Optical absorption spectra of poly(thiophene vinylene) (PTV) conjugated polymers have been studied at room temperature in the spectral range of 450 to 800 nm. A dominant peak located at 577 nm and a prominent shoulder at 619 nm are observed. Another shoulder located at 685 nm is observed at high concentration and after additional treatment (heat, sonification) only. Equilibrium atomic geometries and optical absorption of PTV conjugated polymers have also been studied by first principles density functional theory (DFT). For PTV in solvent, the theoretical calculations predict two equilibrium geometries with different interchain distances. By comparative analysis of the experimental and theoretical data, it is demonstrated that the new measured long-wavelength optical absorption shoulder is consistent with new optical absorption peak predicted for most energetically favorable PTV phase in the solvent. This shoulder is interpreted as a direct indication of increased interchain interaction in the solvent which has caused additional electronic energy structure transformations.
Microwave (MW) assisted enzymatic polymerizations is an area that is largely unexplored. In the current study, the effect of MW reaction parameters on poly-o-caprolactone (PCL) properties has been investigated using a statistical design. A {3,5} modified mixture experimental design was used to identify the parameter values that gave the desired properties of PCL. The three process parameters that were tested are temperature, MW intensity, and the reaction time. Experimental results showed that in the range of values tested, temperature had the highest positive influence on the properties of PCL, whereas high MW irradiation is not desirable. A cubic regression model was developed and optimal process parameters were obtained using this model. Conducting the polymerization reaction under optimal conditions (908C, 240 min, 50 W), PCL with M n of 20,624 and polydispersity index of 1.2 were obtained. The regression model was validated by carrying out validation experiments and by 3D visualization.
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