Curing characteristics of glycidyl azide polymer‐based binders

The curing of a glycidyl azide polymer (GAP) with a triisocyanate, Desmodur N‐100, was followed by measuring the hardness and viscosity. The thermal behavior of the cured samples were investigated by a differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Curing causes an increase in the glass transition temperature of GAP. The T_g of gumstocks also increases with an increasing NCO/OH ratio while the decomposition temperature remains practically unchanged. The ultimate hardness of the cured samples increases with an increasing NCO/OH ratio. The binder with a NCO/OH ratio of 0.8 was found to provide the most suitable thermal and physical characteristics for composite propellant applications. The increase in the glass transition temperature of gumstocks upon curing can be compensated by using a 1:1 mixture of bis‐2,2‐dinitropropyl acetal and formal as the plasticizer. The T_g value of gumstocks can be decreased to −46.7°C by adding 25% b.w. of a plasticizer which does not have any significant effect on the decomposition properties of the gumstocks. Furthermore, a remarkable decrease in the ultimate hardness of the gumstocks is achieved upon addition of a plasticizer, while the curing time remains almost unaffected. The addition of dibuthyltin dilaurate as a catalyst reduces the curing time of the gumstocks from 3 weeks to 5–6 days at 60°C. Use of the curing catalyst also results in the hardening of the gumstocks. The decomposition properties of the gumstocks remain practically unchanged while a noticeable increase is observed in the glass transition temperature with an increasing concentration of the catalyst. This can also be compensated by a reverse effect of the plasticizer. The gel time, an important parameter which determines the pot life of a propellant material, can be measured by monitoring the viscosity of the mixture, which shows a sharp increase when gelation starts. The addition of a curing catalyst shortens the gel time remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 65–70, 2001     

Kinetics of glycidyl azide polymer‐based urethane network formation

Reactions between hydroxyl‐terminated glycidyl azide polymer (GAP) and different isocyanate curatives such as toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), and methylene diicyclohexyl isocyanate (MDCI) at various temperatures viz. 30, 40, 50, and 60°C were followed by Fourier transform infra red spectroscopy. The reactions were found to follow second‐order kinetics. With TDI and IPDI at 30°C, a two‐stage reaction was observed. For GAP‐TDI system, the second stage was slower than the first while for GAP‐IPDI system, the second stage was faster than the first indicating dominance of autocatalytic effect. The stage separation occurred due to the difference in reactivity of the isocyanate groups and was found to narrow down with increase in temperature. The viscosity build up due to the curing reaction was followed for GAP‐TDI system for comparison. The stage separation was evident in the viscosity build up also. Rheokinetic analysis done based on data generated showed a linear correlation between viscosity build up and fractional conversion. The kinetic and activation parameters evaluated from the data showed the relative difference in reactivity of the three diisocyanates with GAP. Both the approaches suggested that the reactivity of the isocyanates employed for the present study could be arranged as TDI > IPDI ? MDCI. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of novel polyurethanes based on fluorine‐containing polyphosphazene

Fluorine‐containing poly[bis‐(2,2,3,3,4,4,5,5‐octafluoro‐1‐pentanol)_1.6 (4‐hydroxybutaneoxy)_0.4 phosphazene] (OFHBP) was synthesized and characterized by Fourier transform infrared (FTIR) spectra, nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The obtained OFHBP was used as a cross‐linker to prepare a series of novel polyurethanes (PUPFs). The composition of the PUPFs was confirmed by FTIR and elemental analysis (EA). The crystalline structure and microstructure of the PUPFs were examined by X‐ray diffraction (XRD) and atomic force microscopy (AFM). The thermal and tensile properties of the PUPFs were characterized by differential scanning calorimetry (DSC) and tensile testing. In addition, the surface energy of the PUPFs was also evaluated by contact angle measurements (CA). The results showed that glass transition temperature of the PUPF‐4 was decreased by 15°C, elongation at break was improved by 61% and a 41% decrease in surface energy in comparison with conventional polyurethane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dielectric and thermal behaviors of fluorine‐containing dianhydride‐modified polybenzoxazine: A molecular design flexibility

