Improving interfacial adhesion between thermoplastic polyurethane and copper foil using amino carboxylic acids

A chemical methodology to improve the adhesion between copper foil and a thermoplastic polyurethane (TPU) matrix is reported. The copper foil (0.127 mm thickness) was treated with aminocarboxylic acid‐based coupling agents such as 6‐aminohexanoic acid and 4‐aminobenzoic acid. 3‐Aminopropyl trimethoxysilane was also used as a conventional silane coupling agent for comparative studies. The interfacial adhesion between copper foil and laminated TPU was examined by means of peel adhesion test, scanning electron microscopy, and attenuated total reflection‐infrared spectroscopic methods. The treatment of copper foils with 6‐aminohexanoic acid resulted in improved adhesion, which was equal to that of the silane‐treated system. The mechanism of how the coupling agents strengthen the interfacial adhesion between TPU and copper foil is discussed. The solution concentrations of the coupling agents were optimized with respect to the peel adhesion of the interface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of ultrasound on the synthesis and properties of polyurethane foam/clay nanocomposites

Polyurethane foam (PUF)/clay nanocomposites were synthesized with clay modified by polymeric 4,4′‐diphenylmethane diisocyanate (PMDI) with the application of ultrasound. Transmission electron micrographs showed that the interlayer distance increased for the polyurethane (PU)/clay nanocomposites where ultrasound was applied. The results of the transmission electron microscopy and X‐ray measurements suggest that the application of ultrasound to the clay modification with PMDI improved the efficiency of the clay modification by the effective breakup of the clay agglomerates and intercalation of the silicate layers. In the mechanical tests of the PUF/clay nanocomposites, the flexural and tensile strengths of the PUF/clay nanocomposites showed the maximum value at 3.0 wt % clay content based on PMDI. These results suggest that the increases in the flexural and tensile strengths were perhaps due to the uniform dispersion of the clay by the application of ultrasound. At the same modified clay content, the fire resistance properties were increased for the PUF/clay nanocomposites with the application of ultrasound compared to the PUF/clay nanocomposites without the application of ultrasound. The cell size and thermal conductivity were decreased for the PUF/clay nanocomposites with the application of ultrasound compared to the PUF/clay nanocomposite without the application of ultrasound. Because of these results, we suggest that the smaller cell size and lower thermal conductivity of the PUF/clay nanocomposites were mainly due to the enhanced dispersion of the clay by the application of ultrasound to the mixture of PMDI and clay. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3764–3773, 2006     

Pulverized polyurethane foam particles reinforced rigid polyurethane foam and phenolic foam

Polyurethane consumption has been increasing in recent years, raising concerns about how to deal with the polymer waste. Post‐consumer rigid polyurethane foams or polyurethane foam scraps (PPU) ground into particles were utilized to strengthen mechanical properties of rigid polyurethane foam (PUF) and phenolic foam (PF). Viscosity of prepolymer with PUF was measured and PPU was well dispersed in prepolymer, as observed by optical microscope. Microstructures and morphologies of the reinforced foam were examined with scanning electron microscope (SEM) while cell diameter and density were measured by Scion Image software. Universal testing machine was employed to optimize compressive properties at various weight ratios of PPU. Both PUF and PF with 5 wt % PPU, respectively, exhibited considerable improvement in mechanical properties especially compressive property. The compressive modulus of PUF with 5 wt % PPU was 12.07 MPa, almost 20% higher than pure PUF while compressive strength of PF with 5 wt % PPU reached 0.48 MPa. The thermal stability of the reinforced foam was tested by thermal gravity analysis (TGA) and the result shows no obvious impact with PPU. The decomposition temperatures of PUF with PPU and PF with PPU were 280°C, because PPU has relatively weak thermal stability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39734.     

