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Fabrication and Characterization of Fibrous Polycaprolactone Blended with Natural Green Tea Extracts Using Dual Solvent Systems

Mohd Rashid Ainatul Aqilah Binti, Jaganathan Saravana Kumar, Mohd Khudzari Ahmad Zahran, Ismail Ahmad Fauzi

Autex Research Journal

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2022

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Vol. 22, no. 4

404--410

EN

Nanofibrous dressings serve as an impeccable candidate in the management of wounds. Nanofibrous composites composed of polycaprolactone (PCL) and green tea using dual solvent systems at different ratios were fabricated through electrospinning. Pure PCL electrospun fibers along with composites were characterized by using scanning electron microscopy (SEM), wettability, water uptake analysis, and Fourier transform infrared spectroscopy (FTIR). SEM indicated that fibrous morphology and the diameter of PCL/green tea were smaller for chloroform/ dimethylformamide (DMF) (601 nm) and acetone/DMF (896 nm) than the pure PCL (673 nm and 1,104 nm for chloroform/DMF and acetone/DMF, respectively). Wettability of the fabricated composites was increased, and pure PCL fibers were slightly more hydrophobic (100°) than PCL/green tea (94°). Water uptake of the composites was enhanced compared with PCL significantly in acetone/DMF. The PCL/green tea nanofibrous wound dressing with enhanced physicochemical properties serves as an indispensable candidate for wound healing applications.

2

Impact of sintering temperature of hydroxyapatite on biological and physicochemical properties of alginate/HA biomaterials for regenerative medicine applications

Kazimierczak P., Syta E., Sochan J., Ginalska G., Przekora A.

Engineering of Biomaterials

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2018

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Vol. 21, no. 145

16--19

EN

Synthetic hydroxyapatite (HA) has gained considerable attention in regenerative medicine over recent decades. It is widely used as a bone filler and constituent of various biomaterials. HA possesses high biocompatibility, osteoconductivity, bioactivity, and bioresorbability. There are many different synthesis methods for HA described in the available literature. It is worth noticing that even slight changes in pH, reaction conditions or chemical composition during synthesis, can influence biological, physicochemical, and mechanical properties of resultant HA. The aim of this study was to evaluate the impact of sintering temperature of hydroxyapatite on biological and physicochemical properties of biomaterial made of alginate and hydroxyapatite granules. Alginate/HA material was produced using HA sintered at temperature of 800oC and HA sintered at temperature of 1150oC. Microstructure of the fabricated biomaterials was visualized by SEM. Osteoblast growth on the composites was assessed using human foetal osteoblast cell line. Moreover, ion reactivity, plasma/serum protein adsorption ability as well as water/NaCl uptake capability of the biomaterials were compared. Obtained results demonstrated that although both biomaterials had the same chemical composition, composite comprising hydroxyapatite sintered at temperature of 1150oC had smoother surface, revealed lower ion reactivity, was more favourable to osteoblast growth, and adsorbed lower amount of fibrinogen (which is known to promote biomaterial-induced inflammatory response), compared to the material made of hydroxyapatite sintered at temperature of 800oC. Thus, the type of bioceramics used for the production of biomaterials should be tailored to their specific applications – bone fillers for primarily in vivo implantation or in vitro cell-seeded scaffolds.

3

Pułapki w chemii cementu

Kurdowski W., Kądzielawski G.

Cement Wapno Beton

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2018

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R. 21/83, nr 4

333--340

PL

W artykule przeprowadzono dyskusję zagadnień z chemii cementu, które nie mają naukowego wyjaśnienia. Są to zagadnienia dotyczące hydratacji cementu, które łączą się ze zwiększeniem objętości zaczynu, pomimo że reakcje klinkierowych faz bezwodnych z wodą są związane zawsze z kontrakcją, czyli ze zmniejszeniem objętości produktów tych reakcji. Z dyskusji tej wynika, że pomimo znacznego rozwoju aparatury badawczej nie opracowano do dnia dzisiejszego podstaw naukowych w pełni rozwiązujących te problemy. Natomiast można stwierdzić, że jako uzasadnienie pozostają w dalszym ciągu procesy przebiegające w małej objętości „in situ” i ciśnienie osmotyczne. Poczyniono jednak znaczny postęp w odniesieniu do ettringitu zwracając uwagę na duże znaczenie wodorotlenku wapnia w tym procesie.

