Structural aspects of alkali treated sisal fiber — A SAXS investigation

Abstract

The present work emphasizes the effect of alkali (NaOH) solution on macromolecular parameters of sisal fiber. The macromolecular parameters of alkali treated sisal fiber were computed along with air-dried sisal fiber by treating fiber as a non-ideal two-phase system characterized by continuous variation of electron density at the phase boundary. Small angle Xray scattering (SAXS) technique was employed to evaluate the macromolecular parameters, using correlation functions, applying the theories of Vonk, Ruland and Misra et al. The finite value of width of transition layer suggests to treat the fiber to be a non-ideal two-phased system. The evaluated macromolecular parameters are: transversal periodicity, specific inner surface, volume fractions of matter and void phases, transversal lengths in both phases, range of inhomogeneity, volume fraction of transition layer and length of coherence.

Comparative SAXS study of heated and alkali‐treated sisal fibers

“…The values of D, the average periodicity transverse to the layers for all the samples were obtained from the first subsidiary maximum of this plot. With the help of relation (13), the value of S/V, the specific inner surface was calculated for all the samples. The second differential coefficients of one-and three-dimensional correlation functions at origins, that is, ½d 2 C 1 ðyÞ=dy 2 À Á y¼0 and ½d 2 CðrÞ=dr 2 À Á r¼0 of each sample were determined by using five-point forward difference double differentiation formula.…”

“…Sisal being a natural cellulosic fiber having macromolecular structure with molecular dimension longer than the wavelength of X‐ray, SAXS technique was used to evaluate the fine structural characteristics of the air‐dried sisal fiber along with the fibers heated and treated with alkali solutions following the procedures of Misra et al4, 5 SAXS theories have been widely applied in the field of biopolymers by Petoukhov et al,8–10 Martel et al,11 to synthetic polymers by Patel et al12 and to natural polymers by Khan et al13 In recent years, SAXS techniques proved to be potential tools in the field of nanostructured materials as evident from the works of Marega et al,14 Neppalli et al,15 Causin et al,16 Gilbert et al,17 and many more.…”

Investigation of Dielectric and Mechanical Properties of Pretreated Natural Sunn Hemp Fiber-Reinforced Composite in Correlation with Macromolecular Structure of the Fiber

“…To get η values, another phase called the void phase with diffuse boundary is taken into account. 1 The phase variation from one phase to another is not abrupt but, instead, continuous over a range called the width of the transition layer (E). SAXS analysis of sunn hemp fiber helps to build a structure−property relation of the fiber and its influence on the properties of the fiber-reinforced polymer composites.…”

“…This is the reason why both phases are considered as one phase named the matter phase (say η 1 ). To get η values, another phase called the void phase with diffuse boundary is taken into account . The phase variation from one phase to another is not abrupt but, instead, continuous over a range called the width of the transition layer ( E ).…”

Effect of cloisite 30B clay and sisal fiber on dynamic mechanical and fracture behavior of unsaturated polyester toughened epoxy network

“…Hence, the surface modification of clays and sisal fibers are necessary before incorporate within the hydrophobic matrix. Surface modification of the fiber removes the wax, hemicelluloses, and other impurities present on the fiber surface and increases the surface roughness; surface modification of the clay removes the weak boundary layer on the surface and to increase the polar groups . Various studies have been carried out on the surface modification of natural fibers to improve their adhesion with the polymer matrix .…”