Study On Preparation And Properties Of Novel Polyphosphazene/Polyurethane Inorganic/Organic Copolymerization Materials

Polyphosphazenes are a class of novel inorganic macromolecules containing alternate phosphorus-nitrogen single and double bonds with two organic side groups being attached to each phosphorus atoms. Because the phosphorus-nitrogen bonds are extremely flexible due to the low torsional energy and a large variety of side groups, polyphosphazenes can be made with a wide range of chemical and physical properties. However, polyphosphazenes have far proven to be of limited their wider applications due to polyphosphazenes of high molecular weight are high production costs and difficult to produce. And mechanical properties of phosphazene oligomers are poor. Polyurethanes are an important and versatile class of polymer materials, which are receiving steadily increasing attention and becoming important engineering materials due to their high abrasion resistance, wearability, chemical resistance, high impact strength and outstanding damping ability. However, conventional polyurethanes have relatively poor thermal, cold, flame resistance and hydrophobicity, which can not meet the special requirements in some application fields. Therefore, phosphazene oligomers are explored to improve thermal, cold and flame resistance properties and hydrophobicity of polyurethane, without dramatic damaging mechanical properties of polyurethanes. In the work, a series of novel polyphosphazene/polyurethane copolymerization materials were prepared.In the paper, a series of phosphazene oligomers with hydroxyl groups had been synthesized and used as different components of polyurethane to synthesize polyphosphazene/polyurethane copolymerization materials, respectively. These components of polyurethane are additives, chain extenders, crosslinkers and polyols. The thermal and cold resistance properties, flame properties and hydrophobicity of polyurethanes were investigated in detail. The main contents were listed below: 1. Thermoplastic polyurethane modified by hexaphenoxytricyclophosphazene- polyphosphazene as additiveThe blending materials were prepared by thermoplastic polyurethane (TPU) blending with different contents of hexaphenoxytricyclophosphazene. The blending materials have better thermal stability. Tonset of the blending material increases 17 oC. The blending materials present flame retardancy, which were observed V-2 rating through the UL 94 test. In addition, hexaphenoxytricyclophosphazene has a good decrease in viscosity to improve TPU processing properties. The MFIs of the blending materials are increased from 52.5 to 59.4 g/10min. The blending materials present lower surface energies than TPU according to contact angle measurements (CA), from 35.9 decreased to 28.0 mN·m-1.2. Synthesis and characterization of poly(oligophosphazene-urethane)s- polyphosphazene as chain extenderHydroxyl terminated phosphazene oligomer containing sulfone groups was synthesized. The results of FTIR, NMR and GPC analysis confirmed the chemical composition. A series of novel thermoplastic poly(oligophosphazene-urethane)s (POUs) were prepared and chain extended by the phosphazene oligomer. X-ray diffraction (XRD) showed that POUs are amorphous. Thermogravimetric analysis (TGA) presented Tonset of POUs increase 22 oC. Differential scanning calorimetry (DSC) showed that present glass transition temperatures (Tg) of POUs decrease from -20.6 to -32.3 oC. The decrease of Tgs showed that POUs could have better low temperature resistance. CA analysis showed water contact angles of POUs increased from 78.6o to 104.5o, which indicated POUs are more hydrophobic than conventional TPU.3. Synthesis and characterization of polyurethanes crosslinked by linear phenoxyphosphazene oligomer-polyphosphazene as crosslinker of polyurethanePhenoxyphosphazene oligomer containing hydroxyl was successfully synthesized. The chemical composition was characterized by FTIR, NMR and GPC. A series of thermosetting polyurethanes (PUOs) were prepared in a two step method, in which polyurethane prepolymer was crosslinked by phenoxyphosphazene oligomer. XRD showed that PUOs are amorphous. TGA presented Tonset of PUOs increased 78 oC. DSC showed that present Tg of PUOs decreased from -13.6 to -32.4 oC. PUOs maintained good tentile properties (CPU is 18.4 MPa and PUO-1 is 17.7 MPa). Break of elongation is slightly enhanced (CPU is 328.5 % and PUO-1 is 386.7 %). CA analysis showed water contact angles of PUOs increased from 74.8o to 94.6o, which indicated PUOs are more hydrophobic than conventional TPU.4. Synthesis and characterization of polyurethanes crosslinked by fluorine containing oligophosphazene- polyphosphazene as crosslinkerFluorine-containing oligophosphazene (OFHBP) was successfully synthesized. The chemical composition was identified by FTIR, NMR and GPC. The obtained OFHBP was used as crosslinker to prepare polyurethanes (PUPFs). The composition of the PUPFs was confirmed by FTIR and EA. XRD showed that PUPFs are amorphous. Studies on atomic power microscope (AFM) had found that PUPFs are higher microseparation than conventional polyurethane. DSC showed that PUPFs have lower glass transition temperatures (Tg)s than CPU, such as Tg of PUPF-4 is -41 oC. It could conclude that PUPFs display in super resistance in low temperature. PUPFs maintained good tentile properties (CPU is 18.4 MPa and PUPF-1 is 16.9 MPa). Break of elongation is slightly enhanced (CPU is 328.5 % and PUPF-1 is 399.5 %). CA analysis showed PUPFs are low surface energies. The surface energy of PUPF-4 is 22 mN·m-1.5. Synthesis and characterization of thermosetting polyphosphazene-urethanes- polyphosphazene as polyolA series of thermosetting polyphosphazene-urethanes (PPUs) were prepared by a two step process using the polyphenoxyphosphazene as polyol, toluene diisocyanate as hard segments and 1, 4-butanediol as chain-extender. The FTIR spectra demonstrated that the composition of PPUs conformed to our expectation. PPUs presented higher thermal stability. LOI of PPUs was estimated from the residues at 800 oC about 32 indicated that flame resistance of PPUs were superior to that of CPU (LOICPU≈18). CA analysis showed water contact angles of PPUs increased from 75.0o to 118.7o, which indicated PPUs are more hydrophobic than CPU.6. Synthesis and characterization of novel polyurethane crosslinked by poly (cyclotriphosphazene-co-4,4′- sulfonyldiphenol) microspheres copolymerization materials -polyphosphazene as nano-crosslinkerThe organic inorganic polyurethane hybrid copolymerization materials based on PZSMs were successfully fabricated with netlike structure for the first time. The results on the microstructure of the copolymerization materials indicated that the PZSMs could be dispersed in the polyurethane matrix well. The copolymerization materials displayed the excellent thermal stability. In addition, copolymerization materials showed evident characteristics as improvement in tensile strength (PU is 12.5 MPa and PU-4 is 19.2 MPa) and almost invariability in elongation at break by adding PZSMs into the polyurethane matrix. The copolymerization materials are more hydrophobic than pure polyurethane, water contact angles increasing from 70.5o to 96.3o.