Senior Comprehensive Paper

The presence of absorbed free radical initiators, such as benzophenone, benzoyl peroxide and bromine may enhance the number of free radicals formed by the radiation of cellulose. These radicals may then become available to initiate the break-up of the cellulose structure. Experimental methods for studying the degradation of cellulose were developed with a particular emphasis on the effect of absorbed species. The first approach focused on determining the amount of glucose present after exposing cotton balls saturated with hydrogen peroxide to gamma radiation dose of 49kGy. The amount of glucose that was present would show if hydrogen peroxide aided in the degradation of cellulose. This method, which used Benedict’s reagent to test for the presence of glucose, failed to show results consistently and the ESR approach was then taken. This is studied by comparing samples of pure cellulose to samples of cellulose with each of the three different initiators. One group of these samples is then subjected to gamma radiation while the other is used as a control. The samples were then analyzed using ESR (Electron Spin Resonance) to determine the free radical production. The spectra of the samples that contained a mixture of benzophenone and cellulose showed unique peaks with the sample of 0.2g benzophenone having peaks at 3347G and 3330G with another smaller one at 3320G while the sample with 0.5 g of benzophenone showing peaks at the same point in the magnetic field but with a stronger intensity. Although there was not sufficient time to obtain all the results, the data that was gathered shows promising results about the concentration of free radicals present in the sample. Introduction: The degradation of cellulose is important to study because it is at the forefront of biofuel research. Cellulose is one of the most widespread natural polymers and is a key component of plant's cell walls, but it is not easily freed from the cell wall's complex and rigid structure. When cellulose is exposed to radiation it acts as a pre-treatment to break-up the cellulose into fragments prior to enzymatic or hydrolytic treatment. The process of decomposing cellulose to glucose is as follows in Fig.1.