Materials science and engineering  physiochemical concepts, properties, and treaments  volume 2

Zaikov Haghi Zaikov Kłodzińska Haghi Kłodzińska Zaikov Haghi Kłodzińska Materials Science and Engineering Volume 2: Physiochemical Concepts, Properties, and Treatments Materials Science andand Engineering Materials Science Engineering This book hasVolume an2:important role in advancing non-classical materials on the macro and Volume Physiochemical Concepts, Properties, and Treatments 2: Physiochemical Concepts, Properties, and Treatments nanoscale The book provides original, theoretical, and important experimental results Some research uses methodologies often unfamiliar to some readers This book hasnon-routine anhas important role inrole advancing non-classical materials on theon macro and and This book an important in advancing non-classical materials the macro Furthermore papers novel applications of more familiar experimental techniques and nanoscale Theonbook provides original, theoretical, and important experimental results nanoscale The book provides original, theoretical, and important experimental results analyses of composite problems are included Some research uses non-routine methodologies often often unfamiliar to some readers Some research uses non-routine methodologies unfamiliar to some readers National Research Technological University, Kazan, Russia He ispublished also prolific author, National Research Technological University, He isaalso a prolific A K Haghi, PhD, is the author and editor of 65 books asKazan, well asRussia 1000 papers inauthor, researcher, and lecturer researcher, and lecturer various journals and conference proceedings Since 1983, he served as a professor at severalA universities He is is currently Editor-in-Chief of65 thebooks Journal of published K Haghi, PhD, the is author and editor of as wellasas 1000 papers in A K Haghi, PhD, the author and editor ofInternational 65 books well as published 1000 papers in Chemoinformatics and Chemical Engineering and Polymers Research Journal and onathe various journals and conference proceedings Since Since 1983, 1983, he served as a isprofessor at various journals and conference proceedings he served as professor at editorial boards of many international journals He is a member ofthe theInternational Canadian Research several universities He is currently Editor-in-Chief of theof International Journal of several universities He is currently Editor-in-Chief Journal of and Development Center of Sciences and Cultures (CRDCSC), Montreal, Quebec, Chemoinformatics and Chemical Engineering and Polymers Research Journal and isand on the Chemoinformatics and Chemical Engineering and Polymers Research Journal is on the Canada.editorial boards of many international journals He is aHe member of theof Canadian Research editorial boards of many international journals is a member the Canadian Research and Development CenterCenter ofatSciences and Cultures (CRDCSC), Montreal, Quebec, and Development of Institute Sciences and Cultures (CRDCSC), Montreal, Quebec, Ewa Kłodzińska, PhD, is working the for Engineering of Polymer Materials and Canada Canada Dyes, Torun, Poland, and investigates surface characteristics of biodegradable polymer material on Kłodzińska, the of zeta measurements She written several original Ewa PhD,potential is working at theat Institute forhas Engineering of Polymer Materials and and Ewabasis Kłodzińska, PhD, is working the Institute for Engineering of Polymer Materials articles,Dyes, monographs, and chapters in books for graduate students and scientists Dr Ewa Torun,Torun, Poland, and investigates surface characteristics of biodegradable polymer Dyes, Poland, and investigates surface characteristics of biodegradable polymer Kłodzińska ismaterial a member of boards ofmeasurements ISRN Analytical Chemistry and the material on theon basis of zetaofpotential She has several original theeditorial basis zeta potential measurements Shewritten has written several original International Journal of Chemoinformatics and Chemical Engineering (IJCCE) articles, monographs, and chapters in books for graduate students and scientists Dr Ewa articles, monographs, and chapters in books for graduate students and scientists Dr Ewa _ Kłodzińska is a member of editorial boards of ISRN Chemistry and the Kłodzińska is a member of editorial boards ofAnalytical ISRN Analytical Chemistry and the Also available: International Journal of Chemoinformatics and Chemical Engineering (IJCCE) International Journal of