Effect Depolymerization residue

Figure 8. Effect of treatment severity on glycol lignin depolymerization in 2% NaOH. C/0 = carbon/oxygen ratio in residual lignins.

Melling and Atkinson29 investigated nuclease treatment as a method for the removal of nucleic acids from bacterial suspensions. Two strains of E. coli were used and for both the strains the nuclease treatment was effective in depolymerizing nucleic acids and, hence, in recovery of supernatant after centrifugation to remove cell debris from disrupted cells. The nucleotide content in the supernatant was found to be 15-20% of total proteins and nucleic acids. The nucleotide content in the supernatant was reduced to a very low level by ammonium sulfate precipitation followed by dialysis of the redissolved precipitate. As stated earlier, direct precipitation of nucleotides resulted in significant residual nucleotides in the proteins. 

In headspace analysis, the plastic is placed in a vial (at a raised temperature) and the volatiles formed are stripped by a flow of carrier gas. The stripped volatiles are trapped in a suitable sorbent (e.g., using a solid-phase microextraction device) and subsequently thermally desorbed into a gas chromatograph. Process gas chromatographs are used in industrial analysis of volatiles in plastics. An example of this technique is the determination of residual vinyl chloride monomer in plastics in the range of 5-50 g per kg. With direct injection of a polymer solution, there is a danger of side-effects (a loss of reactive monomers due to polymerization in the injection port or an increase in its content due to depolymerization at a high injection temperature). 

PLA is well known as a degradable material at higher temperatures. However, the mechanisms of the thermal degradation are complex. To clarify and control the thermal degradation of PLA, many efforts have been made. As a result, the effects of some important factors, such as polymerization catalyst residues, chain-end structures, depolymerization catalysts, stereocomplex structure, racemization, blends with other polymers, and so on, have been clarified. Highly active and selective depolymerization cat-... 

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