Structure of Amorphous Polyamides

Krizan, Timothy D.; Coburn, John C.; Blatz, Philip S.

doi:10.1021/bk-1990-0423.ch005

Cited by 26 publications

(25 citation statements)

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“…There are several commercial semiaromatic, amorphous polyamides that exhibit good oxygen barrier properties, suitable for packaging applications, e.g., Selar ® PA (duPont), Novamid ® (Mitsubishi Chemical), Grivory ® HB (EMS). To improve the oxygen barrier properties of PA-6 (and PA-66), high T g, barriertype amorphous polyamides such as PA-6I/6T (Selar ® PA) have been blended (Krizan et al 1989;Blatz 1989). These blends exhibit improved barrier to oxygen permeation particularly at high relative humidity (Fig.…”

Section: Polyamide/polyamide Blendsmentioning

confidence: 99%

Commercial Polymer Blends

Akkapeddi¹

2014

Polymer Blends Handbook

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Section: Polyamide/polyamide Blendsmentioning

confidence: 99%

Commercial Polymer Blends

Akkapeddi¹

2014

Polymer Blends Handbook

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“…In fact, water molecules occupied part of free volume in polymer matrix available for gas diffusion and reduce the amount of free volume and the pathways for oxygen permeation. Krizan et al reported that water molecules compete with permeate gas for excess free volume in the MXD6 polymer matrix. In another study, Buquet et al showed that a spherulitic water‐induced crystallization phase take place from the water/polymer interface after water immersion at ambient temperature and this presence of crystals improve the barrier properties of MXD6.…”

Section: Introductionmentioning

confidence: 99%

Rheological, crystal structure, barrier, and mechanical properties of PA6 and MXD6 nanocomposite films

2013

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In this study, rheological, crystal structure, barrier, and mechanical properties of polyamide 6 (PA6), poly(m‐xylene adipamide) (MXD6) and their in situ polymerized nanocomposites with 4 wt % clay were studied. The extent of intercalation and exfoliation as well as type of crystals, crystallinity, and thermal transitions were investigated using X‐ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. Dynamic rheological measurements revealed that incorporation of nanoclay significantly increases complex viscosity of MXD6 nanocomposites at low frequencies, which was related to the formation of a nanoclay network and exchange reaction between MXD6 chains. The comparative study of dynamic characteristics (G′ (ω) and G″ (ω)) for aliphatic and aromatic polyamide nanocomposites with their neat resins as well as the relaxation spectra for both polymer systems confirmed the possibility of the aforementioned phenomena. Although, the crystallinity of MXD6 films was lower as compared to PA6 films, the permeability to oxygen was more than 5 times better for the former. Incorporating 4 wt% clay enhanced the barrier property, tensile modulus, and yield stress of PA6 and MXD6 nanocomposite films in both machine and transverse directions without sacrificing much puncture and tear resistances. The PA6‐based films showed higher tear and puncture strength as compared to MXD6 films. POLYM. ENG. SCI., 54:2617–2631, 2014. © 2013 Society of Plastics Engineers

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“…The thermal characterization of new copolymers is fundamental: indeed, the Tg value and the tendency to crystallize strongly influence both the barrier properties and the processability during film manufacturing. 37–39 For instance, based on the previous experience with PA6I and PA6I-6T polyamides, the Authors believe that MXD6-based copolymers, characterized by a high T g value and a scarce tendency to form a crystalline phase, may show a reduced brittleness, an easy stretchability and possibly an enhanced barrier to gases.…”

Section: Resultsmentioning

confidence: 99%

“…Despite its prominent effect on barrier properties, free volume cannot be quantified easily and is often correlated to the density of polymers with a similar structure. 37 Table 4 lists the density for the prepared copolymers.…”

Section: Resultsmentioning

confidence: 99%

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MXD6 in film manufacturing: State of the art and recent advances in the synthesis and characterization of new copolyamides

Vannini

Marchese

Celli

et al. 2019

Journal of Plastic Film & Sheeting

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Semiaromatic polyamides belong to a large family of polymers commonly utilized in demanding engineering applications due to a unique set of outstanding mechanical properties as well as in terms of thermal and chemical resistance. Somewhat less understood is the use of certain members of this family in packaging applications such as the manufacturing of films and sheets or thin-walled containers, as well as the motivations and limitations in designing film structures containing them. This article reviews how m-xylylene diamine (MXD)-based polyamides are used in packaging applications. Attention is also given to film manufacturing and criticalities in its processing. Recent developments in MXD-based polyamides for gas barrier applications are also reported, while examining future perspectives in speciality film manufacturing. The new described copolymers based on MXD6 were synthesized by introducing different co-units, like isophthalic acid, 2,6-naphthalenedicarboxylic acid, glutaric acid, oxalic acid or 1,6-hexamethylene diamine. The performed characterization analyses (DMTA, DSC, density and OTR) allowed the polymer structures and properties to be correlated. Introducing 2,6-naphthalenedicarboxylic acid along the MXD6 chain led to the highest Tg (101°C) and density (1.233 g/cm3) and the lowest OTR (0.0035 cm3·cm/m2·day·atm, up to one order of magnitude lower).

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Structure of Amorphous Polyamides

Cited by 26 publications

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Commercial Polymer Blends

Commercial Polymer Blends

Rheological, crystal structure, barrier, and mechanical properties of PA6 and MXD6 nanocomposite films

MXD6 in film manufacturing: State of the art and recent advances in the synthesis and characterization of new copolyamides

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