Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00029-4
Tadaaki Inoue, Guohua Chen, K. Nakamae, A. Hoffman
{"title":"Temperature sensitivity of a hydrogel network containing different LCST oligomers grafted to the hydrogel backbone","authors":"Tadaaki Inoue, Guohua Chen, K. Nakamae, A. Hoffman","doi":"10.1016/S0966-7822(97)00029-4","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00029-4","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"19 1","pages":"561-575"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85599833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00026-9
G. Paradossi, E. Chiessi, F. Cavalieri, D. Moscone, V. Crescenzi
{"title":"Networks based on chitosan and oxidized cyclodextrin—II. Structural and catalytic features of a copper (II)-loaded network","authors":"G. Paradossi, E. Chiessi, F. Cavalieri, D. Moscone, V. Crescenzi","doi":"10.1016/S0966-7822(97)00026-9","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00026-9","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"24 1","pages":"525-540"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89335993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20Epub Date: 1998-06-23DOI: 10.1016/S0966-7822(97)00029-4
Tadaaki Inoue , Guohua Chen , Katsuhiko Nakamae , Allan S Hoffman
Hydrogels (HGs) containing two different lower critical solution temperature (LCST) oligomers grafted to the same HG backbone were synthesized using macromonomers of the LCST oligomers. Carboxy-terminated oligo(N-iso-propylacrylamide) (oNIPAAm) oligo(N-vinylcaprolactam) (oVCL) and a random co-oligomer of NIPAAm and acrylamide (AAm) (o[NIPAAm-co-AAm]) were selected as the LCST oligomers. The macromonomers were synthesized by reaction of the terminal carboxy groups with glycidyl metha-crylate. Using AAm as the base monomer for the HG macromonomers of the carboxy-terminated oNIPAAm and oVCL were copolymerized with AAm and a cross–linker and the HG was obtained. Despite the lack of temperature-sensitivity of the PAAm HG the grafted HG showed two volume phase transitions corresponding to the LCSTs of the grafted side chains of oNIPAAm and oVCL.
{"title":"Temperature sensitivity of a hydrogel network containing different LCST oligomers grafted to the hydrogel backbone","authors":"Tadaaki Inoue , Guohua Chen , Katsuhiko Nakamae , Allan S Hoffman","doi":"10.1016/S0966-7822(97)00029-4","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00029-4","url":null,"abstract":"<div><p>Hydrogels (HGs) containing two different lower critical solution temperature (LCST) oligomers grafted to the same HG backbone were synthesized using macromonomers of the LCST oligomers. Carboxy-terminated oligo(N-iso-propylacrylamide) (oNIPAAm) oligo(N-vinylcaprolactam) (oVCL) and a random co-oligomer of NIPAAm and acrylamide (AAm) (o[NIPAAm-co-AAm]) were selected as the LCST oligomers. The macromonomers were synthesized by reaction of the terminal carboxy groups with glycidyl metha-crylate. Using AAm as the base monomer for the HG macromonomers of the carboxy-terminated oNIPAAm and oVCL were copolymerized with AAm and a cross–linker and the HG was obtained. Despite the lack of temperature-sensitivity of the PAAm HG the grafted HG showed two volume phase transitions corresponding to the LCSTs of the grafted side chains of oNIPAAm and oVCL.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"5 6","pages":"Pages 561-575"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(97)00029-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72252190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20Epub Date: 1998-06-23DOI: 10.1016/S0966-7822(97)00027-0
T. Fuchs , W. Richtering , W. Burchard , K. Kajiwara , S. Kitamura
The β-1.3/1.6 glucan schizophyllan is a fungal polysaccharide that is known to suppress tumor growth. Thermoreversible, optically transparent gels of schizophyllan were obtained on addition of sorbitol to aqueous solutions of schizophyllan. Gel temperatures were independent of the history of sample preparation. The gelation process was followed by low-amplitude oscillatory shear and by static and dynamic light scattering. Power law behavior of storage modulus G′(ω) and loss modulus G″(ω) was found at the gel temperature with the exponent n=0.5. The static LS measurements showed a strong irregularity at the gel temperature. The intensity time correlation functions (TCFs) as measured by dynamic LS during the gelation process were transformed into the electric field TCFs, taking into account the heterodyne contributions. At the gel temperature which was estimated by rheology, DSC and static LS, no power law was found for the TCF. The angular dependence of the intensity TCF was measured and converted to the field TCF by use of a non-ergodicity treatment and by the heterodyne approximation, respectively. Both methods result in mean relaxation times that agree quite well. Two relaxation modes were found in the whole temperature range (above and below the gel temperature) indicating the existence of inhomogeneities in the gel.
