1997 Fiscal Year Final Research Report Summary
Polymer Characterization by On-Line GPC/NMR
| Project/Area Number |
08405059
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子合成
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| Research Institution | Osaka University |
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Principal Investigator |
HATADA Koichi Fac.Eng.Sci., Osaka University, Prof., 基礎工学研究科, 教授 (60029402)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIURA Takefumi Fac.Eng.Sci., Osaka University, Res.Assoc., 基礎工学研究科, 助手 (70243194)
UTE Koichi Fac.Eng.Sci., Osaka University, Assoc.Prof., 基礎工学研究科, 助教授 (30176713)
KITAYAMA Tatsuki Fac.Eng.Sci., Osaka University, Prof., 基礎工学研究科, 教授 (60135671)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Size Exclusion Chromatography / Gel Permeation Chromatography / Nuclear Magnetic Resonance / Molecular Weight Distribution / LC-NMR / EPDM / Poly (methyl methacrylate) / Stereocomplex |
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| Research Abstract |
(1) A gel peameation chromatograph coupled to a ^1H NMR spectrometer (on-line GPC/NMR) was used to analyze molecular weight distributions of isotactic PMNAs with M_n ranging from 3.27*10^3 to 2.22*10^4. The molecular weight of the polymer in flowing eluate was determined directly (without a conventional calibration procedure) from the relative intensity of NMR signals due to the end-group and repeating units. The molecular weight distribution determined in this manner was proved to be accurate by SEC-NMR experiments on uniform isotactic PMMAs consisting of exactly 23,40, and 80 repeating units. Investigation was also undertaken to optimize flow rate and NMR parameters for quantitative GPC/NMR measurements. The signal-to-noise ratio of 750 MHz GPC/NMR spectra was 9.2 times that obtained previously with 500 MHz GPC/NMR operated under similar conditions.
(2) Chemical compositions in ethylene-propylene- (2-ethylidene-5-norbornene) terpolymers (EPDM) were investigated by 750 MHz on-line GPC/
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NMR.Comparison of the chromatograms obtained by monitoring the CH_2 and CH_3 resonances in a terpolymer sample showed clearly the ethylene/propylene ratio as a function of molar mass. The measurements were carried out with continuous flow of eluent (chloroform-d, 0.2mL/min). Molar mass dependence of a small amount (0.6-1.1mol%) of 2-ethylidene-5-norbornene units in a terpolymer was determined by GPC/NMR using the stop-and-flow technique.
(3) Stereocomplexation between uniform isotactic (mm=100%) and syndiotactic (rr=98%) 46mers of MMA was studied by 750 MHz on-line GPC/NMR.A blend of st-46mer and it-46mer (st-/it-=0.61) in acetone/acetone-d_6 (95/5) was allowed to stand at -15ﾟC for 24h, and then subjected to the GPC/NMR measurements (column temp., -15ﾟC ; probe temp., 45ﾟC). Besides the elution peak due to non-complexed 46mers, a peak due to stereocomplex was observed at a high MW region in the chromatogram. The GPC curves recorded by monitoring it-OCH_3 and st-OCH_3 resonances showed clearly that the non-complexed part consisted essentially of it-46mer and st-/it- ratio in the stereocomplex part was 1.5 to 1.7. When probe temperature was adjusted to the column temperature (-15ﾟC), no resonance due to it-46mer was observed in the GPC/NMR spectra of the stereocomplex part because of the loss of segmental mobility. Less
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