Molecular motions of poly(ethyl acrylate) and poly(n-butyl acrylate) studied by solid-state NMR and molecular dynamics computer experiments

Kikuchi, Hiroaki; Tokumitsu, Hideyuki; Seki, Kazuhiko

doi:10.1021/ma00078a032

Cited by 15 publications

(9 citation statements)

References 14 publications

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“…These peaks are assigned as shown in Table IV. 18 As seen in the figure, the chemical shift and relative intensity of these peaks for the bound rubbers were consistent with those for the original PEA. A small but new peak appeared at 54 ppm for both bound rubbers, which could be assigned to the carbonyl group in the side chain of PEA, which had polar interactions or hydrogen bonding with other groups.…”

Section: Figure 2 Shows 29supporting

confidence: 81%

Structure development in silica-filled polyacrylate rubber composites during mixing

Ono

Ito

Tokumitsu

et al. 1999

J. Appl. Polym. Sci.

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ABSTRACT:The structure of bound rubber in the composites from fumed silica (A200, Nippon Aerosil Co., Japan) and polyethylacrylate rubber (PEA) was studied as a function of mixing temperature. The fraction of bound rubber in the composites increased gradually with increasing the mixing temperature from 80 to 120°C, followed by saturation above 120°C. High-resolution solid-state NMR results revealed that there was no chemical bonding between silanol groups and PEA molecules. Scanning electron microscope and optical microscope observation of the composites indicated that, with increasing mixing temperature, the size of agglomerates formed by silica particles decreased. Further, the molecular weight retention of PEA dropped abruptly above 120°C. Dynamic viscoelastic measurements of the composites suggest that the development of network structure in the composites was greatly affected by the mixing temperature. Based on these data, structure development in composites is discussed.

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Section: Figure 2 Shows 29supporting

confidence: 81%

Structure development in silica-filled polyacrylate rubber composites during mixing

Ono

Ito

Tokumitsu

et al. 1999

J. Appl. Polym. Sci.

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“…4) suggesting that the amorphous phase has higher mobility than its liquid crystalline counterpart. We believe that at 40°C the ln T 1 versus 1000/T graph of the mesomorphous phase reaches a minimum that reflects its mobility at this temperature suggesting that the mesomorphous phase has two minima, one at 40°C and one below 0°C reflecting two different motions one of the α carbon itself and one of the alkyl chain 40. More studies are needed to confirm these results.…”

Section: Resultsmentioning

confidence: 92%

Solid-State Characterization of Amorphous and Mesomorphous Calcium Ketoprofen

Atassi

Chen²,

Masadeh

et al. 2010

Journal of Pharmaceutical Sciences

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“…Traversing the melting point dramatically alters the spin–lattice relaxation in the backbone, reflecting an equally abrupt change in backbone dynamics. Figure 2 compares the CH T 1 values for PA‐18 at 100 MHz with the literature results for PA‐4 [poly(butyl acrylate)] at 63 MHz 7. At −35 °C, PA‐18 and PA‐4 have similar values.…”

Section: Discussionmentioning

confidence: 71%

“… Spin–lattice relaxation time of the CH backbone carbon versus temperature. The circles are for PA‐18 at 100 MHz that are compared with the values for the same backbone carbon in PA‐4 measured at 63 MHz, as reported by Kikuchi et al7 …”

Section: Resultsmentioning

confidence: 90%

“…The transition in mobility upon traversing T m can be monitored. Carbon‐13 spin–lattice relaxation data on poly(ethyl acrylate) (PA‐2) and poly(butyl acrylate) (PA‐4) are available7 that can offer a comparison with these simple systems without side‐chain crystallinity and with easily identified T g 's ( PA‐2, T g = −20 °C and PA‐4, T g = −52 °C). Carbon‐13 spin–lattice relaxation gives a repeat unit level view of melting and possibly the glass transition but only from the standpoint of dynamics.…”

Section: Introductionmentioning

confidence: 99%

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An NMR study of mobility in a crystalline side‐chain comblike polymer

Giotto

Azar

Gosselin

et al. 2001

J Polym Sci B Polym Phys

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Carbon-13 spin-lattice relaxation times are measured for poly(octadecyl acrylate) above and below the melting point of the crystalline side chains. The chain backbone has long spin-lattice relaxation times below the melting point that shorten by more than an order of magnitude as the melting point range is traversed. Below the melting point, the backbone is nearly immobilized with spin-lattice relaxation changing very slowly with temperature. Above the melting point, the shorter spin-lattice relaxation times are typical of a rubber above the glass transition and decrease with increasing temperature. The methylene groups in the side chain are quite mobile well below the melting point, indicating fairly rapid anisotropic motion within the crystal. The methyl group at the end of the chain and the adjacent methylene group have longer spin-lattice relaxation times, indicating the greatest side-chain mobility at the end, which is in the middle of the crystal structure. The side-chain carbon adjacent to the carbonyl group is as mobile as the majority of the side-chain carbon, indicating sidechain mobility extends to all of the side-chain CH 2 groups. The abrupt transition in the mobility of the backbone is not typical of the amorphous phase in a semicrystalline polymer where the backbone units can crystallize. The close proximity of every backbone segment to the crystalline domain locks backbone segmental motion below the melting point. Melting and crystallization of the side chains switch segmental motion of the backbone on and off.

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Molecular motions of poly(ethyl acrylate) and poly(n-butyl acrylate) studied by solid-state NMR and molecular dynamics computer experiments

Cited by 15 publications

References 14 publications

Structure development in silica-filled polyacrylate rubber composites during mixing

Structure development in silica-filled polyacrylate rubber composites during mixing

Solid-State Characterization of Amorphous and Mesomorphous Calcium Ketoprofen

An NMR study of mobility in a crystalline side‐chain comblike polymer

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