13C and 15N Solid-State NMR of Copolymers of Nylons 6 and 7: Observation of a Stable Pseudohexagonal Phase

Johnson, C. G.; Cypcar, Christopher C.; Mathias, Lon J.

doi:10.1021/ma00129a011

Cited by 11 publications

(10 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conclusions were drawn about the nature and inter-mingling of crystal forms, and observations were made of spherulite formation. Johnson et al [172] co-polymerized PA 6 and PA 7 and concluded that the components were randomly distributed. Pure component melting points were measured as 219 and 222 8C, respectively; for 45:55 mol-% mixture of PA 6 to PA 7 the melting point went through a minimum of 151 8C.…”

mentioning

confidence: 99%

Polyamides – Still Strong After Seventy Years

Marchildon¹

2010

Macro Reaction Engineering

332

141

View full text Add to dashboard Cite

Polyamides are a subject of enduring interest because of their variety, their complex internal structures, their commercial importance and versatility, and their various chemistries of preparation and of long‐term use. The present review introduces these polymers and then discusses the first of the above aspects, namely the variety of the polyamides. Here, together, the full family is presented, classified conveniently according to the types and combinations of monomers from which they are constructed. magnified image

show abstract

mentioning

confidence: 99%

Polyamides – Still Strong After Seventy Years

Marchildon¹

2010

Macro Reaction Engineering

332

141

View full text Add to dashboard Cite

show abstract

“…Qualitatively, it can be seen that the intensity of peaks of the Figure 5, are used to determine the crystalline form of the nylon. [9][10][11][12][13][14][15] The major amide nitrogen peak for nylons 6 u18 and 18 u18 are nearly identical, consistent with the a-form with a slight amorphous shoulder. Compared to their saturated analogs, the peaks are narrower, indicating a decrease in amorphous content for the unsaturated nylons, or to more uniform conformations even in the amorphous domain.…”

Section: Resultsmentioning

confidence: 99%

“…CP/MAS solid state 15 N NMR experiments were performed on a Bruker MSL 200 MHz spectrometer operating at 20.28 MHz with a 7.5 mm Chemagnetics double resonance probe with a sample spinning speed of 2.2 kHz. Crosspolarization was conducted using a 3.5 ms 1 H 908 pulse followed by a mixing time of 2 ms. An acquisition time of 42 ms using high powered decoupling was used with a relaxation delay of 3 s between scans.…”

Section: Characterizationmentioning

confidence: 99%

Linear Unsaturated Polyamides: Nylons 6 u18 and 18 u18

Bennett

Mathias

2004

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

Summary: Linear unsaturated nylons 6 u18 and 18 u18 have been made containing a double bond in the center of the diacid segment with potential for additional functionalization. Solution state NMR showed the presence of a small portion of cis amide units. Solid state NMR verified the presence of the double bond in the bulk, and that the polyamides were present in the α‐crystalline form. Thermal stability was comparable to linear saturated nylons, and the melting and crystallization temperatures of the unsaturated nylons were lower compared to the saturated analogs.

show abstract

“…It is well known that the ␣-form can be transformed into the ␥-form by treatment with an aqueous iodine/potassium iodide solution [14,15]. Incorporation of comonomers/polymers into the backbone of the PA6 can also influence the packing of the chains [16]. In general, the ␣-form is dominant when the polymer is melt-crystallized at temperatures higher than 150 • C or slowly cooled, while quenching and low-temperature crystallization promote the formation of the ␥-form [10,12,[16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Incorporation of comonomers/polymers into the backbone of the PA6 can also influence the packing of the chains [16]. In general, the ␣-form is dominant when the polymer is melt-crystallized at temperatures higher than 150 • C or slowly cooled, while quenching and low-temperature crystallization promote the formation of the ␥-form [10,12,[16][17][18]. The ␥-form can be transformed into the ␣-form via slow heating or annealing at an elevated temperature [11,19].…”

Section: Introductionmentioning

confidence: 99%