Effect of Water Vapor Sorption on Local Structure of Poly(vinylpyrrolidone)

Teng, Jing; Bates, Simon; Engers, David; E.Leach, Kevin; Schields, Paul J.; Yang, Yonglai

doi:10.1002/jps.22204

Cited by 57 publications

(54 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The data in Figure 5 indicate that water incursion into the polymer impacts chain mobility; that is, the polymer has transitioned from a glassy rigid state to a rubbery, more flexible state and is manifested by a drop in T g . These findings are in excellent agreement with similar reports on other polymers like polyvinylpyrrolidone (PVP), modified celluloses, and so forth [33,34].…”

Section: Moisture Uptakesupporting

confidence: 92%

Effect of Hydration on Physicochemical Properties of End-Capped PLGA

D’Souza

Dorati

DeLuca

2014

Advances in Biomaterials

View full text Add to dashboard Cite

The objective of this study was to assess the physicochemical effects of hydrating a hydrophobic end-capped poly(lactide-coglycolide) (PLGA) polymer in the liquid and vapor state. PLGA RG503 polymer was incubated at 37 ∘ C in 0.5% polyvinyl alcohol (PVA) solution and at 90% RH. Samples were withdrawn at predetermined intervals and changes to polymer properties like glass transition temperature (T g ), moisture uptake, molecular weight change, and % acid number were determined using differential scanning calorimetry, Karl Fisher titrimetry, gel permeation chromatography, and acid base titrimetry, respectively. Study results showed that T g was depressed instantaneously upon hydration, indicating that bulk water acted as a plasticizer of hydrophobic end-capped PLGA. T g values decreased to levels below the incubation temperature when hydrated in 0.5% PVA solution but not in 90% RH. The drop in T g exhibited a linear relationship ( 2 > 0.99) to the amount of water uptake by the polymer; higher moisture uptake was noted with liquid water. Removal of moisture from the polymer matrix resulted in recovery of T g , only up to a period of 14 days. Presence of water in liquid or vapor form caused a reduction in molecular weight of the polymer and a corresponding increase in % acid number over the duration of the study.

show abstract

Section: Moisture Uptakesupporting

confidence: 92%

Effect of Hydration on Physicochemical Properties of End-Capped PLGA

D’Souza

Dorati

DeLuca

2014

Advances in Biomaterials

View full text Add to dashboard Cite

show abstract

“…In a later article on structure of PVP in the presence of sorbed water, the positions of the two halos in the XRPD pattern gradually changed with increasing water content, representing evidence for "clustering" of water in PVP. 41 The partial molar enthalpy and entropy findings support the conclusions of the structural changes in the H 2 O-PVP system reported in earlier work. Molecular dynamics simulation of water in PVP has also indicated clustering to be present at a water content of 10% (w/w), 42 which corresponds to 30% RH or X w approximately 0.3 (Fig.…”

Section: Discussionsupporting

confidence: 88%

“…The partial molar enthalpy and entropy results appear to support this concept. In a later article on structure of PVP in the presence of sorbed water, the positions of the two halos in the XRPD pattern gradually changed with increasing water content, representing evidence for “clustering” of water in PVP . The partial molar enthalpy and entropy findings support the conclusions of the structural changes in the H 2 O–PVP system reported in earlier work.…”

Section: Discussionsupporting

confidence: 79%

Thermodynamics of Water–Solid Interactions in Crystalline and Amorphous Pharmaceutical Materials

Sacchetti

2014

Journal of Pharmaceutical Sciences

View full text Add to dashboard Cite

“…Finer crystallites are prone to react faster (or to react better as catalysts). Assessment of crystallite shape (in case of anisotropic peak size broadening) Lattice parameters and hence metallic contents can be accurately determined [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…It can identify the polymorph and determine the phase abundance to classify the cement and correlating the performance with composition [9][10][11][12][13][14][15].…”

mentioning

confidence: 99%

Usage of Powder XRD Technique for Material Characterization and Analysis of Portland Cement

Chauhan¹,

Chauhan²

2015

J Anal Bioanal Tech

View full text Add to dashboard Cite

PXRD technique has non-destructive nature, marked sensitivity, reliability, simple and fast sample preparation, user friendly, convenient, fast speed, high resolution, minimum maintenance cost, proper automation, easy interpretation of the information that could be utilized for both qualitative and quantitative aspects of analysis. It is the primary tool for solid state characterization. Material characterization provides the information about the particle size, crystallite size, phase transitions, texture, strain broadening, crystal structure and lattice parameters. It can be used to study the crystallinity, crystalline index, identify the crystalline phases, spacing between lattice planes, scales of existence, preferential order and epitaxial growth of crystallites. Every material or compound has its unique diffraction patterns so materials and compounds can be identified by comparing a database of diffraction patterns. The purity of a sample can be accessed by diffraction pattern (Figure 1) by taking into consideration the proportion and composition of impurities present. PXRD is the prime requisite for differentiating the crystalline sample ( Figure 2) from semi-crystalline like in polymer like cotton and amorphous materials like phenol-formaldehyde complex resin ( Figure 3) [1][2][3][4][5][6][7][8].XRD is helpful in qualitative and quantitative phase abundance analysis. It can identify the polymorph and determine the phase abundance to classify the cement and correlating the performance with composition [9][10][11][12][13][14][15]. Material CharacterizationX-rays were discovered by German Scientist Röntgen in 1868. Von Laue in 1912 discovered X-ray diffraction by crystals. The wavelength of X-rays is similar to the distance between atoms. Atoms in a crystal form a periodic array of coherent scatters. When each object in a periodic array scatters radiation coherently the diffraction occurs that leads to constructive interference at each specific angle. Diffraction from different planes of atom produces a diffraction pattern (diffractogram) that contains information about the atomic arrangement in the crystal (Figure 1). We get information like d-value and peak position at 2-theta scale.The peak position at 2 theta scale depends on instrumental characteristics such as wavelength. The peak position as d hkl is an intrinsic, instrument-independent, material property. XRD diffraction intensity depends upon polarization factor, structure factor (F 2 ), multiplicity factor, Lorentz factor, absorption factor and temperature factor. The diffraction pattern for every phase is as unique as fingerprint. Phases with the same chemical composition can have drastically different diffraction patterns. Peak areas are much more reliable than peak heights as a measure of intensity. Crystallites smaller than 120 nm create broadening of diffraction peaks. Micro strain may also create peak broadening. Presence of coarse particles and bad loading cause several negative effects such as preferred orientation, pattern shifts, poor re...

show abstract

Effect of Water Vapor Sorption on Local Structure of Poly(vinylpyrrolidone)

Cited by 57 publications

References 37 publications

Effect of Hydration on Physicochemical Properties of End-Capped PLGA

Effect of Hydration on Physicochemical Properties of End-Capped PLGA

Thermodynamics of Water–Solid Interactions in Crystalline and Amorphous Pharmaceutical Materials

Usage of Powder XRD Technique for Material Characterization and Analysis of Portland Cement

Contact Info

Product

Resources

About