Preparation and characterization of polyhedral oligomeric silsesquioxane–titania aerogels

The novel polyhedral oligomeric silsesquioxane (POSS)–titania aerogels which contain different contents of titania were successfully prepared by the sol–gel process and subsequently supercritical drying with carbon dioxide. All the aerogels are monolithic and the densities of those aerogels are low. The FTIR spectra of the aerogels showed the resulting POSS–TiO₂ composite aerogels had homogeneous Si–O–Ti bonds. The microstructure, surface composition and thermal stability were measured by FESEM, XPS and TGA. With the increasing of titania contents, the aggregated particles of the aerogels in the microstructure got larger and larger. The texture of the aerogels was measured by XRD and nitrogen adsorption/desorption and showed that they were amorphous and had high surface area (>500 m²/g).     

Preparation, characterization and thermal properties of organic–inorganic composites involving epoxy and polyhedral oligomeric silsesquioxane (POSS)

Organic–inorganic hybrids comprising epoxy resin and polyhedral oligomeric silsesquioxanes (POSSs) were prepared via in situ polymerization of the diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM). The POSSs have an active functional group that takes part in the ring-opening reaction with the oxirane group. The organic and inorganic moieties are joined by covalent bonds. These covalent bonds enhance the compatibility of the inorganic and organic phases. Scanning electron microscope (SEM) analytical results indicate that there was no obvious phase separation between the inorganic and organic phases. The UV/VIS spectrum of the epoxy hybrid demonstrates the excellent optical transparency of the hybrids—the most important characteristic for their application as protective coatings. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), and nuclear magnetic resonance spectroscopy (NMR) of the char showed that the incorporation of the POSSs into epoxy resin improves the thermal stability of the hybrids.     

Synthesis of organic–inorganic polymer hybrids from acrylate polymer having a triphenylimidazole moiety via π–π interactions

Polymer Bulletin - Organic–inorganic polymer hybrids were prepared utilizing π–π interactions. The sol–gel reaction of phenyltrimethoxysilane (PhTMOS) was carried out in...     

Synthesis of some novel silicone-imide hybrid inorganic–organic polymer and their properties

Synthesis and properties of poly(imide-siloxane) hybrid polymers (PIS), having alternate diimide and disiloxane units, based on 1,3-bis(succinyl anhydride)1,1,3,3-tetraorganodisiloxane (I or II) have been described. Polymers have been synthesized by the precursor synthesis i.e., poly(amic acid), using siloxanes (I or II) and 4,4′-diaminodiphenylmethane (DDM) or 4,4′-diaminodiphenylsulphone (DDS) in N,N-dimethylacetamide (DMAc) followed by thermal imidization. FT-IR, thermal (TGA and TMA), solvent resistant and dielectric properties of the compounds have also been studied. The glass transition, thermal stability and char yields of these hybrid polymers increased appreciably. These materials also showed very good solvent resistant properties in protic and aprotic solvents.     

A novel porous gel polymer electrolyte based on poly(acrylonitrile–maleic anhydride) composite by polyhedral oligomeric silsesquioxane for lithium-ion batteries

Journal of Applied Electrochemistry - A novel porous polymer membrane based on polyhedral oligomeric silsesquioxane (POSS) composite poly(acrylonitrile–maleic anhydride) (P(AN–MAH)) is...     

New high performance waterborne organic–inorganic hybrid materials from UV curing

The third generation glycerol based hyperbranched polyester (HBPE-3G) was synthesized by reacting glycerol and 2,2-bis(hydroxymethyl)propionic acid in a stoichiometric molar ratio. This polyester was used as preparation for waterborne hyperbranched UV cured polyurethane–silica hybrid coatings. The acrylic terminated waterborne coatings were prepared by modifying some of the hydroxyl groups HBPE-3G to acidic groups by reacting with maleic anhydride. The remaining hydroxyl groups were reacted with NCO terminated acrylate. Then the prepolymer was neutralized with triethyl amine and dispersed in water. The waterborne hybrid formulations were prepared by mixing 3, 5 and 10% of trimethoxysilylpropyl methacrylate (TMSPM) into the acrylic terminated waterborne coatings. The films were casted and cured under UV light. The various film properties were studied by XRD, AFM, TGA and DMTA instruments. TGA result suggests that the onset degradation temperature and final mass residue increase with increasing TMSPM concentration. DMTA results show that the storage modulus and glass transition temperature increase for the hybrid formulations with increasing TMSPM concentration. The structural characterization of the hybrid coatings was performed using FTIR spectroscopy. The tensile test demonstrated that the mechanical properties improve with the increasing TMSPM content. Surface morphology was studied by atomic force microscopy (AFM). AFM study revealed that TMSPM was crosslinked homogenously through the polymer matrix. The TGA and DMTA data suggest that higher thermal stability and glass transition temperature (T_g) for the TMSPM hybrid films compared to their pure counterparts were obtained with increasing the TMSPM content.     

