Hybrid Polyurethanes Research Articles

Synthesis and Properties of Organic–Inorganic Materials Based on Polyurethane and MQ Resins

Cross-linked polyurethanes (PUs) were obtained by curing with MQ resins bearing oxymethyldimethylsiloxane or oxyethoxymethyldimethylsiloxane groups, their mixtures with 1,4-butanediol, and neat 1,4-butanediol and studied for their physico-mechanical properties. The MQ resins with functional hydroxy groups were found to act as polyols during curing of a urethane prepolymer. The network PU, obtained by curing with the MQ resins, represents a hybrid organic–inorganic polymer with bulk cross-links of inorganic nature, the surface groups of which are chemically bound to the polymer matrix. At a concentration of the MQ resins of 0.5 ppm, the properties of hybrid polyurethanes are comparable to those of the polyurethane obtained using 0.63 ppm of 1,4-butanediol.

Hybrid polyurethanes composed of isobutyl-substituted open-cage silsesquioxane in the main chains: synthesis, properties and surface segregation in a polymer matrix

The resulting polyurethanes exhibited excellent optical transparency and surface hydrophobicity and acted as effective surface modifiers in poly(methyl methacrylate) (PMMA) by surface segregation.

Synthesis and properties of epoxy soybean oil-based polyurethanes modified by 3,13-dimethyhydroxysilyl double-decker phenylsilsesquioxane

Nowadays, environmental problems such as petroleum resources exhaustion, pollution and global warming are in ceaseless aggravation. Consequently, vegetable oil becomes one of the most important resources due to its cheapness, easily availability and environmental regeneration. In this study, a series of sustainable polyurethanes based on epoxy soybean oil modified by different contents of 3,13-dimethyhydroxysilyl double-decker phenylsilsesquioxane [DDSQ(Me)OH] have been prepared. Polyol prepared with epoxy soybean oil has effectively replaced the petroleum-based polyol and the DDSQ(Me)OH performed as chain extender together with 1,4-butanediol (BDO). The structure of DDSQ(Me)OH was verified by 1H NMR and MALDI–TOF–MS. The structure and properties of sustainable polyurethanes were characterized by FTIR, DSC, TGA, SEM, tensile test and static contact angle. TGA demonstrated that hybrid polyurethanes were thermally stable due to the covalent incorporation of DDSQ(Me)OH in polymer main chain, the 5% weight loss temperatures (Td5) of hybrid polyurethane can be 21 °C higher than pure PU. DSC revealed the improved glass transition temperature (Tg) of polyurethanes, and the Tg can be 12.4 °C improved compared with pure polyurethane. SEM showed that the aggregation of DDSQ(Me)OH has dispersed homogeneously in the hybrid polyurethanes matrix. The results of the static contact angle revealed that with the increase of DDSQ(Me)OH content, the surface hydrophobicity has been enhanced significantly, and the static contact angle of water for hybrid polyurethanes can be up to about 110.2°.

Preparation and Characterization of Polyhedral Octaphenylsilsesquioxane Modified Castor oil based Polyurethane

Vegetable oil-based polyurethanes were synthesized using castor oil (CO) as feedstock, which were characterized by their environmental friendly and renewable properties. Aiming to compensate for shortcomings of these materials, a series of polyurethane/polyhedral octaphenylsilsesquioxane (OPS) hybrids with different OPS contents were prepared by physical mixing in the solutions. Thereafter?chemical structure?morphology and thermal properties of hybrids were characterized through Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermal gravimetric analyzer (TGA), tensile test techniques and static contact angle. The results show that the hybrid polyurethanes display both enhanced glass transition temperatures (Tg), initial decomposition temperature (Td5) and tensile strength with low OPS contents. While with high contents?these values decline with the severe aggregation of nano-particles as shown in the SEM images. Meanwhile, the hybrid polyurethanes displayed enhanced surface hydrophobicity as the contact angle with water revealed

Investigations on anticorrosive, thermal, and mechanical properties of conducting polyurethanes with tetraaniline pendent groups

This article describes the synthesis of conducting hybrid polyurethanes from novel tetraaniline‐diol as Gly‐TAni (glycidol with TAni). A new diol Gly‐TAni has been synthesized in a simple process using tetraaniline (TAni) and glycidol via SN2 reaction in a single‐step process. The asymmetric diol (Gly‐TAni) and polyols (PTMEG and TMP) were reacted with isophorone diisocyanate at OH:NCO ratio of 1:1.2 to obtain ―NCO terminated hybrid conducting polyurethanes. These were subjected for curing under atmospheric moisture to obtain conducting polyurethane‐urea coatings. The conducting coatings showed considerable enhancement in thermal and mechanical stabilities. All these conducting coatings films showed excellent corrosion resistance (on mild steel electrode) with an increase in the percentage of Gly‐TANi (5 to 15 wt%). The films of these hybrid polyurethanes containing pendent tetraanilines showed good surface conductivity in the range of 3.69 × 10−4 to 2.21 × 10−3 S/cm. The electrochemical investigation showed 2 single electron oxidation and 2 single reductions reversibly, centred around tetraaniline segments present in the polymer.

