01970nas a2200169   4500008004100000022001400041245006800055210006600123260007100189300001400260490000700274520137000281100001701651700001501668700001601683856010101699       2006                        eng d  a0024-929700aCrystalline phases in nylon-11: studies using HTWAXS and HTFTIR0 aCrystalline phases in nylon11 studies using HTWAXS and HTFTIR  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR  a2841-28480 v393 a<p>Nylon-11 was crystallized into different crystalline phases by appropriate methods. The chance in the structure during heating was monitored in situ by wide-angle X-ray scattering (WAXS). The alpha phase obtained by precipitating nylon-11 in 1,4-butanediol started transforming into the pseudohexagonal phase on heating, but the transformation was not fully completed before melting. The melt crystallized sample at 175 degrees C gave the pseudohexagonal phase, which transformed into the alpha' phase on cooling to room temperature at about 100 degrees C. The d spacing of the 00 1 reflection also showed a change at the transition temperature. The melt-quenched sample showed the pseudohexagonal phase, which did not change during heating, but on cooling transformed into alpha' phase. The gamma phase was obtained by casting nylon-11 in trifluoroacetic acid (TFA), and it changed into the pscudohexagonal phase at about 110 degrees C on heating. The d spacing of the 001 reflection depended on the way in which it was obtained. The studies have shown that nylon-11 is one of the few nylons that exhibit an extensive degree of polymorphism. High-temperature Fourier transform infrared spectroscopy (HTFTIR) studies revealed, apart from the conformational differences between various phases of nylon-11, some information on the formation of the gamma phase.</p>1 aNair, S., S.1 aRamesh, C.1 aTashiro, K.  uhttps://library.ncl.res.in/content/crystalline-phases-nylon-11-studies-using-htwaxs-and-htftir-0