scholarly journals Evaluation of the Mechanical and Biocidal Properties of Lapacho from Tabebuia Plant as a Biocomposite Material

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4241
Author(s):  
Magdalena Stepczyńska ◽  
Alona Pawłowska ◽  
Krzysztof Moraczewski ◽  
Piotr Rytlewski ◽  
Andrzej Trafarski ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Antibacterial Activity ◽  
Physicochemical Properties ◽  
Research Study ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Bacterial Mortality ◽  
Current State ◽  
Biocomposite Material ◽  
Biocidal Properties

The aim of this article is to discuss in detail the physicochemical properties of polylactide (PLA) reinforced by cortex fibers, which may cause bacterial mortality and increased biodegradation rates. PLA biocomposites containing cortex Lapacho fibers from Tabebuia (1–10 wt %) were prepared by extrusion and injection moulding processes. The effects of Lapacho on the mechanical and biocidal properties of the biocomposites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetry (TG), and the method of evaluating the antibacterial activity of antibacterial treated according to the standard ISO 22196:2011. It also presented the effects of Lapacho on the structural properties and biodegradation rates of biocomposites. This research study provides very important results complementing the current state of knowledge about the biocidal properties of Lapacho from Tabebuia plants and about cortex-reinforced biocomposites.

scholarly journals Combined thermal analysis of plant oils

2021 ◽  
Author(s):  
Kinga Tamási ◽  
Kálmán Marossy
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Low Temperature ◽  
Glassy State ◽  
Mechanical Analysis ◽  
Plant Oils ◽  
Scanning Calorimetry ◽  
Natural Plant ◽  
The Moment ◽  
Current Reversal

AbstractThe paper deals with the study of seven selected natural plant oils. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermally stimulated discharge (TSD) methods were used. It has been found that most of the oils tested are in a glassy state at low temperature and have multiple transitions in the low temperature range. DSC shows complex melting-like processes or glass transition. For both DMA and TSD, the scaffold supportive method was used and found as a suitable one. DMA and TSD proved more sensitive than DSC and revealed at least two transitions between − 120 and − 40 °C. In the case of three oils (argan, avocado and sunflower), current reversal was observed by TSD; this symptom cannot be fully explained at the moment.

Physico Chemical Characterization of Nanofibrous Poly(Ε-Caprolactone) Electrospun Templates for Cell Adhesion

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2689-2694
Author(s):  
Karla A. Gaspar-Ovalle ◽  
Juan V. Cauich-Rodriguez ◽  
Armando Encinas
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Cell Adhesion ◽  
Tensile Modulus ◽  
Chemical Characterization ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Physico Chemical ◽  
Static Water

ABSTRACTNanofibrous mats of poly ε-caprolactone (PCL) were fabricated by electrospinning. The nanofiber structures were investigated and characterized by scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, static water-contact-angle analysis and mechanical properties. The results showed that the nanofibrous PCL is an ideal biopolymer for cell adhesion, owing to its biocompatibility, biodegradability, structural stability and mechanical properties. Differential scanning calorimetry results showed that the fibrous structure of PCL does not alter its crystallinity. Studies of the mechanical properties, wettability and degradability showed that the structure of the electrospun PCL improved the tensile modulus, tensile strength, wettability and biodegradability of the nanotemplates. To evaluate the nanofibrous structure of PCL on cell adhesion, osteoblasts cells were seeded on these templates. The results showed that both adhesion and proliferation of the cells is viable on these electrospun PCL membranes. Thus electrospinning is a relatively inexpensive and scalable manufacturing technique for submicron to nanometer diameter fibers, which can be of interest in the commodity industry.

Influence of different surface-coated carbon fibers on the properties of the poly(phenylene sulfide) composites

2018 ◽  
Vol 53 (8) ◽  
pp. 1123-1132 ◽  
Author(s):  
Bedriye Ucpinar ◽  
Ayse Aytac
Keyword(s):  
Differential Scanning Calorimetry ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Mechanical Analysis ◽  
Fiber Reinforced ◽  
Scanning Calorimetry ◽  
Carbon Fiber Reinforced ◽  
Coated Carbon ◽  
Scanning Electron ◽  
Phenylene Sulfide

