Ultra-Short Laser Surface Properties Optimization of Biocompatibility Characteristics of 3D Poly-ε-Caprolactone and Hydroxyapatite Composite Scaffolds

The use of laser processing for the creation of diverse morphological patterns onto the surface of polymer scaffolds represents a method for overcoming bacterial biofilm formation and inducing enhanced cellular dynamics. We have investigated the influence of ultra-short laser parameters on 3D-printed poly-ε-caprolactone (PCL) and poly-ε-caprolactone/hydroxyapatite (PCL/HA) scaffolds with the aim of creating submicron geometrical features to improve the matrix biocompatibility properties. Specifically, the present research was focused on monitoring the effect of the laser fluence (F) and the number of applied pulses (N) on the morphological, chemical and mechanical properties of the scaffolds. SEM analysis revealed that the femtosecond laser treatment of the scaffolds led to the formation of two distinct surface geometrical patterns, microchannels and single microprotrusions, without triggering collateral damage to the surrounding zones. We found that the microchannel structures favor the hydrophilicity properties. As demonstrated by the computer tomography results, surface roughness of the modified zones increases compared to the non-modified surface, without influencing the mechanical stability of the 3D matrices. The X-ray diffraction analysis confirmed that the laser structuring of the matrices did not lead to a change in the semi-crystalline phase of the PCL. The combinations of two types of geometrical designs—wood pile and snowflake—with laser-induced morphologies in the form of channels and columns are considered for optimizing the conditions for establishing an ideal scaffold, namely, precise dimensional form, mechanical stability, improved cytocompatibility and antibacterial behavior.

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Cement-Based Solidification/Stabilization of Soil Contaminated by Polycyclic Aromatic Hydrocarbons Using Organophilic Clay

10.21203/rs.3.rs-974704/v1 ◽

2021 ◽

Author(s):

Nima Heidarzadeh ◽

M. Jebeli ◽

S. Gitipour

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Removal Efficiency ◽

Aromatic Hydrocarbons ◽

Contaminated Soil ◽

Sem Analysis ◽

Absorption Capacity ◽

X Ray Diffraction ◽

The Matrix ◽

Polycyclic Aromatic ◽

Organophilic Clay

Abstract The solidification/stabilization (S/S) method is the most widely used to remediate all types of inorganic pollutants, which has not been developed for organic matters. In this research, the application of cement and organophilic clay (OC) was investigated for the S/S of contaminated soil by polycyclic aromatic hydrocarbons (PAHs). Pyrene, Acenaphthene, Benzo[a]Pyrene, and Benz[a]Anthracene were spiked in a soil specimen. X-ray diffraction analysis (XRD) indicated that OC has a considerable ability to absorb PAHs in its inter-laminar molecular spaces, unlike ordinary bentonite. Toxicity characteristic leaching procedure (TCLP) results showed that application of OC increased PAHs' removal efficiency from contaminated soil up to 80% on average compared to the use of cement only. Samples containing 30% cement and 30% OC with a 14-day curing time had the best removal efficiency. Also, the removal efficiency of heavier PAHs was lower than the lighter ones. Additionally, unconfined compressive strength (UCS) showed a linear descending by increasing OC's proportion. Scanning electron microscopy (SEM) analysis indicated that two reasons have effectively increased the PAHs' removal efficiency of solid samples: a) increasing the amount of OC that increases the PAHs absorption capacity, b) reducing the size of pores in the matrix reduces the pollutant leaching.

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Optical, Structural, and Dielectric Properties of Composites Based on Thermoplastic Polymers of the Polyolefin and Polyurethane Type and BaTiO3 Nanoparticles

Materials ◽

10.3390/ma14040753 ◽

2021 ◽

Vol 14 (4) ◽

pp. 753

Author(s):

M. Baibarac ◽

A. Nila ◽

I. Smaranda ◽

M. Stroe ◽

L. Stingescu ◽

...

Keyword(s):

Crystallization Process ◽

Weight Ratio ◽

Thermoplastic Elastomers ◽

Visible Spectral Range ◽

X Ray Diffraction ◽

Thermoplastic Polymers ◽

The Matrix ◽

Free Films ◽

Batio3 Nanoparticles ◽

Properties Of Composites

In this work, new films containing composite materials based on blends of thermoplastic polymers of the polyurethane (TPU) and polyolefin (TPO) type, in the absence and presence of BaTiO3 nanoparticles (NPs) with the size smaller 100 nm, were prepared. The vibrational properties of the free films depending on the weight ratio of the two thermoplastic polymers were studied. Our results demonstrate that these films are optically active, with strong, broad, and adjustable photoluminescence by varying the amount of TPU. The crystalline structure of BaTiO3 and the influence of thermoplastic polymers on the crystallization process of these inorganic NPs were determined by X-ray diffraction (XRD) studies. The vibrational changes induced in the thermoplastic polymer’s matrix of the BaTiO3 NPs were showcased by Raman scattering and FTIR spectroscopy. The incorporation of BaTiO3 NPs in the matrix of thermoplastic elastomers revealed the shift dependence of the photoluminescence (PL) band depending on the BaTiO3 NP concentration, which was capable of covering a wide visible spectral range. The dependencies of the dielectric relaxation phenomena with the weight of BaTiO3 NPs in thermoplastic polymers blends were also demonstrated.

