Synthesis of Monoacryloxypropyl-POSS-based Hybrid Epoxyacrylate Copolymers and Their Application in Thermally Curable Structural Self-Adhesive Tapes.

Agnieszka Kowalczyk,Krzysztof Kowalczyk,Konrad Gziut

doi:10.3390/polym11122058

Agnieszka Kowalczyk, Krzysztof Kowalczyk + Show 1 more

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https://doi.org/10.3390/polym11122058

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Journal: Polymers	Publication Date: Dec 11, 2019
Citations: 10	License type: CC BY 4.0

Affiliation: West Pomeranian University of Technology

Abstract

New organic-inorganic hybrid copolymers (EA-POSSs) based on butyl acrylate, glycidyl methacylate, hydroxybutyl acrylate, acryloiloxybenzophenone and acryloxypropyl-heptaisobutyl-POSS (A-POSS) were prepared via free-radical solution polymerization (FRP) and applied as a component of thermally curable structural self-adhesive tapes (SATs). The EA-POSS with 0.25, 0.5 or 1 mol % of A-POSS exhibited significantly higher dynamic viscosity (ca. +104%), Mw (+61%) and polydispersity (+109%; measured using gel permeation chromatography) as well as lower Tg value (−16 °C) in relation to the A-POSS-free copolymer (EA-0). Differential scanning calorimetry (DSC) measurements (one glass transition process) confirmed statistic chain structure of the EA-POSS materials. Replacement of EA-0 by the EA-POSS copolymers in a SATs recipe caused simultaneous improvement of their self-adhesive features, i.e., adhesion (+70%), tack (+21%) and cohesion (+1590%). Moreover, the POSS-based copolymers improved the shear strength of thermally cured Al/SAT/Al overlap joints; the best mechanical resistance (before and after accelerated ageing tests) was observed for the sample containing 0.5 mol % of A-POSS (an increment range of 50–294% in relation to the A-POSS-free joints). Thermogravimetric analysis (TGA) revealed markedly improved thermal stability of the A-POSS-based SATs as well.

Highlights

Polyhedral oligomeric silsesquioxanes (POSSs) create a class of organosilicon materials with an empirical formula RSiO3/2.Depending on the functionality and structure of POSSs, they can be used as fillers, comonomers, cross-linking agents or initiators [1].Incorporation of POSSs into polymeric materials can be realized by their blending, as well as grafting andpolymerization [2]
As can be seen in Table 2., the Mw of the modified copolymers generally decreases with increasing content of A-POSS; at the lowest modifier concentration (0.25 mol %), Mw reaches its highest value in relation to the epoxyacrylate copolymers (EA)-0 and the other samples
We have previously reported that the Bisphenol A-based epoxy resin (ER) and the epoxyacrylate

Summary

Introduction

Polyhedral oligomeric silsesquioxanes (POSSs) create a class of organosilicon materials with an empirical formula RSiO3/2 (where R is a hydrogen, alkyl, alkylene, aryl, arylene or other substituent).Depending on the functionality (mono- or multifunctional) and structure (random, ladder, cage or partial cage) of POSSs, they can be used as fillers, comonomers, cross-linking agents or initiators [1].Incorporation of POSSs into polymeric materials can be realized by their blending (non-reactive POSSs or POSS-based polymers), as well as grafting and (co)polymerization (multi- and mono-functionalPOSSs) [2]. Incorporation of POSSs into polymeric materials can be realized by their blending (non-reactive POSSs or POSS-based polymers), as well as grafting and (co)polymerization The first POSS-based copolymer was described by Lichtenhan in 1995 (a conventional free radical polymerization process of methacrylate-functionalized POSS monomers) [3]. Due to the unique features of POSS copolymers (e.g., high thermal stability), different POSS monomers were employed in atom transfer radical polymerization (ATRP), free radical polymerization (FRP), reversible addition fragmentation chain-transfer polymerization (RAFT), anionic polymerization processes, thiol-ene (click) and grafting reactions [4,5,6,7,8,9,10,11] or photoinitiated polymerization processes [12,13,14,15].

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