Mohammad Abdul Salam

While there is considerable on-going molecular-scale modeling in the area of lignocellulosic biomass, the majority focuses on discovering specific conversion pathways.  This work, however, endeavors to utilize molecular-scale modeling to enable the development of meso- to micro-scale simulations that connect with relevant micro-structural and kinetic aspects of biomass pyrolysis.  As a starting point, this work is focusing on exploring the stability of cellulose in various forms and in particular endeavors to better understand the transition states associated with the conversion of cellulose to levoglucosan.

Density Functional Theory (DFT) is being used to study the formation of transition state in the pathway from cellulose to levoglucosan, one of the major products of cellulose pyrolysis.  Of primary interest is the stability of cellulosic chains at the free surface and within both crystalline and amorphous forms, as well as chains in native lignocellulosic frameworks.

A secondary, but related topic is that of diffusion of products through cellulose at different temperatures.  Molecular dynamics simulations are being performed using the PCFF (polymer consistent force field) and, as a starting point, small molecular species such as carbon dioxide. Two cellulosic systems are being considered: native crystalline phase (Iβ) and an amorphous phase. The goal for this work is to explore how the crystallinity affects rate of gas transport.