“…While the baseline and the peak shape were fixed, an iterative procedure was employed to obtain the best fit, without changing the wavenumber of each component. , Although two-, three-, and four-component fittings were conducted, the three-component fitting gave the best results. Thus, each carbonyl vibration is considered to consist of three components: hydrogen-bonded with −OH groups, hydrogen-bonded with >NH groups, and free carbonyl groups (Table ). , Actually, −OH and >NH in Table mean −OD and >ND, respectively, since we used D 2 O as a solvent so that deuterium exchange occurred. , 5 FT-IR spectrum and its deconvolution results for a 5 wt % D 2 O solution of poly(NIPA- co -NALA, 16/4).…”
Aqueous solutions of copolymers, consisting of N-isopropylacrylamide (NIPA) and optically active
N-acryloyl-l-alanine (NALA) (poly(NIPA-co-NALA)), exhibited phase-separation temperatures (cloud point,
T
c), and they were soluble at the lower temperatures and phase-separated at the higher temperatures.
The T
c decreased with increasing NALA composition and increased with increasing pH of the solutions.
The results of T
c measurements in the presence of NaCl and a urea derivative and Fourier transform
infrared measurements with a curve-fitting method indicated that an increase in the composition of NALA
in the copolymers induced hydrogen bonding in and between the copolymer chains. The partition coefficient
(K) and diffusion coefficient (D) of R- and S-[1-(dimethylamino)ethyl]ferrocene (DMAEFc) in poly(NIPA-co-NALA) gels in aqueous solutions were estimated by a membrane permeation method. Negligible difference
was observed for K between R- and S-DMAEFc; however, D of R-DMAEFc became smaller than that of
S-DMAEFc when the gels started to collapse.
“…While the baseline and the peak shape were fixed, an iterative procedure was employed to obtain the best fit, without changing the wavenumber of each component. , Although two-, three-, and four-component fittings were conducted, the three-component fitting gave the best results. Thus, each carbonyl vibration is considered to consist of three components: hydrogen-bonded with −OH groups, hydrogen-bonded with >NH groups, and free carbonyl groups (Table ). , Actually, −OH and >NH in Table mean −OD and >ND, respectively, since we used D 2 O as a solvent so that deuterium exchange occurred. , 5 FT-IR spectrum and its deconvolution results for a 5 wt % D 2 O solution of poly(NIPA- co -NALA, 16/4).…”
Aqueous solutions of copolymers, consisting of N-isopropylacrylamide (NIPA) and optically active
N-acryloyl-l-alanine (NALA) (poly(NIPA-co-NALA)), exhibited phase-separation temperatures (cloud point,
T
c), and they were soluble at the lower temperatures and phase-separated at the higher temperatures.
The T
c decreased with increasing NALA composition and increased with increasing pH of the solutions.
The results of T
c measurements in the presence of NaCl and a urea derivative and Fourier transform
infrared measurements with a curve-fitting method indicated that an increase in the composition of NALA
in the copolymers induced hydrogen bonding in and between the copolymer chains. The partition coefficient
(K) and diffusion coefficient (D) of R- and S-[1-(dimethylamino)ethyl]ferrocene (DMAEFc) in poly(NIPA-co-NALA) gels in aqueous solutions were estimated by a membrane permeation method. Negligible difference
was observed for K between R- and S-DMAEFc; however, D of R-DMAEFc became smaller than that of
S-DMAEFc when the gels started to collapse.
The analysis of hydroxyl groups in polymers is reviewed. Recent achievements of chemical, physico-chemical and physical methods for the determination of hydroxyl groups and their differentiation by reactivity have been examined. Particularly, infrared spectroscopy and nuclear magnetic resonance used for this determination are considered.
Die Bestimmung yon Hydroxylgruppen in Polymeren. FortschrittsberichtIn dem Bericht werden neuere Entwicklungen chemischer, physikalisch-chemischer und physikalischer Methoden zur Bestimmung von Hydroxylgruppen und ihrer Differenzierung hinsichtlich der Reaktivitat dargestellt. Insbesondere wird die Anwendung der Infrarotspektroskopie und der magnetischen Kernresonanz behandelt. Onpeaenenue zur3powuJabnwx zpynn 8 nom.wepax. O630p 0 6 3 0~ IIOCBfiQeH aHaJIH8y rHAPOKCHnbHhIX rpynn B IIOJIEiMepaX. PaCCMOTpeHbI IlOCJIeAHlle AOCTEiXeHllfi XHMH9eCKHX, @H3HHO-XHMH9eCHHX Ei @H3H4eCKHX MeTOAOB KOJIEi9eCTBeHHOrO OIIpeAeneHElH I' HApOKCHJIbHbIX I'pyIIII H HX AH@-@epeHqEi~EiEinOpeaKqHOHHOltCnOCO6HOCTH. ~C O 6 O~B H l l M~H H~~~~j I~H O H H @~~K~~C H O~C I I~K T~O C MarHHTHOMY pe30HaHCy.
Chemical methods of analysisChemical methods a r e simple a n d accessible, t h e y do not require special equipment a n d expensive instruments. At t h e same t i m e t h e y a r e rather time-consuming a n d require considerable amounts of t h e substance t o be analyzed. These methods can mainly give quantitative information. If t h e differentiation of HG is necessary, they become much more time-consuming. Recently t h e effective methods of chemical analysis have appeared which enable HG t o b e determined rapidly a n d exactly enough. Acylation of HG is most widely used, its application for polymers is detailed in t h e handbooks o n polymer analysis. The classical acylation procedure [27, 281 uses acetic (AA) or phthalic anhydride (PA) in pyridine solution, t h e latter being t h e solvent and catalyst of t h e reaction. T h e use of propionic [29], succinic [30--321, nitrobenzoic [33], osulfobenzoic [34], nitrophthalic [35]anhydrides for t h e same purpose is described. As a rule, primary a n d secondary HG a r e fully acylated within 1 t o 2 h a t 100 t o 115°C. Pyromellitic dianhydride (PMDA) [36-381 is more effective. It has as high activity as AA a n d does not interact with aldehyde groups a n d phenolic HG which is characteristic of PA. Dimethylsulfoxide (DMSO) is especially recommended as a solvent [37].T o acylate HG, more active acyl chlorides can b e used.
BOIKO and GRISHCHENKO:Deterinination of liydroryl groups in polymers. Review Acta Polymcrica 36 (1985) Nr. 9
A fast and specific method has been developed for the determination of hydroxyl content in prepolymers that contain hydroxymethylene functional groups. This method involves reaction of the sample with either trifluoroacetic anhydride or hexafluoroacetone to separate the terminal oxymethylene signals in the 'H NMR spectrum from those of the repeating unit and integration against an internal trinitrobenzene standard. This procedure generally requires less than 50 mg of polymer and has been employed in the analysis of prepolymers with number average molecular weights ranging up to 10000. The analysis has been tested using several different prepolymers. Precision of analysis was determined to be within 2.7 percent using a Varian XL-200 spectrometer.
ACKNOWLEDGMENT
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