Synthesis and deblocking of cardanol‐ and anacardate‐blocked toluene diisocyanates

Methyl anacardate and secondary butyl anacardate were prepared from anacardic acid and corresponding alcohols and were used, in addition to cardanol, as blocking agents for 2,4‐toluene diisocyanate (TDI). Blocked diisocyanate adducts were characterized via nitrogen estimation, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy. The deblocking temperatures of the adducts were determined using an FTIR spectrophotometer in conjunction with the carbon dioxide evolution method. The gel times of hydroxyl‐terminated polybutadiene–TDI adducts also were determined. Deblocking temperature and gel time analyses revealed that cardanol‐blocked 2,4‐TDI deblocks at a lower temperature and at a higher rate compared with anacardate‐blocked adducts. In addition, it was found that the electron‐withdrawing ester group reduces the deblocking temperature of the adduct only when it is in solvated form. All adducts were waxy solids that were found to be soluble in polyether polyol, polyester polyol, and polyhydrocarbon polyols. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4047–4055, 2004     

Controlled formation of isocyanate‐terminated star polyethers avoiding chain extension

Star polymers with reactive isocyanate end groups were prepared via the end capping of hydroxy‐terminated star polyether polyols with toluene diisocyanate (TDI; 80% = 2,4 TDI, 20% = 2,6 TDI). The multifunctional polyols and TDI were reacted in bulk without a catalyst. This procedure was optimal in regard to the product yield, minimizing unfavorable coupling side reactions and avoiding crosslinking reactions. The experimental results were based on theoretical studies of the reaction kinetics. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2555–2565, 2000     

Synthesis and Properties of Imidazole-Blocked Toluene Diisocyanates

Abstract

Imidazole-, 2-methyl imidazole-, and benzimidazole-blocked toluene diisocyanates (TDI) were prepared and characterized by elemental analysis, IR, and NMR spectroscopy. Simultaneous TGA/DTA results showed that the thermal stability of the adduct decreases in the following order: imidazole-TDI > 2-methylimidazole-TDI > benzimidazole-TDI. Gelation test involving imidazole-blocked adducts and hydroxyl-terminated polybutadiene were also carried out. The cure rate of the adduct increases from the imidazole- to the 2-methylimidazole- and to the benzimidazole-blocked adduct. It is also found that the benzimidazole-blocked adduct shows better solubility in the polyols.     

Application of selective 1 : 2 addition of ketene N,N-acetal and isocyanates to novel polyamide syntheses

1,1-Bis(dimethylamino)ethylene (ketene N,N-acetal) (1) reacted with isocyanates to give either 1 : 1 adduct 3,3-bis(dimethylamino)acrylamides (3) or 1 : 2 adduct bis(dimethylamino)methylenemalonamides (4), depending on the amount of the charged isocyanate. 3 was obtained selectively in the case of isocyanate/1 = 1, while 4 was exclusively yielded in the case of isocyanate/1 = 2. Isothiocyanate showed similar reaction behavior as isocyanate. Polyaddition of 1 with diisocyanates afforded polyamides bearing a bis(dimethylamino)methylenemalonamide group with higher molecular weight. The obtained novel polyamides are soluble in various organic solvents, and reacted with diacid chloride to give crosslinked polymer quantitatively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3079–3086, 1999     

Synthesis and flame retardant potential of polyols based on bisphenol‐S

Polyether polyols based on bisphenol‐S were prepared by alkoxylation and compared with analogs based on bisphenol‐A, as well as standard aromatic polyester, and polyether polyols for viscosity and temperature stability. Thermo‐oxidative stability was determined by thermo‐gravimetric analysis, pyrolysis gas chromatography/mass spectroscopy, and evolved gas analysis mass spectroscopy. Incorporation of the sulfone moiety was found to dramatically improve the thermo‐oxidative stability of the neat polyol. Significant char formation was observed with gas phase evolution of flame retardant SO₂ and aromatic sulfone only apparent at about 600 °C. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2102–2108     

Design,polymerization, and properties of polyurethane elastomers from miscible,immiscible, and hybridized seed‐oil derived soft segment blends

