Polyurethane Hybrid Research Articles

TESTING OF HYBRID NICKEL-POLYURETHANE FOAMS AT HIGH STRAIN-RATES USING HOPKINSON BAR AND DIGITAL IMAGE CORRELATION

In this paper Split Hopkinson pressure bar (SHPB) was used for dynamic testing of nickel coated polyurethane hybrid foams. The foams were manufactured by electrodeposition of a nickel coating on the standard open-cell polyurethane foam. High strength aluminium alloy bars instrumented with foil strain-gauges were used for dynamic loading of the specimens. Experiments were observed using a high-speed camera with frame-rate set to approx. 100-150 kfps. Precise synchronisation of the high-speed camera and the strain-gauge record was achieved using a through-beam photoelectric sensor. Dynamic equilibrium in the specimen was achieved in all measurements. Digital image correlation technique (DIC) was used to evaluate in-plane displacements and deformations of the samples. Specimens of two different dimensions were tested to investigate the collapse of the foam structure under high-speed loading at the specific strain-rate and strain.

Preparation of novel organo-montmorillonite and its influence on the acid resistance of hybrid cathodic electrodeposition polyurethane coating

Based on the super-composite effect of clay minerals consisting of silicate layers on the polymer, nano-hybrid organic–inorganic composites have attracted great interest. In this paper, a novel organoclay with reactive hydroxyl group was prepared by incorporation into a hydroxyl-terminated cationic polyurethane oligomer (HTCPU) via interlamination. Sodium montmorillonite was organically modified with HTCPU oligomers in the water medium. The modified organo-montmorillonite was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, and thermogravimetric analysis. After sequential poly-addition reactions, the hydroxyl-terminated polyurethane hybrid resins with nano-silica layers were prepared and then the resin mixed with blocked hexamethylene diisocyanate trimer (crosslinking agent) in advance and then was emulsified with deionized water to produce the nano-hybrid electrophoresis coating. A series of PU films were prepared by the electrophoresis process. The optimized baking temperature was determined by in situ FTIR, and the effect of the organo-montmorillonite content on the acid resistance of film was studied. When the mass fraction of organo-montmorillonite was about 0.35%, the PU film showed the best acid resistance. It was found that the desirable appearance and properties could be obtained by a prebake of a temperature of 80°C to remove water in the wet film to avoid the pinholes in the paint film for 20 min, followed by a baking temperature of 135°C for 60 min.

Fabrication and performance of a polyurethane hybrid composite with waste red mud

Polyurethane‐based organic–inorganic hybrid composite is attracting increasing attention due to its excellent performance and low cost. Herein, a facile and effective strategy has been proposed for the fabrication of polyurethane/red mud hybrid composite by anchoring red mud particles into a polyurethane frame. The resulting hybrid composite was mainly composed of amorphous polyurethane and crystalline red mud, and its probable formation mechanism was proposed. The polyurethane/red mud composite with micron particles uniformly embedded into the organic phase exhibited satisfactory mechanical performance, and its compressive and flexural strength could come up to 38.6 and 12.4 MPa after complete curing, respectively. Moreover, the hybrid composite displayed impressive thermal stability, flame retardancy, storage stability, and reinforcement performance. The obtained polyurethane/red mud composite shows potential applications in multiple fields (roadway, dam, underground engineering, etc.). POLYM. COMPOS., 40:2424–2431, 2019. © 2018 Society of Plastics Engineers

Preparation of Carbon Nanotubes/Polyurethane Hybrids as a Synergistic Absorbent for Efficient Oil/Water Separation