Chemoinformatics and Chemical Engineering (IJCCE) Materials Science and Engineering: _ _ Volume 1: Physical Process, Methods, and Models Also available: Also available: Editor: Materials Abbas Hamrang, PhD Science and Engineering: Materials Science and Engineering: Reviewers & Editorial Board Members: Gennady E Zaikov, DSc, and A K Haghi, PhD Volume 1: Physical Process, Methods, and Models Volume 1: Physical Process, Methods, and Models Hardbound ISBN: 978-1-77188-000-8 Editor: Abbas Hamrang, PhD Editor: Abbas Hamrang, PhD Reviewers & Editorial BoardBoard Members: Gennady E Zaikov, DSc, and K Haghi, PhD PhD Reviewers & Editorial Members: Gennady E Zaikov, DSc,A and A K Haghi, Hardbound ISBN: ISBN: 978-1-77188-000-8 Hardbound 978-1-77188-000-8 ISBN: 978-1-77188-009-1 90000 www.appleacademicpress.com 781771 880091 Tai ngay!!! Ban co the xoa dong chu nay!!! Materials Science and Engineering Mat Volume 2: Physiochemical Concepts, Properties, and Treatments Materials Science and Engineering Volume 2: Physiochemical Concepts, Properties, and Treatments Materials Science and Engineering and characteristics of varies materials and compounds • properties and characteristics of varies materials and compounds About •theproperties Editors • E more •Zaikov, moreDSc, is Head of the Polymer Division at the N M Emanuel Institute of Gennady Biochemical Physics, Russian Academy of Sciences, Moscow, Russia, and professor at AboutAbout the Editors the Editors Moscow State Academy of Fine Technology, Russia, as well asat professor Kazan Gennady E Zaikov, DSc,Chemical isDSc, Head of theof Polymer Division at the N M Emanuel Institute of of Gennady E Zaikov, is Head the Polymer Division the N M.atEmanuel Institute National Research Technological University, Kazan, Russia He is also a prolific author, Biochemical Physics, Russian Academy of Sciences, Moscow, Russia,Russia, and professor at Biochemical Physics, Russian Academy of Sciences, Moscow, and professor at researcher, and lecturer Moscow State State Academy of FineofChemical Technology, Russia,Russia, as wellasaswell professor at Kazan Moscow Academy Fine Chemical Technology, as professor at Kazan Volume 2: Physiochemical Concepts, Properties, and Treatments Furthermore papers on novel applications of more familiar experimental techniques and and Furthermore papers on novel applications of familiar experimental techniques The book includes new research and studies, including onmore ofof composite problems are included analyses of composite problems are included • theanalyses efficiency gas purification • theThe transport properties ofresearch films of chitosan-amikacin book includes new and studies, including on on The book includes new research and studies, including • operating conditions of clearing gas in a rotoklon • the efficiency of gas purification • the efficiency of gas of purification • properties and ofofvaries and compounds • the properties films of chitosan-amikacin • transport thecharacteristics transport properties ofmaterials films of chitosan-amikacin • more • operating conditions of clearing of gasofingas a rotoklon • operating conditions of clearing in a rotoklon Materials Science Materials Science Materials Science and Engineering and Engineering and Engineering Volume Volume 2 Concepts, Properties, Volume Physiochemical Concepts, Properties, Physiochemical Concepts, Properties, andPhysiochemical Treatments and Treatments and Treatments Editors Gennady E Zaikov, DSc Editors Editors A K Haghi, PhD Gennady E Zaikov, DSc DSc Gennady E Zaikov, Ewa Kłodzińska, PhD PhD PhD A K.A.Haghi, K Haghi, PhD PhD EwaEwa Kłodzińska, Kłodzińska, MATERIALS SCIENCE AND ENGINEERING Physiochemical Concepts, Properties, and Treatments Volume MATERIALS SCIENCE AND ENGINEERING Physiochemical Concepts, Properties, and Treatments Volume Edited by Gennady E Zaikov, DSc, A K Haghi, PhD, and Ewa Kłodzińska, PhD Apple Academic Press TORONTO NEW JERSEY CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 Apple Academic Press, Inc 3333 Mistwell Crescent Oakville, ON L6L 0A2 Canada © 2014 by Apple Academic Press, Inc Exclusive worldwide distribution by CRC Press an imprint of Taylor & Francis Group, an Informa business No claim to original U.S Government works Version Date: 20140501 International Standard Book Number-13: 978-1-4822-4093-1 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint Except as permitted under U.S Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers For permission to photocopy or use material electronically from