Isotopically pure uniform polymers: The final step toward true uniformity in macromolecules

Vogl, Otto; Jaycox, Gary D.; Simonsick, William J.

doi:10.1002/pola.10164

Cited by 6 publications

(5 citation statements)

References 23 publications

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“…Computer‐based calculations were used to simulate the mass spectra for a number of uniform macromolecules. In many cases, these natural variations in mass exceeded the molecular weight of one or more monomeric repeat units along the polymer backbone, effectively blurring the mass distinction between uniform polymer constructs formed from N and N+l repeat units 113, 114…”

Section: Miscellaneous Programsmentioning

confidence: 99%

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Tsai

Ruaan

Wang

et al. 2002

J of Applied Polymer Sci

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A macrovoid structure was found in polysulfone membranes formed by the wet-inversion method using N-methylpyrrolidinone (NMP) and water as the solvent/nonsolvent pair. The addition of Span series surfactants in the casting solution was found to inhibit the macrovoid formation. Sorbitan monooleate (Span-80) was more effective in inhibiting macrovoids than was sorbitan monolaurate (Span-20). The phenomenon of macrovoid suppression became more prominent at higher temperature. The cloud-point shift might account for the temperature effect. But there was no simple explanation for the effect caused by Span-80. The cloud-point position, the demixing rate, and the viscosity of the casting solution were measured. None of them could explain the effect of macrovoid inhibition by the addition of Span-80. However, the penetration test indicated that the penetration of a nonsolvent into a surfactant-free casting solution was caused by a convective flow, but that into Span-80 was through diffusion. It was found that the retardation of nonsolvent penetration was the major cause of macrovoid inhibition.

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Section: Miscellaneous Programsmentioning

confidence: 99%

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Tsai

Ruaan

Wang

et al. 2002

J of Applied Polymer Sci

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“…PMMA 50‐mer was analyzed by the technique of SEC coupled to Fourier transform mass spectrometry through an electrospray ionization interface 139,140. The results indicate that the uniform polymer actually possesses remarkable levels of mass heterogeneity linked to the presence of naturally occurring isotopes and that the observed isotope distribution agrees with the theoretical one (Figure 39).…”

Section: Uniform Polymer In a Strict Sense And Future Aspects18mentioning

confidence: 58%

“…The results indicate that the uniform polymer actually possesses remarkable levels of mass heterogeneity linked to the presence of naturally occurring isotopes and that the observed isotope distribution agrees with the theoretical one (Figure 39). 139 In the case of PMMA, this natural variation in molecular weight does not exceed the mass equivalent of one monomer unit even in the 500‐mer of MMA but does exceed it in the case of 500‐mer of chloral. These naturally occurring mass variations of macromolecules are likely to have an impact on future developments in the field of material science, and the study of isotopically pure, well‐defined materials will become important in the future 139…”

Section: Uniform Polymer In a Strict Sense And Future Aspects18mentioning

confidence: 97%

“…Fortunately, the common atoms in organic compounds and polymers such as carbon, hydrogen, and oxygen have high percentages of one isotope; only a few atoms like chlorine have high abundance of more than one isotope. This point should still be regarded when speaking of uniform polymers and could be studied by mass spectrometry 139…”

Section: Uniform Polymer In a Strict Sense And Future Aspects18mentioning

confidence: 99%

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Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry

Hatäda

Kitayama

Ute

et al. 2004

Macromol. Rapid Commun.

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Summary: A uniform polymer is a polymer composed of molecules that are uniform with respect to molecular weight and constitution. Besides natural uniform polymers such as nucleic acids and polypeptide, synthetic uniform polymers have been obtained by a variety of approaches. In particular, a combination of living polymerization and supercritical fluid chromatography (SFC) separation is one of the promising ways for the preparation of uniform polymers. End‐functionalized uniform polymers enabled us to prepare uniform polymer architectures such as block, graft, comb, and star polymers. Their use for understanding the fundamental problems in polymer chemistry is discussed; topics include crystallization of polymers, chain conformation in solution, and association of stereoregular polymers in solution.

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“…The effect of polymer structure on the reactivity and properties of reactive moieties is very important for the chemical modifications and for the eventual applications of reactive polymers 5–7. Functionalized polymers have wide applications for various biological and technological purposes 8, 9…”

Section: Introductionmentioning

confidence: 99%

Copolymerization of two new kinds of methacrylate monomers and determination of monomer reactivity ratios

Erol

2006

J of Applied Polymer Sci

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New methacrylate monomers 2-(p-methoxyphenoxy)-2-oxo-ethyl methacrylate (pMPOEMA), 2-(p-chlorophenoxy)-2-oxo-ethyl methacrylate (pClPOEMA), and 2-oxo-2-phenylamino ethylene methacrylate (PAMA) were synthesized for the first time. The free-radical-initiated copolymerization of pMPOEMA and pClPOEMA with PAMA was carried out in 1,4-dioxane solution at 65°C using 2,2Ј-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomers and copolymers were characterized by Fourier transform infrared, 1 H and 13 C NMR spectral studies. The copolymer compositions were evaluated from nitrogen content in polymers. The reactivity ratios of the monomers were determined by applying Fineman-Ross and Kelen-Tü dö s methods. The analysis of reactivity ratios revealed that pMPO-EMA and pClPOEMA are less reactive than PAMA is, and copolymers formed are statistically in nature. The molecular weights (M w and M n ) and polydispersity index of the polymers were determined using gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of pMPOEMA and pClPOEMA in the copolymers. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of PAMA in the copolymers.

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Isotopically pure uniform polymers: The final step toward true uniformity in macromolecules

Cited by 6 publications

References 23 publications

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry

Copolymerization of two new kinds of methacrylate monomers and determination of monomer reactivity ratios

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