Novel PEO-based solid composite polymer electrolytes with inorganic–organic hybrid polyphosphazene microspheres as fillers

Novel solid-state composite polymer electrolytes based on poly (ethylene oxide) (PEO) by using LiClO₄ as doping salts and inorganic–organic hybrid poly (cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres as fillers were prepared. Electrochemical and thermal properties of PEO-based polymer electrolytes incorporated with PZS microspheres were studied. Differential scanning calorimetry (DSC) results showed there was a decrease in the glass transition temperature of the electrolytes and the crystallinity of the samples in the presence of the fillers. Maximum ionic conductivity values of 1.2 × 10⁻⁵ S cm⁻¹ at ambient temperature and 7.5 × 10⁻⁴ S cm⁻¹ at 80° were obtained and lithium ion transference number was 0.29. Compared with traditional ceramic fillers such as SiO₂, the addition of PZS microspheres increased the ionic conductivity of the electrolytes slightly and led to remarkable enhancement in the lithium ion transference number.     

Investigation of crystallisation and interfacial nature of polyhedral oligomeric silsesquioxane/polypropylene composites in the presence of β-nucleating agent

Polyhedral oligomeric silsesquioxane (POSS)/polypropylene (PP) composites in the presence of β-nucleating agent (β-NAs) were prepared by melt-blending, and the interfacial interaction and crystallisation behaviour were investigated. The experimental results indicated that strong hydrogen bonding interactions were generated between amino groups of β-NAs and silicon hydroxyl groups attached to POSS, allowing the absorption/anchoring of the former on the surface of latter. Compared to POSS, β-NAs exhibited higher nucleation effect on PP, as evidenced by an increment of the crystallisation temperature by 7°C in the presence of β-NAs. As a result, the absorbed β-NAs on the surface of POSS not only improved the interfacial interaction between POSS and polymer matrix using interfacial crystallisation but also promoted the formation of β-crystals with toughening effect, which is very important to prepare excellent-performance PP/POSS composite.     

Synthesis and characterization of hybrid organic–inorganic materials based on sulphonated polyamideimide and silica

The preparation of hybrid organic–inorganic membrane materials based on a sulphonated polyamideimide resin and silica filler has been studied. The method allows the sol–gel process to proceed in the presence of a high molecular weight polyamideimide, resulting in well dispersed silica nanoparticles (<50 nm) within the polymer matrix with chemical bonding between the organic and inorganic phases. Tetraethoxysilane (TEOS) was used as the silica precursor and the organosilicate networks were bonded to the polymer matrix via a coupling agent aminopropyltriethoxysilane (APTrEOS). The structure and properties of these hybrid materials were characterized via a range of techniques including FTIR, TGA, DSC, SEM and contact angle analysis. It was found that the compatibility between organic and inorganic phases has been greatly enhanced by the incorporation of APTrEOS. The thermal stability and hydrophilic properties of hybrid materials have also been significantly improved.     

Performance characteristics of organic–inorganic composite electrodes in magnesium reserve batteries

Electrochemical characteristics of m-dinitrobenzene (m-DNB) based composite cathode materials involving compounds such as AgCl, TiO₂, HgO and CuCl have been investigated and (Mg AZ31 alloy anode) as an activated battery system using 2 M magnesium perchlorate aqueous electrolyte. The concentration of the composites has been optimized so as to obtain high electrochemical performance of Mg/m-DNB reserve batteries through constant current discharge studies. Mg/m-DNB cells containing 5-wt % of HgO when discharged at current density of 2.1 mA cm⁻² delivered 5.3 Ah capacity corresponds to a columbic efficiency of 97% as compared to the cells without composite.     

