Organic-inorganic polymer hybrids using octasilsesquioxanes with hydroxyl groups

Summary Polymer hybrids were prepared by three kinds of octasilsesquioxanes having hydroxyl groups and organic polymers such as poly(2-methyl-2-oxazoline) (POZO), poly(N-vinylpyrrolidone) (PVP), and poly(N,N-dimethylacrylamide) (PDMAAm) using hydrogen bonding interaction. The obtained homogeneous and transparent hybrid films could be dissolved in solvents and cast again without any separation. It was found that the high homogeneity of polymer hybrids was the result of hydrogen bonding interaction between octasilsesquioxanes and organic polymers from the carbonyl stretching shifts in IR measurement. Also, the influence of flexibility of eight arms bound to silica-like core on the homogeneity of polymer hybrids was examined. Received: 8 May 2001/Accepted: 24 May 2001     

Synthesis of Hyperbranched Polypropylene/Organoclay Nanocomposites by Metal Catalyzed Living Radical Polymerization and Solvent Blending Method

Isotactic polypropylene-based polymer hybrids linking poly methyl methacrylate was successfully synthesized by a graft copolymerization from maleic anhydride-modified polypropylene (MAH-graft-PP). MAH-graft-PP reacted with ethanolamine to produce a hydroxyl group containing polypropylene (PP-OH) and obtained PP-OH was treated with α-phenyl chloroacetyl chloride and converted to a chloroacetyl group containing polypropylene (PP-Cl). The metal-catalyzed radical polymerization of MMA with PP-Cl was performed using a copper catalyst system in xylene solution at 100°C to give the PP-based polymer hybrids linking PMMA segments (PMMA-graft-MAH-graft-PP). Finally the grafted copolymer/MMt nanocomposite prepared by solution intercalation method.     

Synthesis and characterization of polypropylene-based polymer hybrids linking poly(methyl methacrylate) and poly(2-hydroxyethyl methacrylate)

Isotactic polypropylene-based polymer hybrids linking poly(methyl methacrylate) (PMMA) and poly(2-hydroxyethyl methacrylate) (PHEMA) were successfully synthesized by a graft copolymerization from maleic anhydride-modified polypropylene (PP-MAH). PP-MAH reacted with ethanolamine to produce a hydroxyl group containing polypropylene (PP-OH) and the thus obtained PP-OH was treated with 2-bromoisobutyryl bromide and converted to a 2-bromoisobutyryl group containing polypropylene (PP-Br). The metal-catalyzed radical polymerization of MMA with PP-Br was performed using a copper catalyst system in o-xylene solution at 100 °C to give the PP-based polymer hybrids linking PMMA segments (PP-PMMA hybrids). Thus obtained PP-PMMA hybrids demonstrated higher melting temperature than PP-Br and microphase-separation morphology at the nanometer level owing to the chemical linkage between both segments. On the other hand, the polymer hybrids linking PHEMA segment (PP-PHEMA hybrids) were also obtained by the radical polymerization of HEMA with PP-Br in o-xylene slurry at 25 °C. TEM observation suggested that the polymerization mainly initiated on the surface of the PP-Br powder, led to the peculiar core-shell-like morphology. These PP-PHEMA hybrid powders showed a good affinity with water due to the hydrophilicity of the PHEMA segments.     

Improvement of the surface properties of polycarbonate by organic–inorganic hybrid coatings

Organic–inorganic hybrids (ceramers) were prepared through the sol–gel process with opportune alkoxysilane‐terminated polymer chains as the organic phase and tetraethoxysilane as the inorganic network precursor. The consolidation process, used to reach a high degree of crosslinking between the two phases, was carried out with either conventional oven heating or microwave irradiation. High conversion degrees were obtained with both treatments even when microwave postcuring turned out to be much faster than conventional heating(5–10 s vs 40 min). Scratch‐test and photooxidation investigations showed a significant improvement in scratch, yellowing, and photodegradation resistance for coated polycarbonate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and optical properties of the [2.2]paracyclophane-containing π-conjugated polymer with a diacetylene unit