this work, please access www copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400 CCC is a not-for-profit organization that provides licenses and registration for a variety of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com For information about Apple Academic Press product http://www.appleacademicpress.com ABOUT THE EDITORS Gennady E Zaikov, DSc Gennady E Zaikov, DSc, is Head of the Polymer Division at the N M Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia, and Professor at Moscow State Academy of Fine Chemical Technology, Russia, as well as Professor at Kazan National Research Technological University, Kazan, Russia He is also a prolific author, researcher, and lecturer He has received several awards for his work, including the Russian Federation Scholarship for Outstanding Scientists He has been a member of many professional organizations and is on the editorial boards of many international science journals A K Haghi, PhD A K Haghi, PhD, holds a BSc in urban and environmental engineering from University of North Carolina (USA); a MSc in mechanical engineering from North Carolina A&T State University (USA); a DEA in applied mechanics, acoustics and materials from Université de Technologie de Compiègne (France); and a PhD in engineering sciences from Université de Franche-Comté (France) He is the author and editor of 65 books as well as 1000 published papers in various journals and conference proceedings Dr Haghi has received several grants, consulted for a number of major corporations, and is a frequent speaker to national and international audiences Since 1983, he served as a professor at several universities He is currently Editor-in-Chief of the International Journal of Chemoinformatics and Chemical Engineering and Polymers Research Journal and on the editorial boards of many international journals He is also a member of the Canadian Research and Development Center of Sciences and Cultures (CRDCSC), Montreal, Quebec, Canada vi About the Editors Ewa Kłodzińska, PhD Ewa Kłodzińska, PhD, holds a PhD from Nicolaus Copernicus University, Faculty of Chemistry in Torun, Poland For ten years, she has been doing research on determination and identification of microorganisms using the electromigration techniques for the purposes of medical diagnosis Currently she is working at the Institute for Engineering of Polymer Materials and Dyes and investigates surface characteristics of biodegradable polymer material on the basis of zeta potential measurements She has written several original articles, monographs, and chapters in books for graduate students and scientists She has made valuable contributions to the theory and practice of electromigration techniques, chromatography, sample preparation, and application of separation science in pharmaceutical and medical analysis Dr Ewa Kłodzińska is a member of editorial boards of ISRN Analytical Chemistry and the International Journal of Chemoinformatics and Chemical Engineering (IJCCE) CONTENTS List of Contributors ix List of Abbreviations xiii List of Symbols xv Preface xix   Theoretical and an Experimental Research of Efficiency of Gas Purification in Rotoklon with Internal Circulation of a Liquid R R Usmanova and G E Zaikov   Lecture Note on Quantum-Chemical Mechanism and Synthesis of Selected Compounds 25 V A Babkin, V U Dmitriev, G A Savin, E S Titova, and G E Zaikov   Transport Properties of Films of Сhitosan—Amikacin 39 A S Shurshina, E I Kulish, and S V Kolesov   Research and Calculation of Operating Conditions of Clearing of Gas in a Rotoklon 55 R R Usmanova and G E Zaikov  5 The Effect of the Modification of Silica-Gelatin Hybrid Systems on The Properties of Some Paper Products 77 Przemysław Pietras, Zenon Foltynowicz, Hieronim Maciejewski, and Ryszard Fiedorow   An Influence of a Size and of the Size Distribution of Silver Nanoparticles on Their Surface Plasmon Resonance 93 A R Kytsya, O V Reshetnyak, L І Bazylyak, and Yu M Hrynda   An Influence of the Kinetic Parameters of the Reaction on a Size of Obtained Nanoparticles at the Reduction of Silver Ions by Hydrazine 105 A R Kytsya, Yu M Hrynda, L I Bazylyak, and G E Zaikov   Kinetics and Mechanism of Interaction between Ozone and Rubbers 115 V V Podmasteryev, S D Razumovsky, and G E Zaikov viii Contents   The Intercommunication of Fractal Analysis and Polymeric Cluster Medium Model 131 G V Kozlov, I V Dolbin, Jozef Richert, O V Stoyanov, and G E Zaikov 10 Polymers as Natural Composites: Structure and Properties 147 G V Kozlov, I V Dolbin, Jozef