Preparation and use of hybrid organic–inorganic catalysts

Various approaches towards the immobilization of molecular homogeneous catalysts are introduced, focusing on catalysts where an organic molecule is attached to the surface of an inorganic support material via a covalent bond forming the so-called hybrid organic–inorganic catalysts. The application of this new class of catalysts in a wide variety of organic reactions is reviewed.     

Characterization and flocculation evaluation of a new organic–inorganic hybrid polymer flocculant (PAC-AM-DMC)

A novel organic–inorganic hybrid flocculant PAC-AM-DMC is synthesized using potassium persulfate as an initiator, which was used in industrial wastewater treatment. Comparing with the traditional inorganic flocculant, this new flocculant has the advantage of low dosage and high efficiency. Simultaneously, it is less toxic and more environmentally friendly than the organic flocculant. The organic–inorganic hybrid flocculant PAC-AM-DMC demonstrates better flocculation than the commercial single type flocculant (PAC, PAM), and the effect is better than simply combining the two flocculants. It has potential for commercialization. When PAC:(AM + DMC) = 2:8, the initiator is 0.2 wt%, and the flocculant obtained by reacting at 50°C for 4 h has the best effect on sewage treatment. When the pH is 7, the treatment effect of PAC-AM-DMC is best with the dosage of 10 ppm. Correspondingly, the amount of flocculant is 10 mg/L, and the turbidity of simulated sewage is 172 nephelometric turbidity unit (NTU), which is over 98% of turbidity removal efficiency. In addition, the prepared hybrid flocculant is nearly non-corrosive and posed little damage to the equipment. And the hybrid flocculant has excellent salt resistance.     

Synthesis of ZrB2/SiC composite powders by single-step solution process from organic–inorganic hybrid precursor

A precursor of a zirconium diboride/silicon carbide (ZrB₂/SiC) composite was synthesised via an organic–inorganic hybrid derived from gum karaya, tetraethyl orthosilicate, boric acid and zirconyl chloride starting materials. Fourier transform infrared spectroscopy of the as-synthesised dried hybrid revealed the formation of Si–O, Zr–O–C and B–O–B. X-ray diffraction revealed that the powder consists of only ZrB₂ and β-SiC. Scanning electron microscopy and TEM of the composite powders showed that SiC and ZrB₂ occurred in intimately mixed aggregates of spheroidal submicron sized particles for low (3M) boric acid concentration, while at high (5M) boric acid concentration, the two phases are larger with the ZrB₂ adopting a blocky, angular morphology (～10–30?μm long by 5?μm wide and thick), while the SiC remains spheroidal with ～1?μm diameter particles in 10–20?μm diameter aggregates. Thermogravimetry–differential thermal analysis with the help of X-ray diffraction analysis revealed that the formation temperature was low at 1275°C for ZrB₂ and 1350°C for the SiC with 40?wt-% yield.     

Synthesis,characterization, and ionic conductivity of electrospun organic–inorganic hybrid gel electrolytes

In this work, we described the synthesis of organic–inorganic hybrid gel electrolytes combining electrospinning, sol–gel, and ultraviolet (UV) curing techniques in order to investigate their ionic conductivity properties. First, 3-glycidyloxypropyl trimethoxysilane modified polyamic acid and alkoxysilane functional poly(dimethyl siloxane) were electrospun together. Then, the following thermal imidization, the obtained fiber was cured in the UV curable gel formulation. To improve the interaction between fiber and gel matrix, 3-(trimethoxysilyl)propyl methacrylate was partly hydrolyzed and then used as a bifunctional crosslinker. Finally, the membrane was soaked into 0.5 M LiFP₆ salt solution to obtain organic–inorganic hybrid gel electrolytes. The chemical structure, ionic conductivity, and range of electrochemical stability window of the photocured nanocomposite electrolytes were investigated by using FTIR, thermogravimetric analysis, differential scanning calorimetry, electrochemical impedance spectroscopy, linear sweep voltammetry, and SEM analysis. The acquired results from experiments indicate that a convenient nanocomposite electrolyte for lithium-ion batteries with high electrolyte (Li salt) uptake, adequate conductivity (1.02 × 10⁻³ S cm⁻¹) at ambient temperature and electrochemically stable between 1 and 6 V had been prepared. POLYM. ENG. SCI., 60:619–629, 2020. © 2019 Society of Plastics Engineers     

Adsorption of chromate and para-nitrochlorobenzene on inorganic–organic montmorillonite

