Determination of hydroxyl concentrations in prepolymers from the infrared absorption band of tetrahydrofuran-associated hydroxyl groups

Kim, Chung Sul Youn.; Dodge, Allan L.; Lau, S.; Kawasaki, Andrew M.

doi:10.1021/ac00239a020

Cited by 16 publications

(2 citation statements)

References 11 publications

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“…The carboxyl end groups of oligomers were determined by the method described by Shiota et al5 The hydroxyl groups were determined by IR spectroscopy as described in ref 8. The spectra were obtained on neutralized samples so that the carboxyl and hydroxyl 0-H stretches did not overlap.…”

Section: Methodsmentioning

confidence: 99%

Nature of the active centers and the propagation mechanism of the polymerization of .beta.-propiolactones initiated by potassium anions

Jedliński¹,

Kowalczuk²

1989

Macromolecules

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15) Feijoo, J. L.; Ungar, G.; Owen, A. J.; Keller, A.; Percec, V. Mol. (16) Percec, V.; Asami, K., unpublished data. (17) Keller, A.; Ungar, G.; Yourd, R.; Percec, V., unpublished data.ABSTRACT The chemical structure of the active centers formed during the polymerization of P-propiolactones initiated by potassium anions has been elucidated on the basis of the results of spectroscopic ('H NMR, IR), chemical, and elemental analyses. In the initial step of propagation, two types of active species, carboxylate and alkoxide anions, are formed. The alkoxide anions disappear during the polymerization, and carboxylate anions are eventually the main propagation species.ABSTRACT: The changes in morphology due to the formation of polyethylene in the pores of three silica-supported, chromium oxide catalysts were followed by using mercury porosimetry and electron microscopy. Ethylene polymerization from 0.1 to 20 g of polymer/g of catalyst was carried out from the gas phase in a fluid bed reactor a t 1-atm total pressure with a nitrogen diluent. A catalyst with 1.7 cm3/g pore volume fragmented due to the formation of polymer in the pores and thereby maintained an open structure. Catalysts containing 1.1 and 2.3 cm3/g pore volume did not fragment extensively, and the product polymer congested the pores and impeded the continued polymerization. Total pore volume and pore size are not the only controlling factors in the fracturing process. Mercury porosimetry showed that fracture of the 1.7 cm3/g catalyst started after a polymer yield of just 0.4 gpE/geat, maintaining monomer access to the active sites. The O.l-l-pm catalyst fragments contained a pore microstructure much like that of the starting material, thus demonstrating how the pore structure of the original catalyst particles may influence the polymerization process after fragmentation is complete.

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Section: Methodsmentioning

confidence: 99%

Nature of the active centers and the propagation mechanism of the polymerization of .beta.-propiolactones initiated by potassium anions

Jedliński¹,

Kowalczuk²

1989

Macromolecules

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“…The association of hydroxyl groups in polymers with tetrahydrofuran is the basis of a hydroxyl content determination in polymers. The hydroxy-tetrahydrofuran association complex absorbs strongly at 3450 cm'* thus allowing an infrared analysis of hydroxyl (57).…”

mentioning

confidence: 99%

Functional group analysis

Smith¹,

Patterson²

1984

Anal. Chem.

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Determination of hydroxyl groups in polymers. Review

Boiko¹,

Grischenko²

1985

Acta Polymerica

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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

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Determination of hydroxyl concentrations in prepolymers from the infrared absorption band of tetrahydrofuran-associated hydroxyl groups

Cited by 16 publications

References 11 publications

Nature of the active centers and the propagation mechanism of the polymerization of .beta.-propiolactones initiated by potassium anions

Nature of the active centers and the propagation mechanism of the polymerization of .beta.-propiolactones initiated by potassium anions

Functional group analysis

Determination of hydroxyl groups in polymers. Review

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