Polyurethanization temperature effect to the thermal behaviour of cellulose – fiber based hybrid polyurethane

Polyurethanes are one of many types of polymers that are currently being developed worldwide. Some studies reported many substances involved in synthesizing polyurethanes (PU), with mostly originated from a biomass substance. Our laboratory has synthesized natural fiber – based PU to obtain hybrid PUs through varying reaction variables such as temperature. This study used cellulose, a biomass substance as well as polyethylene glycol and 4,4’ – methylenebis cyclohexyl isocyanate (HMDI) in synthesizing the hybrid PU, and investigated their thermal stability such as decomposition temperature by Differential Scanning Calorimetry (DSC) showed various tendency according to the chain extending temperature for the decomposition temperature. Simultaneous Thermal Analysis (STA) showed glass transition tendency of the product is proportional to the chain extending temperature, where the maximum glass transition obtained from the experimental is 59.8ºC at 70ºC of polymerization. Evaluation of functional group in the hybrid PUs was conducted with FT – IR spectroscopy measurement indicating urethane presence as part of the hybrid PUs.

Novel route of synthesis for cellulose fiber-based hybrid polyurethane

Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

Added value of lignin as lignin-based hybrid polyurethane for a compatibilizing agent

As biomass-based material, lignin contains abundant hydroxyl groups promising to be used as chain extender in building hybrid polyurethanes. Consisting of polyehtylene glycol (PEG) content as hydrophobic part and lignin as hydrophilic part, the hybrid PU is expected to be as a novel compatibilizing agent in new materials production such as polyblends and composites. The hybrid PU was synthesized via two reaction stages, viz. pre-polyurethanization through reacting 4,4'-Methylenebis (Cyclohexyl Isocyanate) (HMDI) and PEG as polyol, and chain extention through adding lignin in the pre-polyurethanization system. The composition effect of lignin in hybrid PU syntehsis, to chemical structure corelated to hydrophobic to hydrophilic ratio, thermal and morphological properties, was evaluated by measuring NMR, FTIR, DSC, TGA and FE-SEM. The experiments showed that addition of lignin was able to extend the pre-polyurethane into hybrid polyurethane and to increase the lignin/polyol ratio in the hybrid polyurethanes, which were indicated by NMR and FTIR Analysis. And change of the ratio lead to increase the glass transition from 60.9 until 62.1°C and degradation temperature from 413.9 until 416.0°C. Observation of the morphology implied that addition of lignin gave more agglomerations. A Further investigation for this characterization study should be focused on a feasibility for this modified lignin as a novel compatibilizing agent.

Synthesis and investigation of well-defined silane terminated and segmented waterborne hybrid polyurethanes

The properties of waterborne polyurethanes were improved significantly by incorporating silane both in the backbone and side chains.

Synthesis and properties of castor oil based polyurethanes reinforced with double-decker silsesquioxane

Hybrid polyurethanes with double-decker silsesquioxane (DDSQ) in the main chains were synthesized using castor oil and isophorone diisocyanate (IPDI) as feedstock. Double-decker octaphenylsilsesquioxanetetraol (DDSQ) was prepared and characterized by 1H NMR and MALDI-TOF–MS. Meanwhile, FTIR, TGA, DSC, SEM, UV–Vis spectrophotometer, tensile test techniques and static contact angle were also carried out to investigate the structures and properties of the hybrid polyurethanes. The DDSQ-containing hybrid polyurethanes exhibited improved thermal stability in terms of thermogravimetric analysis (TGA). DSC analysis demonstrated that the hybrid polyurethanes with DDSQ displayed enhanced glass transition temperature. According to the results of SEM and UV–Vis spectrophotometer, the aggregates of DDSQ were dispersed homogeneously in the hybrid polyurethanes matrix. With the inclusion of DDSQ, the hydrophobicity of the hybrid material was significantly improved as the results of the static contact angles revealed.

Soy-castor oil based polyurethanes with octaphenylsilsesquioxanetetraol double-decker silsesquioxane in the main chains

In these DDSQ-containing hybrid polyurethanes, DDSQ cages in the main chain act as the nanosized crosslinkers to participate in the formation of polymer networks.