Polyurethane (PU) hybrid materials have attracted a great deal of attention as oil-absorbents in oil/water separation because they combine the surface properties of nanomaterials and the excellent absorption properties of PU. Herein, we report a facile two-step process to synthesize the oil-absorbing hybrid materials by integrating carbon nanotubes (CNTs) into porous PU foam architectures. First, the multi-walled carbon nanotubes (MWCNTs) were modified by oxidation in binary H2SO4-HNO3 mixed acid, followed by grafting the silane coupling agent (KH 570) on the on surfaces of MWCNTs. Then, the MWCNTs/PU hybrid materials were synthesized using isocyanate and polyether polyol as monomers for polymerization and surface modified MWCNTs as inorganic components. The physical and chemical properties of hybrid materials were validated by XRD, TEM, SEM, N2 sorption and contact angle analysis. The surface grafted MWCNTs possess superhydrophobic properties with the maximum water contact angle of 153°. The SEM results indicate that the WCNTs/PU hybrid materials consisted of spherical structures with microscale holes, which can separate oils from oil/water mixtures with high absorption properties and high selectivity. Effects of the various MWCNTs contents on the oil absorption behavior of the WCNTs/PU hybrid materials were investigated. The results show that the modified MWCNTs significantly improves the oil absorption properties with the optimal MWCNTs content of 3 %. By combining the structural features of WCNTs and PU foams, the hybrid materials not only exhibit excellent absorption properties for various types of oils and organic solvents, but also show excellent oil recoverability and absorbent regenerability. The as-synthesized WCNTs/PU hybrid have significant potential as oil absorbents for efficient separation of oils and organic solvents from water.

Physical and mechanical properties of sugar palm/glass fiber reinforced thermoplastic polyurethane hybrid composites

This paper studied the physical and mechanical properties of sugar palm and glass fiber reinforced thermoplastic polyurethane hybrid composites with the aim of investigation on the hybrid effects of the composites made of natural and synthetic fibers. The aim of this study is to evaluate the physical properties such as density, thickness swelling, water absorption whereas the tensile, flexural and impact properties of sugar palm, hybrid and glass composites were also investigated. Morphological properties of tensile fracture samples of composites were done by using scanning electron microscopy (SEM). The composites were fabricated at a constant weight fraction of total fiber loading at 40wt.% using melt compounding method. The result revealed that incorporation of glass fiber 30wt.% to sugar palm/TPU composites exhibited the higher density, lower thickness swelling and water absorption properties. The tensile and impact properties of the hybrid composites were improved with the increasing of sugar palm fiber content (30/10 SP/G) as compared to glass fiber reinforced composites (0/40 SP/G) due to the excellent hybrid performance of the two fibers. The flexural properties were increased when the higher amount of glass fiber was introduced at 40wt.% (0/40 SP/G). The fibers cracks, fiber pull out and fiber dislocation of the fractured surfaces are evaluated by using scanning electron microscope (SEM). Overall results indicated that the incorporation of glass fiber to sugar palm fiber composites can improve the physical and mechanical properties and developed hybrid composites can be used as an alternate material for glass fiber reinforced polymer composites for different applications.

Incorporation of silica nanoparticles and polyurethane into hybrid composites for increase of char residue

Effect of different chain extenders, silica nanoparticle loading, and using sol–gel method on the thermal properties of polyurethane (PU) hybrid composites was investigated from the viewpoint of increase of char residue and decomposition temperature. Two different chain extenders were used for this purpose, and the PU products were modified with (3-aminopropyl) triethoxysilane to obtain PUI (ethoxysilane-terminated PU with pyromellitic dianhydride chain extender) and PUBD (ethoxysilane-terminated PU with butanediol chain extender), respectively. Fourier-transform infrared spectroscopy was used for confirmation of synthesis of PUI and PUBD. Thermogravimetric analysis showed that char residue and thermal degradation temperature of PU hybrid composites were increased after incorporation of silica nanoparticles. Also, using pyromellitic dianhydride as chain extender resulted in higher char contents and also thermal stabilities in comparison with butanediol. By the addition of 4 and 8 mass% silica nanoparticles in PUBD hybrids, char residue increased to 15.1 and 16.3%, respectively. In the case of PUI hybrids, addition of 4 and 8 mass% of silica nanoparticles resulted in char residue of 20.8 and 25.7% and Tmax of 409.3 and 411.8 °C, respectively. X-ray diffraction showed an amorphous peak for cross-linked PU at 2θ = 21.7°. Transmission electron microscopy showed dispersion of silica nanoparticles in the hybrid composite of PUI.