Richert, O V Stoyanov, and G E Zaikov 11 A Lecture Note on Cluster Model of Polymers Amorphous State Structure 203 G V Kozlov, I V Dolbin, Jozef Richert, O V Stoyanov, and G E Zaikov 12 Lecture Notes on Quantum Chemical Calculation 257 V A Babkin, G E Zaikov, D S Andreev, Yu Kalashnikova, Yu S Artemova, and D V Sivovolov 13 Research Methodologies on Physicochemical Properties and Structure of Graphitic Carbons 289 Heinrich Badenhorst 14 The Effect of Antioxidant Compounds on Oxidative Stress in Unicellular Aquatic Organisms 323 O V Karpukhina, K Z Gumargalieva, and A N Inozemtsev 15 A Lecture Note on Determination of Acid Force of Components of Synthesis of 1-[2-(О-Acetylmethyl)-3-О-Acetyl-2-Ethyl]Methyldichlorinephosphite 331 V A Babkin, V U Dmitriev, G A Savin, E S Titova, and G E Zaikov 16 Research Methodology on Design and Synthesis of Hydrogel-Based Supports 339 D Horák and H Hlídková Index 361 LIST OF CONTRIBUTORS D S Andreev Volgograd State Architect-build University, Sebrykov Department Michurin Street 21, Michailovka, Volgograd region, Russia Yu S Artemova Volgograd State Architect-build University, Sebrykov Department Michurin Street 21, Michailovka, Volgograd region, Russia V A Babki Volgograd State Architect-Build University Sebrykov Department, 403300 Michurin Street 21, Michailovka, Volgograd region, Russia, E-mail: sfi@reg.avtlg.ru Heinrich Badenhorst SARChI Chair in Carbon Materials and Technology, Department of Chemical Engineering, University of Pretoria, Lynwood Road, Pretoria, Gauteng, 0002, South Africa, P.O Box 66464, Highveld Ext 7, Centurion, Gauteng, 0169, South Africa, Tel.: +27 12 420 4173; Fax: +27 12 420 2516; E-mail: heinrich.badenhorst@up.ac.za L I Bazylyak Physical Chemistry of Combustible Minerals DepartmentInstitute of Physical−Organic Chemistry & Coal Chemistry named after L M LytvynenkoNational Academy of Sciences of Ukraine3а Naukova Str., Lviv–53, 79053, UKRAINEe–mail: andriy_kytsya@yahoo.com V U Dmitriev Volgograd State Architect-Build University Sebrykov Departament, 403300 Michurin Street 21, Michailovka, Volgograd region, Russia, E-mail: sfi@reg.avtlg.ru I V Dolbin Kabardino-Balkarian State University, Nal’chik – 360004, Chernyshevsky st., 173, Russian Federation, E-mail: I_dolbin@mail.ru K Z Gumargalieva N.N.Semenov Institute of Chemical Physics, RAS, Kosygin Street H Hlídková Institute of Macromolecular Chemistry Academy of Sciences of the Czech Republic, v.v.i Heyrovský Sq 2, 162 06 Prague 6, Czech Republic D Horák Institute of Macromolecular Chemistry Academy of Sciences of the Czech Republic, v.v.i Heyrovský Sq 2, 162 06 Prague 6, Czech Republic, E-mail: horak@imc.cas.cz Yu M Hrynda Physical Chemistry of Combustible Minerals Department, Institute of Physical Organic Chemistry and Coal Chemistry, NAS of Ukraine, 3a Naukova Str.Lviv, 79053, E-mail: Ukraineandriy_kytsya@ yahoo.com Research Methodology on Design and Synthesis 347 FIGURE 16.1  LVSEM micrographs showing frozen cross-section of PHEMA hydrogels prepared with (a) 41.4 vol.%, Run 1, (b) 40 vol.%, Run 3, and (c) 37.9 vol.% NaCl (250– 500 µm), Run PHEMA cross-linked with wt.% EDMA (relative to monomers) Interconnection of pores is of vital importance for cell ingrowths in future applications to tissue regeneration This feature was tested by the permeability of the whole hydrogels for different kinds of microspheres under two microscopic observations First, cross-sections of the frozen hydrogels filled with microspheres were observed in LVSEM Second, the water-swollen hydrogels were flowed through by a suspension of microspheres in water and their dried cross-sections were then viewed in HVSEM LVSEM showed water-swollen morphology of hydrogel constructs, which preserved due to their freezing in liquid nitrogen PHEMA Run prepared with neat NaCl (Fig 16.2a) was compared with Run obtained in the presence of NaCl together with a mixture of CyOH/DOH (Fig 16.2d) Addition of liquid porogens did not change the morphology; however, it increased the pore volume (from 0.21 to 0.45 mL CX/g, Table 16.1) and softness of the hydrogel As a result, it had a tendency to disintegrate during the washing procedure LVSEM of both PHEMA hydrogels filled with 2-µm ammonolyzed PGMA and 200–400 nm PANI microspheres is illustrated in Fig 16.2b, e and Fig 16.2c, f, respectively The micrographs showed undistorted morphology of the frozen hydrogels, but just a few microspheres and/or their agglomerates This was attributed to the fact that most of them were washed out during preparation of the