Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

Abstract

Abstract:In this study we used anionic living polymerization to prepare two different homopolymers: a poly(methyl methacrylate) (PMMA) and a PMMA derivative presenting polyhedral oligomeric silsesquioxane (PMA-POSS) units as its side chains. We then employed differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and wide-angle X-ray diffraction (WAXD) to investigate the miscibility and specific interactions of PMMA and PMA-POSS with three hydrogen bonding donor compounds: poly(vinyl phenol) (PVPh), phenolic resin, and bisphenol A (BPA). DSC revealed that all of the PVPh/PMMA, phenolic/PMMA, and BPA/PMMA blends exhibited a single glass transition temperature, characteristic of miscible systems; FTIR spectroscopic analyses revealed that such miscibility resulted from hydrogen bonding interactions between the C=O groups of PMMA and the OH groups of these three hydrogen bonding donor compounds. In contrast, all of the PVPh/PMA-POSS, phenolic/PMA-POSS, and BPA/PMA-POSS blends were immiscible: DSC revealed two OPEN ACCESSPolymers 2014, 6 927 glass transition temperatures arising from strong screening effects (FTIR spectroscopy) and high degrees of aggregation (WAXD) of the POSS nanoparticles. We propose that the value of the intramolecular screening effect (γ) should be very close to 1 for all PMA-POSS blend systems when POSS nanoparticles appear as the side chains of PMMA, such that the OH groups of the hydrogen bonding donor compounds cannot interact with the C=O groups of PMA-POSS.

Synthesis of Poly(N-methylol Methacrylamide/Vinyl Sulfonic Acid) Hydrogels for Heavy Metal Ion Removal

“…These changes have derived from transformations of strong intra- molecular OH···OH, and SO 3 ···OH into weak intermolecular OH···C=O bonds. 19,20 The width of this band has increased with the increase of VSA content. 18,19 The band at 2900 cm −1 has been responsible for main chain asymmetric -CH 2 stretching vibrations.…”

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

“…In this case, it must be noted that the second T g values for the EA-POSS-based SATs generally increased with increasing T g value of the incorporated copolymers ( Table 2). The second T g values may be affected by strong screening effects of POSS cages [46] embedded in the copolymer fraction miscible with the epoxy component. Nevertheless, the above-mentioned macroscopic incompatibility of ER and the majority of the EA-POSS copolymers (i.e., the main components of the SATs) did not negatively influence the mechanical properties of cured aluminum/SAT/aluminum joints (see Section 3.3).…”

Main Chain–Type Block Copolymers through Atom Transfer Radical Polymerization from Double-Decker–Shaped Polyhedral Oligomeric Silsesquioxane Hybrids

“…In addition to BCP/POSS composites formed through specific physical interactions, covalent chemical bonding of BCPs with POSS NPs has also attracted much interest [34][35][36][37][38][39]. For example, POSS NPs have been positioned at chain ends (e.g., in POSS-b-PS [34][35][36], POSS-b-PMMA [37,38], and POSS-b-PBLG [39,40]) and at junction points (e.g., in PS-b-POSS-b-PDMS [41]) through living polymerization and controlled living radical polymerization to obtain related hybrid block copolymers. Furthermore, star block copolymers prepared through living polymerization and controlled living radical polymerization, using POSS NPs as cores, have also been widely investigated in the forms of PS-b-P4VP [42], PS-b-PVPh [42], PS-b-PMMA [43], and PEO-b-PBLA [44] hybrid block copolymers.…”