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The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites

Polymers ◽

10.3390/polym13060890 ◽

2021 ◽

Vol 13 (6) ◽

pp. 890

Author(s):

Mateusz Barczewski ◽

Olga Mysiukiewicz ◽

Aleksander Hejna ◽

Radosław Biskup ◽

Joanna Szulc ◽

...

Keyword(s):

Impact Strength ◽

Mechanical Stability ◽

Thermomechanical Analysis ◽

Thermomechanical Properties ◽

Phenyl Isocyanate ◽

Sem Analysis ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Expanded Vermiculite ◽

Chain Extenders

In this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency of mechanochemical modification was evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The composites of PLA with three vermiculite types were prepared by melt mixing and subjected to mechanical, thermomechanical, thermal, and structural evaluation. The structure of composites containing a constant amount of the filler (20 wt%) was assessed using FTIR spectroscopy and SEM analysis supplemented by evaluating the final injection-molded samples’ physicochemical properties. Mechanical behavior of the composites was assessed by static tensile test and impact strength hardness measurements. Heat deflection temperature (HDT) test and dynamic thermomechanical analysis (DMTA) were applied to evaluate the influence of the filler addition and its functionalization on thermomechanical properties of PLA-based composites. Thermal properties were assessed by differential scanning calorimetry (DSC), pyrolysis combustion flow calorimetry (PCFC), and thermogravimetric analysis (TGA). The use of filler-reactive chain extenders (CE) made it possible to change the vermiculite structure and obtain an improvement in interfacial adhesion and more favorable filler dispersions in the matrix. This translated into an improvement in impact strength and an increase in thermo-mechanical stability and heat release capacity of composites containing modified vermiculites.

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Self-Reinforced Nylon 6 Composite for Smart Vibration Damping

Polymers ◽

10.3390/polym13081235 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1235

Author(s):

Bidita Salahuddin ◽

Rahim Mutlu ◽

Tajwar A. Baigh ◽

Mohammed N. Alghamdi ◽

Shazed Aziz

Keyword(s):

Matrix Material ◽

Nylon 6 ◽

Vibration Damping ◽

Vibration Energy ◽

Damping Factor ◽

Passive Vibration Control ◽

Reinforced Composite ◽

Coiled Structure ◽

The Matrix ◽

3D Printed

Passive vibration control using polymer composites has been extensively investigated by the engineering community. In this paper, a new kind of vibration dampening polymer composite was developed where oriented nylon 6 fibres were used as the reinforcement, and 3D printed unoriented nylon 6 was used as the matrix material. The shape of the reinforcing fibres was modified to a coiled structure which transformed the fibres into a smart thermoresponsive actuator. This novel self-reinforced composite was of high mechanical robustness and its efficacy was demonstrated as an active dampening system for oscillatory vibration of a heated vibrating system. The blocking force generated within the reinforcing coiled actuator was responsible for dissipating vibration energy and increase the magnitude of the damping factor compared to samples made of non-reinforced nylon 6. Further study shows that the appropriate annealing of coiled actuators provides an enhanced dampening capability to the composite structure. The extent of crystallinity of the reinforcing actuators is found to directly influence the vibration dampening capacity.

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Multi-Scale Studies of 3D Printed Mn–Na–W/SiO2 Catalyst for Oxidative Coupling of Methane

Catalysts ◽

10.3390/catal11030290 ◽

2021 ◽

Vol 11 (3) ◽

pp. 290

Author(s):

Tim Karsten ◽

Vesna Middelkoop ◽

Dorota Matras ◽

Antonis Vamvakeros ◽

Stephen Poulston ◽

...