EN

In the paper some problems of cement chemistry which have no scientific basis was discussed. There are the problems concerning the hydration of cement, which are concerning the expansion of cement paste, despite that the clinker anhydrous phases reactions with water is always linked with contraction i.e. the decrease of the total volume of the products. From this discussion it is evident that, despite of the important progress of scientific equipment, the scientific basis explaining these problems was not elaborated till to day. It can be stated, that as explanation the process occurring in the small volume - "in situ" still remains as well as the osmotic pressure. However, the significant progress can be observed relative to ettringite, where among others the importance of Ca(OH)2 content in cement for ettringite expansion was found.

4

Modelowanie konsekwencji zmian opłat za pobór wód zaproponowanych w projekcie prawa wodnego

Berbeka K.

Gospodarka Wodna

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2017

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Nr 1

13--16

PL

Wprowadzona w Ramowej Dyrektywie Wodnej zasada zwrotu kosztu usług wodnych, przetransponowana do projektu nowej ustawy Prawo wodne, budzi gorące emocje, a nawet protesty różnych sektorów gospodarczych, spowodowane pojawiającymi się obawami i wątpliwościami co do, będących konsekwencją wdrażania tej zasady, wielkości wzrostu obciążeń finansowych. Jednym z najbardziej wrażliwych sektorów jest sektor gospodarki komunalnej - jego decyzje co do opłat skutkują na ogół wzrostem obciążeń gospodarstw domowych. Zaproponowano metodykę modelowania konsekwencji zmian opłat i sposobu ich naliczania w odniesieniu do tego sektora.

EN

The principle of water services cost reimbursement, introduced by the Framework Water Directive and transferred to the new Water Law bill, raises fierce emotions or even opposition of different economic sectors, aroused by fears and doubts regarding the increase of financial charges resulting from the implementation of this principle. One of the most sensitive sectors is the municipal economy sector - its decisions regarding the fees usually lead to increased household charges. The author proposes a methodology of modelling the consequences of change.

5

Influence of water on tribological properties of Wood-Polymer Composites

Mysiukiewicz O., Sterzyński T.

Archives of Mechanical Technology and Materials

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2017

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Vol. 37

79--84

EN

Utilization of ecological materials for appliances and products is one of the ways to achieve the goal of sustainability. Wood-polymer composites as a cheap, lightweight, durable and esthetic material has gained attention of scientists, engineers and consumers alike. Different kinds of polymeric matrices, plants used as the fillers, chemical of physical modifiers and processing technologies have already been widely studied. Nonetheless, surprisingly few information on Wood-Polymer Composites' tribology can be found. This paper is an attempt to fill this gap. Polypropylene- and poly(lactic acid)-based composites with varying wood flour content have been analyzed. The Brinell's hardness and coefficient of friction of the samples have been determined. In order to evaluate the influence of the moisture content on the tribological and mechanical properties of the composites, the samples have also been aged in water. The investigation revealed that polymeric composites filled with wood flour can present favorable coefficient of friction, compared to the neat resins. The results of our study can establish a good starting point for further investigation.

6

Rozszerzenie opłat za korzystanie z wód w Polsce

Berbeka K.

Gospodarka Wodna

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2015

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Nr 4

102--105

PL

Część przytoczonych w artykule rozwiązań była przygotowana przez autora na potrzeby prac studialnych prowadzonych w ramach badań zlecanych zarówno przez Krajowy Zarząd Gospodarki Wodnej, jak też i Ministerstwo Środowiska. Niniejszy tekst nie jest jednak oficjalną wykładnią wymienionych instytucji, zaś analiza wariantów podlega dynamicznej ewolucji w czasie, co wskazuje że zamieszczone symulacje są tylko jednymi z wielu możliwych opcji. Wszystkie rozważania dotyczą opłat za pobór wód, czyli za działanie prowadzące do zmiany dyspozycyjnej ilości zasobów.