Synthesis of thermoplastic polyurethane and its physical and shape memory properties

In this article, thermoplastic polyurethane (PU) with a shape memory property was synthesized. First, the PU prepolymer was prepared by reacting poly(tetramethylene glycol) with 4,4′‐diphenylmethane diisocyanate, then extended with various extenders such as linear aliphatic 1,4‐butanediol, benzoyl‐type 4,4‐bis(4‐hydroxyhexoxy)‐isopropylane and naphthalate‐type bis(2‐phenoxyethanol)‐sulfone or naphthoxy diethanol. The experimental results showed that the tensile strength, elongation at break, and initial modulus at 300% of these copolymer films were in the range of 31–64 Mpa, 42%–614%, and 8.26–11.5 MPa, respectively. Thermal analysis showed that the glass‐transition temperature of these copolymers was in the range of ?73°C to ?50°C for the soft segment (T_gs) and 70°C–106°C for the hard segment (T_gh) and that the melting point was in the range of 14.6°C–24.2°C for the soft segment and 198°C–206°C for the hard segment. The extender with a benzoyl or naphthalate group was better able to promote its shape memory property than was the regular polyurethane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 607–615, 2006     

Effect of polyurethane sizing on carbon fibers surface and interfacial adhesion of fiber/polyamide 6 composites

Commercial epoxy sized carbon fibers (CFs) or unsized CFs have poor interfacial adhesion with polyamide 6 (PA6). Here, CFs are coated with polyurethane (PU) and their surface properties in terms of surface chemistry, contact angle, roughness, and morphology, are investigated. The results of Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy demonstrate PU sizing evidently increases the quantity of polar functional groups on the CFs surface. The surface energy of the PU sized fiber is calculated according to the Owens–Wendt method. Compared with unsized fibers, the contact angle of PU sized fibers is decreased while their total surface energy is increased, indicating superior wettability. Moreover, transverse fiber bundle tests are performed to determine the interfacial adhesion between the CFs and PA6 matrix. The transverse fiber bundle strength of unsized CF is measured to be 12.57 MPa. For PU sized CFs processed with sizing concentration of 1.2%, this value is increased to 24.35 MPa, showing an increase of more than 90%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46111.     

Development of water‐blown bio‐based thermoplastic polyurethane foams using bio‐derived chain extender

Water‐blown bio‐based thermoplastic polyurethane (TPU) formulations were developed to fulfill the requirements of the reactive rotational molding/foaming process. They were prepared using synthetic and bio‐based chain extenders. Foams were prepared by stirring polyether polyol (macrodiol), chain extender (diol), surfactant (silicone oil), chemical blowing agent (distilled water), catalyst, and diisocyanate. The concentration of chain extender, blowing agent, and surfactant were varied and their effects on foaming kinetics, physical, mechanical, and morphological properties of foams were investigated. Density, compressive strength, and modulus of foams decrease with increasing blowing agent concentration and increase with increasing chain extender concentration, but are not significantly affected by changes in surfactant concentration. The foam glass‐transition temperatures increase with increasing blowing agent and chain extender concentrations. The foam cell size slightly increases with increasing blowing agent content and decreases upon surfactant addition (without any dependence on concentration), whereas chain extender concentration has no effect on cell size. Bio‐based 1,3‐propanediol can be used successfully for the preparation TPU foams without sacrificing any properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synergistic effect of expandable graphite and aluminum hypophosphite on flame‐retardant properties of rigid polyurethane foam

A series of flame retarding rigid polyurethane foam (RPUF) composites based on expandable graphite (EG) and aluminum hypophosphite (AHP) were prepared by the one‐pot method. The properties were characterized by limiting oxygen index (LOI) test, cone calorimeter test, thermogravimetric analysis (TGA), real‐time Fourier transform‐infrared spectra (RT‐FT‐IR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), etc. The results indicate that both EG and AHP could enhance the flame retardency of RPUF composites. Besides, the flame retardant effect of EG was better than that of AHP. The results also show that partial substitution of EG with AHP could improve the flame retardency of RPUF, and EG and AHP presented an excellent synergistic effect on flame retardancy. What is more, compared with RPUF/20EG and RPUF/20AHP, the heat release rate (HRR) and total heat release (THR) of RPUF/15EG/5AHP were lower.TGA results indicate that partial substitution of EG with AHP could improve the char residue which provided better flame retardancy for RPUF composites. The thermal degradation process of RPUF composites and the chemical component of the char residue were investigated by RT‐FT‐IR and XPS. And the results prove that RPUF/15EG/5AHP had higher heat resistance in the later stage. Compared with the RPUF composites filled with EG, a better cell structure and mechanical properties were observed with the substitution of AHP for part of EG. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42842.     