Polyester seed‐oil derived polyols have been prepared and blended with conventional polyols for making polyurethane elastomers. Miscibility was complete for polypropylene oxide/polyethylene oxide and polytetramethylene oxide (PTMEG). Blends of polyester seed‐oil derived polyols with conventional polyester polyols (polybutylene adipate and ?‐polycaprolactone) were immiscible or nearly so. Furthermore, the phase behavior (miscible vs. immiscible) did not change appreciably for each blend composition explored as a function of temperature at relevant ranges (up to the polyether ceiling temperature). This counter‐intuitive result is found to be actually consistent with calculated solubility parameters for each polyol type and the phase diagrams computed on their basis. The phase behavior of the polyols is shown to have significant effects on the properties of polyurethane elastomers where immiscible polyols cause broadening of the glass transition distribution and significant reduction of ultimate tensile properties. However, here it is shown that immiscible systems containing polyester seed‐oil derived polyols can be transesterified with the appropriate polyol partner of interest to create a new single phase polyol or that the polyester polyol monomers can also be copolymerized to make new single phase polyols, both of which result in improved polyurethane elastomer properties. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 93–102     

Domain structure and interphase dimensions in poly(urethaneurea) elastomers using DSC and SAXS

Small‐angle X‐ray scattering (SAXS) and differential scattering calorimetry (DSC) were used to demonstrate distinct differences in domain size, phase separation, and hydrogen bonding in a series of segmented urethaneurea elastomers prepared from isocyanate‐terminated prepolymers and aromatic diamine chain extenders. Two types of prepolymers were studied. The first contained a broadly polydisperse high molecular mass oligomer with relatively high levels of free isocyanate monomer. The second type of prepolymer contained low levels of high molecular mass oligomers with mass fractions greater than 90% of the two‐to‐one adduct of toluene diisocyanate (TDI) to polytetramethylene glycol (PTMEG). The mass fraction of the residual unreacted diisocyanate was less than 0.1% in the second type. Two chain extenders, 4,4′‐methylene bis‐(2‐chloroaniline)(Mboca) and 4,4′‐methylene bis‐(3‐chloro‐2,6‐diethylaniline) (MCDEA), were used to convert the prepolymers to poly(urethaneurea) elastomers. Materials prepared from the prepolymers with low oligomer polydispersity exhibited smaller hard segment domains with more ordered morphology, greater phase separation, and more hydrogen bonding than those prepared from prepolymers with high oligomer polydispersity. These tendencies were enhanced in those elastomers prepared by chain extension with MCDEA compared to those made with Mboca. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2586–2600, 1999     

Promoting effects of urethane derivatives of phenols on the ring‐opening polymerization of 1,3‐benzoxazines

For the purpose of reducing the induction period of the ring‐opening polymerization of N‐methyl‐1,3‐benzoxazines, several urethanes were examined as promoters. The examined promoters 3a – d were the adducts of resorcinol and phenyl isocyanate, that of bisphenol A and phenyl isocyanate, that of resorcinol and butyl isocyanate, and that of 1,3‐propanediol and phenyl isocyanate, respectively. The aromatic urethanes 3a and 3b , which were adducts of the phenolic compounds and phenyl isocyanate, exhibited significant promoting effects. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of poly(ether naphthalimide)s

A series of new poly(ether imide)s containing the naphthalimide moiety were prepared from bis(4-fluorobenzoyl)naphthalimides and several bisphenols by aromatic nucleophilic displacement polymerization. These polyimides had inherent viscosities in the range of 0.31–1.04 dL/g in chloroform and glass transition temperatures of 283.0–341.6°C by differential scanning calorimetry. The onset temperature for 5% weight loss for all the polymers was over 448°C, as assessed by thermogravimetry at a heating rate 10°C/min in nitrogen. In addition, these novel polyimides exhibited good solubility in organic solvents including N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,1,2,2-tetrachloroethane and chloroform. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3227–3231, 1999     

Synthesis of 1‐methoxypoly(oxyethylene)benzocyclobutene and its diels–alder reactions

A new poly(ethylene glycol) derivative, 1‐methoxypoly(oxyethylene)benzocyclobutene ( 1 ) was prepared from the reaction of 1‐benzocyclobutenyl 1‐hydroxyethyl ether with mesylate of methoxypoly(oxyethylene) in tetrahydrofuran. The degree of end‐group conversion, as determined by NMR, was 100%. The Diels–Alder reactions of 1 with maleic anhydride and N‐phenylmaleimide were carried out in refluxing toluene to obtain the corresponding adducts ( 2 and 3 , respectively) in excellent yields. NMR analyses of 2 and 3 indicated complete conversion of 1 to the corresponding products. The reaction of 2 with o‐toluidine resulted in complete conversion of the anhydride adduct to the corresponding products. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1934–1938, 2004     

