m-Xylylenediamine Polyamide Resins

Carlston, E. F.; Lum, F. G.

doi:10.1021/ie50572a025

Cited by 32 publications

(11 citation statements)

References 4 publications

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“…Reversing the carbonyl position with respect to the amide nitrogen in isomeric MXD6 and 6I also alters the nature of hydrogen bonding. 22 In MXD‐based polyamides, the amide groups rotate freely to optimize intermolecular hydrogen bonding. In HMD‐based polyamides, conjugation with the aromatic ring restricts the amide group to essentially a coplanar orientation.…”

Section: Resultsmentioning

confidence: 99%

Effect of water sorption on oxygen‐barrier properties of aromatic polyamides

Mehta

Schiraldi

et al. 2005

J Polym Sci B Polym Phys

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Aromatic polyamides based on poly(m‐xylylene adipamide) (MXD‐based polyamides) and poly(hexamethylene isophthalamide) (HMD‐based polyamides) were examined. Insight into the excellent gas‐barrier properties was obtained by the characterization of the effect of water sorption on the thermal transitions, density, refractive index, free‐volume hole size, and oxygen‐transport properties. Reversing the carbonyl position with respect to the amide nitrogen substantially lowered the oxygen permeability of MXD‐based polyamides in comparison with that of HMD‐based polyamides by facilitating hydrogen‐bond formation. The resulting restriction of conformational changes and segmental motions reduced diffusivity. The primary effect of water sorption was a decrease in the glass‐transition temperature (Tg) attributed to plasticization by bound water. No evidence was found to support the idea that sorbed water filled holes of free volume. When the polymer was in the glassy state, the drop in Tg accounted for hydration‐dependent changes in the density, refractive index, and free‐volume hole size. The correlation of the oxygen solubility with Tg and density confirmed the concept of oxygen sorption as filling holes of excess free volume. In some cases, water sorption produced a glass‐to‐rubber transition. The onset of rubbery behavior was associated with a minimum in the oxygen permeability. The glass‐to‐rubber transition also facilitated the crystallization of MXD‐based polymers, which complicated the interpretation of oxygen‐transport behavior at higher relative humidity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1365–1381, 2005

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Section: Resultsmentioning

confidence: 99%

Effect of water sorption on oxygen‐barrier properties of aromatic polyamides

Mehta

Schiraldi

et al. 2005

J Polym Sci B Polym Phys

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“…Poly(ethylene terephthalate) (PET) is a semicrystalline thermoplastic polymeric material with a good balance of thermal, mechanical, and barrier properties 41, 42. Poly( m ‐xylylene adipamide) (MXD6) is another semicrystalline thermoplastic that shows high oxygen barrier properties, good transparency, high mechanical strength, and satisfactory heat resistance 43, 44. To further enhance the barrier properties, thermal stability and mechanical properties of PET and MXD6, nanoclays can be added into the matrices of these polymers.…”

Section: Introductionmentioning

confidence: 99%

Novel preparation method for enhancing nanoparticle dispersion and barrier properties of poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

Wang

Jabarin

2012

J of Applied Polymer Sci

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A modified melt blending method has been developed for preparing exfoliated nanocomposites of poly(ethylene terephthalate) with sodium-montmorillonite (Na-MMT) and poly(m-xylylene adipamide) with Na-MMT. In this novel compounding process, a Na-MMT water solution was blended with the polymer in a twin screw extruder. This mixing process ensured that the silica nanoparticles were exfoliated in the polymer matrix through fixing the nanoparticles within the polymer matrix almost as they were in water. Transmission electron microscopy (TEM) and X-ray diffraction were used to determine nanoparticle dispersion level. The absence of the X-ray basal reflections in conjunction with the TEM images revealed the exfoliation of clay platelets. Differential scanning calorimetry illustrated that the nucleating abilities of montmorillonite were related to clay content and dispersion morphology. Oxygen permeation results indicated that the improved morphologies had enhanced the barrier properties of the nanocomposites.

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“…The very high melting point of 6-T reflects a combination of high chain stiffness and strong polar attraction. The preparation and general properties of MXD-6 polymer have been described previously ( 1,2 ] . The polymer used in this study was obtained from the Oronite Chemical Co. and had an I. V. of 1.12 dl/g (in m-cresol @ 25 ° C ) .…”

Section: Structural Considerationsmentioning

confidence: 99%