Fluorine‐containing copolybenzoxazines were successfully prepared by reacting bisphenol‐AF/aniline‐based benzoxazine resin (BAF‐a) with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) in N,N‐dimethylacetamide solvent. The dielectric and thermal properties as well as flexibility of the resulting copolymer films were investigated. The incorporation of fluorine groups into polybenzoxazine was found to substantially decrease the dielectric constant of the resulting copolybenzoxazine to as low as 2.6. The formation of ester linkages between the hydroxyl groups in the poly(BAF‐a) and the carbonyl groups in the 6FDA resulted in substantially enhanced flexibility of the copolybenzoxazines. Moreover, the copolymers showed superior degradation temperature and significant improvement in char yield, up to 464 °C and 56%, respectively. The glass‐transition temperature of the copolybenzoxazines was increased with increasing dianhydride content and exhibited a maximum value of 290 °C at 2.5/1 mole ratio of poly(BAF‐a) to 6FDA. Therefore, the fluorine‐containing dianhydride‐modified polybenzoxazines are appropriate for applications as polymeric films for coatings and as a good electrical insulation material with high thermal resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45204.     

Thermal and mechanical properties of acrylated expoxidized‐soybean oil‐based thermosets

A series of epoxidized‐soybean oil (ESO) with different epoxyl content were synthesized by in situ epoxidation of soybean oil (SBO). The acrylated epoxidized‐soybean oil (AESO) was obtained by the reaction of ring opening of ESO using acrylic acid as ring opener. The acrylated expoxidized‐soybean oil‐based thermosets have been synthesized by bulk radical polymerization of these AESOs and styrene. The thermal properties of the resins were characterized by differential scanning calorimetry (DSC) and thermo‐gravimetric analysis (TG). The results showed that these resins possess high thermal stability. There were two glass transition temperature of each resin due to the triglycerides structure of the resins. The tensile strength and impact strength of the resins were also recorded, and the tensile strength and impact strength increased as the iodine value of ESO decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of fluorine‐containing polysiloxanes obtained via ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO$_{4}^{2-}$/TiO2/Ln3+

Traditional catalysts such as (CH₃)₄NOH, NaOH, KOH, n‐BuLi and CF₃SO₃H can catalyze the copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane to afford fluorine‐containing polysiloxanes. However, use of these catalysts poses significant difficulties in handling and separation. In this work, fluorine‐containing polysiloxanes were synthesized through a novel and environmentally friendly method: ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO /TiO₂/Ln³⁺. The effects of reaction conditions were examined in detail. The yield sequence of various rare earth catalysts is Nd ～ La ～ Y ～ Sm > Gd, while the number‐average molecular weight sequence is Nd > La > Y > Sm > Gd. The optimum conditions for the ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane are as follows: [Nd³⁺] = 0.05 mol L^?1 and mol L^?1 in the immersing solution, SO /TiO₂/Nd³⁺ calcined at 500 °C and the copolymerization conducted at 80 °C for 40 min. Structures of resulting copolymers were characterized using size exclusion chromatography, ¹H NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. According to the copolymerization features, a cationic equilibrium reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry     

Microfluidic assembly of uniform fluorescent microbeads from quantum‐dot‐loaded fluorine‐containing microemulsion