Keyword(s):

Oxidative Coupling ◽

Oxidative Coupling Of Methane ◽

Operating Conditions ◽

Homogeneous Distribution ◽

Silica Support ◽

X Ray Diffraction ◽

Cross Sectional ◽

X Ray ◽

Multi Scale ◽

3D Printed

This work presents multi-scale approaches to investigate 3D printed structured Mn–Na–W/SiO2 catalysts used for the oxidative coupling of methane (OCM) reaction. The performance of the 3D printed catalysts has been compared to their conventional analogues, packed beds of pellets and powder. The physicochemical properties of the 3D printed catalysts were investigated using scanning electron microscopy, nitrogen adsorption and X-ray diffraction (XRD). Performance and durability tests of the 3D printed catalysts were conducted in the laboratory and in a miniplant under real reaction conditions. In addition, synchrotron-based X-ray diffraction computed tomography technique (XRD-CT) was employed to obtain cross sectional maps at three different positions selected within the 3D printed catalyst body during the OCM reaction. The maps revealed the evolution of catalyst active phases and silica support on spatial and temporal scales within the interiors of the 3D printed catalyst under operating conditions. These results were accompanied with SEM-EDS analysis that indicated a homogeneous distribution of the active catalyst particles across the silica support.

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Rapid Thermal Oxidation for Passivation of Porous Silicon

MRS Proceedings ◽

10.1557/proc-342-91 ◽

1994 ◽

Vol 342 ◽

Cited By ~ 6

Author(s):

I. BÁrsony ◽

J.G.E. Klappe ◽

É. Vázsonyi ◽

T. Lohner ◽

M. Fried

Keyword(s):

Porous Silicon ◽

Mechanical Stability ◽

Porous Substrate ◽

X Ray Diffraction ◽

X Ray ◽

Si Substrates ◽

Tetragonal Lattice ◽

Optical Heating ◽

Vertical Inhomogeneity ◽

Highly Porous

ABSTRACTChemical and mechanical stability of porous silicon layers (PSL) is the prerequisite of any active (luminescent) or passive (e.g. porous substrate) integrated applications. In this work X-ray diffraction (XRD) was used to analyze quantitatively the strain distribution obtained in different morphology PSL that were prepared on (100) p and p+Si substrates. Tetragonal lattice constant distortion can be as high as 1.4% in highly porous “as-prepared” samples. Incoherent optical heating RTO is governed by the absorption in the oxidized specimen. PSL show vertical inhomogeneity according to interpretation of spectroscopic ellipsometry (SE) data. Oxygen incorporation during RTO is controlled by specific surface (in p+ proportional, in p inversely proportional with porosity), while the developing compressive stress depends on pore size, and decreases with porosity in both morphologies.

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Preliminary Study of Alginates Extracted from Brown Algae (Sargassum sp.) Available in Madura Island as Composite Based Hydrogel Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.964.240 ◽

2019 ◽

Vol 964 ◽

pp. 240-245 ◽

Cited By ~ 1

Author(s):

Amaliya Rasyida ◽

Thalyta Rizkha Pradipta ◽

Sigit Tri Wicaksono ◽

Vania Mitha Pratiwi ◽

Yeny Widya Rakhmawati

Keyword(s):

Sodium Alginate ◽

Brown Algae ◽

Extraction Process ◽

Composition Analysis ◽

3D Printer ◽

X Ray Diffraction ◽

X Ray ◽

3D Printed ◽

Preliminary Study

Utilization of brown algae especially in Madura, where it’s close to Surabaya, only limited for food. This become a reference for developing and increasing the potential of this algae by extracting one of the ingredients, namely alginate. This paper deals with the characterization of sodium alginate extracted from sargassum sp. using modified-purified calcium routes. The extracted sodium alginate will be further used as composite hydrogel materials and compared with commercial sodium alginate. Hereafter, the synthesized composite is expected to be bio-ink for 3d printer. Chemical composition analysis were analyzed using X-Ray Fluorosense (XRF) followed by Fourier-transform infrared spectroscopy (FTIR) analysis to identify the functional group of composite and X-Ray Diffraction (XRD). Furthermore, viscosity bath is performed to compare the viscosity of extracted and commercial one. The result shows that modified-purified calcium routes in the extraction process of sodium alginate is desirable for improving their properties. Interestingly enough, with the goal of using it as bio-ink in 3d printed fabrication, the synthesized composite shows viscosity, 300 cSt, which meets the criteria for bio-ink in 3d printer.

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Lead inclusions in aluminium

MRS Proceedings ◽

10.1557/proc-157-247 ◽

1989 ◽

Vol 157 ◽

Cited By ~ 6

Author(s):

E. Johnson ◽

L. Gråbaek ◽

J. Bohr ◽

A. Johansen ◽

L. Sarholt-Kristensen ◽

...

