Stress Relaxation Study of Paper and Plastic film based Packaging Material

In this master degree thesis the time dependent deformation of packaging material is studied. Mechanical experimental tests were carried out to monitor the stress decreasing rate on paper. Several viscoelastic models were constructed using various theories and compared with the obtained experimental stress relaxation. The results showed that the modified two-unit Maxwell model suits the best to describe the relaxation behavior of the material in discussion. MATLAB was used to derive the stress relaxation equations which indicate the time dependent stress relaxation behavior of the materials for constant elongation. FE models were created by ABAQUS for analyzing the stress relaxation behavior of the paperboard and the laminate. The simulation results were then compared with the experimental results and the theoretical viscoelastic model. Additionally, specimens with a side crack were also studied.C/O Ramendu Bhusan Roy, Avijatri-13, Jail Road, Sunamganj, 3000, Banglades

Molecular and crystal engineering approaches towards the design of functional supramolecular gelators

Supramolecular gelators are an important class of compounds capable of immobilizing various solvents resulting in gels. Not much is known about the gelation mechanism and consequently, designing gelator molecule is a daunting task. However, efforts are being made to decipher the mystery of gelation and various groups are engaged in designing new gelators. Both molecular- and crystal engineering are being applied to synthesize new gelator molecules. This review article describes briefly the developments including the recent ones in this area; it also covers interesting applications offered by these wonderful materials