We report a facile strategy for fabricating fluorescent quantum dot (QD)‐loaded microbeads by means of microfluidic technology. First, a functional fluorine‐containing microemulsion was synthesized with poly[(2‐(N‐ethylperfluorobutanesulfonamido)ethyl acrylate)‐co‐(methyl methacrylate)‐co‐(butyl acrylate)] (poly(FBMA‐co‐MMA‐co‐BA)) as the core and glycidyl methacrylate (GMA) as the shell via differential microemulsion polymerization. Then, CdTe QDs capped with N‐acetyl‐l ‐cysteine (NAC) were assembled into the poly(FBMA‐co‐MMA‐co‐BA‐co‐GMA) microemulsion particles through the reaction of the epoxy group on the shell of the microemulsion and the carboxyl group of the NAC ligand capped on the QDs. Finally, fluorescent microbeads were fabricated using the CdTe QD‐loaded fluorine‐containing microemulsion as the discontinuous phase and methylsilicone oil as the continuous phase by means of a simple microfluidic device. By changing flow rate of methylsilicone oil and hybrid microemulsion system, fluorescent microbeads with adjustable sizes ranging from 290 to 420 µm were achieved. The morphology and fluorescent properties of the microbeads were thoroughly investigated using optical microscopy and fluorescence microscopy. Results showed that the fluorescent microbeads exhibited uniform size distribution and excellent fluorescence performance. © 2014 Society of Chemical Industry     

Thermal and mechanical properties of polyisobutylene‐based thermoplastic polyurethanes

We investigated thermal and mechanical properties of thermoplastic polyurethanes (TPUs) with the soft segment comprising of both polyisobutylene (PIB) and poly(tetramethylene)oxide (PTMO) diols. Thermal analysis reveals that the hard segment in all the TPUs investigated is completely amorphous. Significant mixing between the hard and soft segments was also observed. By adjusting the ratio between the hard and soft segments, the mechanical properties of these TPUs were tuned over a wide range, which are comparable to conventional polyether‐based TPUs. Constant stress creep and cyclic stress hysteresis analysis suggested a strong dependence of permanent deformation on hard segment content. The melt viscosity correlation with shear rate and shear stress follows a typical non‐Newtonian behavior, showing decrease in shear viscosity with increase in shear rate. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 891‐897, 2013     

Studies of fluorine‐containing bismaleimide resins part I: Synthesis and characteristics of model compounds

A series of fluorine‐containing bismaleimide (FBMI) monomers are synthesized by a 3‐step reaction for using as the applications of low‐k materials. The synthesized FBMI monomers are characterized by the ¹H, ¹³C, ¹⁹F nuclear magnetic resonance (NMR) spectroscopy and element analysis. These FBMI monomers react with free radical initiator or self‐cure to prepare FBMI‐polymers. All the self‐curing FBMI resins have the glass transition temperatures (T_g) in the range of 128–141°C and show the 5% weight loss temperatures (T_5%) of 235–293°C in nitrogen atmosphere. The higher heat resistance of self‐curing FBMI resin relative to FBMI‐homopolymer is due to its higher crosslinking density. The FBMI resins exhibit improved dielectric properties as compared with commercial bismaleimide (BMI) resins with the dielectric constants (D_k) lower than 2.49, which is related to the low polarizability of the C? F bond and the large free volume of CF₃ groups in the polymers. Besides, the flame retardancy of all these FBMI resins could be enhanced via the introduction of Br‐atom. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal,mechanical, and shape‐memory properties of nanorubber‐toughened,epoxy‐based shape‐memory nanocomposites

Epoxy‐based shape‐memory polymers (ESMPs) are a type of the most promising engineering smart polymers. However, their inherent brittleness limits their applications. Existing modification approaches are either based on complicated chemical reactions or done at the cost of the thermal properties of the ESMPs. In this study, a simple approach was used to fabricate ESMPs with the aim of improving their overall properties by introducing crosslinked carboxylic nitrile–butadiene nanorubber (CNBNR) into the ESMP network. The results show that the toughness of the CNBNR–ESMP nanocomposites greatly improved at both room temperature and the glass‐transition temperature (T_g) over that of the pure ESMP. Meanwhile, the increase in the toughness did not negatively affect other macroscopic properties. The CNBNR–ESMP nanocomposites presented improved thermal properties with a T_g in a stable range around 100 °C, enhanced thermal stabilities, and superior shape‐memory performance in terms of the shape‐fixing ratio, shape‐recovery ratio, shape‐recovery time, and repeatability of shape‐memory cycles. The combined property improvements and the simplicity of the manufacturing process demonstrated that the CNBNR–ESMP nanocomposites are desirable candidates for large‐scale applications in the engineering field as smart structural materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45780.     