Liquid‐crystalline thermosets by the curing of dimeric liquid‐crystalline epoxyimine monomers with 2,4‐toluene diisocyanate

We studied the curing processes of several series of dimeric liquid‐crystalline epoxyimine monomers with 2,4‐toluene diisocyanate (TDI) alone or with added catalytic proportions of 4‐(N,N‐dimethylamino)pyridine. We obtained isotropic materials or liquid‐crystalline thermosets with different degrees of order, which depended on the structures of the monomers. To fix ordered networks, we had to do the curing in two steps when TDI was used alone as the curing agent. However, when a tertiary amine was added in catalytic proportions, the ordered networks were fixed in just one step. In this way, we were able to fix both nematic and smectic mesophases. The significance of the polarization of the mesogen for obtaining liquid‐crystalline thermosets was demonstrated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2521–2530, 2003     

Chemistry of sulfonyl isocyanates and sulfonyl isothiocyanates. X. Possible routes to substituted imidazolidinethiones and hexahydropyrimidinethiones

4-Toluenesulfonyl isocyanate (I) reacted with 2-aminoethanol and 3-amino-l-propanol to give 2:1 isocyanate/amino alcohol addition products. 1-Amino-2-propanol and I gave 1:1 and 2:1 adducts while 2-amino-2-methyl-l-propanol afforded only a 1:1 adduct. 4-Toluenesulfonyl isothio-cyanate (III) gave 1:1 adducts with 2-aminoethanol, l-amino-2-propanol and 3-amino-l-propanol, the first two of which were cyclized by concentrated sulfuric acid to 1-(4-toluenesulfonyl)-imidazoline-2-thiones and the third to 1-(4-toluenesulfonyl)hexahydropyrimidine-2-thione. A 1:2 adduct was obtained from III and 2-amino-2-methyl-l-propanol. Amino acids reacted with I and with 4-chlorobenzenesulfonyl isocyanate (II) to give N-(arylsulfonyl)-N¹-(carboxylic acid)-ureas. N-(4-Toluenesulfonyl)-N¹-(acetic acid)-urea (XVI) was converted to the methyl ester (XIX) by concentrated sulfuric acid and methanol and to water-soluble unrecoverable products by sulfuric acid alone. Glycine and III gave N-(4-toluenesulfonyl)-N¹-(acetic acid)-thiourea (XX) which was converted to the methyl ester (XXII) by concentrated sulfuric acid/methanol and to the cyclic 1-(4-toluenesulfonyl)imidazolin-5-one-2-thione (XXI) by sulfuric acid alone.     

Hyperbranched polymers as scaffolds for multifunctional reversible addition–fragmentation chain‐transfer agents: A route to polystyrene‐core‐polyesters and polystyrene‐block‐poly(butyl acrylate)‐core‐polyesters

Polydisperse hyperbranched polyesters were modified for use as novel multifunctional reversible addition–fragmentation chain‐transfer (RAFT) agents. The polyester‐core‐based RAFT agents were subsequently employed to synthesize star polymers of n‐butyl acrylate and styrene with low polydispersity (polydispersity index < 1.3) in a living free‐radical process. Although the polyester‐core‐based RAFT agent mediated polymerization of n‐butyl acrylate displayed a linear evolution of the number‐average molecular weight (M_n) up to high monomer conversions (>70%) and molecular weights [M_n > 140,000 g mol^?1, linear poly(methyl methacrylate) equivalents)], the corresponding styrene‐based system reached a maximum molecular weight at low conversions (≈30%, M_n = 45,500 g mol^?1, linear polystyrene equivalents). The resulting star polymers were subsequently used as platforms for the preparation of star block copolymers of styrene and n‐butyl acrylate with a polyester core with low polydispersities (polydispersity index < 1.25). The generated polystyrene‐based star polymers were successfully cast into highly regular honeycomb‐structured microarrays. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3847–3861, 2003     

Effect of the diisocyanate on the structure and properties of polyurethane acrylate prepolymers