{"title":"Gel point in physical gels: rheology and light scattering from thermoreversibly gelling schizophyllan","authors":"T. Fuchs , W. Richtering , W. Burchard , K. Kajiwara , S. Kitamura","doi":"10.1016/S0966-7822(97)00027-0","DOIUrl":"10.1016/S0966-7822(97)00027-0","url":null,"abstract":"<div><p>The <em>β</em>-1.3/1.6 glucan schizophyllan is a fungal polysaccharide that is known to suppress tumor growth. Thermoreversible, optically transparent gels of schizophyllan were obtained on addition of sorbitol to aqueous solutions of schizophyllan. Gel temperatures were independent of the history of sample preparation. The gelation process was followed by low-amplitude oscillatory shear and by static and dynamic light scattering. Power law behavior of storage modulus <em>G</em>′(<em>ω</em>) and loss modulus <em>G</em>″(<em>ω</em>) was found at the gel temperature with the exponent <em>n</em>=0.5. The static LS measurements showed a strong irregularity at the gel temperature. The intensity time correlation functions (TCFs) as measured by dynamic LS during the gelation process were transformed into the electric field TCFs, taking into account the heterodyne contributions. At the gel temperature which was estimated by rheology, DSC and static LS, no power law was found for the TCF. The angular dependence of the intensity TCF was measured and converted to the field TCF by use of a non-ergodicity treatment and by the heterodyne approximation, respectively. Both methods result in mean relaxation times that agree quite well. Two relaxation modes were found in the whole temperature range (above and below the gel temperature) indicating the existence of inhomogeneities in the gel.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"5 6","pages":"Pages 541-559"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(97)00027-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89655225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00019-1
J. Travas-sejdic, A. Easteal
{"title":"Swelling equilibria and volume phase transition of polyelectrolyte gel with strongly dissociated groups","authors":"J. Travas-sejdic, A. Easteal","doi":"10.1016/S0966-7822(97)00019-1","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00019-1","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"83 1","pages":"481-502"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81172601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00017-8
M. Han, G. Muller, A. Zaitoun
{"title":"Gel formation of polyacrylamide in the presence of glyoxal for water control application","authors":"M. Han, G. Muller, A. Zaitoun","doi":"10.1016/S0966-7822(97)00017-8","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00017-8","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"14 1","pages":"471-480"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74881678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20Epub Date: 1998-06-23DOI: 10.1016/S0966-7822(97)00028-2
T. Takigawa , T. Yamawaki , K. Takahashi , T. Masuda
Mechanical properties of poly(N-isopropylacrylamide) (PNIPA) gels were examined both in swollen and collapsed state. Stress–strain curve of the gel in the swollen state was linear and the collapsed gel also showed almost linear stress–strain behavior. The initial Young’s modulus (E0) in the collapsed state was much higher than that in the swollen state. The number of cross-links increased largely by the introduction of the physical cross-links due to collapse of the gels.
{"title":"Change in Young’s modulus of poly(N-isopropylacrylamide) gels by volume phase transition","authors":"T. Takigawa , T. Yamawaki , K. Takahashi , T. Masuda","doi":"10.1016/S0966-7822(97)00028-2","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00028-2","url":null,"abstract":"<div><p>Mechanical properties of poly(<em>N</em>-isopropylacrylamide) (PNIPA) gels were examined both in swollen and collapsed state. Stress–strain curve of the gel in the swollen state was linear and the collapsed gel also showed almost linear stress–strain behavior. The initial Young’s modulus (<em>E</em><sub>0</sub>) in the collapsed state was much higher than that in the swollen state. The number of cross-links increased largely by the introduction of the physical cross-links due to collapse of the gels.</p></div>","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"5 6","pages":"Pages 585-589"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0966-7822(97)00028-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72252189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00024-5
M. Lesho, N. F. Sheppard
{"title":"A method for studying swelling kinetics based on measurement of electrical conductivity","authors":"M. Lesho, N. F. Sheppard","doi":"10.1016/S0966-7822(97)00024-5","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00024-5","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"40 1","pages":"503-523"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74111364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-04-20DOI: 10.1016/S0966-7822(97)00028-2
T. Takigawa, T. Yamawaki, Katsunori Takahashi, T. Masuda
{"title":"Change in Young’s modulus of poly(N-isopropylacrylamide) gels by volume phase transition","authors":"T. Takigawa, T. Yamawaki, Katsunori Takahashi, T. Masuda","doi":"10.1016/S0966-7822(97)00028-2","DOIUrl":"https://doi.org/10.1016/S0966-7822(97)00028-2","url":null,"abstract":"","PeriodicalId":20331,"journal":{"name":"Polymer Gels and Networks","volume":"20 1","pages":"585-589"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83569615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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