Synthesis of Novel 2‐Vinylcyclopropane Phosphonic Acids

2‐Vinylcyclopropane‐1‐phosphonic acid diesters 1a–d were synthesized by the reaction of trans‐1,4‐dibromo‐2‐butene with α‐substituted phosphonic acid diesters. Esterification of 1‐ethoxycarbonyl‐2‐vinylcyclopropane‐1‐carboxylic acid with dimethyl 2‐hydroxyethyl‐phosphonate gave the 2‐vinylcyclopropane phosphonic acid dimethylester 1e. The silylation of phosphonic acid diesters 1a–e by halotrimethylsilanes followed by solvolysis with methanol or water resulted in the formation of phosphonic acids 2a–e. In the case of steric hinderance of the phosphoryl group, monoesters 3c,d were also formed. Furthermore, ethyl carboxylate 1b could be chemoselectively cleaved by aqueous potassium hydroxide to carboxylic acid 4.     

Synthesis and properties of liquid crystalline polyurethanes

Liquid crystalline polyurethanes were prepared from 4,4′-bis(2-hydroxyethoxy)biphenyl (BHBP) and 2,4-tolylene diisocyanate (TDI). The effect of partial replacement of BHBP by 25–75 mol % poly(oxytetramethylene) diol (PTMO, M _n = 250) on the liquid crystalline properties was studied. The BHBP/TDI/PTMO polyurethanes were obtained by one- and two-step polyaddition. The polyurethanes were investigated by DSC, polarizing microscopy, x-ray, and IR spectroscopy. The molecular weight distribution was determined by GPC. The morphology of the polymers was investigated by the SALS method. Thermogravimetric investigations of the polyurethanes were also performed. All polyurethanes containing BHBP units have liquid crystalline properties. Partial replacement of BHBP by PTMO-250 considerably changes the phase transition temperatures and the range of mesophase occurrence. More homogeneous polyurethanes were obtained, if the two-step polyaddition method was applied. The polyaddition method affects the phase transition temperatures. © 1993 John Wiley & Sons, Inc.     

Linear polyurethanes made from naturally occurring tartaric acid

Naturally occurring tartaric acid was used as raw material for the synthesis of novel linear polyurethanes (PURs) bearing two carboxylate side‐groups in the repeating unit. Aliphatic and aromatic PURs were obtained by reaction in solution of alkyl and benzyl tartrates with hexamethylene diisocyanate and 4,4′‐methylene‐bis(phenyl isocyanate), respectively. All the novel PURs were thermally stable and optically active. The aliphatic carboxylate‐containing PURs had M_w in the 40–70 kDa range, with PD between 2.1 and 2.5; all were semicrystalline polymers with melting temperatures between 100 and 150 °C and T_g in the 50–80 °C range. The aromatic PURs were amorphous materials with molecular weights between 18 kDa and 25 kDa and T_g above 130 °C. Hydrogenolysis of the PUR made from hexamethylene diisocyanate and benzyl tartrate yielded PURs containing up to 40% of free carboxylic side‐groups. The tartrate‐derived PURs displayed enhanced sensitivity to hydrolysis compared with their unsubstituted 2,6‐PUR homologs. The PURs bearing free carboxylic groups were unique in being degraded by water upon incubation under physiological conditions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2391–2407, 2009     

Synthesis and properties of polyurethanes bearing urethane moieties in the side chain

Polyurethanes bearing urethane groups in the side chains were prepared by the addition of isocyanates to the hydroxyl groups in poly(hydroxyurethane) prepared by the polyaddition of a bifunctional cyclic carbonate with 1,12‐diaminododecane. The urethanization proceeded quantitatively in the presence of a catalytic amount of di‐n‐butyltin dilaurate. The resulting polyurethane had a higher glass transition temperature than the original poly(hydroxyurethane), although its esterified product had a lower glass transition temperature. The urethanization with 3‐(triethoxysilyl)propyl isocyanate also proceeded effectively to afford both soluble and insoluble polymers, depending on the reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3408–3414, 2007     

Lysine‐based functional blocked isocyanates for the preparation of polyurethanes provided with pendant side groups

