Investigations in two-step ultrasonic synthesis of PMMA/ZnO nanocomposites by in–situ emulsion polymerization. (2nd September 2016)

• Record Type: Journal Article
• Authors: Poddar, Maneesh Kumar; Sharma, Sachin; Moholkar, Vijayanand S.
• Is Part Of: Polymer. Volume 99(2016)
• Page Start: 453
• Page End: 469
• Publication Date: 2016-09-02
• Subjects: Nanocomposites -- Ultrasound -- PMMA -- Thermal stability -- Emulsion polymerization -- Zinc oxide; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2016.07.052
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: This paper reports two-step ultrasonic method for in-situ synthesis of PMMA/ZnO nanocomposites. First step comprises nanoscale ZnO synthesis through ultrasound-assisted in-situ hydrolysis of zinc acetate. In second step, PMMA/ZnO nanocomposites have been synthesized via ultrasound-assisted in-situ emulsion polymerization in presence of native ZnO particles (1–5 wt%, without surface modification). Approx. 10 × -enhancement in polymerization kinetics is obtained. Properties of nanocomposites for different ZnO loadings are: particle size = 77.7–109.7 nm, maximum degradation temperature = 386.4 °C, maximum glass transition temperature = 122.5 °C, UV–visible absorption band width = 350–375 nm, electrical conductivity = 0.028–0.207 μS/cm, tensile strength = 25.8–36.57 MPa, Young's modulus = 1.09–1.47 GPa, percentage elongation = 10.98–17.56%. These enhanced properties (as compared to previous literature) are essentially attributed to uniform dispersion of ZnO in polymer matrix due to intense micro-convection generated by sonication. This results in strong interfacial interactions and adhesion between phases with increased crystallinity. Graphical abstract: Highlights: Two-step sonochemical method for synthesis of PMMA/ZnO nanocomposites. First step: nanoscale ZnO synthesis by in-situ sonochemical hydrolysis of Zn-acetate. Second step: sonochemical emulsion polymerization with native ZnO nanoparticles. Enhanced thermal, mechanical, electrical, and optical properties of the nanocomposites. Micro-convection due to sonication achieves uniform distribution of ZnO in PMMA.