sample for LVSEM 348 Materials Science and Engineering Vol FIGURE 16.2  LVSEM micrographs showing frozen cross-section of PHEMA constructs; (a–c) Run 3, (d–f) Run 8; (a, d) neat and filled with (b, e) 2-mm ammonolyzed PGMA and (c, f) 200–400 nm PANI microspheres Morphology of the PHEMA hydrogels flowed through by a suspension of microspheres was observed by HVSEM Figure 16.3 shows HVSEM micrographs of cross-sections of the top and bottom part of the hydrogels from Runs 3, and flowed through by a suspension of 8-µm sulfonated PSt microspheres in water While the microspheres flowed through the hydrogel construct from Run 3, they did not penetrate the ones from Run and prepared in the presence of a rather low content of NaCl (37.9 vol.%) At the same time, surface and inner structure of the hydrogels slightly differed Figure 16.4 shows HVSEM of the longitudinal section of the PHEMA scaffold obtained with cubic NaCl crystals as a porogen (Run 7) While Fig 16.4a shows the bulk, Fig 16.4b–d detailed sections Again, small superpores with an average size about 13 mm were in the walls between the large superpores, forming small channels through which water flowed To prove or exclude the interconnection of at least some pores, a suspension of 8-µm sulfonated polystyrene (PSt) microspheres in water was poured on the center of the topside of the gel While water flowed through the hydrogel bulk, the microspheres were retained on the surface of the hydrogel or penetrated only superficial layers due to the surface Research Methodology on Design and Synthesis 349 cracks (Fig 16.4 a,b) This confirmed that the pores of PHEMA hydrogels obtained with a low content of NaCl porogen (35.9 vol.%) did not communicate In contrast, Fig 16.5 presents longitudinal section of the PHEMA hydrogel from Run (both bulk and detailed) obtained with needle-like (NH4)2SO4 crystals as a porogen This porogen allowed formation of connected pores, which is explained by the needle-like structure of ammonium sulfate crystals that are linked to the gel structure At the same time, the crystals grew to large structures due to the presence of saturated (NH4)2SO4 solution in the feed As a result, long interconnected large superpores—channels—were formed This is documented in Fig 16.5a–d by the fact that suspension of 8-µm sulfonated PSt microspheres in water deposited in the center of the topside of the hydrogel flowed through The captured microspheres are well visible in Fig 16.5b–d They accumulated at the places of pore narrowing; their majority, however, was found on the bottom part of the hydrogel In such a way, the flow of water suspension of microspheres in the hydrogel was traced FIGURE 16.3  HVSEM micrographs of PHEMA hydrogels Run (a, d), Run (b, e) and Run (c, f) showing top (a–c) and bottom (d–f) of the hydrogels after the flow of a suspension of 8-µm sulfonated PSt microspheres in water 350 Materials Science and Engineering Vol FIGURE 16.4  Selected HVSEM micrographs showing longitudinal section of PHEMA hydrogel mm thick (Run 7) obtained with NaCl (250–500 µm) as a porogen after passing of a suspension of 8-µm sulfonated PSt microspheres in water (in the direction of the dotted line) (a) The whole cross-section through the hydrogel and selected details from (b) top, (c) center and (d) bottom PSt microspheres are denoted with white arrows Research Methodology on Design and Synthesis 351 FIGURE 16.5  Selected HVSEM micrographs showing longitudinal section of PHEMA hydrogel mm thick (Run 9) obtained with (NH4)2SO4 (100 ì 600 àm) as a porogen after passing of a suspension of 8-µm sulfonated PSt microspheres in water (in the direction of the dotted line) (a) The whole section through the construct and selected details from (b) top, (c) center and (d) bottom PSt microspheres are denoted with white arrows 352 Materials Science and Engineering Vol Mechanical properties of the porous constructs were sensitive to the concentration of porogen in the feed Hydrogels with lower contents of NaCl and therefore higher proportion of PHEMA had thicker walls between the pores and were more compact allowing increased swelling of polymer chains in water Two PHEMA hydrogels with the highest contents of NaCl in the feed (41.4 vol.%—Run and 40.8 vol.%—Run 2) possessing thin polymer walls between large superpores easily disintegrated as well as hydrogel prepared using (NH4)2SO4 (42.3 vol.