals. Finally, the maximum and remnant polarization increases with increasing TrFE content up to a maximum of 25% TrFE content, after which it starts to decrease due to the lower dipole moment of the TrFE defect inclusion within the PVDF crystals.

(PVDF)2(PEO)2 miktoarm star copolymers: Synthesis and isothermal crystallization leading to exclusive β-phase formation

In this work, we study how chain topology can induce different polymorphic behaviors in poly(vinylidene fluoride) (PVDF)-based materials. A linear PVDF precursor with two azido groups at the junction point, (PVDFx-N3)2 and three 4-miktoarm star copolymers (PVDFx)2-b-(PEOy)2 with two poly(ethylene oxide) (PEO) and two PVDF arms were synthesized and employed in this study. The amphiphilic miktoarm copolymers were prepared by a combination of anionic ring-opening polymerization, iodine transfer radical polymerization (ITP), and copper-catalyzed azide-alkyne cycloaddition (CuAAC). They have practically similar overall molar mass but different compositions, ideal for performing bulk morphology and crystallization investigations. The isothermal overall crystallization kinetics of the PVDF and PEO arms of the 4-miktoarm star copolymers and representative PEO and PVDF precursors was determined by Differential Scanning Calorimetry (DSC). The results indicate that the star arms crystallized faster than the equivalent precursors as the kinetics are dominated by nucleation effects. The phases formed by the PVDF components in the materials examined were analyzed by studying their melting behavior by DSC, their superstructural morphology by Polarized Light Optical Microscopy (PLOM), and the phase structure by Fourier Transform Infrared Spectroscopy (FTIR). The linear PVDF and (PVDF29-N3)2, exhibited α, β and γ-phases (with a majority of β-phase formation) during melting after isothermal crystallization. The ratio of the different phases depends on the crystallization temperature. An analysis of the multiple melting behavior indicated that the sample forms both α and β-phases initially, and the α-phase partially transforms into the γ-phase during isothermal crystallization when the temperature of crystallization increases. We found a remarkable behavior for the 4-miktoarm star copolymers, as the PVDF arms only form the ferroelectric β-phase when all three materials were isothermally crystallized regardless of the crystallization temperature employed. The presence of the polymorphism in the PVDF was detected by DSC, PLOM, and FTIR. Hence, we have shown that tailoring chain topology in PVDF copolymers can lead to exclusive β-phase formation, a path that can be exploited for future piezoelectric applications.

Biodegradable binary blends of poly (butylene succinate) or poly (ε-caprolactone) with poly (butylene succinate-ran-ε-caprolactone)copolymers: Crystallization behavior

Poly (butylene succinate) (PBS) and polycaprolactone (PCL) are two immiscible biocompatible and biodegradable polymers. Aiming to combine the properties of these biodegradable polymers, this work explores for the first time blending PBS or PCL with PBS-ran-PCL copolymers (BSxCLy) at 75/25, 50/50, and 25/75 wt% compositions, with various copolymer contents: BS78CL22, BS46CL54, and BS15CL85. The crystallization behavior of these novel binary blends was systematically studied with non-isothermal and isothermal differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), and simultaneous wide- and small-angle X-ray scattering (WAXS and SAXS). All the blends displayed a miscible character in the amorphous state, judging by a single glass transition temperature, and in the melt state (as indicated by SAXS), but their miscibility in the crystalline state depends on the specific blend. In both PBS/BS78CL22 and PCL/BS15CL85 evidences of co-crystallization between the matrix and the crystallizable fraction of the copolymer were found. However, high comonomer exclusion, higher in the BS15CL85 than in the BS78CL22, greatly affects blend miscibility. Thus, the results show that the PBS/BS78CL22 blend is miscible, in the crystalline state, at high PBS (homopolymer) content, i.e., 75/25 and 50/50 compositions, whereas its “counterpart”, the PCL/BS15CL85 displays partial miscibility, even for high PCL (homopolymer) content. For the 25/75 blends, i.e., copolymer-rich, the homopolymer addition favors the crystallization of the copolymer-rich component. Blending PBS or PCL with BS46CL54 leads to blends that exhibit a much lower miscibility in the crystalline state than the blends prepared with BS or CL-rich copolymers, independently of the composition. But, interestingly, a novel behavior is found, since the BS46CL54 copolymer can crystallize either in PBS type crystals or in PCL type crystals depending on the polymeric matrix (PCL or PBS). The PBS favors the crystallization of the BS component, while the PCL favors the crystallization of the CL component within the random copolymer. The crystallization behavior found in this work evidences the interactions of the PBS or PCL with the BSxCLy copolymer, representing a potential strategy to combine the properties of the PBS and PCL through blending.

Preparation of Nanostructured Graphene Oxide and Its Application in Drug Loading and Sustained Release

Nanostructured graphene oxide (GO) with long-range ordered lamellar or hexagonal structure were prepared by lyotropic liquid crystals (LLCs) templating strategy and used as anticancer drug carriers.