Effects of addition orders on the properties of fluorine‐containing copolyimides

A series of fluorine‐containing copolyimides were synthesized by three different orders of addition of monomers. The fluorine‐containing copolyimides were prepared by the reaction of 4,4′‐diaminodiphenylmethane (DDM) with 2,2′‐bis(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), and pyromellitic dianhydride (PMDA). The synthesis reactions of the copoly(amic acid)s (PA) were carried out by three different orders of addition of the monomers with different molar ratios of 6FDA to PMDA. The viscosity of the PA solution obtained by DDM–(6FDA+PMDA), that is, 6FDA and PMDA added simultaneously to DDM in N‐methyl‐2‐pyrrolidinone (NMP), was higher than the other two addition orders (i.e., DDM–6FDA–PMDA and DDM–PMDA–6FDA). The viscosity decreased as the relative amount of 6FDA to PMDA increased. The copolyimides formed by different addition orders but the same 6FDA‐to‐PMDA molar ratios contained different properties, such as dielectric constant, moisture absorption, contact angle, and optical transparency. All of these copolyimides were insoluble in common organic solvents, such as NMP and tetrahydrofuran. Thermogravimetric analysis showed that the onset temperature of 8% weight loss decreased slightly as [6FDA] : [PMDA] increased. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3252–3258, 2000     

Mechanical and thermal properties of phenolic/glass fiber foam modified with phosphorus‐containing polyurethane prepolymer

Phenolic foam exhibits outstanding flame, smoke and toxicity properties, good insulation properties and low production costs. However, the brittleness and pulverization of phenolic foam have severely limited its application in many fields. In this study, a novel phosphorus‐containing polyurethane prepolymer (DOPU) modifier was firstly synthesized, and then the foaming formula and processing of toughening phenolic foam modified with DOPU and glass fiber were explored. The structure and reactive behavior of prepolymer and phenolic resin were investigated using Fourier transform infrared spectroscopy. The effects of DOPU and glass fiber on the apparent density, compressive strength, bending strength and water absorption were investigated. The results suggested that the apparent density, compressive strength and bending strength of modified phenolic foam tended to increase irregularly with increasing content of DOPU. The addition of DOPU led to lower water absorption of glass fiber‐filled foam. Thermal stability and flame retardancy were examined using thermogravimetric analysis and limiting oxygen index (LOI) tests. It was found that foam with 3% DOPU and 0.5% glass fiber added exhibited good thermal stability and high char yields. The LOI value of modified phenolic foams decreased with increasing DOPU content, but it still remained at 41.0% even if the amount of modifier loaded was 10 wt%. © 2012 Society of Chemical Industry     

Synthesis,spectral and DSC analysis of glycidyl azide polymers containing different initiating diol units

Glycidyl azide polymers (GAPs), containing different diol units, were prepared by treating the corresponding poly(epichlorohydrin)s (PECHs) with sodium azide in DMF solvent at 110°C for 8–10 h. The poly(epichlorohydrin)s containing different diol units were synthesized by the polymerization of epichlorohydrin using borontrifluoride etherate as initiator in the presence of a small amount of low molecular weight diols. The formation of these PECHs was confirmed by IR spectroscopy. The nature of terminal hydroxyl group present in the polymer chain was confirmed by proton NMR spectroscopy. The structure of GAPs containing different initiating diol units was confirmed by UV, IR, and proton NMR spectral analysis. Thermal properties of the GAPs were evaluated using differential scanning calorimetry; the stabilities and glass‐transition temperatures of the GAPs varied according to the initiating diol unit present in the polymer chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2157–2163, 2004     

