Isolation and characterisation of cellulose nanocrystals from sago seed shells.

Sago (Cycas circinalis) seed shells are agricultural waste materials discarded after taking the pith. In the present study Cellulose nanocrystals (CNCs) are isolated from the sago seed shells by acid hydrolysis. The hydrolysis was performed with 64% (w/w) sulphuric acid. The resulting CNCs were characterized by FTIR, XRD, SEM, TEM, AFM, DLS, Zeta (ζ) potential and TGA. FTIR spectrum of CNCs shows similar frequencies as that of α-cellulose, but with reduced intensity. XRD diffraction pattern shows co-existence of cellulose I and cellulose II with crystallinity index of 72% for cellulose II, 69% for cellulose I and crystallite size dimension of 9.4nm for cellulose I. SEM analysis clearly reveals the considerable size reduction during acid hydrolysis. TEM analysis shows that the isolated CNCs contain networked structures and almost spherical shaped particles having 10-15nm in size. Morphological examination through AFM also shows that isolated CNCs are in nano dimensions, having the size ∼50nm. DLS analysis gives an average size of 50nm and zeta (ζ) potential measured has a value of -37.8mV. DLS and AFM analyses support each other. TGA reveals lower thermal stability for CNCs.

Molecular dynamics and the translational-rotational coupling of an ionically conducting glass-former: amlodipine besylate.

We studied the conductivity relaxation originating from a glass-former composed of cations and anions, and the relation to the structural α-relaxation at temperatures above and below the glass transition temperature. The material chosen was amorphous amlodipine besylate (AMB), which is also a pharmaceutical with a complex chemical structure. Measurements were made using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and X-ray diffraction, and the characterization was assisted using density functional theory (DFT). The X-ray diffraction pattern confirms the amorphous nature of vitrified AMB. Both the ionic and dipolar aspects of the dynamics of AMB were examined using these measurements and were used to probe the nature of the secondary conductivity and dipolar relaxations and their relation to the conductivity α-relaxation and the structural α-relaxation. The coupling model predictions and quantum mechanical simulations were used side by side to reveal the properties and nature of the secondary conductivity relaxation and the secondary dipolar relaxation. Remarkably, the two secondary relaxations have the same relaxation times, and are one and the same process performing dual roles in conductivity and dipolar relaxations. This is caused by the translation-rotation coupling of the AMB molecule. Thus, AMB has both conductivity α- and ß-relaxations, and application of the coupling model shows that these two relaxations are related in the same way as the structural α-relaxation and the Johari-Goldstein ß-relaxation are. This important result has an impact on the fundamental understanding of the dynamics of ionic conductivity.

Polyaniline modified lignocellulosic fibers from sago seed shell powder for electrochemical devices.

We report the development of a novel electrode material from agrarian waste, sago (Cycas circinalis) seed shell powder (SSP). Lignocellulosic fibers obtained from sago seed shell powder were modified with polyaniline (PANI) by an in situ oxidative polymerization technique. Morphological changes, thermal stability and crystallinity of modified SSP were investigated using FTIR, XRD, SEM, TGA and DSC techniques. The structural organization of SSP with the monomer of PANI significantly influenced the thermal and electrical properties of resulting PANI-SSP composite material. The developed PANI-SSP composite showed enhanced thermal stability up to 308 °C with appreciable dc-conductivity in the range of 10-1 S cm-1 having very low activation energy of 0.0153 eV. The I-V characteristics of the composite exhibited nonohmic behaviour similar to a diode. Thus, the chemical modification of lignocelluloses fibers opens up a new avenue for fabricating cheap, eco-friendly substrates for energy storage devices, disposable electronic applications and diverse scopes for research and development.