Synthesis and characterization of sustainable polyurethane modified by cyclic polysiloxane

ABSTRACTIn this article, a series of sustainable polyurethanes are prepared by introducing different content of cyclic polysilanol, which may act as a chain extender to replace 1, 4‐butanediol (BDO). Consequently, cyclic polysiloxanes are successfully incorporated into the molecular chains to afford organic–inorganic polyurethanes and then their effects on polyurethanes thermal properties and surface hydrophilicity are fully characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and contact angle testing. Results show that the hybrid polyurethanes display enhanced glass transition temperatures (Tg). While in terms of TGA, the effects of cyclic polysilanol on thermal properties seem complex, which would reduce the thermal stability in the first degradation process but enhance in the second process. The morphology observed by scanning electron microscopy (SEM) show that the inorganic constitutions, namely, cyclic polysilanol, may occur to self‐condensation or aggregation, which can help to explain the uncommon thermal phenomenon above. Thus, an opportunity of future applicability in the areas of sustainable polymer with improved properties can be envisioned in our research method of hybrid polyurethanes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41277.

Synthesis and properties of hybrid urethane polymers containing polyhedral oligomeric silsesquioxane crosslinker

ABSTRACTThe synthesis and properties of novel hybrid silsesquioxane‐containing urethane polymers using octakis(hydroxypropyldimethylsiloxy)octasilsesquioxane (OHPOSS) as a crosslinker and a hydroxyl‐terminated polybutadiene were studied. Mixing of the OHPOSS with polyurethane prepolymer and chain extenders in solution was found to be successful when tetrahydrofuran was used as the solvent. Thin films of hybrid polyurethanes were obtained. The hybrid materials were elastomers with improved water and solvent resistivity and good thermal stability. The studied OHPOSS appeared to be an effective crosslinker of polyurethanes suitable for, for example, surface coatings applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2023–2030, 2013

Organic–inorganic polyurethanes with 3,13-dihydroxypropyloctaphenyl double-decker silsesquioxane chain extender

In this contribution, we reported the synthesis of organic–inorganic polyurethanes with polyhedral oligomeric silsesquioxane (POSS) in the main chains. Toward this end, 3,13-dihydroxypropyloctaphenyl double-decker silsesquioxane (DDSQ) was synthesized; this POSS diol was used as a chain extender to obtain hybrid polyurethanes with DDSQ in the main chains. By controlling the molar ratio of 3,13-dihydroxypropyloctaphenyl DDSQ to 1,4-butanediol (BDO), organic–inorganic polyurethanes were obtained with a content of DDSQ up to 48 wt%. The results of 1H nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC) showed that 3,13-dihydroxypropyloctaphenyl, DDSQ, can be successfully used as a chain extender to afford linear organic–inorganic polyurethanes. Differential scanning calorimetry (DSC) showed that the organic–inorganic polyurethanes displayed enhanced glass transition temperatures (Tg's) compared to control polyurethane; the Tg's increased with increasing content of DDSQ in the main chains. Compared to control polyurethane, the organic–inorganic polyurethanes displayed improved thermal stability in terms of thermogravimetric analysis (TGA). With the inclusion of DDSQ in the main chains, the organic–inorganic polyurethanes displayed enhanced surface hydrophobicity.

Thermal and mechanical behaviour of self-curable waterborne hybrid polyurethanes functionalized with (3-aminopropyl)triethoxysilane (APTES)

Two series of self curable polyurethanes were synthesized using an aliphatic diisocyanate (isophorone diisocyanate), an anionic diol (2-bis(hydroxymethyl) propionic acid) and two different soft segments poly(1,4-butylene adipate) end capped diol (semicrystalline polyester) and poly (propylene glycol) end capped diol (amorphous polyether). In both cases the polyurethanes were end-capped with (3-aminopropyl)triethoxysilane to impart the films the ability to crosslink at room temperature. The thermal and mechanical properties of the cured films can be tailored with the alkoxysilane concentration. Thus, as the alkoxysilane content increases, the resulting systems present a higher degree of phase separation, according to both DSC and DMTA results. In addition, TGA results confirm that their thermal stability also increases and finally, the modulus increases and the strain decreases as a function of the crosslinking degree.

Synthesis and performance evaluation of polyurethane/silica hybrid resins

Purpose – The aim of this paper is to synthesise polyester/silica hybrid resins and their hybrid polyurethanes via in situ (IS) and blending (BL) methods and to evaluate the effect of preparation method, interaction type and silica content on the physico‐chemical and thermal properties of polyurethane/silica (PU/Silica) hybrid coatings.Design/methodology/approach – Silica particle‐containing silica sol was prepared according to Stober method using tetraethylorthosilicate as the precursor and then introduced into polyester matrix by in situ and direct blending method. The modified polyester/silica resin was further crosslinked with TMP‐TDI adduct to synthesise PU/Silica hybrid coatings and studied for thermo‐mechanical, physico‐chemical properties.Findings – It was found IS polymerisation caused more polyester segments to chemically bond onto the surface of silica particles than BL process. Results also reveal that due to stronger interaction between silica particles and PU matrix, hybrid resins prepared b...