%—Run 9) 16.3.2  CHARACTERIZATION OF POROSITY BY SOLVENT REGAIN Dependences of porosity of PHEMA hydrogels calculated from water or cyclohexane regain and also from mercury porosimetry on NaCl content in the polymerization feed showed similar behavior (Fig 16.6) Porosities 81–91 and 49–57% for water regain were obtained by suction and centrifugation, respectively, 14–42% for cyclohexane regain and 31–70% for mercury porosimetry The porosity determined by centrifugation of samples soaked with water and cyclohexane (solvents with different affinities to polar methacrylate chain) consists of two contributions: filling of the pores and swelling (solvation) of PHEMA chains The uptake of cyclohexane, a thermodynamically poor solvent that cannot swell the polymer, is a result of the former contribution only, reflecting thus the pore volume The water regain from centrifugation was always higher than the cyclohexane regain demonstrating thus swelling of polymer chains with water (Table 16.1) Solvent regains were affected by the concentration of NaCl porogen in the polymerization feed Porosities according to both water and cyclohexane regains by centrifugation slightly increased with increasing volume of NaCl porogen in the polymerization feed from 35.9 to 40 vol.% and then decreased with a further NaCl increase up to 41.4 vol.% (Fig 16.6) In the latter range of NaCl, the porosity evaluated by mercury porosimetry exhibited an analogous dependence This decrease in solvent and mercury regains can be explained by thin polymer walls between large superpores inducing collapse of the porous structure In the concentration range of NaCl in the feed 35.9–40 vol.%, mercury porosimetry provided Research Methodology on Design and Synthesis 353 higher porosities than those obtained from regains by centrifugation at 980 g because it obviously did not retain solvents in large superpores Retained water reflected thus only small superpores, closed pores and solvation of the polymer in water similarly as observed earlier for macroporous PHEMA scaffolds [34] Water regain was determined also by the suction method (Table 16.1) which gave the values several times higher (3.3–7.5 mL/g) than by centrifugation due to filling all the pores in the polymer structure, including large superpores As expected, porosity by the suction method increased with increasing volume of NaCl porogen in the polymerization feed (Fig 16.6) FIGURE 16.6  Dependence of porosity of PHEMA hydrogels determined from cyclohexane (■) and water regain measured by centrifugation (●) or suction (▼) and mercury porosimetry (▲) on the content of NaCl (250–500 µm) porogen in the polymerization feed The hydrogel from Run formed in the presence of NaCl and CyOH/ DOH porogen showed higher solvent regains and mercury penetration than the comparable hydrogel from Run obtained with the same content of neat NaCl (Table 16.1) This can be explained by the higher total amount of porogen in the former hydrogel In contrast, the hydrogel from 354 Materials Science and Engineering Vol Run prepared with needle-like (NH4)2SO4 crystals as a porogen had the lowest solvent and mercury regains of all the samples The exception was water regain by centrifugation, which was identical with that of sample Run (Table 16.1) having a similar content of the NaCl porogen in the feed This can imply that only large continuous superpores were present in this hydrogel and small superpores, macro and mesopores were almost absent as evidenced by the low values of solvent and mercury regains 16.3.3  CHARACTERIZATION OF POROSITY BY MERCURY POROSIMETRY The advantage of mercury porosimetry is that it provides not only pore volumes, but also pore size distribution not available by other techniques The method measures samples dried by lyophilization, which does not distort the pore structure As already mentioned, porosities determined by mercury porosimetry were lower than those obtained from water regain by the suction, which included large superpores, and higher than those from water and cyclohexane regain detected by centrifugation This was due to better filling of the compact xerogel structures obtained at lower contents of NaCl in the feed with mercury under a high pressure than with water or cyclohexane under atmospheric pressure Figure 16.7 shows the dependence of most frequent mesopore size of PHEMA scaffolds and their pore volumes on the NaCl porogen content in the polymerization feed Predominantly, 4–5 nm mesopores were detected with their volume increasing from 0.03 to 0.1 mL/g with increasing NaCl content in the polymerization feed Macropores were absent and very low values of specific surface areas (