Preparation and characterization of organic-inorganic hybrid nanomaterials using polyurethane-b-poly[3-(trimethoxysilyl) propyl methacrylate] via RAFT polymerization

Abstract

Abstract.A series of novel block-type amphiphilic copolymers have been prepared by copolymerizing methacrylate endcapped oligo-urethane and 3-(trimethoxysilyl) propyl methacrylate (TPM) via the sol-gel process. Copolymers with welldefined end groups and narrow polydispersity were prepared through Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization. As-synthesized copolymer was characterized 1 H nuclear magnetic resonance ( 1 H NMR), gel permeation chromatography (GPC), Fourier transform infrared (FTIR). The copolymer precursors self-assembled in form of spherical micelles (in selective solvents) have been hydrolyzed and then condensed via sol-gel process in order to generate polyurethane-silica (PU-SiO2) hybrid materials. The hybrid copolymers thus prepared possess excellent thermal stability and mechanical property. The structures and properties of the copolymer precursors and their hybrid copolymers were characterized by thermogravimetric analysis (TGA), tensile test and atomic force microscopy (AFM). Vol.4, No.1 (2010) 17-25 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2010.4 sol-gel method, permits access to hybrid nanoballs through a very simple one-pot procedure. TPM with reactive trimethoxysilane groups is widely used in the preparation of organic-inorganic hybrid nanomaterials [15][16][17][18][19]. With a base catalyst, the R-Si(OCH 3 ) 3 groups can be easily hydrolyzed into R-Si(OH) 3 which can subsequently transform into cross-linked polysilsesquioxane nanocages by condensation, thus producing organic-inorganic hybrid nanoballs [7,20,21]. Recently, some research interests have sparked in the studies of self-assembly of copolymers based on poly [3-(trimethoxysilyl) propyl methacrylate] (PTPM). For example, Chen et al. reported the preparation and self-assembly behavior of novel organic-inorganic hybrid nanoparticles with a complex hollow structure based on a reactive amphiphilic diblock copolymer, poly(ethylene oxide)-b-poly [3-(trimethoxysilyl) propyl methacrylate] (PEO-b-PTPM) [22]. Polyurethanes (PU), as organic matrices, have received most attention for their versatile properties and a variety of starting materials. Therefore, the tailor-made properties of this class of materials can be obtained from well-designed combinations of monomeric materials, catalysts, auxiliary compounds. Polyurethanes can be tailored to meet the highly diversified demands of modern technologies such as coatings, adhesives, reaction injection molding, fibers, foams, rubbers, and thermoplastic elastomers. The linear structures of segmented PU take the form of (A-B) n . The soft segment part B represents the polyester or polyether macrogels with molecular weights ranging from 1000 to 3000; and the hard segment part A is consisted of lowmolecular weight diol or diamine being able to react with diisocyanate. Because of the incompatibility between the hard segments and the soft ones, PU undergoes microphase separation resulting in a hard-segment domain, soft-segment mat...

Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

“…However, APDS moieties also self-aggregate via urea bond formation [23]. This specific morphology, observed in the AFM images of Figure 6, can be related both to the inorganic domains formed by condensation of the alkoxysilane precursors or the phase separation of aromatic disulfide moieties [34][35][36][37]. From the phase image it was not possible to differentiate the hard segments formed by silicon-oxygen networks from those corresponding to the aromatic disulfide moieties.…”

Preparation of breathable and superhydrophobic polyurethane electrospun webs with silica nanoparticles

“…Drops of water on superhydrophobic surfaces exhibit high contact angles (CAs) (>150 ) and roll off at slight inclination (<10 ). [9][10][11][12] Researches have been conducted to develop superhydrophobic PU by introducing inorganic nanoparticles on the PU surfaces [13][14][15][16] or fluorinating PU surfaces. 17,18 It is well known that micro-nano roughness is the prerequisite for superhydrophobic surfaces, [9][10][11][12] thus inorganic nanoparticles have been widely used to impart nanoroughness on the electrospun fibers.…”

Distributed feedback grating fabricated from hybrid polymer precursor gel by employing short‐pulse laser interference for photopumped polymer laser applications

“…Therefore, the FTIR and NMR spectroscopies were employed to clarify the chemical bonds formed in the resulted precursor gels and hybrid polymers, which were prepared with rather different compositions and environmental conditions compared with the other previous works reported in the literature. The FTIR spectrum of TMSPMA monomer shows major absorption bands located at ν = ~800 and ~1090 cm −1 , which are attributed to Si―O―CH 3 vibrations . Figure shows the FTIR spectra of the precursor gel spin casted on a silicon substrate before and after photopolymerization.…”