This paper aims to study the effect of different surface coatings of carbon fiber on the thermal, mechanical, and morphological properties of carbon fiber reinforced poly(phenylene sulfide) composites. To this end, unsized and different surface-coated carbon fibers were used. Prepared poly(phenylene sulfide)/carbon fiber composites were characterized by using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, tensile test, dynamic mechanical analysis, and scanning electron microscopy. Tensile strength values of the surfaced-coated carbon fibers reinforced poly(phenylene sulfide) composites are higher than the unsized carbon fiber reinforced poly(phenylene sulfide) composite. The highest tensile strength and modulus values were observed for the polyurethane-coated carbon fiber reinforcement. Dynamic mechanical analysis studies indicated that polyurethane-coated carbon fiber reinforced composite exhibited higher storage modulus and better adhesion than the others. Differential scanning calorimetry results show that melting and glass transition temperature of the composites did not change significantly. Scanning electron microscopic studies showed that polyurethane and epoxy-coated carbon fibers exhibited better adhesion with poly(phenylene sulfide).

Novel shape-memory polyurethane fibers for textile applications

2018 ◽  
Vol 89 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Míriam Sáenz-Pérez ◽  
Tariq Bashir ◽  
José Manuel Laza ◽  
Jorge García-Barrasa ◽  
José Luis Vilas ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shape Memory ◽  
Tensile Testing ◽  
Melt Spinning ◽  
Mechanical Analysis ◽  
Knitted Fabric ◽  
Scanning Calorimetry ◽  
Moisture Management ◽  
Potential Applications ◽  
Shape Memory Polyurethane

In this work, thermoresponsive shape-memory polyurethane (SMPU) fibers were produced by melt spinning from different SMPU pellets. Afterwards, the knitted fabric samples were prepared by the obtained fibers. Some of the SMPUs used were synthesized previously in our laboratory whereas a commercial one, named DIAPLEX MM4520, was also evaluated in order to carry out comparative studies. All the SMPUs were characterized by different techniques, such as thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Moreover, the shape-memory capabilities of the fabrics were measured by thermo-mechanical analysis. The obtained results show that the synthesized SMPUs could be attractive candidates for potential applications such as breathable fabrics or moisture-management textiles.

scholarly journals Examining the Influence of Re–Used Nanofiller—Pyrolyzed Montmorillonite, on the Thermal Properties of Polypropylene–Based Engineering Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2636
Author(s):  
Tomasz M. Majka ◽  
Oskar Bartyzel ◽  
Konstantinos N. Raftopoulos ◽  
Joanna Pagacz ◽  
Krzysztof Pielichowski
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Control Sample ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Stabilization Effect ◽  
Polypropylene Melt ◽  
Better Than

Pyrolysis of the polypropylene/montmorillonite (PP/OMMT) nanocomposites allows for recovery of the filler that can be then re–used to produce PP/pyrolyzed MMT (PMMT) nanostructured composites. In this work, we discuss the thermal properties of PP/PMMT composites investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It has been found that effect of PMMT (5 wt. % and 10 wt. %) on matrix thermal stability occurs at temperatures above 300 °C. Addition of 5 wt. % and 10 wt. % of PMMT into polypropylene system gave good stabilization effect, as confirmed by the overall stabilization effect (OSE) values, which increased by 4% and 7%, respectively, compared to the control sample (PP). Interestingly, the presence of 1 wt. % and 3 wt. % of pyrolyzed clay stabilizes the system better than the same concentrations of organoclay added into polypropylene melt. DSC data revealed that pyrolyzed clay has still the same tendency as organoclay to enhance formation of the α and β crystalline PP phases only. The pyrolyzed MMT causes an improvement of the modulus in the glassy as well as rubbery regions, as confirmed by DMA results.

scholarly journals Stepwise Glucoheptoamidation of Poly(Amidoamine) Dendrimer G3 to Tune Physicochemical Properties of the Potential Drug Carrier: In Vitro Tests for Cytisine Conjugates

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 473 ◽  
Author(s):  
Anna Czerniecka-Kubicka ◽  
Piotr Tutka ◽  
Marek Pyda ◽  
Małgorzata Walczak ◽  
Łukasz Uram ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Physicochemical Properties ◽  
Drug Carrier ◽  
Human Fibroblasts ◽  
Pamam Dendrimer ◽  
In Vitro Tests ◽  
Scanning Calorimetry ◽  
Ζ Potential ◽  
Cell Accumulation