Summary Novel through-spaceπ-conjugated polymer based on poly(p-henyleneethynylene)/poly(p-phenylenebutadiynylene) hybrids containing a [2.2]paracyclophane unit in the main chain was synthesized by copper-catalyzed alkyne coupling reaction. The structure of the polymer was supported by ¹H NMR and IR spectra. The obtained polymer was soluble in common organic solvents such as THF, CH₂C1₂, CHC1₃ and toluene. The number-average of molecular weight of the polymer was estimated to be 63000 by GPC. The polymer emitted a bluish green light in solution and in the solid state. Received:24 September 2002/Revised version: 19 November 2002/Accepted: 19 November 2002 Correspondence to Yoshiki Chujo     

Formation of IPN organic-inorganic polymer hybrids utilizing the photodimerization of thymine

Summary Formation of an interpenetrating polymer network (IPN) composed of organic polymer gel and silica gel in the form of polymer hybrids was conducted by utilizing the photodimerization of thymine bases. Thymine-modified poly(2-methyl-2-oxazoline) (POZO-T) was synthesized by the condensation reaction of partially hydrolyzed polyoxazoline and 1-(2-carboxyethyl)thymine. Organic-inorganic polymer hybrids were prepared from POZO-T and tetramethoxysilane (TMOS). Transparent and homogeneous polymer hybrids could be obtained. The photodimerization and the reverse reaction of thymine in the polymer hybrids were monitored by the UV absorption spectroscopy. Received: 27 March 2000/Revised version: 5 June 2000/Accepted: 15 June 2000     

Preparation of sorbitol-based polyurethanes and their semiinterpenetrating polymer networks

Sorbitol is a useful agro-based substance that is inexpensive and commercially available. In the interest of adding value to bio-based raw materials, we have synthesized polyurethanes from sorbitol and toluene-2,4-diisocyanate (TDI) through both conventional heat and microwave processes. Relative to conventional heat, the microwave process achieved the same reaction at a faster rate, thereby saving time and energy. The nature of the resulting polyurethane products depended on the stoichiometry of the reaction. At increasing TDI levels, a viscous liquid, a soft gel, or a hard thermoset could be obtained. The polymers were fully characterized with ¹³C-NMR, Fourier transform infrared, size exclusion chromatography, and thermogravimetric analysis. The polyurethanes obtained near the gel point could be used to make semiinterpenetrating polymer networks (semi-IPNs) with a second polymer, thereby imparting some of the properties of the second polymer onto the sorbitol-based polyurethane. For illustration, the sorbitol-based polyurethane semi-IPNs were made in combination with poly(vinyl pyrrolidone) and poly(lactic acid). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47602.     

Synthesis and characterization of polymeric foaming agent containing sulfonyl hydrazide moiety

New monomer, methacryloyl toluenesulfonylhydrazide (MATSH) containing foamable sulfonylhydrazide functional group after decomposed by heating, was synthesized from p-toluenesulfonylhydrazide (TSH) with methacryloyl chloride, and used to obtain poly(MATSH) as a polymeric foaming agent (PFA) in dry THF at 70 °C using AIBN as an initiator. The structures of synthesized MATSH and poly(MATSH) were identified by FT-IR and ¹H-NMR spectroscopies. The decomposition temperature of poly(MATSH) was determined to be 224 °C and this temperature was decreased into around 160 °C by adding an activator such as surface-treated urea to polymer. The exothermic temperature and heat determined by the decomposition of the polymer were 260 °C and 447 J/g. The amount of gas evolution for poly(MATSH) measured at decomposition temperature was 90 mL/g. Furthermore, the polymer incorporated with PFA showed better skin and fine cell structure as well as better mechanical properties such as elongation and compression set due to better compatibility of the developed PFA with polymers than those added with TSH.     