Synthesis of room temperature self-curable waterborne hybrid polyurethanes functionalized with (3-aminopropyl)triethoxysilane (APTES)

Room temperature self-curable silanized waterborne polyurethanes (Si-WPU) were synthesized by means of the acetone process employing covalently linked (3-aminopropyl)triethoxysilane (APTES) as curing agent. The insertion of this curing agent was confirmed using FTIR spectroscopy, liquid NMR and elemental analysis. The APTES concentration induced an increase of particle size, this effect being more pronounced at higher concentrations due to the condensation of the alkoxysilane groups. The condensation of silanol groups was evidenced by means of TEM, FTIR and SEM measurements. The presence of silanol groups on the particle surface was demonstrated by ς-potential analyses. Finally, the curing process of the dispersions was followed by means of gel content measurements, solid-state 29Si-NMR and FTIR studies. All the samples were able to cure at room temperature, and the extent of curing was dependent on the APTES concentration and curing temperature.

Polyisobutylene‐based polyurethanes. III. Polyurethanes containing PIB/PTMO soft co‐segments

AbstractThe synthesis, characterization, and structure–property behavior of polyurethanes containing polyisobutylene (PIB)/poly(tetramethylene oxide) (PTMO) soft co‐segments and bis(4‐isocyanatocyclohexyl)methane (HMDI)/hexanediol (HDO) hard segments is presented. The mechanical (stress/strain, hardness, and hysteresis) properties of these novel polyurethanes were investigated over a broad composition range. PIB‐based polyurethanes with HMDI/HDO hard segments showed better mechanical properties than earlier polyurethanes containing highly crystalline hard segments. The addition of moderate amounts (20% by weight) of PTMO significantly increased both tensile strengths and elongation. In the presence of larger amounts of PIB, these polyurethanes are expected to possess oxidative/hydrolytic/enzymatic stabilities superior to commercially available polyurethanes. These polyurethanes are softer and exhibit hysteresis superior to or comparable with conventional polyurethanes. According to initial thermal studies, these materials show good melt processibility. Overall, the mechanical properties of PIB based hybrid polyurethanes are similar to commercially important polyurethane type biomaterials. Our results show that the incorporation of PTMO segments to PIB‐based polyurethanes significantly improves elastomeric properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5278–5290, 2009

Tailored drug release from biodegradable stent coatings based on hybrid polyurethanes

Highly adjustable and precisely controllable drug release from a biodegradable stent coating was achieved using a unique family of nanostructured hybrid polyurethanes. These polyurethanes are polyhedral oligosilsesquioxane thermoplastic polyurethanes (POSS TPUs) featuring alternating multiblock structures formed by nanostructured hard segments of POSS and biodegradable soft segments of a polylactide/caprolactone copolymer (P(DLLA-co-CL)) incorporating polyethylene glycol (PEG) covalently. POSS aggregated to form crystals serving as physical crosslinks on the nanometer scale, while the soft segments were designed carefully to modulate the drug release rate from the POSS TPU stent coatings in PBS buffer solution, with 90% of the drug releasing from within half a day to about 90 days. In order to interpret the underlying drug release mechanisms, an approximation model capable of describing the entire drug release process was developed. This model is based on Fickian diffusional transport, but also takes into account the polymer degradation and/or swelling of the coating, depending on the dominance of the degradation/swelling behavior compared to that of the diffusion characteristics. A general methodology was utilized for statistically fitting the drug release curves from the POSS TPU stent coatings using the model. We observed that the fitted initial drug release diffusion coefficient covered more than three orders of magnitude, depending on the polymer glass transition temperature ( T g), according to a modified Williams–Landel–Ferry (WLF) equation. In addition, two additional rate constants describing the impact of degradation and swelling on drug elution were determined and found to be consistent with independent measurements. Our results clearly show that the studied hybrid polyurethane family allows a drug release rate that is effectively manipulated through variation in polymer T g, degradation rate, and thickness increment rate.

Interaction and Microstructure of Polyurethane/Silica Hybrid Films Prepared by Sol-Gel Process

The polyester/silica hybrid resins and their hybrid polyurethanes were prepared via in situ (IS) or blending (BL) method using different silica sols. The effects of preparation methods, silica type and content on the interaction and microstructure of polymer/silica hybrid materials were investigated by FTIR, viscosity measurement, TGA, DMA and SAXS, respectively. It was found that both IS and BL methods formed agglomerates of silica-rich phases and primary silica-rich phases in the hybrid films, but the former caused stronger interaction between silica and polymer than the latter, resulting in much bigger agglomerates and compacter structure. The ethoxy group at silica was favorable for enhancing the interaction between silica phase and polymer, even between silica phases as well. The interaction between silica phase and polymer caused increasing viscosity, modulus and Tg, while the interaction between silica phases themselves increased the extent of micro-phase separation, especially for the hybrid films prepared by IS method.