1,2-Propanediolizobutyl POSS as a co-flame retardant for rigid polyurethane foams

Polyurethane (PU) foams physically modified by two additive phosphorous flame retardants (FR)—phenol isobutylenated phosphate or phenol isopropylated phosphate, and chemically reinforced by functionalized 1,2-propanediolizobutyl POSS (PHI-POSS) have been synthesized and investigated towards thermal and mechanical properties, as well as flammability behaviour. The foamed PU hybrid materials were prepared in a two-step process using a polyether polyol and polymeric 4,4′-diphenylmethane diisocyanate. On the basis of the obtained results of mechanical properties, thermal insulation, thermal stability and flammability investigations, the influence of the applied additives—including POSS nanoparticles, on the rigid polyurethane foams was determined. The analysis of thermogravimetric and microcalorimetry data revealed an improved resistance to burning of the PU foams containing hybrid reactive (POSS)/additive (phosphate) FR systems, as evidenced by reduced rate of heat release. Importantly, mechanical properties tests showed that incorporation of bulky silsesquioxane nanoparticles to polyurethane structure via covalent bonds strengthens the foam integrity.

Effect of the silica nanofiller on the properties of castor oil-based waterborne polyurethane hybrid dispersions based on recycled PET waste

The paper describes the chemical depolymerization of the polyethylene terephthalate (PET) waste from postconsumer soft drink bottles and a search for the way to use this product. The depolymerized oligoester obtained from glycolysis of PET waste using tiethylene glycol was transesterified with castor oil which resulted in the formation of hydroxyl-functional polyester polyol, with hydroxyl value of 391 mg KOH g−1. In the presented paper, series of castor oil-based waterborne polyurethane (CPU)/silica hybrid dispersions were prepared using dimethylolpropionic acid as an ionic center. The polyurethane prepolymers with pendent castor oil groups were prepared first, and then different concentrations of hydrophilic fumed silicas (0, 0.5, 0.75, 1.0 and 2.0 wt%) were added. For waterborne polyurethane dispersions of hydrophilic fumed silica with the surface area (50 ± 15 m2/g) and a primary particle size of 40 nm in the polymer matrix, ultrasound waves were used. The hybrid dispersions were prepared by adding the required amount of triethylamine and water. The molecular structures and mass of glycolyzed PET oligoesters, castor oil-based polyol and castor oil-based polyurethane–silica hybrid dispersions were estimated by FTIR method and gel permeation chromatography.The incorporation effect of SiO2 nanoparticles into the PU matrix on the thermal and mechanical properties of resulting polyurethane films has been examined by Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis, differential scanning calorimetry (DSC), SEM microscope, and measurement of the coatings properties. The DSC data results suggest that hard segment glass temperature decreases, but mixed-phase glass transition temperature increases with increasing SiO2 content. The FTIR deconvolution result of the degree of phase separation between oxide nanoparticles and hard segment supports to the DSC analysis. The addition of silica oxide caused the increase in the thermal stability. The T10% and T50% of CPU films (the temperatures where 10 and 50% weight loss occurred) increased with increasing the SiO2 content. UV–Vis spectrophotometry showed that introduction of nanosilica particles into polyurethane enhanced the shielding property of obtained films for UV light. The hardness, adhesion, and gloss quality of the polyurethane films were also determined considering the effect of the phase separation and the SiO2 content, so this paper confirmed the suitability of using these castor oil-based waterborne polyurethane/silica hybrid dispersions as new materials with high-performance coatings materials.

Mechanical performance of roselle/sugar palm fiber hybrid reinforced polyurethane composites

The effect of sugar palm fiber (SPF) loading was studied relative to the mechanical properties of roselle (RF)/SPF/thermoplastic polyurethane (TPU) hybrid composites. RF/SPF/TPU hybrid composites were fabricated at different weight ratios (100:0, 75:25, 50:50, 25:75, and 0:100) by melt mixing and hot compression. The mechanical (tensile, flexural, and impact test) and morphological properties of tensile fractured samples were examined using a universal testing machine, impact machine, and scanning electron microscope. It was found that the hybridization of RF/SPF increased its impact strength corresponding to the increases in the SPF content of the composites. The tensile and flexural properties of the hybrid composites decreased due to poor interfacial bonding between the fiber and matrix. Scanning electron micrographs of the tensile fractured surface of the RF/SPF hybrid composites revealed fiber pullouts and poor adhesion bonding. In conclusion, the hybridization of SPF with RF/TPU composites enhanced its impact strength while decreasing the tensile and flexural strength.