Preparation of graphite oxide/polyurethane foam material and its removal application of malachite green from aqueous solution

Synthetic dyes are commonly used in textile, paper, leather, food, plastic and cosmetic industries. In this study, a series of novel graphite oxide/polyurethane (GO/PU) polymeric foam materials were prepared by foaming technique. The GO/PU was applied to remove malachite green (MG) from aqueous solution. When static adsorption experiment was carried out with a GO content of 3.0%, a GO/PU dosage of 40 mg/mL, a temperature of 50°C, and a time of 3 h, the highest adsorption efficiency can reach 99.7%. The kinetics, equilibrium and thermodynamics of MG adsorption onto GO/PU polymeric foam material were investigated. The results indicated that adsorption behavior was found to follow closely the pseudo‐second order kinetics, equilibrium data were well fitted by Langmuir adsorption model and the adsorption process was spontaneous and endothermic. Prepared GO/PU foam material has potential application for the wastewater treatment containing MG dye. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40988.     

Polyglycidyl nitrate (PGN)‐based energetic thermoplastic polyurethane elastomers with bonding functions

PGN‐based ETPUEs were synthesized using mixture of chain extenders including 1, 4‐butanediol and Diethyl Bis(hydroxymethyl)malonate (DBM). Through the special chain extenders DBM, the –COOR was introduced into the energetic thermoplastic polyurethane elastomers (ETPUEs) and further enhances the adhesion between ETPUE and nitramine solid ingredients in propellants. From the analysis, with the percentage of DBM increasing, the work of adhesion (W_a) between nitramine solid ingredients and ETPUEs increased and the maximum stress (σ_m) of ETPUEs decreased on the other hand. In order to test the bonding functions of different ETPUEs, the RDX/ETPUE propellants were prepared and the stress–strain curves of all propellants were tested. The results showed that the ETPUE‐75 with 75% DBM can prevent the dewetting and improve the mechanical properties of propellants. The ETPUE prepared with chain extender including 1, 4‐butanediol and DBM were valuable for application in propellants. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42026.     

Effect of curing moisture on the indentation force deflection of flexible polyurethane foam

The moisture effect on the indentation force deflection (IFD) of flexible polyurethane foam was examined through the curing of the foam with different moisture contents. The employed foam was cured at 30, 40, 50, 60, 70, and 80% relative humidity, and the corresponding curing temperature was constant at 23°C. The experiments showed that the measured IFD and support factor of the flexible polyurethane foam decreased, and the hysteresis increased with the curing moisture. A statistical conversion formula was generated experimentally to correct the measured IFD of the flexible polyurethane foam to eliminate the deviation caused by the moisture effect. The measured IFD was inversely exponentially proportional to the curing moisture. The accuracy of the correction formula was verified by the conditioning of the foam again with different moisture contents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1679–1682, 2007     

Preparation and characterization of surface‐modified ammonium polyphosphate and its effect on the flame retardancy of rigid polyurethane foam

A functional surface‐modification agent was synthesized via a reaction between hexachlorocyclotriphosphazene and γ‐aminopropyl triethoxysilane. Ammonium polyphosphate (APP) was modified with this agent and then incorporated into a rigid polyurethane foam (RPUF). Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray photoelectron spectroscopy were used to characterize the modified ammonium polyphosphate (M‐APP). The results show that the dispersibility was improved and the particle size decreased after the modification. The limiting oxygen index and cone calorimetry test results show that M‐APP enhanced the flame‐retardant properties of RPUF. The peak heat‐release rate of polyurethane (PU)/20% M‐APP decreased by 51.18% compared with that of PU–APP. The scanning electron microscopy results illustrate that M‐APP facilitated the formation of intumescent and compact char. The excellent flame‐retardant performance of M‐APP resulted from the flame‐inhibition and barrier effects, which were attributed to the phosphazene group and the intumescent char, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45369.     

