MARC details
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05610nam a2200385Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER |
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MX-MdCICY |
| 005 - DATE AND TIME OF LATEST TRANSACTION |
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20250625160150.0 |
| 040 ## - CATALOGING SOURCE |
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| Transcribing agency |
CICY |
| 090 ## - LOCALLY ASSIGNED LC-TYPE CALL NUMBER (OCLC); LOCAL CALL NUMBER (RLIN) |
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| Classification number (OCLC) (R) ; Classification number, CALL (RLIN) (NR) |
B-16363 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION |
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250602s9999 xx |||||s2 |||| ||und|d |
| 245 10 - TITLE STATEMENT |
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| Title |
Dianhydride architectural effects on the relaxation behaviors and thermal and optical properties of organo-soluble aromatic polyimide films |
| 490 0# - SERIES STATEMENT |
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| Volume/sequential designation |
Polymer, 40(18), p.4987-5002, 1999 |
| 520 3# - SUMMARY, ETC. |
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| Summary, etc. |
Dianhydrides of specific molecular architecture was designed and synthesized based on 2,2'-disubstituted 4,4',5,5'-biphenyltetracarboxylic dianhydrides (2,2'-disubstituted BPDAs). Eight dianhydrides were polymerized with two 4,4'-diamino-2,2'-disubstituted biphenyl diamines (trifluoromethyl disubstituted groups, or PFMB, and methyl disubstituted groups, or DMB)to obtain two series of PFMB- and DMB-based aromatic polyimides. As the backbone structures of these two series of polyimides are unchanged throughout each series, the effects of the 2,2'-disubstituted groups of both the dianhydride and diamine constituents on the solubility and thermal and optical properties as well as the relaxation behavior of these polyimides can be identified. It was found that the PFMB-based polyimides with 2,2'-disubstituted BPDAs show excellent solubility while the DMB-based polyimides with the same dianhydrides are less soluble. The same trends can be found for both thermal and thermo-oxidative stability and optical transparency in the ultraviolet and visible light regions. These two series of polyimides exhibit glass transition temperatures (T(g)) which show a competition between chain rigidity and linearity with regards to molecular of the 2,d'-disubstituted groups is small and their shape is close to spherical, the T(g)initially increases with the size of packing. When the size these 2,2'-disubstituted groups. This is because of the fact that the steric hindrance of these groups prevents the appearance of a cis-conformation of BPDA. However, once these groups possess large size and exhibit anisotropic shapes, their effect on the molecular packing becomes dominant and the T(g)starts to decrease. Further, this is the first time that three relaxation processes (the ß1,ß2, and a processes)were observed above room temperature in these aromatic polyimides. We have identified that the ß1 process is attributed to the local motion of the diamine constituents while the ß2 process is caused by the local motion of the dianhydride constituents. The a process is associated with the glass transition. The cooperativity of the molecular motion associated with the ß1 and ß2 processes are also discussed. Dianhydrides of specific molecular architecture was designed and synthesized based on 2,2'-disubstituted 4,4',5,5'-biphenyltetracarboxylic dianhydrides (2,2'-disubstituted BPDAs). Eight dianhydrides were polymerized with two 4,4'-diamino-2,2'-disubstituted biphenyl diamines (trifluoromethyl disubstituted groups, or PFMB, and methyl disubstituted groups, or DMB)to obtain two series of PFMB- and DMB-based aromatic polyimides. As the backbone structures of these two series of polyimides are unchanged throughout each series, the effects of the 2,2'-disubstituted groups of both the dianhydride and diamine constituents on the solubility and thermal and optical properties as well as the relaxation behavior of these polyimides can be identified. It was found that the PFMB-based polyimides with 2,2'-disubstituted BPDAs show excellent solubility while the DMB-based polyimides with the same dianhydrides are less soluble. The same trends can be found for both thermal and thermo-oxidative stability and optical transparency in the ultraviolet and visible light regions. These two series of polyimides exhibit glass transition temperatures (Tg)which show a competition between chain rigidity and linearity with regards to molecular packing. When the size of the 2,2'-disubstituted groups is small and their shape is close to spherical, the Tg initially increases with the size of these 2,2'-disubstituted groups. This is because of the fact that the steric hindrance of these groups prevents the appearance of a cis-conformation of BPDA. However, once these groups possess large size and exhibit anisotropic shapes, their effect on the molecular packing becomes dominant and the Tg starts to decrease. Further, this is the first time that three relaxation processes (the ß1, ß2, and a processes)were observed above room temperature in these aromatic polyimides. We have identified that the ß1 process is attributed to the local motion of the diamine constituents while the ß2 process is caused by the local motion of the dianhydride constituents. The a process is associated with the glass transition. The cooperativity of the molecular motion associated with the ß1 and ß2 processes are also discussed. |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
CHEMICAL RELAXATION |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
GLASS TRANSITION |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
HYDRIDES |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
LIGHT |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
MOLECULAR STRUCTURE |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
POLYIMIDES |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
POLYMERIZATION |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
SOLUBILITY |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
SYNTHESIS (CHEMICAL) |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
TEMPERATURE |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
THERMODYNAMIC STABILITY |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
TRANSPARENCY |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Li, F. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Ge, J.J. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Honigfort, P.S. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Fang, S. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Chen, J.-C. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Harris, F.W. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Cheng, S.Z.D. |
| 856 40 - ELECTRONIC LOCATION AND ACCESS |
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| Uniform Resource Identifier |
<a href="https://drive.google.com/file/d/1d8nBzDiRH1FfLs9iqgXyXhaEh53OC9jH/view?usp=drivesdk">https://drive.google.com/file/d/1d8nBzDiRH1FfLs9iqgXyXhaEh53OC9jH/view?usp=drivesdk</a> |
| Public note |
Para ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
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| Source of classification or shelving scheme |
Clasificación local |
| Koha item type |
Documentos solicitados |