Thermal properties of sugar palm/glass fiber reinforced thermoplastic polyurethane hybrid composites

The aim of this work to investigate the effect of glass fiber (GF) on the thermal properties of sugar palm (SP)/thermoplastic polyurethane (TPU) hybrid composites. Sugar palm/glass fiber hybrid composites at the different weight fraction of 0/40, 10/30, 20/20 and 30/10 were prepared by using melt-mixing compounding followed by hot pressing machine. Thermal properties of hybrid composites carried out by using Dynamic mechanical analyzer (DMA) and thermo-gravimetric analyzer (TGA). The storage modulus (E′), loss modulus (E″) and damping factor (tan δ) were evaluated as a function of different relative sugar palm/glass fiber weight fraction. Also, the peak height was investigated for tan δ curves. At higher glass fiber loading exhibited the highest storage and loss modulus while the lowest damping factor was observed for higher sugar palm fiber loading. Thermogravimetric analysis (TGA) demonstrated that the amount of residue decreased as the glass fiber loading decreased. Overall, the hybridization of glass fiber with sugar palm/TPU composites enhances the thermal properties of the hybrid composites for automotive applications.

Enhanced thermal conductivity and mechanical properties of hybrid MoS2/h‐BN polyurethane nanocomposites

ABSTRACTNanocomposites based on molybdenum disulfide (MoS2), hexagonal boron nitride (h‐BN) and hybrid MoS2/h‐BN nanofillers with different wt % in elastomeric polyurethane (PU) were studied with respect to their microstructure, thermal and mechanical properties. Tensile tests showed increases up to 80% in Young`s modulus for both h‐BN and hybrid MoS2/h‐BN composites. These results agree with dynamic mechanical analysis tests, which confirm an increase of up to 106% in storage modulus for hybrid MoS2/h‐BN with 0.5 wt % content. When the hybrid MoS2/h‐BN nanofillers were incorporated into the polymeric matrix, increases up to 102% in crosslink density were observed, indicating that strong interactions between the hybrid nanofillers and PU were established. However, the most important synergistic effect between the mixture of MoS2 and h‐BN nanoadditives was the increase of up to 752% in thermal conductivity with respect to neat polymer. Therefore, hybrid composites based in two‐dimensional MoS2/h‐BN nanofillers with multifunctional attributes can be applied in advanced polymeric materials that require high mechanical and thermal performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46560.

Dynamic mechanical properties of sugar palm/glass fiber reinforced thermoplastic polyurethane hybrid composites

Hybrid composites based on thermoplastic polyurethane were fabricated with the addition of sugar palm fiber and glass fiber. The best ratio of 30 wt% sugar palm fiber to 10 wt% glass fiber was used to reinforce the hybrid composites, which were then subjected to dynamic mechanical analysis (DMA) to determine their dynamic properties. Three types of fiber treatment were assessed as follows: 6% alkaline (TNSP), 2% silane (TSSP) and combined 6% alkaline‐ 2% silane (TNSSP) for 3 h. The untreated and treated hybrid composites were fabricated by the melt‐compounding method, followed by a hot pressing moulding. The DMA properties, including storage modulus, loss modulus and damping factor, were measured by a Dynamic Mechanical Analyzer. The hybrid composites of TNSSP showed highest storage modulus, loss modulus as compared to other treated hybrid composites. The peak height of damping factor was low for TNSSP and highest for TSSP hybrid composites. The Cole–Cole analysis was carried out to investigate the phase behavior of the untreated and treated hybrid composites. The study demonstrated that the combined 6% alkaline‐2% silane fiber treatment was the most effective in enhancing the dynamic mechanical properties of the SPF/GF reinforced TPU hybrid composites. It is clear that, the treated fibers influenced the DMA of thermoplastic polyurethane hybrid composites. The overall result showed that treated sugar pam/glass reinforced thermoplastic polyurethane improved the dynamic mechanical analysis for hybrid composites suitable for automotive parts. POLYM. COMPOS., 40:1329–1334, 2019. © 2018 Society of Plastics Engineers

Rigid polyurethane foams reinforced with disilanolisobutyl POSS: Synthesis and properties