EN

Some of the solutions presented in the article were prepared by the author for the purposes of studies carried out as part of the research ordered by the National Water Management Authority and the ministry of Environment. However, this text is not an official interpretation of the aforesaid institutions and the analysis of variants is subject to dynamic evolution in time, what indicates that the published simulations are only several of numerous possible options. All considerations refer to water uptake rates, i.e. fees for activities leading to changes in available resources.

7

Water induced evolution of dielectric and micro-structural properties of rice starch

Starzyk F., Chrzanowska A., Łużny W., Śniechowski M.

Archives of Materials Science and Engineering

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2009

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Vol. 39, nr 2

111-115

EN

Purpose: The purpose of this paper was to record and correlate mass (m) changes of population of rice starch micro-granules and their effective dielectric permittivity(ε'), as well as X-ray diffraction (XRD) changes observed in this system during humidification. Design/methodology/approach: Changes of mass of bio-polymeric-granular sample occurring during its exposition on saturated water vapour at room temperature, was recorded in the time. The ε' evolution was recorded by means of fringe-field-interdigit-dielectric spectroscopy (FFIDS) method. The temperature and relative humidity (RH %) of ambient atmosphere were controlled. Microstructure changes induced by water absorption were recorded by means of XRD diffractometer. Findings: The FFIDS method turned out to be sensitive technique to follow details of humidification process. Correlation between changes of ε' with simultaneously occurring mass increase can be a way to describe the humidification and drying processes of micro-granular bio-polymeric sample. The changes observed by means of XRD should enable to point the regions within granules structures where water molecules effectively interact with internal granules physical organisation on macromolecular level. Research limitations/implications: The time length of m(t) record was limited to ~11000 s in case of humidification by the nature of the process. The whole range of measurements was limited to max ~23 % of water uptake in order to prevent the molecular structure irreversible changes. Practical implications: The ε' monitoring of humidification turned out to be much more selective than only gravitational measurement of mass change. The correlation of both is giving new possibilities of modelling approach. The XRD observed changes within physical structures of rice starch granules seems to be of great importance for modelling of water behaviour in starch. Originality/value: For the first time humidification process was monitored in statu nascendi, without disturbing geometry of granules starch by means of ε' evolution record. It was enabled by application of interdigit comb capacitor as sensing unit. The high quality of XRD records enables a new insight into details of reversible swelling process of rise starch granules. Keywords: Bio-polymers; Micro-granular matter; Water uptake; Interdigit dielectrometry; Biological water

8

Humidification and drying of granular matter - correlation of mass change and effective dielectrometry

Starzyk F.

Archives of Materials Science and Engineering

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2008

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Vol. 34, nr 1

19-22

EN

Purpose: The purpose of this paper was to record and mutualy correlate mass changes of population of micro-granules of rye starch and effective dielectric permittivity of this system taking places during humidification and drying processes. Design/methodology/approach: Mass changes of biopolymeric mirco-granular sample occuring during its exposition on saturated water vapour at room temperature, was recorded in the time by means of precise torsional balance equipped with special chamber. The same was done in case of drying. Monitoring of effective dielectric permittivity was performed by means of interdigit comb capacitor and precise RLC meter equipped with PC program. Specially designed and constructed measuring chamber was applied to control temperature and relative humidity (RH %) of ambient sample atmosphere. Findings: Interdigit dielectric spectroscopy method turned out to be more sensitive technique to follow details of humidification as well as drying processes. Correlation of changes of effectife dielectric permittivity with simultaneously occurring mass increase or decrease can be a way to describe the humidification and drying processes of micro-granular biopolymeric sample. Practical implications: Effective dielectric permittivity monitoring of humidification and drying processes turned out to be much more selective than only gravitational measurement of mass change. For modeling purpose correlation of both is giving new possibilities of modelling approach. Originality/value: For the first time practically important humidification and drying processes were monitored in statu nascendi, without disturbing geometry of granules starch by means of ε' values evolution record. It was enabled by application of interdigit comb capacitor as sensing unit.