Characterization of Poly(N-isopropylmethacrylamide) in Water

Kubota, Kenji; Hamano, K.; Kuwahara, N.; Fujishige, Shoei; Ando, Isao

doi:10.1295/polymj.22.1051

Cited by 72 publications

(60 citation statements)

References 20 publications

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“…19 The k f,0 of PNIPAM was reported to be 5.3 in water, which means that PNIPAM is a fairly flexible polymer, whose coil dimension is influenced by tacticity. 20 Previous research on the effect of tacticity on chain dimension of polypropylene showed that the statistical segment length (i.e., repeating tactic unit) of syndiotactic polypropylene is substantially higher than isotactic polypropylene. 21 Accordingly, one can rationalize these results in that PNIPAM v70 with a higher syndiotactic percentage has a higher segment length than PNIPAM v50.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Kinetic Hydrate Inhibition of Poly(N-isopropylacrylamide)s with Different Tacticities

et al. 2012

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Poly(N-isopropylacrylamide)s (PNIPAMs) and poly(N-isopropylmethacrylamide)s have been investigated recently as kinetic hydrate inhibitors (KHIs). Now, poly(N-isopropylmethacrylamide) is commercialized. These are usually made by standard radical polymerization methods, which do not allow for control over the polymer tacticity. For this study, PNIPAMs were synthesized using new polymerization methods, giving a fairly high degree of tacticity control. We report here results on the performance of different tacticities of PNIPAMs with similar molecular weights in KHI tests with natural gas in stirred autoclaves and on tetrahydrofuran (THF) structure II hydrate crystal growth. From the results, we can conclude that the polymer tacticity does affect the KHI performance of PNIPAMs. PNIPAM with a higher syndiotactic percentage performed better than PNIPAM with a lower syndiotactic percentage. Both polymers demonstrated some kind of crystal surface adsorption by affecting the morphology of the THF hydrate crystals. ■ INTRODUCTIONNatural gas hydrates are crystalline solids, in which gas molecules (guest molecules) are trapped inside hydrogenbonded water cavities. Typical guest molecules include carbon dioxide and small hydrocarbons, such as methane, ethane, and propane. In the mid-1930s, it was discovered that thermodynamic conditions (elevated pressure and low temperature) favoring hydrate formation occur in pipelines and that natural gas hydrates were blocking gas transmission lines. 1 Natural gas hydrate plugging is one of the costly and challenging problems for the oil and gas industry, especially for deepwater fields. The prevention of gas hydrate formation can be accomplished in a few methods. Among them is the chemical treatment, which includes the usage of kinetic hydrate inhibitors (KHIs). They are generally water-soluble polymers. The mechanism is to delay the nucleation and crystal growth. The main classes of KHIs that have been in commercial use are polymers based on homo-polymers and co-polymers of vinyl caprolactam (VCap) as well as hyperbranched polyesteramides. 2 A group of KHIs based on the polymer of alkylacrylamide was developed. It was also pointed out that poly(N-monoalkyl(meth)acrylamide)s are also known to perform well as KHIs, especially when isopropyl serves as the alkyl group. 3 Therefore, we are interested in studying the KHI performance of this new KHI class.One of the important properties of polymers are their tacticity, which describes the relative stereochemistry of adjacent chiral centers within a macromolecule. 4 As shown in Figure 1, there are three types of tacticities, namely, isotactic with all pendant groups located on one side of the backbone, syndiotactic with alternating orientated pendant groups, and atactic with randomly orientated pendant groups. In a previous work, the KHI performance of poly(N,N-dialkylacrylamide)s was studied to determine the effect of polymer tacticity of this KHI class. 5 The results show that syndiotactic poly(N,Ndialkylacrylamide)s perform better than other...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Kinetic Hydrate Inhibition of Poly(N-isopropylacrylamide)s with Different Tacticities

et al. 2012

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“…Below the transition temperature the 3 value for the VDP-PNNPAM [12.6] system was almost the same value to that for the VDP-PNIPAM [12.6] system, however, that for the VDP-PNIPMAM [12.6] system was larger than that for the VDP-PNIPAM [12.6] system. It is reported that linear PNIPMAM in aqueous solution takes a more expanded structure than linear PNIPAM due to the presence of a methyl group to the a-carbon [41]. Similarly PNIPMAM chains in the microgel particles could take more expanded structures than PNIPAM chains.…”

Section: Microenvironments Of Three Kinds Of Vdp-labeled Microgel Parmentioning

confidence: 99%

Synthesis and thermo-responsive behavior of fluorescent labeled microgel particles based on poly(N-isopropylacrylamide) and its related polymers

Matsumura

Iwai

2005

Polymer

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“…For instance, the solubility of poly (N-isopropylmethacrylamide͒ in water is better than the PNiPAM in water. 42 On the other hand, poly (N-n-propylacrylamide͒ is less soluble in water. 43 These facts indicate that the solution properties of PNiPAM are significantly affected by a solvation and a competition between hydrophobic and hydrophilic interactions.…”

Section: B Thermal Diffusion Of Pnipammentioning

confidence: 99%

Thermally induced sign change of Soret coefficient for dilute and semidilute solutions of poly(N-isopropylacrylamide) in ethanol

Kita

Kircher

Wiegand

2004

The Journal of Chemical Physics

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We studied the thermal diffusion behavior of poly(N-isopropylacrylamide͒ ͑PNiPAM͒ in ethanol in a temperature range from Tϭ14.0°C to Tϭ40.0°C by means of thermal diffusion forced Rayleigh scattering. The obtained Soret coefficient S T of PNiPAM was positive for lower temperatures (TϽ34°C), while S T showed a negative value for higher temperatures (TϾ34°C). This means PNiPAM molecules move to the cold side for temperatures TϽ34°C, whereas they move to the warm side for TϾ34°C. This is the first nonaqueous polymeric system for which a sign change with temperature has been observed. We performed static and dynamic light scattering experiments in the same temperature range. The second virial coefficient determined from dilute solutions by static light scattering ͑SLS͒ was positive in the comparable temperature range. The results of SLS for the semidilute solution showed a strong repulsion among PNiPAM chains which was enhanced by increasing temperature. These results imply that the observed thermally induced sign change of S T does not depend on the intermolecular interactions among PNiPAM chains.

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Characterization of Poly(N-isopropylmethacrylamide) in Water

Cited by 72 publications

References 20 publications

Kinetic Hydrate Inhibition of Poly(N-isopropylacrylamide)s with Different Tacticities

Kinetic Hydrate Inhibition of Poly(N-isopropylacrylamide)s with Different Tacticities

Synthesis and thermo-responsive behavior of fluorescent labeled microgel particles based on poly(N-isopropylacrylamide) and its related polymers

Thermally induced sign change of Soret coefficient for dilute and semidilute solutions of poly(N-isopropylacrylamide) in ethanol

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