Keyword(s):

Hysteresis Loop ◽

Room Temperature ◽

Noble Gas ◽

Melting Transition ◽

X Ray Diffraction ◽

Free Surfaces ◽

The Matrix ◽

Mean Size ◽

The Mean ◽

Spontaneous Phase

ABSTRACTIon implantation at room temperature of lead into aluminium leads to spontaneous phase separation and formation of lead precipitates growing topotactically with the matrix. Unlike the highly pressurised (∼ 1–5 GPa) solid inclusions formed after noble gas implantations, the pressure in the lead precipitates is found to be less than 0.12 GPa.Recently we have observed the intriguing result that the lead inclusions in aluminium exhibit both superheating and supercooling [1]. In this paper we review and elaborate on these results. Small implantation-induced lead precipitates embedded in an aluminium matrix were studied by X-ray diffraction. The (111) Bragg peak originating from the lead crystals was followed during several temperature cycles, from room temperature to 678 K. The melting temperature for bulk lead is 601 K. In the first heating cycle we found a superheating of the lead precipitates of 67 K before melting occurred. During subsequent cooling a supercooling of 21 K below the solidification point of bulk lead was observed. In the subsequent heating cycles this hysteresis at the melting transition was reproducible. The full width of the hysteresis loop slowly decreased to 62 K, while the mean size of the inclusions gradually increased from 14.5 nm to 27 nm. The phenomena of superheating and supercooling are thus most pronounced for the small crystallites. The persistence of the hysteresis loop over successive heating cycles demonstrate that its cause is intrinsic in nature, and it is believed that the superheating originates from the lack of free surfaces of the lead inclusions.

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Study on the Preparation and Performance of Carboxymethyl Chitosan Calcium and Carboxymethyl Chitosan Zinc Composite Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.852.1319 ◽

2016 ◽

Vol 852 ◽

pp. 1319-1324 ◽

Cited By ~ 1

Author(s):

Jing Li ◽

Chang Ping Wei ◽

Feng Ming Wang ◽

Li Dan Dong ◽

Shuang Sun ◽

...

Keyword(s):

Chloride Solution ◽

Water Solubility ◽

Chloroacetic Acid ◽

Sem Analysis ◽

Carboxymethyl Chitosan ◽

X Ray Diffraction ◽

Test Study ◽

Alkaline Conditions ◽

And Performance ◽

Better Than

In this paper,under alkaline conditions,with chloroacetic acid to modify chitosan,obtained carboxymethyl chitosan. At pH<7 conditions,the obtained carboxymethy chitosan respectively were reacted with calcium chloride solution,zinc chloride solution,after fully reacted,obtained carboxymethyl chitosan calcium and carboxymethyl chitosan zinc .Through infrared spectrum,X-ray diffraction and scanning electron microscopy (sem) analysis means,the structure of the products were characterized.Through the cutting of mice tail hemostasia test ,study the performance of the product.The results showed that the water solubility of carboxymethyl chitosan is better than that of chitosan and with excellent performance,and the performance of carboxymethyl chitosan calcium and carboxymethyl chitosan zinc was better than that of carboxymethyl chitosan.

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Development of Ternary Concrete Utilizing Agricultural Waste Material

10.21203/rs.3.rs-1107515/v1 ◽

2022 ◽

Author(s):

Sunita Kumari ◽

Dhirendra Singhal ◽

Rinku Walia ◽

Ajay Rathee

Keyword(s):

Rice Husk ◽

Rice Husk Ash ◽

Agricultural Waste ◽

Xrd Analysis ◽

Sem Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Concrete Mix ◽

Maize Cob

Abstract The present project proposes to utilize rice husk and maize cob husk ash in the cement to mitigate the adverse impact of cement on environment and to enhance the disposal of waste in a sustainable manner. Ternary concrete / MR concrete was prepared by using rise husk and maize cob ash with cement. For the present project, five concrete mixes MR-0 (Control mix), MR-1 (Rice husk ash 10% and MR-2.5%), MR-2 (Rice husk ash 10% and MR-5%), MR-3 (Rice husk ash 10% and MR-2.5%), MR-4 (Rice husk ash 10% and MR-2.5%) were prepared. M35 concrete mix was designed as per IS 10262:2009 for low slump values 0-25mm. The purpose is to find the optimum replacement level of cement in M35 grade ternary concrete for I – Shaped paver blocks.In order to study the effects of these additions, micro-structural and structural properties test of concretes have been conducted. The crystalline properties of control mix and modified concrete are analyzed by Fourier Transform Infrared Spectroscope (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results indicated that 10% Rice husk ash and 5% maize cob ash replaced with cement produce a desirable quality of ternary concrete mix having good compressive strength. The results of SEM analysis indicated that the morphology of both concrete were different, showing porous structure at 7 days age and become unsymmetrical with the addition of ashes. After 28 day age, the control mix contained more quantity of ettringite and became denser than ternary concrete. XRD analysis revealed the presence of portlandite in large quantity in controlled mix concrete while MR concrete had the partially hydrated particle of alite.

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