Conformational changes in the induction period of crystallization as measured by FT-IR

Jiang, Yong; Gu, Qun; Li, Lin; Shen, Deyan; Jin, Xigao; Chan, Chi‐Ming

doi:10.1016/s0032-3861(03)00278-7

Cited by 22 publications

(16 citation statements)

References 20 publications

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“…Therefore, its vibration behavior would be altered specially in the acetoamide groups of the acetylated moiety of chitosan. These groups are more likely to suffer conformational changes than the glucopyranose rest because of their spacial mobility …”

Section: Resultsmentioning

confidence: 99%

TEOS as an improved alternative for chitosan beads cross‐linking: A comparative adsorption study

Copello

Villanueva

González

et al. 2014

J of Applied Polymer Sci

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In this work the use of tetraethoxysilane (TEOS) for cross‐linking of chitosan hydrogel beads was studied at the level of 1 mmol TEOS per gram of chitosan. They were compared with glutaraldehyde and epichlorohydrin cross‐linked beads. The hydrogels were characterized by FTIR, SEM, water content, nitrogen content, and their point of zero charge. The performance of the anionic dye Remazol Black (RB) and the cationic Cd(II) adsorptions was assessed in order to characterize the sorbate–sorbent interaction. Adsorption experimental data were analyzed using two‐ and three‐parameter isotherm models along with the evaluation of mean adsorption energy and standard free energy. The adsorption was observed to be pH dependent. The uptake rate of RB and Cd(II) showed that the three type of beads followed a similar kinetic behavior. For both sorbates the TEOS cross‐linked beads showed the higher maximum adsorption capacity, followed by epichlorohydrin and glutaraldehyde cross‐linked beads. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41005.

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Section: Resultsmentioning

confidence: 99%

TEOS as an improved alternative for chitosan beads cross‐linking: A comparative adsorption study

Copello

Villanueva

González

et al. 2014

J of Applied Polymer Sci

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“…21,22 Structural changes in PTT during crystallization have been studied by infrared (IR) spectroscopy. 8,11,19 Fourier transform infrared (FT-IR) spectroscopy has been successful in studying the conformational changes in crystalline polymers during crystallization [1][2][3][4][5]8,11,19,[23][24][25][26][27][28][29][30][31][32][33][34][35] because the IR absorption bands originate due to the different functional moieties in the polymer chain and their conformation are sensitive to temperature. As the temperature decreases during melt crystallization, the crystalline bands emerge and the absorbance increases synchronously.…”

Section: Introductionmentioning

confidence: 99%

Structural Changes in Poly(trimethylene adipate) and Poly(trimethylene succinate) During Melt Crystallization Studied Using In Situ Infrared Spectroscopy

et al. 2017

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This paper investigates the structural changes occurring in poly(trimethylene adipate) (PTAd) and poly(trimethylene succinate) (PTSu) during melt crystallization using differential scanning calorimetry (DSC) and in situ Fourier transform infrared (FT-IR) spectroscopy. Cooling thermograms revealed that PTAd had a faster crystallization rate than PTSu. Infrared (IR) bands of the two polyesters were assigned by correlating with the IR bands of polymers containing the trimethylene and the diacid segments. The bands at 1478, 1459, 1393, and 1364 cm in PTAd and 1475, 1459, 1393, and 1361 cm in PTSu were designated to the CH of the trimethylene segment. Changes in the IR band absorbance intensities of the CH and the C-O-C groups were monitored with time during melt crystallization. Structural changes of the trimethylene and diacid segments of PTAd occurred synchronously, while in PTSu the two segments changed sequentially. Normalized band intensities showed a time lag between the trimethylene and succinic acid segments. The acid segment showed a faster change compared to the trimethylene segment. Fourier transform infrared spectroscopy is shown to be a useful technique to study conformational changes during crystallization in polymers.

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“…[22][23][24][25][26][27] In situ FTIR results for the crystallization processes of isotactic polypropylene have shown that crystallization occurs as soon as the ordered helix length exceeds the critical persistent length. 22 FTIR investigation of the crystallization of syndiotactic polypropylene (sPP) revealed a trans-gauche transition at around 0 1C, which may be one important factor controlling the formation of sPP crystals with characteristic conformations at this temperature.…”

Section: Introductionmentioning

confidence: 99%

A two-dimensional IR correlation spectroscopic study of the conformational changes in syndiotactic polypropylene during crystallization

Zheng

Liu

Huang

2010

Polym J

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The conformational changes of syndiotactic polypropylene (sPP) during melting and isothermal crystallization processes were studied by infrared (IR) and two-dimensional (2D) correlation analysis. The band at 963 cm À1 is assigned to the contribution of the amorphous component, and the band at 978 cm À1 is assigned to a shorter helical conformational length than the bands at 867 and 812 cm À1 , which are related to crystalline helical conformation. The difference spectra and 2D correlation spectra analysis of the crystallization process indicated that the changes in these regular bands occur in rapid sequence, which is not easily detected by conventional IR spectroscopy. It was found that the absorption intensity of the band at 963 cm À1 increases earlier than that of the band at 978 cm À1 , as well as of the bands at 867 and 812 cm À1 . The results suggest that the partial chains among the amorphous component change in conformation first, then the sPP chains adjust their local conformations to form short helical conformations and finally crystallization occurs.

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Conformational changes in the induction period of crystallization as measured by FT-IR

Cited by 22 publications

References 20 publications

TEOS as an improved alternative for chitosan beads cross‐linking: A comparative adsorption study

TEOS as an improved alternative for chitosan beads cross‐linking: A comparative adsorption study

Structural Changes in Poly(trimethylene adipate) and Poly(trimethylene succinate) During Melt Crystallization Studied Using In Situ Infrared Spectroscopy

A two-dimensional IR correlation spectroscopic study of the conformational changes in syndiotactic polypropylene during crystallization

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