CRYSTAL-STRUCTURE AND THERMODYNAMIC PARAMETERS OF NYLON-1010

WAXD, SAXS, FTIR, DSC and density techniques have been used to investi gate the crystal structure, crystal density rho(c), amorphous density rho(a), equilibrium heat of fusion DELTAH(m)degrees and equilibrium me lting temperature T(m)degrees. By extrapolating the straight lines in the FTIR absorbance against density plot to zero intensity, rho(c) and rho(a) were estimated to be 1.098 and 1.003 g/cm3 respectively. The r ho(c) obtained was too low in value. From X-ray diffraction patterns o f uniaxially oriented fibres, the crystal structure of Nylon-1010 was determined. The Nylon-1010 crystallized in the triclinic system, with lattice dimensions: a = 4.9 angstrom, b = 5.4 angstrom, c = 27.8 angst rom, alpha = 49-degrees, beta = 77-degrees, gamma = 63.5-degrees. The unit cell contained one monomeric unit, the space group was P1BAR, and the correct value of rho(c) was 1.135 g/cm3. The degree of crystallin ity of the polymer was determined as about 60% (at RT) using Ruland's method. SAXS has been used to investigate the crystalline lamellar thi ckness, long period, transition zone, the specific inner surface and t he electron density difference between the crystalline and amorphous r egions for Nylon-1010. The analysis of data was based upon a one-dimen sional electron-density correlation function. DELTAH(m)degrees was est imated to be 244.0 J/g by extrapolation of DELTAH(m)degrees in the plo t of heat of fusion against specific volume of semicrystalline specime ns to the completely crystalline condition (V(sp)c = 1/rho(c)). Owing to the ease of recrystallization of melt-crystallized Nylon-1010 speci mens, the well-known Hoffman's T(m)-T(c) method failed in determining T(m)degrees and a Kamide double extrapolation method was adopted. The T(m)degrees value so obtained was 487 K.