This work reports the synthesis of rigid polyurethane (PU) foams modified by disilanolisobutyl polyhedral oligomeric silsesquioxane (DSIPOSS). This open‐cage nanostructure silsesquioxane has 2 hydroxyl groups and therefore can be chemically built directly in the PU backbone to form hybrid polyurethane‐POSS foam. Synthesis procedure using polymeric 4,4′‐diphenylmethane diisocyanate, polyetherol, and DSIPOSS has been elaborated, and the influence of POSS on the cell structure, closed cell content, apparent density, thermal conductivity, and compression strength of the rigid polyurethane composites has been evaluated. The hybrid composite foams containing 1.5 and 2.0 wt% DSIPOSS showed a reduced number of cells and an increased average area of foam cells in comparison with the unmodified PU, while the addition of 0.5wt% of DSIPOSS causes an increase in the number of cells of the foam as compared with the reference and thus a reduction in the average area of cells. X‐ray microtomography provided data on the porous structure of polyurethane hybrid materials, including reduction of the pore surface area. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy analysis revealed a good homogenization of DSIPOSS in polyurethane matrix. Thermogravimetric analysis results have shown that incorporation of POSS nanoparticles into PU foam does not significantly change the degradation process. The compressive strength of PUF‐POSS hybrids in the direction parallel and perpendicular to the direction of foam rise is greater than the strength of the reference foam already for the lowest DSIPOSS content.

Preparation and investigation of hybrid self-healing coatings containing linseed oil loaded nanocapsules, potassium ethyl xanthate and benzotriazole on copper surface

The effectiveness of self-healing epoxy and polyurethane hybrid coatings filled with linseed oil (LO) containing nano-sized capsules, potassium ethyl xanthate and benzotriazole was investigated for self-healing and anti-corrosion performance on the copper metal films. The characteristics of synthesized nanocapsules were studied by fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) for chemical structure, thermal stability and surface morphology investigations. Furthermore, size distribution of the prepared nanocapsules was investigated using dynamic light scattering (DLS). The anti-corrosion effect of coatings was studied by electrochemical impedance spectroscopy (EIS) and optical microscopy imaging. Taguchi method was used to reduce the number of experiments and anti-corrosion efficiency evaluations. The synthesized nanocapsules have 459–712 nm diameters. LO loading efficiency was almost 60%. Hybrid self-healing coatings which contain self-healing and anti-corrosion agents together showed synergistic effect at optimum levels (3 wt% LO and 5 wt% anti-corrosion agent). Adhesion pull-off test shows that higher amounts of nanocapsules, potassium ethyl xanthate and benzotriazole resulted in weaker adhesion for coatings.

Anisotropic meanfield modeling of debonding and matrix damage in SMC composites

This paper presents an anisotropic, micromechanical damage model for sheet molding compound (SMC) composites, that is a thermoset matrix reinforced with long (≈25mm) glass fibers. The model captures the dominant damage mechanisms – matrix damage and fiber-matrix interface debonding – in a Mori-Tanaka homogenization framework. Matrix damage is modeled as a phase-averaged isotropic stiffness degradation. The interface damage is governed by an equivalent interface stress on the lateral fiber surface. Hereby, the inhomogeneous stress distribution in the fiber-matrix interface is taken into account in the definition of the equivalent stress. A Weibull distribution for the interface strength is assumed. The model can account for an anisotropic distribution and evolution of load-carrying fibers with intact interfaces. The model is validated by means of tensile tests on unsaturated polyester polyurethane hybrid and epoxy resin systems with different glass fiber contents (23-50vol.%). The model yields satisfyingly accurate predictions under uniaxial and biaxial stress states.

Hybrid waterborne polyurethane/acrylate dispersion synthesized with bisphenol A-glicidylmethacrylate (Bis-GMA) grafting agent

New hybrid waterborne polyurethane/acrylate (WPUA) dispersions were synthesized by grafting with bisphenol-A-glycidyl dimethacrylate (Bis-GMA) in order to create chemical bonds between polyurethane and polyacrylate chains. WPUAs were prepared by using prepolymer self-emulsifying method with isophorone diisocianate, poly(tetramethylene ether) glycol, dimethylolpropionic acid, and ethylenediamine in the polyurethanic part, and styrene and n-butyl acrylate in the polyacrylate portion. A redox pair system consisting of ascorbic acid and hydrogen peroxide were used as polymerization initiator. The particle size of the WPUA dispersions increased by increasing the Bis-GMA/1,4 butanediol ratio, stable dispersions of negatively charged particles were obtained, and they had low viscosity (around 1.3 mPa.s) in spite of the relatively high solids content (27 wt%). Higher thermal stability was obtained when 50 mol% of chain extension was carried out with Bis-GMA. Using Bis-GMA/BD, instead of HEMA, as grafting agent, allowed obtaining hybrid polyurethane dispersions with the lowest mean particle size and better colloidal stability. Finally, the addition of 35 wt% Bis-GMA increased noticeably the cross-cut adhesion of polyurethane/acrylate coatings to stainless steel.