Third-generation poly(amidoamine) dendrimer (PAMAM) was modified by stepwise primary amine group amidation with d-glucoheptono-1,4-lactone. The physicochemical properties of the conjugates—size, ζ potential in lysosomal pH 5 and in neutral aqueous solutions, as well as intramolecular dynamics by differential scanning calorimetry—were determined. Internalization and toxicity of the conjugates against normal human fibroblasts BJ were monitored in vitro in order to select an appropriate carrier for a drug delivery system. It was found that initial glucoheptoamidation (up to 1/3 of amine groups of neat dendrimers available) resulted in increase of conjugate size and ζ potential. Native or low substituted dendrimer conjugates accumulated efficiently in fibroblast cells at nontoxic 1 µM concentration. Further substitution of dendrimer caused consistent decrease of size and ζ potential, cell accumulation, and toxicity. All dendrimers are amorphous at 36.6 °C as determined by differential scanning calorimetry (DSC). The optimized dendrimer, half-filled with glucoheptoamide substituents, was applied as carrier bearing two covalently attached cytisine molecules: a rigid and hydrophobic alkaloid. The conjugate with 2 cytisine and 16 glucoheptoamide substituents showed fast accumulation and no toxicity up to 200 µM concentration. The half-glucoheptoamidated PAMAM dendrimer was selected as a promising anticancer drug carrier for further applications.

scholarly journals Application of Differential Scanning Calorimetry (DSC) and Modulated Differential Scanning Calorimetry (MDSC) in Food and Drug Industries

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 5 ◽  
Author(s):  
César Leyva-Porras ◽  
Pedro Cruz-Alcantar ◽  
Vicente Espinosa-Solís ◽  
Eduardo Martínez-Guerra ◽  
Claudia I. Piñón-Balderrama ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermomechanical Analysis ◽  
Mechanical Analysis ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Transition Issues

Phase transition issues in the field of foods and drugs have significantly influenced these industries and consequently attracted the attention of scientists and engineers. The study of thermodynamic parameters such as the glass transition temperature (Tg), melting temperature (Tm), crystallization temperature (Tc), enthalpy (H), and heat capacity (Cp) may provide important information that can be used in the development of new products and improvement of those already in the market. The techniques most commonly employed for characterizing phase transitions are thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), and differential scanning calorimetry (DSC). Among these techniques, DSC is preferred because it allows the detection of transitions in a wide range of temperatures (−90 to 550 °C) and ease in the quantitative and qualitative analysis of the transitions. However, the standard DSC still presents some limitations that may reduce the accuracy and precision of measurements. The modulated differential scanning calorimetry (MDSC) has overcome some of these issues by employing sinusoidally modulated heating rates, which are used to determine the heat capacity. Another variant of the MDSC is the supercooling MDSC (SMDSC). SMDSC allows the detection of more complex thermal events such as solid–solid (Ts-s) transitions, liquid–liquid (Tl-l) transitions, and vitrification and devitrification temperatures (Tv and Tdv, respectively), which are typically found at the supercooling temperatures (Tco). The main advantage of MDSC relies on the accurate detection of complex transitions and the possibility of distinguishing reversible events (dependent on the heat capacity) from non-reversible events (dependent on kinetics).

Thermal and Mechanical Properties of Cyclized Polybutadiene Dielectrics

1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Infrared Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
The Difference ◽  
Thermal Mechanical Analysis ◽  
Lower Glass Transition Temperature

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.

Dynamic Mechanical and Crystallization Properties of PTT/EPDM-g-MA/OMMT Blends

2012 ◽  
Vol 466-467 ◽  
pp. 23-26
Author(s):  
Kun Yan Wang ◽  
Ying Ye ◽  
Xiao Qing Zhu ◽  
Feng Cao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Melting Point ◽  
Maleic Anhydride ◽  
Dynamic Mechanical Analysis ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Ethylene Propylene ◽  
Dynamic Mechanical ◽  
Crystallization Properties ◽  
Trimethylene Terephthalate

The blends of poly(trimethylene terephthalate) (PTT) with ethylene-propylene-diene copolymer grafted with maleic anhydride (EPDM-g-MA) and organoclay(OMMT) were prepared by melt blending.The composites were characterized by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). The results suggest that the PTT is immiscible with EPDM-g-MA when OMMT was added to the blends. Strorage modulus of the PTT/EPDM-g-MA/OMMT are higher than those of pure PTT. The melting point of pure PTT and blends was almost constant. The crystallinity of the blends with OMMT were higher than that of pure PTT.

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