Studies on structure property correlation of cross‐linked glycidyl azide polymer

Glycidyl azide polymer (GAP) has been evaluated for use as binder for solid propellants. The effects of various parameters like cross‐linking conditions, concentration of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties were studied in detail. It was observed that the type of curing agent and the NCO/OH ratio have a strong influence on the gum‐stock properties. Similar impact was seen for cross‐linker concentration also. The swelling characteristics of the cross‐linked binder prepared with different NCO/OH ratios were evaluated with toluene and tetrahydrofuran (THF). The polarity and the solubility parameter of the solvents were found to influence the swelling of GAP. The NCO/OH ratio and cross‐linker concentration of the polymer were also found to affect the swelling characteristics. The sol fraction determined for the polymer was found to follow a similar pattern. The cross‐link density and average molecular weight between crosslinks (Mc) were determined from the swelling studies and also from the stress–strain relationship. The Mc values were found to be influenced by the NCO/OH ratio. Finally, the Mc values determined from the swelling data were correlated to the gum‐stock properties, and the model parameters were estimated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Structure and mechanical properties of crosslinked glycidyl azide polymers via click chemistry as potential binder of solid propellant

Depending upon the advantages of high efficiency, insensitivity to humidity and so on, the reaction of azide groups in glycidyl azide polymers (GAP) with alkynyl compounds has been used as a substitute of the urethane curing strategy to develop GAP‐based binder for solid propellant. In this work, an alkynyl compound of dimethyl 2,2‐di(prop‐2‐ynyl)malonate (DDPM) reacted with GAP to produce new crosslinked materials under the catalysis of Cu(I)Cl at ambient temperature, and showed great potential as a binder in composite propellant. As the feeding molar ratio of DDPM vs. GAP increased from 1 : 1 to 5 : 1, the crosslinking densities of as‐prepared materials gradually increased, together with simultaneous enhancement of Young's modulus and tensile strength. The breaking elongation showed the maximum value of ca. 82% when the feeding molar ratio of DDPM vs. GAP was 3 : 1. In addition, with an increase of the crosslinking densities, the glass transition temperatures of as‐prepared materials significantly increased from ?43.9°C to ?5.1°C while the mechanical loss peaks also gradually broadened and shifted up to high temperature, and even presented two peaks at the feeding molar ratio of DDPM vs. GAP higher than 4 : 1. It indicated that the formation of triazole‐based network resulted in structural heterogeneity in the as‐prepared materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40636.     

Synthesis,Characterization and Thermal Properties of Poly(glycidyl azide‐r‐3‐azidotetrahydrofuran) as Azido Binder for Solid Rocket Propellants

Azido polymers have been investigated as energetic binders in the area of solid rocket propellants. However, the low temperature mechanical properties of them are not comparable with the traditional propellant binders. In this work, a new kind of azido binder named poly (glycidyl azide‐r‐3‐azidotetrahydrofuran) (PGAAT) was successfully synthesized. The molecular structures of monomers and copolymers were characterized. The sensitivity and thermal properties of the azido binder were studied. The cationic copolymerization of 3‐methylsulfonyloxytetrahydrofuran with ternary cyclic ethers was confirmed. The PGAAT azido binder exhibited attractive features like low glass transition temperature (T_g, −60 °C) and high energy (1798 J/g). The results indicate that the polymer is a suitable candidate binder for the solid rocket propellants.     

Rheological and thermal properties of glycidyl azide polyol‐based energetic thermoplastic polyurethane elastomers