Fabrication of an electroconductive, flexible, and soft poly(3,4-ethylenedioxythiophene)-thermoplastic polyurethane hybrid scaffold by in situ vapor phase polymerization.

The inherent insolubility and brittleness of poly(3,4-ethylenedioxythiophene) (PEDOT) reduce its processability and practical applicability. Herein, we use in situ vapor phase polymerization (VPP) of 3,4-ethylenedioxythiophene (EDOT) on an oxidant-impregnated thermoplastic polyurethane (TPU) matrix comprising a three-dimensional silica particle assembly to produce a soft, flexible, and conductive TPU-PEDOT hybrid scaffold. The selective removal of silica yielded a highly porous (∼95%) skeletal structure, with the effective penetration, diffusion, and polymerization of EDOT resulting in uniform PEDOT formation both on the surface and the inner side of the TPU matrix. The mechanical and electrical properties of the obtained scaffold were investigated by bending, compression testing, and stress-strain and electrical measurements. The electrical resistance of the scaffold equaled 17 kΩ and did not change after ∼500-fold bending, whereas the observed elastic modulus was much lower (300 kPa) than that of TPU (3.3 MPa). In vitro biocompatibility was investigated by MC3T3-E1 cell culturing with cell viability evaluated using the WST assay and cell morphology examined by confocal microscopy. Thus, the soft and flexible TPU-PEDOT hybrid scaffold produced by VPP might be practically useful, implying that this preliminary investigation needs to be extended to study the behavior of muscle and nerve cells under electrical stimulation.

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.

Effect of Surface Treatment on the Mechanical Properties of Sugar Palm/Glass Fiber-reinforced Thermoplastic Polyurethane Hybrid Composites

Effects of various surface modifications were evaluated relative to the mechanical properties of sugar palm fiber/glass fiber (SPF/GF) reinforced thermoplastic polyurethane (TPU) hybrid composites. The 6 wt.% alkaline, 2 wt.% silane, and combined 6 wt.% alkaline-2 wt.% silane treatment of SPF were carried out for 3 h to improve the fiber/matrix interaction of SPF/GF with TPU. The SPF and GF were fixed at 30 wt.% and 10 wt.% fiber loading, respectively, and were fabricated using the melt compounding method followed by hot compression in a moulding machine. Mechanical properties, such as tensile, flexural, and impact strength, were evaluated using a universal testing machine and an Izod impact tester. The untreated and treated hybrid composites were characterized by FTIR spectroscopy. The tensile, flexural, and impact strength of the combined 6 wt. % alkaline-2 wt. % silane treatment was improved 16%, 39%, and 18%, respectively, as compared to the untreated SPF/GF reinforced TPU hybrid composites. Moreover, the scanning electron microscopy (SEM) showed a good fiber and matrix interfacial bonding in the hybrid composites. Thus, this treated hybrid composites could be suitable for fabricating automotive parts.

Conductive Tough Hydrogel for Bioapplications.

Biocompatible conductive tough hydrogels represent a new class of advanced materials combining the properties of tough hydrogels and biocompatible conductors. Here, a simple method, to achieve a self-assembled tough elastomeric composite structure that is biocompatible, conductive, and with high flexibility, is reported. The hydrogel comprises polyether-based liner polyurethane (PU), poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(4-styrenesulfonate) (PSS), and liquid crystal graphene oxide (LCGO). The polyurethane hybrid composite (PUHC) containing the PEDOT:PSS, LCGO, and PU has a higher electrical conductivity (10×), tensile modulus (>1.6×), and yield strength (>1.56×) compared to respective control samples. Furthermore, the PUHC is biocompatible and can support human neural stem cell (NSC) growth and differentiation to neurons and supporting neuroglia. Moreover, the stimulation of PUHC enhances NSC differentiation with enhanced neuritogenesis compared to unstimulated cultures. A model describing the synergistic effects of the PUHC components and their influence on the uniformity, biocompatibility, and electromechanical properties of the hydrogel is presented.