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Composition‐dependent crystallization behavior of copolyperoxides from methyl methacrylate and 4‐vinylbenzyl stearate
Author(s) -
Mete Sourav,
Goswami Krishna Gopal,
De Priyadarsi
Publication year - 2020
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200029
Subject(s) - differential scanning calorimetry , thermogravimetric analysis , small angle x ray scattering , lamellar structure , materials science , polymer chemistry , crystallization , polymer , copolymer , thermal stability , methyl methacrylate , chemical engineering , lamella (surface anatomy) , scattering , composite material , physics , optics , engineering , thermodynamics
To study the composition‐dependent crystallization behavior of copolyperoxides, herein a series of copolymers were prepared by varying the ratios of methyl methacrylate (MMA) and 4‐vinylbenzyl stearate (VBS) under 100 psi oxygen pressure using AIBN as an initiator at 50°C in toluene. Both 13 C NMR and electron impact mass spectroscopy (EI‐MS) approved an alternative placement of either of the monomer and peroxy (–O–O–) links throughout the polymer chain. Thermal stability of the resulting copolyperoxides was investigated by thermogravimetric analysis (TGA) and the degradation fragments have been recognized from EI‐MS study. In addition, differential scanning calorimetry (DSC) displayed an endothermic peak as well as an exotherm associated with the melting of the side chain crystalline domains and degradation of –O–O– links in the polymer main chain, respectively. Furthermore, DSC thermograms unveiled a systematic decrease of the crystalline melting temperature ( T m ) with the enhancement of MMA content in the copolymers. Small angle X‐ray scattering (SAXS) revealed the existence of lamellar morphology (depends on VBS content in the copolyperoxide) in the synthesized polyperoxide materials, further supported by atomic force microscopy (AFM) analysis showing a layered fibrillar assembly with multiple heights of the lamella. The significant crystalline nature of the polyperoxides was further evidenced from the appearance of lattice fringes in the transmission electron microscope (TEM) micrographs. The crystalline morphology with birefringent texture was further evidenced from the polarized optical microscopy (POM) study. Thus, the present study reported the effective variation of crystalline behavior in copolyperoxide materials with the incorporation of MMA units in the copolyperoxide chains.