선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- 57). In order to determine the molecular weight of the resulting PS block more accurately, each block copolymer was cleaved by hydrolysis (K2CO3, THF/H2O, reflux) to provide the polystyrene blocks by pre cipitating in MeOH, and they were analyzed by GPC. From the analyses, the molecular weights of the polystyrene bk*ks for 19 and 20 were determined to be 18, 000 g/m이 and 17, 000 g/mol, respectively.
- Commer cially available monomethyl poly(ethylene glycol) (Aldrich, M = 5, 000 g/mol, Mw/Mn=lA0i5) and poly(ethylene 이y- col) (Aldrich, Mn= 10, 000 g/mol, Mw/Mn=lA0i5') were sub jected to functionalization with succinic anhydride in refluxing toluene in the presence of pyridine and 4-dimethyl- aminopyridine (DMAP) as a catalyst to produce carboxy terminated PEGs 15 and 16, respectively. The functionalityof each polymer was determined to be over 95% from 500 MHz ]H-NMR spectroscopic analysis of the polymer by comparing the resonance integrals of COCH2CH2CO2H against that of OCH3 (for 15) or against that of CH2OH. (for16).
대상 데이터
- Polymer Characterization. Polymer molecular weights were estimated using a Sykam GmbH GPC system equipped with a Sykam SI 122 HPLC pump, a S5200 autosampler, a S3580 differential RI and a S3210 UV/VIS detectors, and three Jordi Gel DVB GPC columns (500 A, 1, 000 A, 10, 000 A, 300 mm X 7.8 mm). The UV detector was set at 256 nm and CHCI3 was used as an eluent at flow rate 1 mL/min.
- After stirring the reaction mixture for 3 h, water (1 mL) was added. The mixture was extracted with CH2C12 (X 3). The organic layers were combined and washed with brine, dried over MgSO4, filtered, and concentrated in vacuo.
이론/모형
- 2 for CDCI3 in 13C NMR). Elemental analyses were performed by the Organic Chemis try Research Center at Sogang University using a Carlo Erba EA 1180 elemental analyzer. Tandem gas chromatog- raphy/low resolution mass spectroscopy (GC/LRMS) using electron impact (El) ionization were obtained with a Agilent 6890 series gas chromatography and a 5973N mass selec tive detector at 70 eV.
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