Research on properties of rigid polyurethane foam with heteroaromatic and brominated benzyl polyols

Rigid polyurethane foams (RPUFs) were prepared with specific heteroaromatic and brominated benzyl polyols. The mechanical properties and thermal stability were studied using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TG). The limiting oxygen index (LOI) was used to investigate the flame retardancy of the RPUFs. The results showed that the glass transition temperature (T_g) of the RPUF prepared by heteroaromatic polyol was 182°C, demonstrating an improved thermal stability for this specific heteroaromatic polyol. Brominated benzyl polyol exhibited less negative influence on mechanical properties of the RPUFs at the same time of improving the flame retardancy. The LOI values increased with an increase in the brominated polyol content to 27.5%, and the char‐forming ability of the RPUF improved; the char residue rate reached 12.6% at 700°C, but it was only 6.2% without the flame retardant. Scanning electron microscope (SEM) and energy‐dispersive spectrometry (EDS) verified that the mechanism of flame retardancy was due to a synergistic effect of the gas phase and the condensed phase. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42349.     

New applications for foam composites of polyurethane and recycled rubber

In Portugal, most end‐of‐life tires are recycled through a process involving a cryogenic grinding technology. The purpose of this work was to envisage new applications for recycling rubber from end‐of‐life tires. In this work, rubber was supported in a polyurethane matrix generating two new products of distinct characteristics and properties. The choice of these products was ruled by the requests of potential clients: (a) Floating trays to withstand the load of plants capable of cleansing polluted water from lagoons, ponds, or basins; (b) Compression‐absorbing buoys to dampen the shocks and the compressive stresses between ships and docks. The polyurethane formulations developed herein were based on methylene diphenyl diisocyanate and a trifunctional polyol such that the final foam would be flexible. As the floating trays' density should be lower than the water density, the best formulation found comprised 150% of rubber, 4% of water (relative to the polyol mass), with an isocyanate index of 105% and a density of 89 kg m^?3. The foam that presented the optimal compression behavior to be applied in compression absorbing buoys, comprised 200% of rubber, 3% of water, with an isocyanate index of 105% and a density of 121 kg m^?3. In both cases, the composite foam materials obtained showed final properties compatible with the envisaged applications, pointing out that the implied methodology may be used in the future to recycle rubber from end‐of‐life tires. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The thermoresponsive shape memory characteristics of polyurethane foam

The purpose of this study is to develop a protective and thermally intelligent filler by optimizing the preparing conditions and the thermoresponsive property of PU foam. The specimens were polyurethane synthesized by a one step process with 4,4′‐diphenylmethane diisocyanate, polycaprolactone and 1,4‐butanediol. After dissolving the polyurethane in tetrahydrofuran, the polyurethane foam was manufactured by the salt leaching method. The appearance, compressive property, and thermal property of the manufactured foam as well as the shape memory effects were evaluated. In addition, air and water vapor permeabilities and the thermal insulation property were measured to examine the basic properties of the foam. The cell sizes of the completed foam were distributed in the range of 400–1,000 μm. The compressive stress of the foam was low in the initial compressive strain but increased dramatically above a compressive strain of 70%. However, the foam showed a very low capacity for compressive stress compared with an electrospun web or a film manufactured by using the identical shape memory polyurethane. The transition temperature of the foam was 30°C. The shape recovery and shape retention were 98% or higher. The foam, with a porous structure, was found to be generally good in both air and water vapor permeability. In the case of the foam that maintained its compressed shape below the transition temperature, these permeabilities of the foam decreased slightly, but not significantly. Because of the porous structure of the foam, the shape memory effect did not noticeably influence the permeability change with a change in temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Processing and tribology of thermoplastic polyurethane particulate composite materials

