Mechanochemical tuning of molecular weight distribution of styrene homopolymers as postpolymerization modification in solvent-free solid-state |
| |
Authors: | Milton Jimenez-Francisco Jose Gonzalo Carrillo Luis Alfonso Garcia-Cerda |
| |
Affiliation: | 1. Unidad de Materiales, Centro de Investigacion Cientifica de Yucatan, Merida, Mexico;2. Departamento de Materiales Avanzados, Centro de Investigación en Química Aplicada, Saltillo, Coahuila, Mexico |
| |
Abstract: | Mechanochemical degradation by planetary ball milling (PM) is used for postpolymerization modification of styrene homopolymers (PS). A complete factorial design was chosen to study the effect of radical scavengers, milling time, initial molecular weight, and revolution radius (Rp), on the shape of molecular weight distributions (MWDs) of PS. Size-exclusion chromatography analysis shows the feasibility of fine-tuning MWD of PS at up to 40% conversion. Distributions ranged from unimodal to bimodal in a PM with Rp = 150 mm at different stage of milling, whereas in a PM with Rp of 60.8 mm the adjustment of unimodal distributions is achieved. Initial polydispersity is more important to develop bimodal distributions when compared with initial molecular weight. Fourier transform infrared and X-ray electron spectrometry analysis show some suppression of PS degradation and complete oxidation inhibition of macromolecular radicals with the incorporation of radical scavengers, which we considered as additional aids when adjusting the MWDs. |
| |
Keywords: | coatings degradation recycling spectroscopy structure-property relationships |
|
|