This article describes a methodology to prepare polyurethanes (PUs), decorated with pendant (bio)functional side groups, by polymerizing (bio)functionalized blocked diisocyanates with polyols. Caprolactam blocked lysine diisocyanate methyl ester (BLDI‐OMe) was prepared in high yields, by reacting the methyl ester of lysine with carbonyl biscaprolactam. In the absence of a catalyst, the polymerization of BLDI‐OMe with polycaprolactone and polytetrahydrofuran resulted in strictly linear PUs due to the high selective reactivity of the blocked isocyanates (BIs). Although the ester appeared to be less reactive, we found hydrolyzing conditions for the ester, without affecting the BIs. The free acid groups were converted into a N‐hydroxysuccinimide (NHS) activated ester, which was a versatile intermediate for further functionalization. After having demonstrated that model amines were able to substitute NHS without effecting the BIs groups, the same chemistry was used to couple biotin, giving a biotin functional caprolactam blocked lysine diisocyanate. The polymerization with polyols afforded the corresponding biotin‐functional PUs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2036–2049     

Pi‐conjugated chain extenders for the synthesis of optoelectronic segmented polyurethanes

The optical properties of mechanochromic materials change under mechanical stress. Segmented polyurethanes are elastomers composed of amorphous, saturated chain soft segments, and rigid pi‐conjugated hard domains. Within aggregates of hard domains pi–pi interactions may form and result in perturbation of the optoelectronic properties of the system. Disruption and restoration of these electronic interactions within the material may lead to observable mechanochromic response. A series of oligothiophene diols and diamines, as well as a naphthalene diimide diol, have been synthesized for incorporation into the hard domains of segmented polyurethanes and polyureas using long poly(tetramethylene oxide) chains as soft segments. The resulting polymers were evaluated to determine their extent of polymerization and their thermal stability. The optical properties of the materials were studied in solution and as thin films. Where possible the electrochemical properties of the polymers were also explored. The length of the soft segment chains in the segmented polyurethanes hindered electronic coupling of hard domains. Future work involving smaller, more solubilizing soft segments may allow for easier material characterization and mechanochromic response. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

The stability of aliphatic azo linkages influences the controlled scission of degradable polyurethanes

A better understanding of polymer degradation and post-degradation processes are essential for the development of novel degradable polymers. Herein, we present the synthesis of a new aliphatic azo-containing polyurethane and its degradation behavior toward external stimuli like heat and UV light. A relatively stable radical forming azo-monomer present in the current polyurethane is readily undergoing thermal degradation, whereas the azo-group is less susceptible to optical degradation. A comparison of the stimuli-responsive properties of the new azo-polymer with a previously known, relatively active radical forming monomer incorporated azo-polymer reveals the dependencies of the monomer and radical stability in the controlled degradation process. Our results point toward the importance of radical activity in azo-containing polymers.     

Phase morphology of hydrolysable polyurethanes derived from aqueous dispersions

Biodegradable polyurethanes are an interesting alternative to many applications that involve plastics since they can minimize environmental problems caused by the low rates of natural degradation of synthetic polymers. In addition, since waterborne polyurethanes are based on aqueous dispersions, they restrict the use of organic solvents during processing and application of the polymer, thus contributing furthermore to reduce environmental damage. In this work, aqueous anionic polyurethane dispersions (PUD) with tailorable susceptibility for hydrolysis were synthesized by progressively replacing polypropylene glycol (PPG) with a biodegradable polycaprolactone diol (PCL) as soft segments. The hard segments were formed by extending isophorone diisocyanate (IPDI) with hydrazine (HZ). Dimethylol propionic acid (DMPA) was used as ionic center and triethyl amine (TEA) as neutralizer. The degree of phase separation was evaluated mainly by infrared spectroscopy (FTIR) and small angle X-ray scattering (SAXS). The results indicated that phase separation between hard and soft segments of poly(ester-urethane) is more significant than that of poly(ether-urethane). Data obtained from SAXS experiments indicated that phase separation within soft domains can also be present in samples containing both polyester and polyether soft segments. Hydrolytic degradation of the polymers in buffer solution of pH 7.4 and alkaline solution was performed as an initial test. The results showed that the fraction of polyester soft segments in the polyurethanes can be used to tailor the susceptibility of the materials to hydrolytic attack. Polyurethanes having higher contents of polyester were more promptly hydrolytically degraded than polyurethanes containing only polyether segments.     