The purpose of this study was to investigate the effects of polyol on glycidyl azide polyol (GAP)‐based energetic thermoplastic polyurethane elastomers (ETPEs). Briefly, a series of GAP/polyol‐based ETPEs (GAP/polyol ETPEs) with different copolyol ratios and hard segment contents were synthesized using GAP‐diol with common polyol and 4,4‐methylenebis(phenylisocyanate)‐extended 1,5‐pentanediol as soft and hard segments, respectively, by solution polymerization in dimethylformamide. The three types of polyols used were poly(tetramethylene ether) glycol (PTMG), polycarbonate‐diol (PCL‐diol) and polycaprolactone‐diol (PCD‐diol). The synthesized GAP/polyol ETPEs were identified and characterized using Fourier transform infrared and ¹H NMR spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and rheometric mechanical spectrometry. For GAP/PCL ETPEs with lower hard segment content, DSC results showed that the GAP segment failed to interact with either the PCL segment or PCL melting. In addition, the results of DMA showed that the presence of PCL segments in ETPEs improved the storage modulus below the melting temperature of the PCL block. Further, the crystalline PCL segments were attributed to reinforcing the ETPEs in a manner similar to that of the hard domain. As the hard segment content increased in the GAP/polyol ETPEs, both GAP/PTMG ETPEs and GAP/PCL ETPEs exhibited microphase separation transitions, while rheological experiments demonstrated a sudden decrease in complex viscosity in neighboring microphase separation transitions. © 2012 Society of Chemical Industry     

Synthesis of polycarbonate‐silica nanocomposites from copolymerization of CO2 with allyl glycidyl ether,cyclohexene oxide,and sol‐gel

The copolymerization of carbon dioxide, allyl glycidyl ether, and cyclohexene oxide catalyzed by the system consisting of Y(CF₃CO₂)₃, Zn(Et)₂, and pyrogallol in the solvent of 1, 3‐dioxolane was performed in this study. The IR, ¹H NMR, and ¹³C‐NMR spectra, as well as the elemental analysis, indicated that the resulting copolymer was an alternating polycarbonate possessing more than 90% of carbonate units. The molecular weight could be as high as 1.5 × 10⁵, and the polydispersity index was 4.5. The resultant polycarbonate was found to effectively react with 3‐(trimethoxysilyl)propyl methacrylate via a free radical reaction to result in a precursor used in the sol‐gel process to synthesize a polycarbonate‐silica nanocomposite. The nanocomposites were characterized by SEM, ²⁹Si NMR, TGA, DSC, and UV–Vis. Silica particles with size less than 100 nm were found to disperse uniformly in the nanocomposites. It was also found that the thermal properties were dependent on the content of cyclohexene carbonate units. Both the thermal and mechanical properties of the resultant nanocomposites could be adjusted with silica content, while the transparency was comparable to the base copolymer even at high silica contents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 750–757, 2005     

Synthesis,thermal, and dynamic mechanical properties of 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane‐containing polydimethylsiloxanes

New and effective approaches to the synthesis of 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane‐containing polydimethylsiloxanes ( P1 and P2 ) were developed. P1 was obtained by polycondensation of cyclodisilazane lithium salt and chloroterminated polydimethylsiloxane. P2 was produced by hydrosilylation of vinyl‐terminated cyclodisilazane and hydrogen‐terminated polydimethylsiloxane. The polycondensation completed quickly at room temperature, while the hydrosilylation was facile and did not require cumbersome air‐sensitive operations. P1 and P2 were characterized by Fourier transform infrared, nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis (TGA), and isothermal gravimetric analysis (IGA). TGA revealed the outstanding thermal properties of P1 and P2 with 5% weight loss temperatures (T_d5) higher than 450°C. IGA proved their better thermal stability at 450°C for 800 min, compared to polydimethyldiphenylsiloxane. Dynamic mechanical analysis showed that silicone rubbers made from cyclodisilazane‐containing polydimethylsiloxanes could have a maximum tan δ value as high as 1.13 and had good prospects for damping material applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of polyurethane urea based on fluorine‐containing bisphenoxydiamine

A fluorine‐containing bisphenoxydiamine, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (BAPF₆P), was synthesized and characterized by means of Fourier transform infrared spectrometry (FTIR), NMR, and elemental analysis. The obtained BAPF₆P was used as a chain extender to prepare polyurethane urea (PUU), whose morphology and properties were measured through FTIR, differential scanning calorimetry, thermogravimetric analysis, tensile measurements, and atomic force microscopy. The results show that the PUU elastomers based on BAPF₆P exhibited good mechanical properties and thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1863–1869, 2006