Batch studies of chromate and para-nitrochlorobenzene (p-NCB) on montmorillonite modified by poly(hydroxo aluminium) ions (Al) and cetyl trimethylammonium bromide (CTMAB) are reported. The amounts adsorbed decreased in the order Al-CTMA-mont > CTMA-mont > Al-mont > montmorillonite. Adsorption of chromate on Al-CTMA-mont reached a maximum at pH = 4 while p-NCB was pH independent. The adsorption kinetics could be described by the pseudo-second-order model. The adsorption rates for chromate and p-NCB were 9.73 and 5.78 mg g^? 1 min^? 1, respectively. The adsorption capacity of chromate and p-NCB on Al-CTMA-mont calculated by the Langmuir model was 2.3 × 10^? 4 and 2.2 × 10^? 4 mol/g, the values of the adsorption energy of the Dubinin-Radushkevitch (D-R) model were 13.9 and 7.8 kJ/mol. These results implied that the chromate adsorption proceeded as chemisorption, mainly by ion exchange whereas p-NCB was bound by van der Waals forces.     

Pervaporation separation of an azeotropic mixture of a tetrahydrofuran–water system with nanostructured polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol)

Cage - structured polyhedral oligomeric silsesquioxane (POSS) molecules were used as modifiers in the fabrication of poly(vinyl alcohol) (PVA) membrane for the separation of an azeotropic mixture of tetrahydrofuran (THF) and water system. Poly(ethylene glycol) and anionic octa(tetramethyl ammonium)-functionalized POSS were used for this study. The membranes exhibited excellent water selectivity and permeance because of their preferential interactions toward water molecules in the azeotropic THF–water mixture. In the presence of poly(ethylene glycol)–POSS and anionic octa(tetramethyl ammonium)–POSS, the PVA membrane exhibited a significant increase in selectivity. A modified Maxwell–Stefan equation was used for the computation of the theoretical flux, which was compared with the experimental values. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47060.     

Synthesis and characterization of pyrrole and thiophene functional polystyrenes via “click chemistry”

Novel side-chain pyrrole or thiophene functional polystyrenes (PS-Py and PS-Th) were synthesized by using ‘‘click chemistry’’ strategy. First, approximately 40% of chloro groups of poly(styrene-co-chloromethylstyrene) P(S-co-CMS), prepared by nitroxide mediated radical polymerization (NMRP), were converted to azido groups by using NaN₃ in N,N-dimethylformamide. Propargyl pyrrole was prepared by etherification of 4-(1H-pyrrol-1-yl)phenol prepared by Clauson-Kaas reaction using propargylbromide. Propargyl thiophene was synthesized by heterogeneous esterification reaction between 3-thiophenecarboxylic acid and propargylbromide. Finally, azido-functionalized polystyrene was coupled to these propargyl functional heterocyclics with high efficiency by click chemistry. The intermediates at various stages and final polymers were characterized by spectral analysis and cyclic voltammetry.     

A series of crystalline organic polymer–inorganic hybrid material zinc-phosphonate-phosphates synthesized in the presence of templates for superior performance catalyst support

New types of organic copolymer–inorganic hybrid material zinc-phosphonate-phosphates are prepared with amines as templates. Notably, crystalline samples are obtained not with traditional methods but with simple reactions. Moreover, the samples are provided with the potential application as superior performance catalyst supports.     

Synthesis of novel UV-curable difunctional thiourethane methacrylate and studies on organic–inorganic nanocomposite hard coatings for high refractive index plastic lenses

This study relates to the development of ultraviolet (UV)-curable, organic–inorganic nanocomposite hard coatings for plastic lens substrates, especially for polythiourethane (PTU) and polycarbonate (PC). Novel difunctional thiourethane methacrylate (mercaptoethylsulfide-thiourethane methacrylate: coded MES-TUMA and isophorone diisocyanate-mercaptoethylsulfide-thiourethane methacrylate: coded IPDI-MES-TUMA) was synthesized to enhance the adhesive strength for PTU. On the basis of IR, ¹H NMR, electron spray ionisation-mass spectrometry (ESI-MS) analysis and gel permeation chromatography (GPC), the expected structures were confirmed. These difunctional thiourethane methacrylates were easily mixed with multifunctional urethane acrylate, surface-modified ZrO₂–TiO₂ nanoparticles and photoinitiator in coating formulations. The UV-cured organic–inorganic nanocomposites were very useful as hard coatings for high refractive index plastic lenses such as PTU and PC.