Synthesis and properties of bio‐based polyurethanes bearing hydroxy groups derived from alditols

Four kinds of bio‐based polyurethanes bearing hydroxy groups in the pendants were synthesized by the polyaddition of D ‐mannitol‐ and D,L ‐erythritol‐derived diols (1,2:5,6‐di‐O‐isopropylidene‐D ‐mannitol and 1,2‐O‐isopropylidene‐D,L ‐erythritol) with hexamethylene diisocyanate and methyl (S)‐2,6‐diisocyanatohexanoate and the subsequent deprotection of the isopropylidene groups. They were hydrolyzed much more quickly than the corresponding protected polyurethanes at 50 °C and pH 7.0, although their hydrolytic degradation rate was lower than that of polyurethanes with saccharic and glucuronic lactone groups, which had been reported in our previous articles. The introduction of D ‐mannitol units to the polyether‐polyurethanes containing poly(oxytetramethylene) glycol units also enhanced their hydrolyzibility. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and application of isocyanates radiolabeled with carbon-11

Carbon-11 labeled isocyanates are efficiently prepared by dehydration of [(11) C]carbamate salts, which in turn are easily formed from cyclotron-produced [(11) C]CO(2) and amines in the presence of a CO(2) fixation agent. The [(11) C]isocyanates are useful radiosynthons for the synthesis of a variety of [carbonyl-(11) C]-labeled asymmetrical ureas and carbamate esters. The method is well suited to incorporate any isotope of carbon, and is especially useful for positron emission tomography (PET) radiotracers for in vivo imaging. This is demonstrated by using the method to make [carbonyl-(11) C]-6-hydroxy-[1,1'-biphenyl]-3-yl cyclohexylcarbamate which is a novel radiotracer for PET imaging of fatty acid amide hydrolase.     

Synthesis and thermal crosslinking of oxazolidine‐functionalized polyurethanes

A new oxazolidine derivative was obtained from phenol, 2‐amino‐2‐methylpropane‐1,3‐diol and paraformaldehyde. The reaction of this novel oxazolidine diol with phenylisocyanate lead to a urethane model compound which can be polymerized thermally by oxazolidine ring opening to give a Mannich bridge structure. Linear segmented polyurethanes were prepared by reaction of different ratios of oxazolidine diol and commercial polyethylenglycol (M_w ～ 400) with 4,4′‐methylenbis (cyclohexylisocyanate) (HMDI, 90% isomers mixture). The polyurethanes were thermally characterized and crosslinked by oxazolidine ring opening to obtain materials which showed improved thermal stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4965–4973, 2007     

Evaluation of tg data of htpb-based polyurethanes

Thermogravimetry (TG) was used to provide some new information on some polybutadiene-based polyurethanes. The results showed two main mass decomposition stages, from 230 to 564°C. The first mass loss stages were used to quantify the hard segments of the polymers. The results correlated well with the ASTM methodology. In addition, two 2³ factorial design studies were applied to evaluate the importance of some selected factors on the TG results of the polyurethanes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and characterization of side-chain liquid crystal polyurethanes

A series of liquid crystal α-[bis(2-hydroxyethyl)amino]-ω-(4-nitroazobenzene-4′-oxy)alkanes (Cn-diol) with different alkyl chain length has been synthesized. All Cn-diols exhibit a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. These compounds are suitable monomers for the synthesis of side-chain liquid crystalline polyurethanes and polyesters. They were polymerized with hexamethylene diisocyanate to corresponding SCLC polyurethanes in which the spacer length was varied from 2 to 12 methylene units. Polyurethanes (CnP) with spacer lengths n ≥ 4 exhibited liquid crystalline behavior. Fourier transform infrared temperature studies of the CnP were done focusing on H-bonds between the N H and CO groups of the urethane backbone. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2871–2888, 1997     

Synthesis of novel moisture‐curable polyurethanes end‐capped with trialkoxysilane and their application to one‐component adhesives

Novel silane endcappers and novel polyurethanes end‐capped with trimethoxysilane (silylated polyurethanes) were developed as water‐curable materials in which the curing reaction occurred under humid conditions in the presence of dioctyltin diversatate as a curing catalyst. A variety of amine‐terminated trimethoxysilane compounds were synthesized by the Michael addition reaction of commercially available 3‐aminopropyltrimethoxysilane with acrylates, and the resulting silane endcappers were used to react with isocyanate‐terminated polyurethanes, providing the silylated polyurethanes. The moisture‐curable silylated polyurethanes were used for the preparation of novel one‐component and solvent‐free adhesives. The evaluated properties were the curing speed, the tensile shear bond strength, and the adherence to some substrates. The longer alkyl chains of the silane endcappers derived from various acrylates led to a slower curing speed, lower tensile strength at break, and longer elongation at break of the silylated polyurethanes. The tensile shear bond strength of the silylated polyurethane‐based adhesive decreased with decreasing the trimethoxysilane end‐capping ratio, whereas an increase in the adherence was observed. The adherence to the acrylic substrate was improved by changes in the main‐chain structure of the polyurethane based on the composition of poly(propylene oxide) and poly(ethylene oxide). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2689–2704, 2007     