Synthesis of colloidal polyoxazoline/silica hybrids prepared in an aqueous solution

New colloidal polymer hybrids with polyoxazolines such as poly(2-methyl-2-oxazoline) (PMeOZO) and poly(2-ethyl-2-oxazoline) (PEtOZO) were obtained in an aqueous solution as a sol-gel solvent. The polyoxazoline segment was incorporated into the siliceous particle and formed strong hydrogen bonds with silanol moieties, judging from TGA and FT-IR studies. Colloidal polymer hybrids exhibited no glass transition temperature of the polyoxazoline and showed excellent thermal stability and solvent-resistant property. Porous silica obtained by charring the colloidal polymer hybrids at 600 °C exhibited the peak at 3.5 Å. These results strongly indicate the homogeneous molecular scale dispersion of polyoxazoline in the colloidal silica gel matrix.     

Polyimide nanocomposites: Comparison of their properties with precursor polymer nanocomposites

A precursor poly(amic acid) was obtained by solution polymerization of pyromellitic dianhydride and benzidine in N, N‐dimethylacetamide. Poly(amic acid)/Organoclay hybrids were prepared by the solution intercalation method with dodecylamine‐montmorillonite. A polyimide hybrid was obtained from poly(amic acid) hybrid by heat treatment at various temperatures. The film type polyimide hybrids showed better thermal properties than poly(amic acid) hybrids. Also, the thermal stability of the two polymer hybrids were enhanced linearly with increasing clay content from 0 to 8 wt%. Tensile properties and gas barriers of the hybrids, however, were enhanced remarkably compared to pristine polymers. Intercalations of the polymer chains in clar were examined through wide angle X‐ray diffraction (XRD) and electron microscopy (SEM and TEM). Transmission electron microscopy revealed that a partially exfoliated structure had been obtained from polyimide/organo‐clay hybrids.     

A new addition to the family of polyesters—Synthesis and characterization of novel (alternating) poly(ether ester)s, poly(butylene 3-/4-hydoxy benzoate)s

Novel, predominantly alternating poly(ether ester)s, poly(butylene-3/4-hydroxy benzoate)s (PBHB)s were synthesized by the hydrogenation of the corresponding unsaturated polymers obtained by forming ether and ester linkages under one pot conditions. The ether substitution caused a reduction in glass transition temperature, T_g. The melting transition was also lowered by more than 100°C compared to poly(butylene terephthalate) as studied by the differential scanning calorimetry (DSC). Crystallization was observed during heating as well as cooling in the DSC studies. Wide angle X-ray diffraction (WAXRD) analysis also indicated that PB-4-HB was semi-crystalline in nature. The thermal stability of hydrogenated polymer was better than that of the unsaturated polymer.     

Self-adhesive plasticized regenerated silk on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) for bio-piezoelectric force sensor and microwave circuit design

This study shows that regenerated silk (RS), a natural biodegradable and biocompatible polymer, can behave as a self-adhesive thermoplastic material with multifunctional properties. In particular, Ca ions-plasticized RS hybrids with gold nanorods have been produced. It has been found that at mild conditions of temperature and pressure, RS hybrids undergo to the loss of the β-sheet content and forms a tough self-adhesive material on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) substrate. The structure-dependent piezoelectricity of such RS adhesives on PHBV films was investigated and it was demonstrated that this forms a RS/PHBV piezoelectric sensor that can be used for the monitoring of force. The constitutive parameters (i.e., permittivity and loss tangent) of both PHBV and RS/PHBV were measured in view of their use as dielectric substrates in microwave circuit design. Being fully made of biodegradable and biocompatible materials, this self-adhesive material can be used in tissue engineering for different applications.     