In this study, we investigated the role of diisocyanate on the properties of polyurethane acrylate (PUA) prepolymers based on polypropylene oxide (M̄_n = 2000 g · mol⁻¹). The diisocyanates studied were isophorone diisocyanate, 4‐4′dicyclohexylmethane diisocyanate, and toluene diisocyanate (pure 2,4‐TDI, pure 2,6‐TDI, and a TDI mixture, TDI_tech). The molecular structure of the diisocyanate had a major role on the course of the polycondensation and, more precisely, on the sequence length distribution of the final prepolymer. Moreover, the structural organization of the prepolymer also strongly depended on the nature of the diisocyanate. Two types of behaviors were particularly emphasized. On the one hand, the PUA synthesized from 2,4‐TDI displayed an enhanced intermixing between soft polyether segments and hard urethane groups, as revealed by the analysis of hydrogen bonding in Fourier transform infrared. Consecutively, the glass transition shifted to higher temperatures for these polymers. On the other hand, strong hard–hard inter‐urethane associations were observed in 2,6‐TDI‐based prepolymers; these led to microphase segregation between polyether chains and urethane groups, as revealed by optical microscopy. This inhomogeneous structure was thought to be responsible for the unusual rheological behavior of these PUA prepolymers. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2750–2768, 2000     

Studies on stable aqueous poly(o-toluidine) prepared with the use of a water soluble support polymer,polyacrylamide

Polymerization of o-methylaniline or o-toluidine (OT) was studied in aqueous acidic (HCl) medium with or without the use of the support of a water soluble polymer, polyacrylamide (PAAm). Poly(o- toluidine) (POT) produced with PAAm support was in the form of aqueous solution or dispersion that showed high stability and good processibility. High degree of dispersion or near solubility and storage stability of POT thus prepared are explained on the basis of establishment of hydrogen bonding between segments of POT being formed and the PAAm present in the medium thus resulting in a template effect. Studies by UV-visible spectroscopy and FTIR spectroscopy lend support to this view. POT-PAAm composites commonly show higher thermal stability than POT and the composites show DC-electrical conductivities in the range of 10⁻⁹–10⁻¹ S · cm⁻¹ depending on the POT content. Morphological analysis of the optically clear aqueous POT-PAAm solution by transmission electron microscopy (TEM) shows the presence of large clusters of PAAm-supported near-spherical POT nanoparticles in the aqueous PAAm solution. Scanning electron microscopic (SEM) analysis of isolated POT-PAAm composites shows a cocontinuous phase morphology without any trend of gross phase separation. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3243–3256, 1999     

Morphology of polyurethanes with triol monomer crosslinked on hard segments

Polyester‐based polyurethanes containing ≈60 wt % of polyester were synthesized from low molecular weight polyester (M_n ≈2000) and 4,4′‐methylene bis(phenyl isocyanate) (MDI), with butanediol as a chain extender and glycerol as a crosslinker. The triol crosslinker was used in substitution for the 1,4‐butanediol chain extender; thus, the crosslinker was chemical bonded to the hard segments of polyurethane. The morphologies of these polyurethanes were studied by differential scanning calorimetry (DSC), small‐angle X‐ray scattering (SAXS), TMA (thermal mechanical analysis), and FTIR (Fourier transform infrared spectroscopy). Owing to the highly steric hindrance, the presence of triol crosslinker in the hard segments resulted in a decrease in the aggregation of hard segments through hydrogen bonding. The experimental results revealed that the degree of phase segregation of soft and hard segments decreased with increasing the triol crosslinker content in the hard segments. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2673–2681, 1999     

Poly(propylene imine) dendrimer complexes of Cu(II), Zn(II), and Co(III) as catalysts of hydrolysis of p-nitrophenyl diphenyl phosphate

Poly(propylene imine) dendrimers having 8, 32, and 64 primary amine end groups form diamino Cu(II), diamino Zn(II), and tetramino Co(III) complexes that are identified spectrophotometrically and titrimetrically. The dendrimer–metal ion complexes catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate in zwitterionic buffer solutions at pH ≤ 8.1 with relative activities Cu(II) > Zn(II) > Co(III). The rates of hydrolysis are faster with sodium perchlorate than with sodium chloride to control ionic strength. In sodium perchlorate solutions with Cu(II) the rates increase with increasing size of the dendrimer. In sodium chloride solutions with Cu(II) the rates decrease with increasing size of the dendrimer. Rate constants in buffered sodium chloride solutions of dendrimers and 1.0mM Cu(II) are 1.3–6.3 times faster than in the absence of Cu(II). The fastest hydrolyses occurred at a dendrimer primary amine to Cu(II) ratio NH₂/Cu ≤ 2. At NH₂/Cu = 4 and with the 1,4,7,10-tetraazacyclodecane complex of Cu(II) hydrolysis rates were much slower. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2727–2736, 1999     