Synthesis and evaluation of new phosphonic acid‐functionalized acrylamides with potential biomedical applications

Phosphorus‐containing acidic monomers are able to interact with the inorganic phase of mineralized tissues such as enamel, dentin, and bone. From this perspective, three phosphonic acid‐containing acrylamide monomers with different lengths of alkyl chains were synthesized to be used for both self‐etching dental adhesives and mineralized hydrogel scaffolds. Monomers were synthesized by the reaction of α‐aminophosphonates (diethyl aminomethylphosphonate, diethyl 2‐aminobutan‐2‐ylphosphonate, and diethyl 2‐aminooctan‐2‐ylphosphonate) with acryloyl chloride followed by the hydrolysis of phosphonate groups by using trimethylsilyl bromide. The properties such as pH in the range of mild self‐etching adhesives, hydrolytic stability, high rate of copolymerizations with 2‐hydroxyethyl methacrylate (HEMA) and HEMA/glycerol dimethacrylate, giving high‐molecular‐weight polymers on thermal polymerization, and strong decalcification ability of hydroxyapatite make these monomers good candidates for self‐etching adhesives, although no appreciable effect of the number and size of the α‐substituents was observed. Hydrogel scaffolds containing phosphonic acid groups were fabricated, characterized, and mineralized. Altogether, the results suggest that these phosphonic acid‐containing monomers have suitable properties to be used in fabrication of biomaterials for both dental and bone tissue engineering applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2755–2767     

Synthesis and characterization of polyurethanes from epoxidized methyl oleate based polyether polyols as renewable resources

Oligomeric polyether polyols were obtained through the acid‐catalyzed ring‐opening polymerization of epoxidized methyl oleate and the subsequent partial reduction of ester groups to give primary alcohols. The oligomers were characterized with titration, spectroscopic techniques (Fourier transform infrared and nuclear magnetic resonance), matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, size exclusion chromatography, and differential scanning calorimetry. Depending on the degree of reduction, polyols of different hydroxyl content values were obtained and were reacted with 4,4′‐methylenebis(phenyl isocyanate) to yield polyurethanes. These materials, which were characterized by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical thermal analysis, could behave as hard rubbers or rigid plastics. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 634–645, 2006     

Synthesis and properties evaluation of quaternized polyurethanes as antibacterial adhesives

We present new side‐chain quaternized polyurethanes as antibacterial adhesives made by polyaddition polymerization followed by quaternization for different time intervals. The degree of quaternization of N‐diol units in the polymer is changed from 13.6 to 99.0 mol % (almost complete) for tuning the antibacterial action (leaching/contact type) and studying effect on adhesive strength. The degree of quaternization of about 26 mol % provided the nonleaching antibacterial effect with adhesive strength more than 60 N cm^?2 on aluminum and glass substrates. The increase in the degree of quaternization enhanced polymer polarity shifting nonleaching (contact type) antibacterial behavior to the leaching type but maintaining the high adhesive strengths. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 752–757     

Synthesis,photopolymerization and adhesive properties of new hydrolytically stable phosphonic acids for dental applications

Novel monomers 2‐(N‐methylacrylamido)ethylphosphonic acid, 6‐(N‐methylacrylamido)hexylphosphonic acid, 10‐(N‐methylacrylamido)decylphosphonic acid, and 4‐(N‐methylacrylamidomethyl)benzylphosphonic acid have been prepared in good yields for use in dental adhesives. They have been fully characterized by ¹H‐NMR, ¹³C‐NMR, ³¹P ‐ NMR, and by HRMS. All monomers are hydrolytically stable in aqueous solution. Free radical homopolymerizations of these monomers have been carried out in solution of ethanol/water (2.5/1:v/v), using 2,2′‐azo(2‐methylpropionamidine) dihydrochloride (AMPAHC) as initiator. They lead to homopolymers in moderate to excellent yields. Structure of the polymers has been confirmed by SEC/MALLS and ¹H‐NMR spectra. The photopolymerization behavior of the synthesized monomers with N,N′‐diethyl‐1,3‐bis(acrylamido)propane has been investigated by DSC. New self‐etch primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on (N‐methylacrylamido)alkylphosphonic acids assure a strong bond between the tooth substance and a dental composite. Moreover, the monomer with the longest spacer group provides the highest shear bond strength. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7074–7090, 2008     

三苯基锗烯或炔基膦酸衍生物的合成

由三苯基氯化猪与烯或炔基膦酸盐反应,合成了８种新的三苯基锗烯基或炔基膦酸衍生物,利用元素分析,ＩＲ和ＨＮＭＲ表征了这些化合物的结构