Photochromic organic-inorganic polymer hybrids from spiropyran-modified poly(N,N-dimethylacrylamide)

Summary Photochromic organic-inorganic polymer hybrids were prepared by the sol-gel reaction of tetramethoxysilane (TMOS) in the presence of spiropyran-modified poly(N,N-dimethylacrylamide) 3. The obtained polymer hybrids were characterized by thermogravimetric analysis (TGA) and FT-IR, and photochromic behavior was followed by electronic absorption spectroscopy. Upon an irradiation of ultraviolet light, an absorption around 557 nm appeared in the visible region and the color of the hybrid turned to be violet. The effect of silica gel on the isomerization behavior seemed to be relatively small. Received: 8 November 1999/Revised version: 13 December 1999/Accepted: 15 December 1999     

Microwave absorption of poly‐N‐vinylcarbazole–polyaniline composites

Poly‐N‐vinylcarbazole–polyaniline (PANI) composites were synthesized using different loading concentration of aniline (0.025–0.1 M) for their microwave absorption characteristics. The obtained composites were studied by Fourier transform infrared spectroscopy, thermogravimetric analysis technique, and atomic force microscope for their chemical structure, thermal stability, and the surface modifications, respectively. The conductivity increased much with the increase of aniline concentration in the composites. The composite sheets exhibited a strong microwave absorption in the microwave range of 1–10 GHz and achieved a maximum absorption value of 33 dB. The position of absorbing peak shows a mixed trend moving from lower to higher and again to lower with an increasing the concentration of aniline in the poly‐N‐vinylcarbazole–PANI. The new polymer composite exhibited an appreciable electromagnetic interference shielding efficiency compared with the previously reported PANI composites. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Poly(hydroxyether of bisphenol A) ‐alt‐polydimethylsiloxane: a novel thermally crosslinkable alternating block copolymer

BACKGROUND: An important strategy for making polymer materials with combined properties is to prepare block copolymers consisting of well‐defined blocks via facile approaches. RESULTS: Poly(hydroxyether of bisphenol A)‐block‐polydimethylsiloxane alternating block copolymers (PH‐alt‐PDMS) were synthesized via Mannich polycondensation involving phenolic hydroxyl‐terminated poly(hydroxyether of bisphenol A), diaminopropyl‐terminated polydimethylsiloxane and formaldehyde. The polymerization was carried out via the formation of benzoxazine ring linkages between poly(hydroxyether of bisphenol A) and polydimethylsiloxane blocks. Differential scanning calorimetry and small‐angle X‐ray scattering show that the alternating block copolymers are microphase‐separated. Compared to poly(hydroxyether of bisphenol A), the copolymers displayed enhanced surface hydrophobicity (dewettability). In addition, subsequent crosslinking can occur upon heating the copolymers to elevated temperatures owing to the existence of benzoxazine linkages in the microdomains of hard segments. CONCLUSION: PH‐alt‐PDMS alternating block copolymers were successfully obtained. The subsequent self‐crosslinking of the PH‐alt‐PDMS alternating block copolymers could lead to these polymer materials having potential applications. Copyright © 2008 Society of Chemical Industry     

Microwave‐irradiated ring‐opening polymerization of D,L‐lactide under atmosphere

Poly(D ,L ‐lactide) (PDLLA) was synthesized by microwave‐irradiated ring‐opening polymerization catalyzed by stannous octoate (Sn(Oct)₂) under atmosphere. The effects of heating medium, monomer purity, catalyst concentration, microwave irradiation time, and vacuum level were discussed. Under the appropriate conditions such as carborundum (SiC) as heating‐medium, 0.15% catalyst, lactide with purity above 99.9%, 450 W microwave power, 30 min irradiation time, and atmosphere, PDLLA with a viscosity–average molecular weight (M_η) over 2.0 × 10⁵ and a yield over 85% was obtained. The dismission of vacuum to ring‐opening polymerization of D ,L ‐lactide (DLLA) under microwave irradiation simplified the process greatly. The temperature under microwave irradiation and conventional heating was compared. The largely enhanced ring‐opening polymerization rate of DLLA under microwave irradiation was the coeffect of thermal effects and microwave effects. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2244–2247, 2006     

Synthesis and properties of novel flame‐retardant poly(amide‐imide)s containing phosphine oxide moieties in main chain by microwave irradiation