The processing, mechanical and tribological properties of wax containing thermoplastic polyurethane–filler composites were studied for different weight ratios of graphite, TiO₂, MoS₂, and ZrO₂ microparticles and SiO₂ nanoparticles. The composites were compounded by extrusion and processed by compression molding. The rheological, thermal, and mechanical properties were measured, and the wear characteristics were tested with ball-on-plate reciprocating tribometer tests under fixed friction conditions and then observed by scanning electron microscopy. Correlations between the friction, wear, and mechanical properties were observed, and their mechanisms are discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of polyurethane/silica aerogel nanocomposite materials

In this investigation, silica aerogel (SA)/Rigid Polyurethane (PUR) foam composites and silica aerogel/Polyurethane (PU) composites were prepared by dry mixing of granular and grinded silica aerogels with polyol part. They were then combined with diisocyanate part. Three different types of PUR foams and an elastomeric coating grade of PU were studied as well. Results show that thermal conductivity of foams did not decrease by adding silica aerogel. It even increased for some grades which is assumed to be due to the change in cell configuration of these foams. It was also found that sound insulation performance of these cellular composites did not improve significantly. Unlike foam composites, addition of silica aerogel into elastomeric PU improved its thermal and acoustic insulation properties. Because of the more promising properties of elastomeric PU composites, further examinations including measurements of compression strength and water contact angle of silica aerogel/PU composites were also taken. Final results showed a significant improvement in general properties of PU coatings by adding little amounts of silica aerogel (1–4 wt %). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44521.     

Effect of cenosphere surface treatment and blending method on the tensile properties of thermoplastic matrix syntactic foams

The influence of cenosphere surface treatment and blending method on the properties of injection molded high‐density polyethylene (HDPE) matrix syntactic foams is investigated. Cenospheres are treated with silane and HDPE is functionalized with dibutyl maleate. Tensile test specimens are cast with 20, 40, and 60 wt % of cenospheres using injection molding. Modulus and strength are found to increase with increasing cenosphere content for composites with treated constituents. Highest modulus and strength were observed for 40 and 60 wt % untreated mechanically mixed and treated brabender mixed cenospheres/HDPE blends, respectively. These values are 37 and 17% higher than those for virgin and functionalized HDPE. Theoretical models are used to assess the effect of particle properties and interfacial bonding on modulus and strength of syntactic foams. Brabender mixing method provided highest ultimate tensile and fracture strengths, which is attributed to the effectiveness of Brabender in breaking particle clusters and generating the higher particle–matrix surface area compared to that by mechanical mixing method. Theoretical trends show clear benefits of improved particle–matrix interfacial bonding in the strength results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43881.     

f-CTBN/PEG聚氨酯材料的合成及性能研究

以三乙醇胺得到的功能化丁腈橡胶（f-CTBN）和不同相对分子质量聚乙二醇（PEG）为基本物质,逐步聚合得到一系列高支化嵌段聚氨酯材料。探究f-CTBN、PEG的用量和固化剂（HDI与H12MDI）的不同对材料性能的影响,通过形貌观察、力学性能测试、毒性试验来综合评价,发现物料比m（f-CTBN）/m（PEG）为3∶7聚氨酯有望成为医用薄膜。     

Abnormalities in electrical and acoustic properties of thermoplastic polyurethane

The temperature dependence of ultrasonic pulse velocity C and specific volume resistance ρ_v of crystallizing thermoplastic polyurethane (TPUR) was investigated. It was revealed that under certain conditions TPUR acquired abnormally low ρ_v values and C values uncharacteristic of polymers. An explanation for the observed abnormalities could be based on the assumption of the presence of ‘hot’ electrons in TPUR.     

Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer

To prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH₂ provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007