Synthesis and characterization of novel poly(amide-imide)s containing hexafluoroisopropylidene linkage

A series of novel soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[N-(4-carboxyphenyl)-phthalimidyl]hexafluoropropane, with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl₂ using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.78–1.63 dL g⁻¹. The polymers were amorphous and readily soluble in aprotic polar solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide as well as in less polar solvents such as pyridine and γ-butyrolactone, and also in tetrahydrofuran. The polymer films had tensile strength of 84–129 MPa, an elongation at break range of 6–22%, and a tensile modulus range of 2.0–2.7 GPa. The glass transition temperatures of the polymers were determined by DSC method and they were in the range of 240–282°C. These polymers were fairly stable up to a temperature around or above 400°C, and lose 10% weight in the range of 450–514°C and 440–506°C in nitrogen and air, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2629–2635, 1999     

Gas sorption and characterization of poly(ether‐b‐amide) segmented block copolymers

The solubilities of He, H₂, N₂, O₂, CO₂, CH₄, C₂H₆, C₃H₈, and n‐C₄H₁₀ were determined at 35°C and pressures up to 27 atmospheres in a systematic series of phase separated polyether–polyamide segmented block copolymers containing either poly(ethylene oxide) [PEO] or poly(tetramethylene oxide) [PTMEO] as the rubbery polyether phase and nylon 6 [PA6] or nylon 12 [PA12] as the hard polyamide phase. Sorption isotherms are linear for the least soluble gases (He, H₂, N₂, O₂, and CH₄), convex to the pressure axis for more soluble penetrants (CO₂, C₃H₈, and n‐C₄H₁₀) and slightly concave to the pressure axis for ethane. These polymers exhibit high CO₂/N₂ and CO₂/H₂ solubility selectivity. This property appears to derive mainly from high carbon dioxide solubility, which is ascribed to the strong affinity of the polar ether linkages for CO₂. As the amount of the polyether phase in the copolymers increases, gas solubility increases. The solubility of all gases is higher in polymers with less polar constituents, PTMEO and PA12, than in polymers with more polar PEO and PA6 units. CO₂/N₂ and CO₂/H₂ solubility selectivity, however, are higher in polymers with higher concentrations of polar repeat units. The sorption data are complemented with physical characterization (differential scanning calorimetry, elemental analysis, and wide angle X‐ray diffraction) of the various block copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2463–2475, 1999     

Effect of isocyanate structure on deblocking and cure reaction of N-methylaniline-blocked diisocyanates and polyisocyanates

Two series of N-methylaniline-blocked isocyanates based on monomeric diisocyanates such as 4,4′-methylene bis(phenyl isocyanate), toluene-2,4-diisocyanate, isophorone diisocyanate and 1,6-diisocyanato hexane and their NCO terminated polyurethane prepolymer (polyisocyanates) were prepared and characterized thoroughly by FTIR, ¹H NMR, ¹³C NMR and EI-Mass spectroscopic methods. The blocking reaction of N-methylaniline with aromatic isocyanates and aromatic polyisocyanates occur faster when compared to the aliphatic isocyanates. The deblocking reactions of blocked isocyanates were carried out under dynamic and isothermal conditions using hot-stage FTIR spectrophotometer. The dynamic method was used to determine the deblocking temperature, and the isothermal method was used to calculate kinetics and thermodynamics parameters. Cure reactions of blocked isocyanates with hydroxyl-terminated polybutadiene were also followed to establish the structure-property relationship of the N-methylaniline-blocked isocyanates. The deblocking studies of blocked isocyanates reveal that the aromatic isocyanates undergo deblocking easily compared to aliphatic isocyanates. The rate of deblocking reaction of N-methylaniline-blocked aromatic polyisocyanates was found to be higher compared to N-methylaniline-blocked aromatic monomeric diisocyanate adducts. On the other hand, this trend was just reverse in the cure-reaction studies. The dissolution behavior of N-methylaniline-blocked isocyanates in Terathane-2000, polypropylene glycol-2000, polycaprolactone diol-2000 and hydroxyl-terminated polybutadiene-2500 was also studied and found that all adducts are soluble in these polyols.