Eight new flame‐retardant poly(amide‐imide)s with high inherent viscosities containing phosphine oxide moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7, with eight ;aromatic diamine 8a–h by two different methods such as solution and microwave‐assisted polycondensation. Results showed that the microwave‐assisted polycondensation by using a domestic microwave oven proceeded rapidly, compared with solution polycondensation and were completed within about 10–12 min. The resulting poly(amide‐imide)s 9a–h showed high thermal stability and flame‐retardant properties. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties of the PAIs 9a–h were investigated by using thermal gravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Char yield measurements at 600°C demonstrated that incorporating phosphine oxide moieties in polymer backbone markedly improves their flame retardancy. All of the earlier polymers were soluble at room temperature in various organic solvents such as NMP, DMF, DMSO, DMAc, and concentrated sulfuric acid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4263–4269, 2006     

Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene‐co‐(acrylic acid)]

Four binary polymer blends containing poly [ethylene‐co‐(acrylic acid)] (PEAA) as one component, and poly(4‐vinyl phenol‐co‐2‐hydroxy ethyl methacrylate) (P4VPh‐co‐2HEMA) or poly(2‐ethyl‐2‐oxazoline) (PEOx) or poly(vinyl acetate‐co‐vinyl alcohol) (PVAc‐co‐VA) or poly (vinylpyrrolidone‐co‐vinyl acetate) (PVP‐co‐VAc) as the other component were prepared and used as a matrix of a series of composite materials. These binary mixtures were either partially or completely miscible within the composition range studied and were characterized by differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). Carbon nanotubes (CNTs) were prepared by a thermal treatment of polyester synthesized through the chemical reaction between ethylene glycol and citric acid over an alumina boat. High resolution transmission electron microscopy (HRTEM) was used to characterize the synthesized CNTs. Films of composite materials containing CNTs were obtained after evaporation of the solvent used to prepare solutions of the four types of binary polymer blends. Young's moduli of the composites were obtained by thermomechanical analysis at room temperature. Only one glass transition temperature was detected for several compositions on both binary blends and the composite material matrices. Evidence of hydrogen bond formation was recorded for both miscible blends and composite materials. The degree of crystallinity and Young's moduli of the CNT‐polymer composites increased compared to the single polymer blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Morphology and photophysical properties of a thermally responsive fluorescent material based on a rod‐coil tri‐block copolymer

A thermally responsive rod‐coil poly[poly (N‐isopropylacrylamide)‐b‐polyfluorene‐b‐poly(N‐isopropylacrylamide)] triblock copolymer has been successfully synthesized by atom transfer radical polymerization from an end‐functionalized macroinitiator. The thermochromic behavior and relevant morphology of this polymer were investigated by UV‐vis spectra, DLS, and AFM, respectively, at various temperatures. A thermally responsive fluorescent material was achieved facilely by combining the optically active polyfluorene with temperature‐responsive poly(N‐isopropylacrylamide). All the measurements demonstrated that in the region of 25–45°C, the polymer underwent a phase transition and the corresponding change in optical properties in its water solution. However, the polymer did not show completely reversible behavior upon heating and cooling. On the basis of the comparison with two other thermally responsive conjugated polymers in literatures, a tentative mechanism has been proposed that π–π interaction induced rigid segments to remain chain conformation and packing styles as in collapsed state. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Microwave‐assisted preparation of temperature sensitive poly(N‐isopropylacrylamide) hydrogels in poly(ethylene oxide)‐600

In this article, a series of poly(N‐isopropylacrylamide) (PNIPAM)‐based hydrogels were prepared under microwave irradiation using poly(ethylene oxide)‐600 (PEO‐600) as reaction medium and microwave‐absorbing agent as well as pore‐forming agent. All of the temperature measurements, gel fractions, and FTIR analyses proved that the PNIPAM hydrogels were successfully synthesized. Within 1 min, the PNIPAM hydrogel with a 98% yield was obtained under microwave irradiation. The PNIPAM hydrogels thus prepared exhibited controllable properties such as pore size, equilibrium swelling ratios, and swelling/deswelling rates when changing the feed weight ratios of monomer (N‐isopropylacrylamide, NIPAM) to PEO‐600. These properties are well adapted to the different requirements for their potential application in many fields such as biomedicine. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4177–4184, 2006